绿茶对微囊藻毒素LR诱导肝细胞凋亡、Bcl_2表达及骨髓嗜多染红细胞微核的影响

Effect of Green Tea on Microcystin-LR-induced Hepatocelluar Apoptosis, Bcl-2 Expression and Micronucleus

背景与目的:研究绿茶(greentea,GT)对微囊藻毒素LR(MC-LR)诱导肝细胞凋亡、Bcl-2蛋白表达及微核发生的影响以探讨毒性拮抗机制。材料与方法:雄性小鼠50只随机分为5组,分别为空白对照、MC-LR染毒组、GT高低剂量拮抗组和环磷酰胺对照组。实验第1d起GT高、低剂量拮抗组小鼠每日分别给予12g/L和2g/L两种浓度的GT自由饮用,连续18d。自第6d开始,染毒小鼠每日给予MC-LR10μg/kg腹腔注射1次,空白对照给予DMSO腹腔注射,连续13d。环磷酰胺对照组以50mg/kg剂量间隔24h两次给药后6h取材。小鼠处死后采用免疫组化和计数法对肝细胞凋亡、Bcl-2蛋白表达以及骨髓嗜多染红细胞(PCEs)微核发生率进行检测和分析。结果:(1)MC-LR染毒明显诱导小鼠肝细胞凋亡增加。高剂量GT处理后明显抑制MC-LR染毒所致小鼠肝细胞凋亡的发生(P<0.05);(2)单纯MC-LR染毒肝细胞Bcl-2表达未见明显变化,GT各剂量组小鼠肝脏Bcl-2的表达明显增加,与MC-LR染毒组相比差异具有统计学意义(P<0.01)。(3)GT拮抗组小鼠骨髓嗜多染红细胞微核率(PCEs-MN)与MC-LR染毒对照和空白对照相比,其差异均无统计学意义(P>0.05)。结论:GT能上调抑癌基因Bcl-2的表达,抑制细胞凋亡。MC-LR染毒及GT拮抗对微核发生均未有显著影响。

BACKGROUND ＆ AIM： To evaluate the effects of green tea （GT） on Microcystin-LR （MC-LR）-induced hepatocelluar apoptosis, Bcl-2 expression and micronucleus test so as to explore antagonistic mechanism of GT. MATERIALS AND METHODS： 50 male mice were randomly divided into five groups. Mice in GT pretreated groups were given green tea as free drink at doses of 2 g/（L·d） and 12 g/（L·d） prior to MC-LR intoxication, consecutively for 18 days. The toxin treatment mice in group MC-LR control received continual intraperitoneal injections of MC-LR at dose of 10 μg/（kg·d） for 13 days from day 6 till sacrifice. CP control group was treated with intraperitoneal cyclophosphamide twice at dose of 50 mg/（kg · d） 24 h interval on days 17 and 18. Mice were sacrificed and immediately subjected to autopsy. Hepatocellular apoptosis, Bcl-2 protein expression and micronucleus frequencies of bone marrow were evaluated immediately. RESULTS： （1） MC-LR induced obvious hepatocellular apoptosis. High dose of GT pretreatment significantly inhibited MC-LR-induced hepatocellular apoptosis（P〈0.05） .（2） There was no significant change of Bcl-2 protein expression in MC-LR control compared with control. As compared with only MC-LR, the expression of Bcl-2 protein was significantly increased in GT pretreatment groups（P 〈 0.01）. （3） No significant difference in micronucleus frequencies was found in either MC-LR control or GT pretreatment groups compared with control （P 〉 0.05） . CONCLUSION： GT could increase Bcl-2 protein expression and inhibit hepatocellular apoptosis, MC-LR and GT pretreatment did not cause damage to mice chromosome.