细胞凋亡的特征、检测方法及生物学意义

细胞死亡的方式有两种：凋亡和坏死。细胞坏死（necro—sis）是极端的物理、化学因素或严重的病理性刺激引起的细胞损伤和死亡。坏死细胞胞质不是浓缩,而是显著肿胀,也不形成凋亡小体。组织中的坏死,大量存在坏死细胞,病灶周围伴有炎症反应。而组织切片中凋亡细胞往往为单个或者几个细胞散在分布。细胞凋亡（apoptosis）是生物体内重要的生命现象,由Kerr等在1972年首先提出的。当凋亡受到抑制,会导致肿瘤的发生和各种疾病的发生,而不适当的细胞凋亡激活（许多外源性因素如药物、物理辐射等均可引发细胞凋亡）,是中风、心肌梗死、帕金森病、AIDS等发生的重要原因。因此,生物内环境的稳定不但依赖于细胞的增殖分化,也依赖于细胞的凋亡。     

细胞凋亡与疾病

细胞凋亡(apoptos is)是普遍存在于人体组织细胞内的细胞死亡的形式之一,是不同于坏死的正常生理性的程序性细胞死亡。细胞抗凋亡是生物机体为了适应环境变化,维持生理平衡的一种主动的自我保护行为。凋亡或抗凋亡均是在基因控制下,多样性、偶联性、多途径的信号转导过程。它也受到内外生存因子的影响和制约,肿瘤等多种疾病均能影响细胞凋亡过程。     

兔脑炎原虫引起肾上皮凋亡的研究

对 16只具有兔脑炎原虫病的示病症状 ,即出现不同程度的头颈歪邪、震颤、平衡失调和转圈运动等运动障碍症状的獭兔 ,运用原位末端标记技术和基因染色技术 ,着重对病兔肾组织损伤的发生进行了研究。结果表明 :肾远曲小管和集合管是脑炎原虫主要的寄生部位 ,在此常能检出虫体或假囊 ;凋亡的细胞多见于集合小管的上皮细胞。用TUNEL染色 ,不同阶段的凋亡细胞可出现不同的病理形态学变化。初期的凋亡细胞 ,其胞核浓缩 ,胞膜增厚 ,着色较均匀 ;后期的凋亡细胞 ,其胞核的体积明显变小 ,胞浆减少 ,胞膜呈皱襞状 ,紧紧地包绕着皱缩而浓染的细胞核 ,形成典型的凋亡小体。用 P53和 Bcl- 2染色 ,由于基因表达产物的扩散 ,不仅受损细胞的核染色较深 ,而且胞浆染色也较深。研究证明 ,TUNEL 染色是一种检测由脑炎原虫引起肾细胞凋亡的灵敏、可靠的方法 ;P53和 Bcl- 2基因参与了肾细胞的凋亡过程 ;临床上病兔多尿与脱水可能主要与肾远曲小管和集合管的上皮细胞凋亡有关。     

小鼠腔前卵泡卵母细胞体外培养过程中Bcl-2/bax基因表达的研究

<正>细胞凋亡是由多基因参与调控的细胞生理性、主动性死亡过程,其最主要特征是DNA发生核小体之间的断裂,结果形成长度为180~200 bp整数倍的寡聚核苷酸片段,组蛋白和其他核内蛋白质不降解,核基质不发生改变。当大部分细胞发生凋亡时,这一特征通过DNA琼脂糖凝胶电泳检测,形成了特征性的梯状条带[1]。Bcl-2蛋白家族对各阶段卵泡的生长发育具有调节作用,其中Bcl-2/bax两蛋白之间的     

甘肃新生羔羊腹泻症的病理学研究

对３７ 例因腹泻症而死亡的初生羔羊（７ 日龄内）心、肝、脾、肺、肾、真胃、小肠、淋巴结、骨骼肌和平滑肌进行了病理形态学观察。结果表明,这些组织器官主要表现为程度不同的细胞变性和坏死。在多种组织器官的间质,发生局灶性纤维素样坏死。此外,还发现心脏浦金野氏纤维的退行性变化。     

细胞凋亡检测技术的研究进展

细胞凋亡是一种不同于细胞坏死的细胞死亡方式，是在一定的生理或病理情况下，机体为维护内环境的稳定，通过基因调控，激活内源性核酸内切酶而发生的细胞自动消亡的过程，亦称为程序化细胞死亡(programmed cell death，PCD)。自1972年Kerr等根据细胞发生了与坏死完全不一样的死亡过程而提出细胞凋亡(apoptosis)的概念后，引起细胞生物工作者的注意，但由于当时检测技术的限制，这种细胞凋亡现象只停留于形态描述，缺乏定     

