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[讨论] 让细胞死亡的方式都有哪些? [复制链接]

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楼主
发表于 2011-2-12 08:46 |只看该作者 |倒序浏览 |打印
我们想研究一下同一种活细胞和死细胞在功能上是否有差异,比如某些细胞因子是否还发挥功能,或者死细胞的功能更有价值,所以想采用几种不同的方法让细胞死去,请大家帮帮忙,看都有什么方法,谢谢啦。
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沙发
发表于 2011-2-12 09:25 |只看该作者
死亡是生命的自然规律,这是必然发生不可避免的事实,既见于人体也同样适用于每个细胞。但细胞死亡并非与机体死亡同步。细胞是在分裂、增殖、分化而死亡。所以,正常的组织中,经常发生“正常”的细胞死亡,它是维持组织机能和形态所必需的。也可以有病理性死亡。
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细胞死亡的方式
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4 T6 s8 y* \1 T细胞死亡的方式通常有 3 种:即①细胞坏死 (Necrosis) ,非正常细胞死亡属于细胞坏死,是病理性变化。;②细胞凋亡 (Apoptosis) ,正常细胞死亡亦属于细胞凋亡,通常是生理性变化,以上均是形态学观察和描述,而③细胞程序性死亡 ( Programmed cell death ),是一种选择性的生理死亡,属于分子水平的观察,所以,有学者提出细胞凋亡和细胞程序性死亡有所不同,但,也是细胞凋亡的一种形式。目前也有认为 2 种细胞死亡形式。
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& w0 D, D  Z0 u! u$ h; d3 M& [(一)细胞坏死:  f& R. l" w" Z( o5 O- e

, D* P% m+ U  l- X细胞坏死是细胞受到急性强力伤害时,立即出现的早期反应。包括胞膜直接破坏,大量水份进入细胞,线粒体外膜肿胀而密度增加。核染色质呈絮状,蛋白质合成减慢。如及时去除伤害因素,以上早期反应尚可逆转。若伤害外因持续存在,则发生不可逆的变化。 Ca2+ 升高、引起一系列变化,如细胞骨架破坏,溶酶体释放, pH 下降,最后细胞膜和细胞器破裂,脱氧降解,细胞内容物流出,引起周围组织炎症反应(图 1 )。
% T2 M2 y# j% v6 Q 细胞死亡.jpg : N2 T1 k' n6 Q5 d* z
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(二)细胞凋亡( Apoptosis )
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1 .细胞凋亡( apoptosis )的概念,是借用古希腊语,意指细胞的死亡犹如秋天的树叶或花瓣的凋落的死亡方式。 1973 年 Kerr 和 Wyllin 最先提出这一概念,他发现结扎大鼠肝的左,中叶门静脉后,其周围细胞发生缺血性坏死,但由肝动脉供应区的实质细胞仍存活,只是范围逐渐缩小,其间一些细胞不断转变成细胞质小块,不伴有炎症,后在正常鼠肝中也偶然见到这一现象。与细胞坏死的区别的形态特征是:. c3 ~# W  _& {  d$ y7 p4 n
① 染色质聚集、分块、位于核膜上,胞质凝缩,最后核断裂,细胞通过出芽的方式形成许多凋亡小体(图 2 );
. p3 \8 y; T/ q. x9 a1 P) A6 _② 凋亡小体内有结构完整的细胞器,还有凝缩的染色体,可被邻近细胞吞噬消化,因始终有膜封闭,没有内溶物释放,故不会引起炎症;
0 w# k1 ?: X6 @7 d: y- [& S③线粒体无变化,溶酶体活性不增加;
) L3 D, ]1 `- x$ g2 ~$ j. Y③ 内切酶活化, DNA 有控降解,凝胶电泳图谱呈梯状;
: [% o) W) s+ p4 B1 J④ ⑤凋亡通常是生理性变化,而细胞坏死是病理性变化。
+ o! f0 E  \3 l. A$ D% B 细胞死亡2.jpg 8 _! [. n% ~9 Y5 T9 ~

2 F  I1 S' e, {3 S9 W% I% |2 .细胞经历凋亡的过程4 }; m2 m# n- l

8 n" x  D/ F5 y/ _3 \+ F( }/ F7 @细胞凋亡的形态改变[ 1 , 2 ]是多阶段的,首先是细胞缩小,胞质凝缩,内质网疏松并和胞膜融合,核糖体、线粒体等聚集,但结构无明显改变。细胞内合成一种蛋白质,这种蛋白质可以破坏细胞中溶酶体的外包膜。溶酶体在失去外包膜之后,溶酶体释放出酶,这些酶可以破坏细胞的结构蛋白和 DNA ,形成有线粒体和空泡。但是,细胞膜并不受影响。染色质逐渐凝集成新月状,附在核膜周边,嗜碱性增强。以后细胞核固缩成均一的致密物,进而核碎裂,胞膜完整。继之核膜出芽,固缩染色质脱落。当酶将细胞内部物质消耗之后,细胞即分裂成多个由细胞膜包裹的凋亡小体。形成包膜凋亡小体( apoptotic bodies )。最终凋亡小体被周围吞噬细胞吞噬降解。凋亡细胞或称死亡细胞既告消失。
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(三)细胞程序性死亡 Programmed cell death1 i9 I9 M% [9 Q% d9 v* d5 Q

