小鼠病毒性心肌炎细胞凋亡相关蛋白的表达

Expression of apoptosis related proteins perforin,granzyme B and caspase-8 in experimental viral myocarditis of mice

目的 探讨嗜鼠心肌 Coxsackie B3病毒 (CVB3m)诱导的 BAL B/ C小鼠病毒性心肌炎 (VMC)细胞凋亡的机制。方法 给 BAL B/ C小鼠腹腔接种 0 .1ml10 0 TCD5 0 CVB3m,感染后分批断脊处死小鼠。应用双重荧光染色技术、原位末端标记法 (TU NEL)和共聚焦显微镜对小鼠心肌细胞凋亡及部分相关蛋白表达进行检测。结果 CVB3m可诱发小鼠 VMC。感染病毒后 9～ 12 d病变达到高峰 ,检出率达 10 0 %。 TUNEL法检测发现 ,感染后 7～ 15 d,小鼠心肌中可见明显的心肌及炎细胞凋亡 ,5 0 d时可见少数散在的凋亡的心肌细胞。感染鼠心肌可见穿孔素 (perforin)、granzyme B、caspase- 8和 Bax蛋白异常表达。阳性细胞分布区域与凋亡细胞分布区域基本一致 ,表达量的动态改变与炎性损伤程度一致。双重荧光染色显示 ,病灶内部分 Bax阳性炎细胞可见凋亡染色。结论 穿孔素和 granzym e B在 VMC小鼠心肌炎性损伤过程中表达并参与细胞凋亡的调节。 caspase- 8及 Bax/ Bcl- 2比值升高与细胞凋亡有关。

Objective To explore the mechanisms of apoptosis in mice myocaditis induced by CVB_ 3m .Methods BALB/C mice were inoculated with 0.1ml 100 TCD_ 50 CVB_ 3m and batch sacrificed later.Histologic,immunohistochemical observations including TUNEL labeling method,and dual fluorescent labeling techniques were performed on mice hearts,and the results were detected by a confocal laser scanning microscopy.Results The myocarditis were detected from all 100% CVB_ 3m infected mice and were most severe at 7~12 days.Apoptosis also increased markedly in inflammatory cells and myocyted at 9~15 days after infection.Immunoreactivities for perforin,granzyme B,caspase-8 and Bax increased considerably in myocardium after infection,and decreased gradually after 20 days,as inflammation subsided.No significant differences were observed in hearts of infected mouse as compared to controls for Bcl-2.Double staining for Bax demonstrated apoptosis in some inflammatory cells.Conclusions The perforin and granzyme B take part in the regulation of myocyte damage and apoptosis in mice myocarditis.Our data suggest that increases of reaction of Caspase-8 and Bax/Bcl-2 was related to apoptosis.