摘要目的 探讨表没食子儿茶素没食子酸酯(epigallocatechin-3-gallate,EGCG)对微囊藻毒素LR(microcystin-LR,MC-LR)诱导小鼠肝细胞氧化损伤的化学拮抗作用及细胞色素P450 2E1(eytochrome P450 2E1,CYP2E1)表达的影响.方法 24只无特定病原体(specific pathogen free,SPF)级雄性BALB/c小鼠数字表法随机分为对照组、MC-LR染毒组、EGCG低剂量拮抗组、EGCG高剂量拮抗组,每组6只,持续暴露14 d.第15天处死小鼠,对肝脏脏体比、病理改变、抗氧化酶及脂质过氧化物水平、CYP2E1基因和蛋白表达进行检测和分析.结果 (1)EGCG可拮抗MC-LR所致小鼠体重下降,减轻MC-LR造成的肝脏病理损伤.(2)MC-LR染毒组小鼠脂质过氧化物丙二醛(malonaldehyde,MDA)水平[(2.87±0.03)nmol/mg prot]、超氧化物歧化酶(superoxide dismutase,SOD)水平[(168.18±2.86)U/mg prot]与EGCG两处理组相比,差异均有统计学意义[低、高剂量组MDA值分别为(2.37±0.05)、(1.44±0.05)nmol/mg prot,F=906.63,P<0.01;SOD值分别为(176.55±2.98)、(184.89±1.53)U/mg prot,F=32.32,P<0.01].(3)MC-LR可显著上调CYP2E1mRNA和蛋白表达平均吸光度值(CYP2E1 mRNA表达水平:MC-LR染毒组为1.41±0.26,对照组为0.86±0.13,t=-4.22,P=0.003;蛋白表达水平:MC-LR染毒组为0.24±0.03,对照组为0.12±0.02,t=-9.21,P<0.05),EGCG可显著降低该表达(低、高剂量组CYP2E1 mRNA表达水平分别为1.09±0.08、0.99±0.09,与MC-LR染毒组比较,F=9.03,P=0.004;蛋白表达水平分别为0.21 ±0.03、0.14±0.02,与MC-LR染毒组比较,F=24.76,P<0.05).结论 EGCG可抑制MC-LR诱导CYP2E1的表达,对MC-LR诱导的肝细胞氧化损伤有一定拮抗作用.

abstractsObjective To evaluate the effects of antagonistic action of epigallocatechin-3-gallate(EGCG) on microcystin LR (MC-LR) induced oxidative damage on mice and the expression of cytochrome P450 2E1 ( CYP2E1 ) which was one of phase Ⅰ detoxification enzymes. MethodsA total of 24 specific pathogen free(SPF) male BALB/c mice were randomly divided into four groups,including control group,MC-LR group,low concentration EGCG group, and high concentration EGCG group. Mice were sacrificed on the 15th day, body weight, and the relative organ weight, liver antioxidant enzyme level and lipid peroxidation product, liver histopathology and CYP2E1 gene and protein expression were detected and analyzed respectively. Results( 1 ) EGCG could antagonise the liver injury which had been damaged by MC-LR.(2) The malonaldehyde (MDA) level ( (2. 87 ±0. 03 ) nmol/mg prot)and superoxide dismutase(SOD) level((168. 18±+2. 86) U/mg prot)in MC-LR group were significantly different when compared with the two EGGG treatment groups ( the MDA values of the low and high concentration EGCG group were (2. 37±0. 05) nmol/mg prot and ( 1.44±0. 05 ) nmol/mg prot, F = 906. 63, P < 0. 01 ; the SOD values were(176.55+2.98) U/mg prot and (184.89±1.53) U/mg prot, F=32.32,P<0.01). (3) MC-LR up-regulated the mRNA and protein expression of CYP2E1 ( the mRNA values of MC-LR group and control were 1.41±0. 26,0. 86±0. 13, t = - 4. 22, P = 0. 003 ; the protein values of MC-LR group and control were 0. 24±0. 03,0. 12±0. 02 ,t = - 9. 21 ,P < 0. 05 ). EGCG down-regulated the mRNA ( the values of the low and high concentration EC, CG group were 1.09±0. 08,0. 99±0. 09, F = 9. 03, P = 0. 004 ) and protein expression (the values of the low and high concentration EGCG group were 0. 21±0. 03,0. 14±0. 02,F =24. 76 ,P < 0. 05 )of CYP2E1 which activated by MC-LR. ConclusionThe up-regulation of CYP2E1 which induced by MC-LR was inhibited by EGCG intervention. EGCG might antagonize the oxidation damage of hepatocytes in a certain degree.