烧伤对胸腺细胞凋亡的影响

THE INDUCTION OF APOPTOSIS OF THYMIC CELLS IN MICE BY BURN

小鼠４０％体表面积经６０℃，１２ｓ烧伤后胸腺细胞出现明显的病理性调亡，表现为：与对照组比，ＤＮＡ断裂（ＤＮＡＦｒａｇｍｅｎｔａｔｉｏｎ）百分率显著增高；琼脂糖凝胶电泳出现明显的细胞凋亡特有的“梯状”条带。动态观察发现烧伤后３ｈＤＮＡ断裂百分率明显升高，１２ｈ胸腺活细胞总数明显降低，而胸腺重量和细胞总数降低则于烧伤后１８ｈ才出现。结果提示：①烧伤可诱导胸腺细胞发生严重的病理性凋亡；②烧伤后胸腺细胞病理性凋亡导致的胸腺萎缩可能与烧伤后免疫力降低有关。

hhough it was reported that there were immune dysfunction and thymus atrophy afterburn,its rnechanism was unclear.This study is an attempt to determine whether burn could in-duce apoptosis of thymic cells. We found that the genomic DNA of thymic cells was fragmented,which was confirmed by increase of DNA fragmentation percentage and specific Zone(DNA“ladder”of about 180-200 bp)for apoptosis showed by agarose gel electrophoresis. We alsofound that the DNA fragmentation of thymic cells began at the 3rd h,reached peak at the 18th hand declined partly at the 24th h after burn. However,the thymmatrophy did not appear untilthe 18th h and the 24th h after burn. These results suggest that apoptosis of thymic cells could beinduced by burn in vivo and might be responsilbe for the immune dysfunction and thymus atrophyafter burn.