中华鳖病毒感染宿主的细胞病理学研究

CELLULAR PATHOLOGICAL STUDIES ON VIRUS INFECTION OF SOFT SHELLED TURTLES

中华鳖病毒（Ｔｒｉｅｎｙｘｓｉｎｅｎｓｉｓｖｉｒｕｓ，ＴＳＶ）经人工感染可引起健康中华鳖发病和死亡。对病鳖组织细胞的超微结构观察，同时见有以染色质高度凝集和边缘化、核碎裂并形成“凋亡小体”等表现有典型的类似于细胞凋亡（ａｐｏｐｔｏｓｉｓ）形态变化的细胞，和以核膜崩解、线粒体外膜膨大、细胞膜破裂、细胞质严重液泡化等表现为坏死（ｎｅｃｒｏｓｉｓ）性变化的细胞。ＤＮＡ片段化分析表明，感病鳖组织细胞的ＤＮＡ发生了严重的片段化，且以肝组织细胞的ＤＮＡ片段化最为严重。研究揭示，中华鳖病毒导致宿主死亡同时存在凋亡和坏死两种细胞病变机制。

Artificial infections of soft shelled turtle virus (Trionyx sinensis virus, TSV) showed that the virus could cause disease and death of soft shelled turtles. Some reactions similar to apoptosis, such as distinctive condensation and margination of chromatin, nuclear fragmentation, as well as the resulted apoptotic bodies, and process of necrosis, such as nuclear and cytoplasma membrane breakage, mitochondrial outer membrane enlarging, strong cytoplasm changes and flowing out, were observed from different tissue sections of the infected turtles by electron microscopy. DNA fragmentation assay demonstrated that DNA fragmentation occurred strongly in tissue cells of the infected turtles and liver was the most severely affected tissue by the virus infection, whereas no fragmentation was observed in the uninfected turtles. It is suggested that there exists at least two cellular pathological mechanisms including apoptosis and necrosis.