7 W, t7 V0 m0 j' A# B$ s在细胞凋亡一词出现之前,胚胎学家已观察到动物发育过程中存在着细胞程序性死( programmed death , PCD )现象,近年来 PCD 和细胞凋亡常被做为同义词使用,但两者实质上是有差异的 。首先, PCD 是一个功能性概念,描述在一个多细胞生物体中,某些细胞的死亡是个体发育中一个预定的,并受到严格控制的正常组成部分 ,而凋亡是一个形态学概念,指与细胞坏死不同的受到基因控制的细胞死亡形式;其次, PCD 的最终结果是细胞凋亡,但细胞凋亡并非都是程序化的。
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# N: F3 q2 \  i' x2002 年 10 月 7 日英国人悉尼•布雷诺尔、美国人罗伯特•霍维茨和英国人约翰•苏尔斯顿,因在器官发育的遗传调控和程序性死亡方面的研究,获诺贝尔生理与医学奖。其主要研究是应用线虫( Caenorhabditis elegans ) 个体发育和细胞程序性死亡作为理想的材料。因为其生命周期短,细胞数量少,成熟的成虫若是雌雄同体则有 959 个体细胞,约 2000 个生殖细胞。若是雄虫则有 1031 个体细胞和约 1000 个生殖细胞。神经系统由 302 个细胞组成。这些细胞来自于 407 个前体细胞。这些前体细胞中有 105 个发生了程序死亡。7 f' [8 v2 ^6 ?* ]# [% E$ |& ^

. S% F8 L  V/ f; d他们鉴定出了线虫的两个死亡基因 Ced-3 和 Ced-4 。有功能的基因 Ced-3 和 Ced-4 正是细胞发生死亡的先决因素(条件),在人类基因组中也存在着 Ced-3 相似的基因。后来霍维茨又发现了 Ced-9 基因, Ced-9 可以与 Ced-3 和 Ced-4 相互作用,阻止细胞死亡。
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6 C1 r2 f* N. v& x! x5 |- m; w为此,已经知道,控制线虫细胞凋亡的基因主要有 3 个 Ced-3 、 Ced-4 和 Ced-9 , Ced-3 和 Ced-4 的作用是诱发凋亡。在缺乏 Ced3 、 Ced-4 的突变体中不发生凋亡。有多余细胞存在。Ced-9 抑制 Ced-3 、 Ced-4 的作用。使凋亡不能发生、 Ced-9 功能不足导致胚胎因细胞过度凋亡而死亡。目前人们已经了解到有些信号传导途径是高度保守的,像线虫 Ced-3 、 Ced-4 和 Ced-9 参与调控的细胞死亡途径,在人类中同样存在。因此对线虫中控制细胞死亡的基因进行研究,将有可能使科学家很快在人体中鉴定出有类似功能的相关基因,对难治之症提供新思路
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藤椅
发表于 2011-2-12 09:32 |只看该作者
Cell Death and Differentiation (2005) 12, 1463–1467. doi:10.1038/sj.cdd.4401724$ x+ O( _; K, R+ ?4 J
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Classification of cell death: recommendations of the Nomenclature Committee on Cell Death

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G Kroemer1, W S El-Deiry2, P Golstein3, M E Peter4, D Vaux5, P Vandenabeele6, B Zhivotovsky7, M V Blagosklonny8, W Malorni9, R A Knight10, M Piacentini11, S Nagata12 and G Melino10,13
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/ j2 _" H6 O' `) k- ^  l0 p6 e3 v1CNRS-UMR8125, Institut Gustave Roussy, 39 rue Camille-Desmoulins, F-94805 Villejuif, France
4 f# q$ ]# z% v: v, b2University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
' H& b2 l6 U+ S* _& f! q3 @3Centre d'Immunologie INSERM/CNRS/Universite de la Mediterranee de Marseille-Luminy, Case 906, Avenue de Luminy, 13288 Marseille Cedex 9, France! e, N. ~8 f( O1 G# p: }
4The Ben May Institute for Cancer Research, University of Chicago, 924 E 57th Street, Chicago, IL 60637, USA; S9 h" |- V& h/ W  F5 h& [, D* \
5Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK2 V( a) W0 ?. R9 p$ h! \6 g
6Molecular Signalling and Cell Death Unit, Department for Molecular Biomedical Research, Flanders Interuniversity Institute for Biotechnology (VIB) and Ghent University, B9052 Ghent, Belgium
. F& i1 J  U* [" Z, }7Institute of Environmental Medicine, Karolinska Institutet, Box 210, Nobels vag 13, SE-171 77 Stockholm, Sweden
( f' I, J5 D  s! s, Z! T8Brander Cancer Research Institute, New York Medical College, 19 Bradhurst Avenue, Hawthorne, NY 10532, USA
" [: Z3 X1 q6 ]% s* ?9Istituto Superiore di Sanita, viale Regina Elena 299, I-00161 Rome, Italy
: C4 v. F0 U  \, h8 r8 ?10Medical Research Council, Toxicology Unit, Leicester University, Leicester, UK
4 X( D; P: \( x+ }" b11Department Biology University Tor Vergata and Natl Inst. For Infectious Diseases 'L Spallanzani', Rome, Italy. S/ v! @$ {" f, _0 U. r8 y
12Department Genetics, Osaka University Medical School, Osaka, Japan& I9 O3 J2 D  {7 B# D
13IDI-IRCCS, c/o Department of Experimental Medicine, University of Rome Tor Vergata, Rome, Italy
( U, V# Q& g7 o- E$ J* r8 HCorrespondence: G Kroemer, CNRS-UMR 8125, Institut Gustave Roussy, Pavillon de Recherche 1, 39 rue Camille-Desmoulins, F-94805 Villejuif, France. Tel: +33-1-42-11-60-46; Fax: +33-1-42-11-60-47; E-mail: kroemer@igr.fr