细胞凋亡与疾病

早在1972年Kerr等已发现从细胞形态、超微结构和生化变化等方面来分析,细胞有二种死亡形式,一种是早被熟知的细胞坏死（Necrosis）,另一种是细胞凋亡（Apoptosis）。细胞凋亡是正常的生理过程,但是凋亡过多或过少都可引起疾病发生。因此,近年来对于细胞凋亡与疾病间关系的研究,已成为医学界的关注热点。细胞凋亡是机体维持细胞群体数量稳态的重要手段,细胞凋亡失调（凋亡不足或／和凋亡过度）可成为某些疾病的重要发病机制。     

细胞凋亡与疾病

早在1972年Kerr等已发现从细胞形态、超微结构和生化变化等方面来分析,细胞有二种死亡形式,一种是早被熟知的细胞坏死（Necrosis）,另一种是细胞凋亡（Apoptosis）。细胞凋亡是正常的生理过程,但是凋亡过多或过少都可引起疾病发生。因此,近年来对于细胞凋亡与疾病间关系的研究,已成为医学界的关注热点。细胞凋亡是机体维持细胞群体数量稳态的重要手段,细胞凋亡失调（凋亡不足或／和凋亡过度）可成为某些疾病的重要发病机制。     

TUNEL法检测PCV2感染仔猪的淋巴细胞凋亡

利用一种常规的细胞凋亡检测方法 TUNEL法检测感染PCV2(猪圆环病毒2型)的仔猪淋巴结淋巴细胞的凋亡变化情况,并从组织病理学的角度验证PCV2是否能引发仔猪淋巴结淋巴细胞凋亡。通过HE染色镜下可见仔猪皮质区淋巴结皮质部淋巴小结内坏死的淋巴细胞染色变深,胞核固缩,出现坏死,导致淋巴细胞稀疏,出现细小的细胞缺失区,有的还出现严重的淋巴细胞浸润或弥散性出血,严重者成团的淋巴细胞细胞质溶解以及核碎裂出现溶解坏死,多数淋巴细胞缺失区相连形成空洞,生发中心消失;通过TUNEL法检测可见淋巴小结内出现多量的细胞胞核固缩、凋亡,常堆集在一起呈多量散在分布,细胞凋亡后,在淋巴小结中可以明显地看到细胞凋亡形成的碎片,造成细胞密度疏松,严重者可见大量的细胞碎片,消失形成空洞。阴性对照组仔猪淋巴组织结构比例较正常,细胞形态清晰。通过HE染色和TUNEL法对比观察发现细胞的坏死和凋亡有重叠现象,从病理学的角度非常直观地证明了PCV2能够引起仔猪免疫系统淋巴细胞的凋亡,为阐明PCV2诱导猪的淋巴细胞发生凋亡这一现象奠定基础,并为探讨PCV2导致猪PMWS的致病机制提供基础资料。     

人工感染弓形虫患猪脏器病理形态学的研究

关于急性猪弓形虫病病理形态学方面的报道很多,一般认为该病的主要变化为间质性肺炎,肝、脾和淋巴结的灶性坏死,并认为细胞的坏死是因虫体直接作用的结果。但是,在一些急性病例中,除灶性坏死外,在肝、肾、肺、肠等器官的实质细胞呈广范围的坏死,并在这样死亡病例的细胞中未查到虫体,因而对该病实质细胞的大量坏死的机理和原因应加以探讨。此外,作者曾报道过对该病有特征意义的一些病理现象,如肝小叶纤维囊中的     

Morphological and biochemical aspects of apoptosis,oncosis and necrosis

Recent investigations have demonstrated the need for a precise differentiation of various forms of cell death such as apoptosis, oncosis, necrosis and programmed cell death. Apoptosis is marked by cellular shrinking, condensation and margination of the chromatin and ruffling of the plasma membrane with eventually breaking up of the cell in apoptotic bodies. Cell death marked by cellular swelling should be called oncosis, whereas the term necrosis refers to the morphological alterations appearing after cell death. Apoptosis and oncosis are therefore pre-mortal processes, while necrosis is a post-mortal condition. The term programmed cell death refers to the 'fixed' pathway followed by dying cells, whether or not with the characteristic morphology of apoptosis. Three mechanisms are actually known to be involved in the apoptotic process: a receptor-ligand mediated mechanism, a mitochondrial pathway and a mechanism in which the endoplasmic reticulum plays a central role. All three mechanisms activate caspases which are responsible for the characteristic morphological changes observed during apoptosis. A review of the different methods used for detecting apoptotic cells demonstrates that most of these techniques are not entirely specific.     

