中文摘要：

为研究六价铬（Cr（Ⅵ））对生物体的细胞凋亡以及凋亡相关蛋白的改变，用0、25、50和100mg·kg^-1的重铬酸钾（K2Cr2O7）对小鼠进行1d或持续5d灌胃，检测肝脏细胞凋亡以及p53、Bcl-2、Bax蛋白表达水平和caspase-3酶的激活．实验结果显示，Cr（Ⅵ）染毒1d或5d后，小鼠肝细胞凋亡率随染毒剂量的增加而增加，并呈明显的剂量-反应关系；p53、Bax蛋白表达升高，Bcl-2蛋白表达下降，caspase-3酶激活增加，且p53、Bcl-2蛋白表达水平和caspase-3酶激活水平在100mg·kg^-1剂量组的2个染毒时间段与对照组相比均具有显著性差异，Bax蛋白表达水平仅在100mg·kg^-1染毒5d的实验组与对照组相比具有显著性差异．结果表明，Cr（Ⅵ）能诱导小鼠肝脏细胞凋亡，p53、Bcl-2、Bax和caspase-3在这个过程中可能起重要作用．

英文摘要：

To explore apoptosis and the change of apoptosis-related proteins in organisms induced by hexavalent chromium, mice were administered by oral garage with potassium dichromate at a dose of 0, 25, 50 or 100 mg·kg^-1 once daily for 5 consecutive days. One day and five days after treatment the animals were sampled and the changes of apoptosis as well as p53, Bcl-2, Bax protein expression and caspase-3 activation in the liver were measured. Results showed that dose- dependent increased apoptotic rates were observed after 1 day or 5 days of Cr（Ⅵ） exposure. Expression of p53 and Bax protein and activation of caspase-3 increased, and expression of Bcl-2 protein decreased after 1 day or 5 days of exposure. Furthermore, significant differences were observed on the p53, Bcl-2 expression level and caspase-3 activation level at 100 mg·kg^-1 at both timepoints as compared to the control animals. A significant increase in Bax protein expression level was observed only at 100 mg·kg^-1 after 5 days of exposure. Results indicated that Cr（Ⅵ） could induce apoptosis in mice liver, and p53, Bcl-2, Bax, caspase-3 may play an important role in this process.