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* S/ Y4 z3 Z, Z; [) aDifferent cell death types are defined by morphological criteria, without a clear reference to precise biochemical mechanisms. The Nomenclature Committee on Cell Death (NCCD) proposes unified criteria for the definition of cell death and of different cell death morphologies, while formulating several caveats against the misuse of words and concepts that slow down progress in the area of cell death research. Nomenclature must be open to improvements and amendments to entail new discoveries, and the NCCD will help to update and clarify these points. Authors, reviewers and Editors of scientific periodicals are invited to abandon expressions like 'percentage apoptosis' and to replace them by more precise descriptions of the parameters that are actually measured. Moreover, at the present stage, it should be accepted that 'apoptosis', as a form of cell death, can occur with or without, caspase activation and that 'autophagic cell death' represents a type of cell death with (but not necessarily through) autophagic vacuolization. This article details the 2005 recommendations of NCCD. Over time, molecular definitions are expected to emerge for those forms of cell death that remain descriptive.
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/ q" k3 M3 g- ^4 r7 S$ q Preface2 p2 n; @$ r2 ^+ `
It is obvious that clear definitions of objects that are only shadows in Plato's cage are difficult to be achieved. Cell death and the different subroutines leading to cell death do not escape this rule. Even worse, the notion of death is strongly influenced by religious and cultural beliefs, which may subliminally influence the scientific view of cell death. As an example, it appears counterintuitive that some cells exert essential functions when they are 'dead' (such as erythrocytes and keratinocytes), and this underscores the importance of clearly defining what is referred to as 'cell death' as well as the multiple processes leading to it. Knowing that the meaning of scientific words changes when knowledge advances and that words, especially when they express changing concepts,1, 2, 3, 4 can increase confusion, one may adopt one of two opposing views. A significant fraction of the community of cell death researchers refutes nomenclature as an intellectual cage and as forever 'premature', remembering that many investigators desperately searched for 'DNA ladders' during the 1980s and 1990s. Indeed, such an alteration was thought to constitute the obligate manifestation of apoptosis, and reviewers and Editors often insisted that authors should discriminate between apoptosis and necrosis, based on this criterion (which nowadays has become somewhat obsolete). Some in the research community refute the preponderant idea that words can be used in a subjective fashion. Scientists simply should not behave as a Court of Justice confronted with the issue of pornography: the witness said that although he could not provide a clear definition of pornography, he knew what it was when he saw it. As a result of the need for more precise classification and following earlier discussions,5, 6 the Editors of Cell Death and Differentiation have created the NCCD, which formulated the following recommendations and caveats.; e* ^- x& @/ L4 \: l7 ?% ^' r9 V

1 L( e: D; y6 GThe NCCD suggests that it is important to discriminate between dying as a process and death as an end point. Dying can, of course, occur by several mechanisms, each characterized by a number of criteria, although not all need necessarily be present to satisfy the definition. It must be remembered that dying in a cell population is not a synchronous but rather a stochastic process, and that at a given time, individual cells will be at different stages of the dying process. This makes it all the more important to precisely define the criteria used to assess a dying population. It is not the intention of the NCCD to replace single terms in common usage with repeated cumbersome phrases like 'percentage of cells undergoing phosphatidylserine exposure'. Clearly, this would dramatically lengthen articles and presentations and may prove highly unpopular. Rather, the intention of the NCDD is to clearly define the available criteria used to evaluate a particular dying process. It is clear that as the field advances even more precise molecular definitions will likely emerge, and the nomenclature will need to be revised and updated. The NCCD suggests that more precise definitions will also serve a purpose to accelerate molecular understanding by demonstrating how much or how little we know about certain forms of cell death.
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Recommendation to Authors, Reviewers and Editors of Scientific Journals+ @+ q( l6 o2 n! Q/ G/ Z
Percentage apoptosis
. f' z4 d0 I5 J6 ^0 N# L4 k; xAs discussed above, authors frequently use expressions like 'percentage apoptosis' without mentioning the method used to assess ongoing cell death. Such expressions are confusing and imprecise and should be abandoned. Cell Death and Differentiation will actively enforce a policy in which expressions like 'percent apoptosis', 'percent necrosis', 'percent cell death' and 'percent cell survival' must be replaced by more descriptive terms such as 'percent cells with condensed chromatin', 'percent propidium iodine-positive'; 'percent annexin V-binding', 'percent active caspase-3 positive', 'percent TUNEL positive' cells, 'percent cells with DNA fragmentation', 'percent cells with a low mitochondrial transmembrane potential', or 'percent clone forming' cells. This applies to the description of experimental results, be it in the text or in the abstract, as well as to the labeling of figures and figure legends. The NCCD encourages investigators studying cell death to quantify this process using more than one assay whenever possible. This has been the general practice in the field by many, and it is hoped that over time specific criteria will emerge regarding what is necessary or sufficient to measure apoptosis or to predict death as an subsequent outcome based on any particular measurement.: Y9 F, N3 b1 Y4 i7 h. T6 @

