草苁蓉环烯醚萜苷对二乙基亚硝胺诱发肝癌大鼠细胞凋亡的影响

目的观察二乙基亚硝胺（DEN）诱发大鼠肝癌的病理变化，探讨草苁蓉环烯醚萜苷（IGBR）对细胞凋亡的作用及对p53、Bcl-2蛋白表达的影响。方法132 只Wistar雄性大鼠随机分为对照组、模型对照组、阳性对照组及IGBR 组。除对照组，各组大鼠给予DEN 0.2 g/kg 腹腔注射1 次，而后0.05%的DEN 水溶液用于自由饮水；阳性对照组腹腔注射5- 氟尿嘧啶（5-FU）0.025 g/kg 每周3 次；IGBR 组每日IGBR 0.5 g/kg 灌胃1次。实验第12、20及28周末，分批处死动物，观察肝脏病理变化及细胞凋亡，免疫组织化学法和Western blot检测p53、Bcl-2 的表达。结果与对照组比较，模型对照组肝细胞核大且深染，肝细胞变性、异型增生，有些增生灶可见癌变细胞。凋亡的肝细胞皱缩、核固缩及核仁消失。IGBR组与阳性对照组凋亡指数高于模型对照组，差异有统计学意义（P <0.05），但两组比较差异无统计学意义（P >0.05）。免疫组织化学结果，p53 和Bcl-2 阳性细胞主要分布于不典型增生灶和癌灶的胞浆中。与模型对照组比较，IGBR 组和阳性对照组p53 表达强度增强，而Bcl-2 表达强度减弱，差异有统计学意义（P <0.05），IGBR 组和阳性对照组比较，差异无统计学意义（P >0.05）。结论大鼠肝癌发生与细胞凋亡相关，IGBR通过调控p53、Bcl-2 来抑制DEN 诱发大鼠肝癌。

Effect of Iridoid Glucosides from Boschniakia Rossica on rat models of diethylnitrosamine-induced hepatocarcinomat

Objective To investigate the effect of Iridoid Glucosides from Boschniakia Rossica (IGBR) on apoptosis and the expression of p53 and Bcl-2 proteins. Methods A total of 132 Wistar male rats were randomly divided into control group, model group, positive control group and IGBR group. DEN was administered once by intraperitoneal injection (0.2 g/kg), then through drinking water (0.05%) for the rest of experimental duration in each group except for the control group. Animals from the positive control group was injected with 5-FU 3 times per week (0.025 g/kg). Rats in the IGBR group were treated intragastrically with IGBR daily (0.5 g/kg). Animals were sacrificed on 12, 20 or 28 weeks post insults. Pathological alterations and apoptosis of liver cells were observed and expression of p53 as well as Bcl -2 were determined by Immunohistochemistry and Western blot. Results Compared with the control group, the enlarged and deeply stained nuclei, hepatocellular degeneration, dysplasia and cancer cell were observed in the liver tissue of the model group. Apoptotic hepatocyte showed cytoplasmic and nuclear shrinkage without nucleolus.Immunohistochemistry results showed that p53 and Bcl -2 positive signals were mainly distributed in the cytoplasm of atypical hyperplasia and carcinoma. Expression of p53 increased while Bcl-2 decreased in the IGBR group as well as the positive control group significantly compared with the model group (P < 0.05). No obvious differences were observed between the IGBR group and the positive control group (P > 0.05). Conclusions Hepatocarcinoma is closely associated with apoptosis, and IGBR inhibits DEN -induced hepatocarcinoma through mediating p53 and Bcl-2 pathway.