铅引起细胞急性死亡的途径

以不同质量浓度的铅（１０、２０、４０、８０mg/Ｌ）作用于Ｗish细胞３、６、１２、２４h,探索了铅对细胞急性死亡的影响。结果表明,１０mg/Ｌ的铅使Ｗish细胞出现;了以 环死为特征的细胞死亡铅导致细胞死亡可通过２条不同途径：一个途径为一定剂量的铅通过启动细胞内的凋亡程序,出现以细胞体积缩小、胞质浓缩、ＤＮＡ琼脂糖电泳呈梯状图像、流式细胞仪检测出现明显凋亡峰为特征的细胞凋亡;另一个途径是在铅质量浓度过大时,导     

A histopathologic,immunohistochemical, and ultrastructural study of the intestine in pigs inoculated with classical swine fever virus

The aim of this study was to report on the lesions occurring in the intestine during experimental classical swine fever (CSF) and to clarify the nature of infected cells and the distribution of viral antigen. Thirty-two pigs were inoculated with the virulent CSF virus (CSFV) isolate Alfort 187 and slaughtered from 2 to 15 postinoculation days; four animals of similar background served as a control group. Immunohistochemistry, electron microscopy, and the transferase-mediated deoxyuridine triphosphate nick-end labeling method were used to detect viral antigens and apoptosis. The results showed progressive lymphoid depletion and mucosal necrosis. The lymphoid depletion could have been caused by apoptosis of lymphocytes but could not be directly attributed to the effect of CSFV on these cells. Vascular changes, pathogenic bacteria, and viral infection of epithelial cells were ruled out as causes of necrotic lesions. However, large virally infected monocytes-macrophages with ultrastructural changes indicative of activation were observed in the intestine. This suggests that monocytes-macrophages play an important role in the pathogenesis of intestinal lesions. An understanding of the function of these cells will require additional study.     

Vascular ultrastructure and DNA fragmentation in swine infected with Shiga toxin-producing Escherichia coli

Shiga toxins (Stx) produced by Escherichia coli cause systemic vascular damage that manifests as edema disease in swine and hemolytic uremic syndrome in humans. In vitro, Stx inhibit protein synthesis and, depending on circumstances, induce necrosis, apoptosis, or both. The mechanism of in vivo Stx-mediated vascular damage is not known. The ability of Stx to cause apoptosis of vasculature in vivo was studied in pigs with edema disease that was produced by oral inoculation with Stx-producing E. coli. Arterioles of ileum and brain were evaluated by terminal dUTP nick-end labeling (TUNEL) assay for DNA fragmentation in myocytes (10 infected pigs, 5 control pigs) and by transmission electron microscopy for ultrastructural changes characteristic of apoptosis (17 infected pigs, 8 control pigs). In comparison with controls, increased numbers of TUNEL-positive arterioles were detected in 6/10 (60%) subclinically affected pigs 14-15 days after inoculation. Ultrastructurally, lesions in myocytes consisted of lysis (necrosis), with cytoplasmic debris and nuclear fragments contained between intact basement membranes. Endothelial cell changes ranged from acute swelling to necrosis and detachment from basement membrane. Subclinically affected pigs (n = 14) tended to have changes predominantly in myocytes, whereas pigs with clinical illness (n = 3) more commonly had changes in endothelial cells. The arteriolar lesions and clinical signs of edema disease are attributed to the effects of Stx on vasculature. Therefore, our findings suggest that the Stx-induced arteriolar lesions seen in this study were primarily necrotic, not apoptotic. We suspect that necrosis was the principal cause of the DNA fragmentation detected.     