9 X0 K: C% E9 L& M: A7 F' M# GAutophagy, C: ^; \; @, ^- }7 n
Along the same lines, 'vesicular redistribution of LC3' or the 'presence of double-membraned microvesicles' (or whatever was actually observed) is better than 'autophagy'. Thus, rather than formalizing nomenclature, the use of functional terms should be encouraged as a general policy. The NCCD urges all life science journals and, more specifically, all journals in the areas of cell biology, cancer research and pharmacology to adopt a similar policy.# ^6 L0 r, b9 U6 h+ N, ^1 {- ~

$ O( F1 i5 N( t& H4 F8 }When is a Cell 'Dead'?- r8 Q. ^; \$ O2 @
Point-of-no-return
8 I$ d; Z8 S  p% GDying cells can engage in a process that is reversible until a first irreversible step or 'point-of-no-return' is trespassed. It has been proposed that this step could be massive caspase activation, loss of the mitochondrial transmembrane potential (m),7 complete permeabilization of the outer mitochondrial membrane,8 or exposure of phosphatidylserine residues that emit 'eat me' signals to neighboring normal cells. However, there are examples in which caspases are activated in nonlethal activation and differentiation pathways. Moreover, the m can be dissipated by protonophores without that this would lead to immediate cell death.9 Finally, phosphatidylserine exposure can be reversible, for instance in neutrophilic granulocytes.10 Thus, the concept of a restriction point for cell death as was described by Pardee for the cell cycle has yet to be specifically defined for apoptosis.
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" v6 h% Z5 {1 ~6 z  RDead cells1 k& d- C& G7 Q  ~5 w
In the absence of a clear, generally accepted view of the 'point-of-no-return', the NCCD suggests that a cell should be considered dead when any of the following molecular or morphological criteria are met: (1) the cell has lost the integrity of the plasma membrane, as defined by vital dyes in vitro; (2) the cell including its nucleus has undergone complete fragmentation into discrete bodies (which are frequently referred to as 'apoptotic bodies'); and/or (3) its corpse (or its fragments) have been engulfed by an adjacent cell in vivo. Thus, 'dead cells' would be different from bona fide 'dying cells' that are in the process of cell death, which can occur through a variety of different pathways (see below). Moreover, cells whose cell cycle is arrested (as it occurs in senescence) would be considered as alive and the expression 'replicative cell death' (which alludes to the loss of the clonogenic capacity) should be avoided.
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Mechanism-based Definitions of Cell Death Types* P0 g9 P, u. x: V& G9 q# t
It is evident that death may occur through different mechanisms leading to distinct morphologies. Consequently, different names have been coined. The NCCD strongly recommends a limit on new names except where specific molecular mechanisms, or at least pathognomonic morphological characteristics, have been defined.
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Apoptosis9 P  Q' X% |7 m' V# f4 L7 @
The word 'apoptosis' has been coined by Kerr et al.,11 describing a particular morphological aspect of cell death, and it would be erroneous and confusing to replace this definition, which remains a merely morphological description. Apoptosis is a type of cell death that is accompanied by rounding-up of the cell, retraction of pseudopodes, reduction of cellular volume (pyknosis), condensation of the chromatin, fragmentation of the nucleus (karyorhexis), little or no ultrastructural modification of cytoplasmic organelles, plasma membrane blebbing, and maintenance of an intact plasma membrane until late stages of the process (Figure 1). Biochemical analyses such as DNA ladders should not be used to define apoptosis, because this type of cell death can occur without oligonucleosomal DNA fragmentation. Frequently, active suppression of DNA fragmentation or caspase activation demonstrates that these changes are not required for the execution of the cell death program, although caspase activation may be required for the acquisition of the apoptotic morphology. The measurement of DNA fragmentation or of caspase activation, however, may be helpful in diagnosing apoptosis. Another approach to consider here is to use the terms 'apoptosis associated with caspase activation' and 'apoptosis without evidence of caspase activation'. Thus, it may be reasonable to use caspase activation not only to diagnose but also to better define the type of cell death, that is, apoptosis associated with caspase activation. Indeed, at the biochemical level, apoptotic cell death is often accelerated by or even dependent on caspase activation.
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Figure 1.Morphological ultrastructural appearance of cell death by transmission electron microscopy. (a) Human epithelial cell undergoing necrosis after oxidative stress. Note the plasma membrane rupture, intracellular vesicle swelling and loss of mitochondrial ultrastructure (arrows). Magnification:  4000. (b) Human epithelial cell undergoing apoptosis induced by radiation. Note the chromatin clumping and the integrity of mitochondria (arrow). Magnification  4000. (c, d) Human epithelial cell undergoing autophagic vacuole formation after tamoxifen treatment. Note in (c) the normal morphology of the nucleus, the dilation of the perinuclear endoplasmic reticulum and the presence of some large vacuoles containing digested materials and in (d) the typical double membrane (arrows) characterizing the autophagic vacuoles. Magnifications: (c)  8000 and (d)  16000
5 r) Y" l* w% d. N# pFull figure and legend (309K)
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0 @' d! j( C# VAutophagy9 o3 r5 E9 q* }3 Y8 l" H( V2 A
'Autophagic cell death' is also morphologically defined, especially by transmission electron microscopy, as a type of cell death that occurs without chromatin condensation, accompanied by massive autophagic vacuolization of the cytoplasm. These vacuoles, by definition, are two-membraned and contain degenerating cytoplasmic organelles or cytosol.12 Thus, autophagic vacuoles are distinguishable by electron microscopy from other types of vesicles such as endosomes, lysosomes or apoptotic blebs. Another bona fide marker of autophagic vacuolization is the redistribution of an LC3-GFP fusion protein into vesicular structures.13 Although the term 'autophagic cell death' is a linguistic invitation to believe that cell death is occurring through autophagy, the term simply describes cell death with autophagy. Indeed, there is no in vivo evidence, thus far, that the knockdown or knockout of genes required for autophagy reduces cell death, and some reports even suggest that cells presenting features of 'autophagic cell death' can still recover upon withdrawal of the death-inducing stimulus.14  j. M" Z& Q2 e& y2 N- b

