表没食子儿茶精的小鼠急性肝损伤和代谢动力学的性别差异

Gender role in acute hepatotoxicity and pharmacokinetics of epigallocatechin gallate in mice

目的从对表没食子儿茶精(EGCG)药物代谢动力学差异性角度,探索EGCG导致小鼠急性肝损伤的性别差异。方法小鼠ip给予EGCG 300 mg·kg-1后,采用试剂盒检测小鼠血清酶谷丙转氨酶(GPT)、乳酸脱氢酶(LDH)、琥珀酸脱氢酶(SDH)和鸟氨酸氨基甲酰转移酶(OCT)的活性变化,荧光酶标仪检测肝线粒体膜电位变化,反相高效液相色谱法分析EGCG的血药浓度,荧光免疫组织化学法检测小鼠肝细胞中羧酸酯酶Ⅱ含量。结果小鼠ip给予EGCG后,雌雄小鼠血清中GPT和LDH均显著升高(P<0.05),雌性较雄性小鼠升高显著(P<0.01),SDH和OCT活性变化均不显著。雌性小鼠肝细胞线粒体膜电位变化较雄性小鼠显著(P<0.05)。HE肝组织学观察显示,雌性和雄性小鼠肝组织形态变化均不明显。但电子显微镜组织学观察表明,雌性小鼠肝细胞线粒体溶胀、裂解及电子密度增加均较雄性显著。雄性小鼠较雌性对EGCG代谢迅速,消除半衰期较短。代谢酶鉴定结果表明,羧酸酯酶Ⅱ为EGCG发生水解反应的主要酶类。荧光免疫组织化学法研究表明,羧酸酯酶Ⅱ在雄性小鼠体内含量较雌性高。结论 EGCG导致雌性小鼠急性肝损伤比雄性小鼠严重。

OBJECTIVE To investigate the possible mechanism and sex-dependence of hepatotoxicity induced by epigallocatechin gallate（ EGCG） after administration by intraperitoneal injection. METHODS ICR mice were ip given EGCG 300 mg·kg^-1. Their plasma enzyme activity and mitochondrial membrane potential（ MMP） were detected and used as indicators of hepatic damage. Liver histology was examined by light and electron microscopy. Then,the sex-dependent toxicokinetics and expression of carboxylesteraseⅡ were both determined. RESULTS Glutamic-pyruvic transaminase（ GPT） and lactate dehydrogenase（ LDH） values significantly increased in serum of mice. GPT increased more significantly in female mice than in male mice. However,the succinic dehydrogenase（ SDH） and ornithine carbamyl transferase（ OCT） values in serum did not increase significantly between female and male mice. EGCG also contributed to the changes in MMP in the livers of female and male mice after intraperitoneal injection. MMP increased more in female mice than in male mice. Although liver slices stained with hematoxylin and eosin revealed few necrotic cells in male and female mice,liver histology examined by an electron microscope demonstrated that EGCG produced severe hepatic damage at the subcellular level. Sexdifferent toxicokinetics showed faster elimination of EGCG in male mice than in female ones. EGCG was mainly metabolized by hydrolysis and carboxylesteraseⅡ was determined to be the main metabolic enzyme in mice. Immunohistochemistry detection showed that the protein expression of carboxylesteraseⅡ was very lower in female mice than in male ones. CONCLUSION EGCG produces more severe hepatotoxicity in female mice than in male ones.