砷剂作用下大鼠肝癌的形态学及细胞动力学变化

THE MORPHOLOGICAL AND CELLULAR DYNAMIC CHANGES IN ARSENIC TRIOXIDE TREATED RAT LIVER CANCER

目的 研究砷剂对大鼠体内实验性肝癌的治疗作用及其作用机制。方法 选择健康Wistar大鼠 ,以二乙基亚硝胺 (DEN)灌胃制备大鼠肝癌模型。以三种浓度的As2 O3 溶液注射于大鼠腹腔 ,每日 1次 ,2周后改为每周 2次 ,总给药时间为 4周 ;设治疗对照组 (顺铂 )及空白对照组 (NS)。治疗开始第 7、14、2 8天获取肝肿瘤结节组织 ,HE染色 ,光镜下观察肝脏组织形态学变化 ;流式细胞仪检测肿瘤细胞动力学变化。结果 砷剂引起大鼠体内肝癌细胞凋亡率上升 (P <0 0 5 ) ,中等剂量砷剂组 (1mg/kg)上升明显 (P <0 0 0 1) ;S期百分率 (SPF)明显下降 (P <0 0 1)。大剂量砷剂 (5mg/kg)致肝癌细胞凋亡数量增多 ,但同时出现大量坏死 ,引发炎症反应 ,细胞增殖指数 (PI)明显下降 ,DNA指数 (DI)明显上升 ;中等剂量砷剂引起G2 /M期细胞数明显增多 ,且大量发生凋亡 ,癌细胞坏死少见 ;小剂量砷剂引起凋亡率上升 ,但强度明显减弱。结论 砷剂治疗大鼠肝癌有效 ,可诱导大鼠肝癌细胞凋亡 ,但存在最适剂量问题 ,剂量过高可致细胞毒杀伤作用 ;砷剂抑制肝癌细胞增殖 ,并呈剂量—时间相关性 ;一定剂量的砷剂使细胞周期阻滞于G2 /M期 ;间断腹腔给药 。

Objective To study the efficiency of the treatment of experimental hepatocellular carcinoma in rats with arsenic trioxide and to elucidate the possible mechanism.Methods Wistar rats were fed with diethylnitrosamine (DEN) to induce HCC, then treated with As 2O 3. The histological changes in liver tissue were observed under microscope, and the cellular dynamic parameters were studied by flow cytometry. Results Treatment with As 2O 3 caused HCC cells death via both apoptotic and non apoptotic mechanisms when the dose was high (5 mg/kg), the necrosis was seldom and apoptosis was common when the dose was appropriate (1 mg/kg). Proliferation index (PI) decreased sharply in high dose (5 mg/kg) group ( P <0 01), but not in other two (1 mg/kg, 0 2 mg/jg) groups ( P >0 05). However, S phase fraction (SPF) decreased dramatically in all three groups ( P <0 01). Although apoptosis of HCC cells was common in all three groups, it reached the top only when the dose (1 mg/kg) was appropriate ( P <0 001), and it was obviously accompanied with accumulation of cells in G 2/M (G 2/M restriction). Conclusion These date demonstrate that arsenic trioxide induces apoptosis of rat HCC cells, and it is closely associated with G 2/M restriction when apoptosis reaches the top. The data also suggest that arsenic trioxide can inhibit cell proliferation, which is dose dependent and time dependent. The fact that continuous intermittent i.p. injection of arsenic trioxide can also be effective may afford a novel way to use the drug more safely.