, c: t9 d5 Q) w' x$ G# i'Necrosis' and 'oncosis'
  `, d- u0 z* d) W1 L4 F* R7 `'Necrosis' is usually considered as a type of cell death with no signs of apoptosis or of autophagy, which is a negative definition.15 The morphological appearance of necrosis is often that of oncosis. The expression 'oncosis' defines a cell death morphology with cytoplasmic swelling, mechanical rupture of the plasma membrane, dilation of cytoplasmic organelles (mitochondria, endoplasmic reticulum and Golgi apparatus), as well as moderate chromatin condensation. The NCCD recommends limiting the use of the expression 'oncosis', as it overlaps with necrosis, and with a partial apoptosis evolving into necrosis. Although the name 'oncosis' corresponds well to the morphological appearance of this type of cell death, 'necrosis' should be maintained for historical reasons. The NCCD recommends not using the term 'apoptonecrosis', which could generate further confusion (see below). Pathways leading to necrosis in vivo need to be elucidated so that in the future a more precise definition can be developed.
- r+ i. r3 n, N! b
0 E$ @% `6 v! m' tMitotic catastrophe
, ^. Z! f7 ~6 d! {* L'Mitotic catastrophe' is a cell death occurring during or shortly after a dysregulated or failed mitosis and can be accompanied by morphological alterations such as micronuclei (which often are chromosomes or chromosome fragments that have not been distributed evenly between the daugher nuclei) and multinucleation (the presence of two or more nuclei with similar or heterogeneous sizes, resulting from deficient separation during cytokinesis). However, there is no broad consensus on the use of this term,16, 17, 18 and the NCDD recommends instead the use of terms such as 'cell death preceded by multinucleation' or 'cell death occurring during the metaphase', which are more precise and more informative. It is clear, however, that cell death during metaphase may have nothing to do with a cytokinesis or chromosome segregation defect but may occur because of exposure of cells to apoptotic stimuli during mitosis. The NCCD recommends including associated molecular events to describe cell death in any part of the cell cycle. For death during mitosis, it is clear there are potential overlaps with other terms such as loss of clonogenicity following radiation exposure due to chromosome damage.% m& O; f9 R$ r4 `1 K5 z
$ ?% p5 L  v# c) S4 o: r2 A/ P1 i
There are some critiques that can be formulated against the clearcut distinction of different cell types in the triad of apoptosis, autophagic cell death, and necrosis. First, these terms have been developed to a large extent by observing cultured cells and can only partially reflect the in vivo physiology of cell death. In tissues, cells are usually engulfed well before signs of advanced apoptosis can be detected. Thus some criteria for apoptosis may not be evident in vivo whereas other may suffice (see above). Thus, in vivo it may be acceptable – if irreversibility of the phenomena is demonstrated – to detect caspase activation and DNA fragmentation to diagnose apoptotic cell death. In mammals, autophagic cell death has only been described in pathological situations, for instance in degenerating neurons in the central nervous system. Accumulating evidence is suggesting a molecular pathway associated with autophagy and a potential molecular definition (see above). There are also numerous examples in which cell death demonstrates mixed features, for instance with signs of both apoptosis and necrosis, a fact that coined expressions like 'necroapoptosis' and 'aponecrosis'.19 Similarly, in the involuting Drosophila salivary gland, autophagic vacuolization precedes signs of apoptosis again arguing against a clearcut distinction between different forms of cell death.20 Thus, the frontiers between distinct cell death types are indistinct, precluding a neat taxonomy. Moreover, it should be noted that expressions like 'apoptosis' suggest a biochemical uniformity although there might be in reality several distinct subtypes of apoptosis that, however morphologically similar, are functionally distinct cell death subroutines.
- h% y- V- X3 [5 |* A9 l
4 s" P( b7 I9 G8 m7 RAnoikis
6 n6 I' g+ M9 Z' ^0 ]( OApoptosis induced by loss of the attachment is to the substrate or to other cells is called anoikis. Besides its specific form of induction, the molecular mechanisms seem to be classic apoptosis. The NCCD suggests accepting this nomenclature for historical reasons, since it is already quite diffuse in the literature. However, it will be necessary to determine whether under certain circumstances other forms of death may occur in vivo following detachment, that is, whether there are forms of anoikis refractory to caspase inhibitors or others with features of autophagy.
: B8 H# ~- w+ z. u3 v2 l+ f5 I5 F" R# d7 Y6 _+ Y% i
Excitotoxicity
1 C$ p/ U0 [. G' S  i9 oThis is a form of death occurring in neurons when excitatory aminoacids, such as glutamate, leading to the opening of the N-methy-D-aspartate (NMDA) calcium channel, with subsequent increase of cytosolic calcium and death.21 It is possible that this form of death may overlap with other types of death being unraveled and in the future it may be possible to determine whether this pathway involves ER stress and/or mitochondrial events.+ ]9 i$ H% o& u) z; r
8 }! t: X& p' z* ^( v7 p" W4 k
Wallerian degeneration3 y! h+ n3 f8 {7 @0 _+ I
Additional, less characterized forms of cell death occurs in the nervous system, such as Wallerian degeneration, where part of a neuron or axon degenerates without affecting the main cell body. As in the case of excitotoxicity more molecular characterization may better define this form of cell death as similar or distinct from other general processes or pathways.
! H6 [+ G+ i! E2 E& Z
' y& |" N. A; p. P. |- O# vCornification+ U) t# d' n# Q+ q  F* U
Cornification is a very specific form of programmed cell death occurring in the epidermis, different from apoptosis. It leads to the formation of the cornified envelope (or corneocyte), a dead keratinocyte containing an amalgam of specific proteins (e.g. loricrin, SPR, involucrin) and lipids (e.g. fatty acids, ceramides), necessary for the function of the cornified envelope (mechanical resistance, elasticity, water repellence, structural stability). Cornification is less often called 'keratinization' or 'cornified envelope formation'.22
2 x! l: I3 W8 R5 Y2 T& ~; v
" E, h, |4 A5 ^2 @* G9 G0 k* U; A Ill-defined Notions on Upstream Events and Terms Describing Cell Death Mechanisms3 x: i; }$ J: z: p0 I( s0 M) d
Programmed cell death
- o% y  V( P& s8 W$ R: h/ ]Frequently, apoptosis is referred to as synonymous to 'programmed cell death' (PCD). PCD is an expression that insinuates that cell death has been genetically programmed, as this is the case during development and aging. PCD is generally opposed to 'accidental cell death', that is necrosis induced by pathological stimuli. However, there are many circumstances that are difficult to consider as either 'programmed' or 'accidental', for instance when cytotoxic agents are added to cultured cells. So, these expressions are imprecise and should be replaced by expressions like 'developmental cell death', 'etoposide-induced cell death', 'cell death induced by osmotic shock', 'death induced by repeated freezing and thawing', etc. 'Death by neglect' can be conveniently translated by 'death induced by interleukin-3 withdrawal' or 'death induced by Akt inhibition'. Similarly, 'cell death following detachment' is more readily understood by those outside of the field, is less ambiguous than 'anoikis', and can be tested experimentally.5 L& Y* h' i* e" S
/ A5 V9 u! D% B2 `) e% [- Z1 y# l5 ^
Caspase-independent apoptosis
) @# O: U; x8 o9 e, [" U' t6 [Another classification of cell death types is based on the impact of inhibitors or genetic manipulations. Thus, cell death is frequently considered to be 'caspase-dependent' when it is inhibited by broad-spectrum caspase inhibitors such as N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (Z-VAD-fmk). As a word of caution, however, it should be noted that Z-VAD-fmk does not inhibit all caspases in an equally efficient fashion, yet does inhibit calpains and cathepsins. Thus, 'Z-VAD-fmk-inhibitable' is more precise than 'caspase-dependent', while using the same number of words. A second difficulty arises from the fact that caspase inhibition frequently inhibits signs of apoptosis (such as chromatin condensation and DNA fragmentation), yet only retards cell death.23 In some instances, caspase inhibition simply induces a shift from an apoptotic morphology to a mixed morphology or even to full-blown pictures of necrotic or autophagic cell death, which, however, can manifest with some delay.24 So under certain circumstances, an alternative to 'caspase-dependent death' may be 'Z-VAD-fmk-inhibitable chromatin condensation', if there is no information on the long-term behavior of the experimental system. 'Caspase independent cell death' (CICD)23 can occur despite the effective inhibition of caspases and can manifest with the morphological signs of apoptosis, autophagy or necrosis. So while the idea that apoptosis equals caspase activation should be abandoned, caspase activation can be a major predictor of death and can be a defining feature of apoptosis.1 s+ v" L* G: @( n! ?: n
( v  C: g2 y. h$ k  W5 o* H
Postface: f9 A# [5 S# G- C, E* V
Although it may be true that rigorous, 'legal' classifications of types of death are more important for the forensic department of the police than for the cell death research community, it is essential that scientists use terminology in a generally accepted and correct fashion. The NCCD has begun formulating clear recommendations that apoptosis, autophagic cell death and necrosis/oncosis are purely morphological entities and that conceptual short circuits such as programmed cell death=apoptosis=caspase-dependent cell death or accidental cell death=necrosis=caspase-independent cell death should be avoided. Moreover, the NCCD issues a firm recommendation against the use of poorly defined terms such as the percentage of apoptosis, necrosis, death or survival suggesting that they should be substituted by a precise description of the parameters that are measured. In the future, as progress unravels a clear distinction between different cell death subroutines, in molecular terms, the NCCD will formulate updated recommendations on cell death terminology.) [! ?* P4 y% V% C) s/ f  a) n

