机体组织细胞在各种损伤、感染或丧失血液供应的条件下会出现局部死亡的现象。细胞死亡时既有细胞核的改变,也有细胞浆的变化。体外培养的神经元在剥夺神经生长因子后数小时即呈现蛋白合成下降,继而DNA发生碎裂,细胞死亡已不可避免。死亡的细胞还有细胞膜损伤、线粒体破坏、溶酶体裂解等。其中,认为DNA碎裂和线粒体破坏是细胞死亡的重要标志。细胞生物学家区分出两种类型的细胞死亡:一种表现是细胞核DNA的改变,称为细胞凋亡(Apoptosis);另一种首先有明显的胞浆肿胀,膜通透性改变,细胞器损毁,后期才有核深染、DNA非特异性解聚和核溶解,称为细胞坏死(Necrosis)。细胞凋亡和细胞坏死在发生机理上有很大的差别,其意义正受到广泛重视。1 细胞凋亡的概念 Tissue cells may show localized fatalities under various conditions of injury, infection or loss of blood supply. Cell death, both the changes in the nucleus, there are changes in the cytoplasm. Neurons cultured in vitro deprived of nerve growth factor in a few hours after the protein synthesis showed decreased, followed by DNA fragmentation, cell death has been inevitable. There are cell death of the cell membrane damage, destruction of mitochondria, lysosome lysis and so on. Among them, DNA fragmentation and mitochondrial damage are considered as important markers of cell death. Cell biologists distinguish between two types of cell death: one is a change in the nucleus DNA called Apoptosis; the other is first of all obvious cytoplasmic swelling, altered membrane permeability, organelle destruction Later, only nuclear staining, non-specific DNA disaggregation and nuclear lysis, known as cell necrosis (Necrosis). Apoptosis and necrosis in the mechanism of occurrence of great differences, its significance is being widely appreciated. 1 apoptosis concept