Bax蛋白在大鼠肝癌发生过程中的表达和意义

通过动态观察Bax蛋白在实验性大鼠肝癌发生过程中肝细胞的表达，探讨Bax蛋白与肝癌发生的关系及其生物学意义。用DEN饲喂大鼠，分别于第4、8、12、16、18周处死大鼠，取其肝脏，石蜡切片，ABC法免疫组织化染色。结果显示：正常成年大鼠肝细胞均有中等程度Bax蛋白表达。至诱癌第4周大鼠肝小叶内有少数肝细胞呈Bax蛋白免疫阳性反应，随诱癌发展进程，呈Bax蛋白免疫阳性反应肝细胞进一步减少，第12周，只可见肝细胞增生结节的多数肝细胞呈Bax蛋白免疫阳性反应。诱癌晚期（第18周），癌结节内肝癌细胞均呈Bax免疫反应阳性，其强度较正常肝细胞明显增强，Bax蛋白免疫反应产物为胞质内粗大的棕褐色颗粒。部争肝细胞胞质和胞膜均呈阳性，肝癌细胞最为常见。结果表明：Bax蛋白表达减少或缺失是肝癌发生过程中的早期事件，可能参与肝癌的启动过程。

THE EXPRESSION AND SIGNIFICANE OF BAX PROTEIN DURING HEPATOCARCINOGENESISIN THE RATS

To explore the relation between Bax protein and carcinogenesis of liver and its biological significance, a dynamical observation of the expression of Bax protein was made during the experimental hepatocarcinogenesis of rats.The rats were fed with diethylnitrosamine ( DEN) and killed in 4,8,1 2 ,1 6 and 1 8th week respectively.The liver of rats was removed and embeded by paraffin and stained by using immunohistochemical ABC method.The result showed thatthe expression of Bax protein was detected in all hepatocytes of normal rats.A few of Bax- protein- positive hepatocytes were detected in4th week after DEN treatment.Along with the process of carcinogenesis,the number of hepatocytes expressing Bax protein decreased progressively.But the majority of hepatocytes in the neoplastic nodules expressed Bax protein at1 2 th week.All the malignanthepatocytes in the hepatocellularcarcinoma expressed Bax protein at 1 8th week.The immunoreactive product was shown as brown colored granules in the cytoplasm.The expression of Bax protein in the malignant hepatocytes was higher than that in normal control.Our observation suggests that the decrease or deletion of Bax protein might be related to the occurence of hepatocarcinoma.