; U( A9 G1 b0 S- CReferences
, q2 s, F" z9 }9 E2 Y0 c! xMelino G. 2001; Nature 412: 23. | Article | PubMed | ISI | ChemPort |
% j1 p- i. e0 P6 I5 EAmeisen JC. 2002; Cell Death Differ. 9: 367–393. | Article | PubMed | ISI | ChemPort |
7 E7 G5 E7 ^% |% d. Q0 @Ameisen JC. 2004; Cell Death Differ. 11: 4–10. | Article | PubMed | ISI | ChemPort | # b8 [) C! }8 k- j
Zhivotovsky B & Kroemer G. 2004; Nat. Rev. Mol. Cell Biol. 117: 4461–4468.
' J+ P( w" R, U/ H# e" v7 hVaux DL. 1999; Cell Death Differ. 6: 493–494. | Article | PubMed | ISI | ChemPort | ; W% k( w' l4 \6 t0 w5 e  u$ V8 X
Samali A et al.. 1999; Cell Death Differ. 6: 495–496. | Article | PubMed | ISI | ChemPort |
3 |6 ]7 O3 p) IGreen DR & Kroemer G. 1998; Trends Cell Biol. 8: 267–271. | Article | PubMed | ISI | ChemPort | , ?% Y: P( F# Z1 M. }
Green DR & Kroemer G. 2004; Science 305: 626–629. | Article | PubMed | ISI | ChemPort | : _  k5 t+ g5 `( z
de Graaf AO et al.. 2004; Exp. Cell Res. 299: 533–540. | PubMed | ISI | ChemPort |
- k( v# f6 d/ C- a- T! AYang MY et al.. 2002; J. Leukocyte Biol. 71: 231–237. | PubMed | ISI | ChemPort |   m. s9 F% w# A6 N: ^5 n) }- v3 [
Kerr JFR, Wyllie AH & Currie AR. 1972; Br. J. Cancer 26: 239–257. | PubMed | ISI | ChemPort | ' H- J2 j+ U0 D& X) k1 M
Levine B & Klionsky DJ. 2004; Dev. Cell 6: 463–477. | Article | PubMed | ISI | ChemPort |
$ x0 S; T; C8 ?4 UMizushima N et al.. 2004; Mol. Biol. Cell 15: 1101–1111. | Article | PubMed | ISI | ChemPort |
' Y7 o2 H# v1 j% C4 }Boya P et al.. 2005; Mol. Cell Biol. 25: 1025–1040. | Article | PubMed | ISI | ChemPort |
  c7 j* w6 v% x) }' gDenecker G et al.. 2001; Cell. Mol. Life Sci. 58: 356. | PubMed | ISI | ChemPort |
6 W$ \6 K$ A# z1 W, X; e% q4 |Roninson IB, Broude EV & Chang B-D. 2001; Drug Resistance Updates 4: 303–313. | Article | PubMed | ISI | ChemPort | , C! R) X6 u/ c# D2 q
Castedo M et al.. 2004; Oncogene 23: 2825–2837. | Article | PubMed | ISI | ChemPort | ) i# y8 g. X: l: F& Y
Okada H & Mak TW. 2004; Nat. Rev. Cancer 4: 519–603. | Article | PubMed | ChemPort | 3 m# v9 l1 G- s" ?: w/ _) N
Nicotera P & Melino G. 2004; Oncogene 23: 2757–2765. | Article | PubMed | ISI | ChemPort | . ^! J) a; w7 ~$ O6 q
Martin DN & Baehrecke EH. 2004; Development 131: 275–284. | Article | PubMed | ISI | ChemPort |
/ R& v0 t6 P$ x% A8 ?0 o5 gOrrenius S, Zhivotovsky B & Nicotera P. 2003; Nat. Rev. Mol. Cell Biol. 4: 552–565. | Article | PubMed | ISI | ChemPort | 7 t9 W) R$ b8 ~- G) q' |' I+ f  s& ?
Candi E, Schmidt R & Melino G. 2005; Nat. Rev. Mol. Cell Biol. 6: 328–340. | Article | PubMed | ISI | ChemPort |
  i1 V; D9 h9 z3 [% G5 yChipuk JE & Green DR. 2005; Nat. Rev. Mol. Cell. Biol. 6: 268–275. | Article | PubMed | ISI | ChemPort | 3 _; k% J' I9 C8 o
Golstein P & Kroemer G. 2005; Cell Death Differ. in press. | Article | PubMed |
& z3 [2 e1 {0 Q) q
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板凳
发表于 2011-2-12 09:42 |只看该作者
干细胞之家微信公众号
【百度百科】细胞死亡  
* D, y/ |0 E( q8 ]- p: V细胞因受严重损伤而累及胞核时,呈现代谢停止、结构破坏和功能丧失等不可逆性变化,此即细胞死亡。   细胞死亡包括坏死和凋亡两大类型。   
% d$ _: v8 t8 R8 @死亡的原因很多,一切损伤因子只要作用达到一定强度或持续一定时间,从而使受损组织的代谢完全停止,就会引起细胞、组织的死亡。   3 ^) H+ L# D5 X' k8 z% Z. I$ }
在多数情况下,坏死是由组织、细胞的变性逐渐发展来的,称为渐进性坏死。坏死多为细胞受到强烈理化或者生物因素作用引起细胞无序变化的死亡过程。表现为细胞胀大、细胞膜破裂、细胞内容物外溢。   
9 F9 r7 [( }. i9 [4 p在此期间,只要坏死尚未发生而病因被消除,则组织、细胞的损伤仍可恢复(可复期)。   7 g! H3 @9 ~! t- |0 C$ ^" E
但一旦组织、细胞的损伤严重,代谢紊乱,出现一系列的形态学变化时,则损伤不能恢复(不可复期)。   
' R7 K5 X/ I5 ~' f" x8 v: b/ F在个别情况下,由于致病因子极为强烈,坏死可迅速发生,有时甚至可无明显的形态学改变。4 X/ {0 G) ?0 Q* J

