熊果酸对荷人骨肉瘤裸小鼠移植瘤生长的影响

The effects of ursolic acid on xenografts growth in osteosarcoma of nude mice

目的:研究熊果酸(ursolic acid,UA)对荷人骨肉瘤裸小鼠移植瘤生长的抑制作用及其机制探讨。方法:采用裸小鼠背部皮下注射接种人骨肉瘤MG-63细胞的方法建立荷人骨肉瘤裸小鼠模型并给予不同剂量熊果酸[5、10、20mg/(kg·d)]和顺铂[2mg/(kg·d)]进行干预治疗,疗程5天。称取瘤重并计算抑瘤率,HE染色观察肿瘤组织形态结构改变。TUNEL染色检测细胞凋亡状况并计算细胞凋亡指数(apoptosis index,AI)。免疫组织化学染色(immunohistochemistry,IHC)观察肿瘤组织中caspase-3、Bax、bcl-2蛋白表达并进行半定量分析。结果:较模型组,熊果酸干预组荷人骨肉瘤裸小鼠移植瘤呈现细胞皱缩、片状坏死等病理性改变,凋亡细胞数量明显增多、AI显著升高,瘤体重量显著减轻、抑瘤率显著升高,caspase-3和Bax蛋白表达显著上调,bcl-2蛋白表达显著下调,Bax/bcl-2比值显著升高,熊果酸上述作用均具有一定的剂量依赖性。结论:熊果酸可能通过促进肿瘤细胞凋亡而对荷人骨肉瘤裸小鼠移植瘤生长起到一定的抑制作用,其作用机制可能与熊果酸能够调节凋亡相关蛋白(caspase-3、Bax、bcl-2)并提高Bax/bcl-2比值有关。

Objective：To investigate the effects of ursolic acid（ UA） on xenografts growth in osteosarcoma of nude mice. Methods：Nude mice models bearing human osteosarcoma were made by injecting inoculation human osteosarcoma cancer MG- 63 cell line and were treated with different concentrations of UA [5,10,20 mg /（ kg·d） ]and cisplatin（ 2mg / kg） for 5 days,once a day. The histopathological changes of tumor tissue was observed by HE staining. The tumor cells apoptosis was detected by TUNEL. The expression of caspase- 3,Bax,bcl- 2 protein were detected by IHC and were semi- quantitative analyzed. Results：Compared with model group,the necrosis presentation,tumor cell shrinkage and other pathological morphological changes appeared. The number of apoptotic cells in tumor tissue of UA treated groups were significantly increased. The tumor weight were decreased and the inhibition rate were increased.The expression of Bax and caspase- 3 were significantly increased and the bcl- 2 protein was significantly decreased,and the ratio of Bax / bcl- 2 were significantly increased. All of the effects of UA above were dose- dependent with a certain. Conclusion：UA had inhibitive effects on xenografts growth in osteosarcoma cancer of nude mice perhaps through depressing apoptosis,which perhaps related to its effects of regulating the expression of apoptosis- related proteins（ caspase- 3,Bax,bcl- 2） and increasing the ratio of Bax / bcl- 2.