Arteriolar nephrosclerosis in the Syrian hamster

Syrian hamsters developed spontaneous renal lesions that resembled those of arteriolar nephrosclerosis in man, and differed from other spontaneously occurring or virus-induced renal diseases in other rodent species. Morphologic changes were mainly degenerative with little cellular exudation and were associated with histologic changes in the intrarenal vasculature. The renal lesions were progressive, often fatal and sometimes were complicated by glomerular amyloidosis with the nephrotic syndrome and uremia. Endstage kidneys often had fibrinoid necrosis of intrarenal arterioles and thus resembled lesions characteristic of the malignant phase of human essential hypertension. Fibrinoid necrosis of small arterioles was common in the uterus, ovaries or testes of affected animals; it was less frequent in mesenteric or coronary vessels. Cardiac thrombosis, often involving the left atrium or left atrioventricular valves, also was common. Changes occurred earlier and often were more severe in females than in males. This disease was a major cause of morbidity and mortality and hampered life-span studies.     

The pathogenesis and pathology of bovine tuberculosis with insights from studies of tuberculosis in humans and laboratory animal models

This paper reviews key insights the discipline of pathology has contributed to our understanding of bovine tuberculosis in the context of findings of studies of tuberculosis in humans and laboratory animal models. Analysis and extrapolation of data from other species have the potential to expand our understanding of the pathogenesis of the disease in cattle. The distribution of lesions in affected cattle, humans and laboratory animals illustrate the primacy of the respiratory tract as portal of infection and raise questions about the role of the upper respiratory tract surface, tonsil and dorsal lung regions in disease pathogenesis and transmission. The mechanisms behind significant pathological processes such as necrosis, apoptosis and liquefaction, occurring within lesions, are explored and their potential practical significance assessed in the context of herd disease dynamics and vaccine development. It is proposed that effective 'innate' host defences result in many animals and humans remaining disease-free and tuberculin test negative following exposure to infection. Furthermore, the concepts of latency and disease reactivation, considered significant factors in perpetuating tuberculosis in human populations, are explored in the context of the bovine disease.     

Adrenocortical involution in rats during oestrus synchronisation with medroxyprogesterone

Daily treatment of female rats with medroxyprogesterone acetate in aqueous suspension resulted in adrenocortical atrophy. The doses given were those used for oestrus synchronisation. Intramuscular injections of 2-0 mg medroxyprogesterone acetate were used to investigate the atrophic process. Adrenocortical involution was associated with extensive single cell deletion (apoptosis). It is suggested that theses changes were due to suppression of pituitary ACTH secretion. The cytological changes support the concept that single cell death plays an important role in organ remodelling. Biochemical determinations of DNA, RNA, protein and dry matter, and histological examination, did not reveal significant changes in the liver.     

Apoptosis in the mammalian CNS: Lessons from animal models

It is generally assumed that about half of the neurons produced during neurogenesis die before completion of maturation of the central nervous system (CNS). Neural cell death is also relevant in aging and several neurodegenerative diseases. Among the modalities by which neurons die, apoptosis has very much attracted the interest of investigators because in this type of cell death neurons are actively responsible for their own demise by switching on a number of genes and activating a series of specific intracellular pathways. This review focuses on the cellular and molecular mechanisms of apoptosis in normal and transgenic animal models related to naturally occurring neuronal death within the CNS. We will also consider some examples of apoptotic cell death in canine neuropathologies. A thorough analysis of naturally occurring neuronal death in vivo will offer a basis for parallel and future studies involving secondary neuronal loss such as those in neurodegenerative disorders, trauma or ischaemia.     

Regulation of granulosa cell apoptosis by death ligand–receptor signaling

Several hundred thousand primordial follicles are present in the mammalian ovary, however, only 1% develop to the preovulatory stage and finally ovulate. The remainder will be eliminated via a degenerative process called ‘atresia’. The endocrinological regulatory mechanisms involved in follicular development and atresia have largely been characterized but the precise temporal and molecular mechanisms involved in the regulation of these events remain unknown. Many recent studies suggest that apoptosis in ovarian granulosa cells plays a crucial role in follicular atresia. Notably, death ligand‐receptor interaction and subsequent intracellular signaling have been demonstrated to be the key mechanisms regulating granulosa cell apoptosis. In this review we provide an overview of granulosa cell apoptosis regulated by death ligand‐receptor signaling. The roles of death ligands and receptors [Fas ligand (FasL)]‐Fas, tumor necrosis factor α (TNFα)‐TNF receptor and TNFα‐related apoptosis‐inducing ligand (TRAIL)‐TRAIL receptor (TRAILR)] and intracellular death‐signal mediating molecules (Fas‐associated death domain protein), TNF receptor 1‐associated death domain protein, caspases, apoptotic protease‐activating factor 1, TNFR‐associated factor 2 and cellular FLICE‐like inhibitory protein in granulosa cells are discussed.