* f8 ~. o" `1 Q1 f+ w" M细胞死亡的方式:
0 D/ z! O4 E  \9 |5 Z  凋亡小体 坏死与凋亡及其异同   
! ^7 {$ K; D- J6 C* ~①细胞的死亡方式有两种:A被动死亡——细胞坏死,它是指细胞受到环境因素的影响,导致细胞死亡的病理过程。B主动死亡(程序性死亡)——即细胞凋亡,为了维持机体内环境的稳定,细胞发生主动的,由基因控制的自我消亡过程,此过程需要消耗能量。   
6 b* n* ]! {  E/ ^) w# Y②凋亡小体是指细胞凋亡过程中,细胞膜反折,包围细胞碎片,如染色体片段和细胞器等,形成芽状突起,以后逐渐分离所形成的结构就形成凋亡小体。它是细胞眺望的特征性形态结构,凋亡小体最后为邻近的细胞所吞噬。   8 l3 a/ o5 [* u% L$ F/ Y
③坏死与凋亡的异同   9 |! F9 U2 d& `/ k5 u' {
A。细胞凋亡与坏死在形态学上的差别 & d5 o$ h# D( @% H) m
细胞凋亡                细胞坏死
7 C$ [: {1 S& w单细胞丢失              细胞成群丢失
- n1 n* i/ Q+ z2 o: Z9 g# E. L( N- w细胞膜发泡,            膜仍然完整 细胞膜不完整
* \4 d+ X* p: t+ T; o细胞膜内陷,            浆细胞分割成凋亡小体 细胞肿胀、溶解 ( L3 L3 u( s/ t1 q, m) e
不发生炎症              发生严重炎症反应 0 e' o6 c# {) G. r  f! J, x
被邻近的正常细胞8 q: N  y8 M7 L: v6 f& ?6 X
或吞噬细胞所吞噬       被巨噬细胞所吞噬
5 M# H) @  j3 Z/ `3 g1 H% z9 l( K溶酶体完整             溶酶体裂解
+ Z3 ?( X1 {6 I/ n1 a& V染色质均一凝集         染色质凝集成块,不均一
, ?  ~5 n9 s' L6 M8 z  x2 A: U* l  }  }1 W3 T/ w. D
B细胞凋亡与坏死在生物化学特征上的比较   
; J( A+ q7 A8 A( I$ ~9 L0 X细胞凋亡                   细胞坏死 6 \; R0 u4 N9 V5 }: X
生理因素诱导的主动性坏死   非生理因素造成的意外的被动性死亡 " ?6 Q( X3 t! ~8 K/ u
需要能量                   不需要能量
: U3 e; S8 |1 |7 a& _需要大分子合成             不需要核算和蛋白质的合成
4 ?% \3 l8 g" b& N有新基因从头转录           没有新基因转录
  P3 U' ^8 \$ T; a- s% v染色质非随机降解为DNA    Ladder 染色质DNA被随机降解
6 |6 c; E- ~; k9 b7 h. O

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报纸
发表于 2011-2-12 09:58 |只看该作者
以上提供了一些细胞死亡的背景材料,定义上细胞死亡(cell death)是指细胞功能和结构不可逆丧失。) W$ A. D, f  [+ I1 g" H# |
老狼认为细胞死亡在体内(in vivo)和 体外(in vitro)的定义还是有区别的。
! |# `6 F$ i0 }0 m) ]- M: G; c体内细胞死亡主要表现为细胞凋亡和细胞坏死;6 T2 s; q1 k8 C& ~/ o! z0 A
体外的情况类似于微生物死亡(不可逆地失去增殖能力),放射源照射照射或丝裂霉素处理后细胞停止生长,但部分功能和结构仍能够保持。
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地板
发表于 2011-2-14 08:20 |只看该作者
回复 sunsong7 的帖子, C  _" o: q) O6 ^" m8 L  B

5 ]+ e* i  ?+ m; ~- y6 Q9 c% \太感谢你了

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发表于 2011-2-14 10:26 |只看该作者
太好了,非常全面,非常谢谢

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发表于 2011-2-15 09:09 |只看该作者
,学习了

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发表于 2012-2-13 01:57 |只看该作者
2009--Classification of cell death recommendations of the Nomenclature Committee.pdf (140.54 KB)
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发表于 2012-2-14 12:34 |只看该作者
“比如某些细胞因子是否还发挥功能,或者死细胞的功能更有价值”7 n$ c. r" Q' I/ K( \" T
用低渗液体处理,使细胞破裂,释放细胞内因子。还有听说用装完细胞的瓶子
2 K% V# D0 c3 c+ D直接拿盐水润洗的。
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