姜黄素对汞染毒大鼠肾核转录相关因子2及相关抗氧化酶表达的影响

Effect of curcumin on expressions of Nrf2 and antioxidant enzymes in kidney of rats exposed to mercury

目的探讨姜黄素对汞致大鼠肾损伤的影响,为汞中毒的发病机制和防治提供实验依据。方法将30只清洁级Wistar大鼠按体重随机分为5组,分别为对照(生理盐水)组和2.2、4.4、8.8μmol/kg氯化汞染毒组及姜黄素干预(8.8mol/kg氯化汞+100 mg/kg姜黄素)组,每组6只,雌雄各半。采用腹腔注射方式染毒氯化汞,染毒容量为5 ml/kg;采用皮下注射方式染毒姜黄素,染毒容量为1 ml/kg,每天1次,连续染毒3 d。测定肾皮质汞含量、肾皮质细胞ROS水平和细胞凋亡率及肾皮质Nrf2、HO-1、γ-GCS和Gpx-1 mRNA和蛋白的表达水平。结果与对照组比较,各剂量氯化汞染毒组和姜黄素干预组大鼠肾皮质汞含量和细胞凋亡率均升高,4.4、8.8μmol/kg氯化汞染毒组和姜黄素干预组大鼠肾皮质细胞ROS水平均升高,差异有统计学意义(P<0.05,P<0.01)。与对照组比较,各剂量氯化汞染毒组和姜黄素干预组大鼠肾皮质Nrf2、HO-1、γ-GCS mRNA的表达水平均升高,而Gpx-1 mRNA的表达水平均降低,除2.2μmol/kg氯化汞染毒组HO-1、GPx-1mRNA的表达水平及姜黄素干预组GPx-1 mRNA的表达水平外,差异均有统计学意义(P<0.05,P<0.01)。与对照组比较,各剂量氯化汞染毒组和姜黄素干预组大鼠肾皮质Nrf2、HO-1、γ-GCS蛋白的表达水平均升高,而Gpx-1蛋白的表达水平均降低,除2.2μmol/kg氯化汞染毒组γ-GCS蛋白的表达水平外,差异均有统计学意义(P<0.05,P<0.01)。且随着氯化汞染毒剂量的升高,大鼠肾皮质汞含量、ROS水平和细胞凋亡率及肾皮质Nrf2、HO-1、γ-GCS蛋白和mRNA的表达水平均呈上升趋势,而GPx-1蛋白的表达水平呈下降趋势。与8.8μmol/kg氯化汞染毒组比较,姜黄素干预组大鼠肾皮质ROS水平和细胞凋亡率均下降,差异有统计学意义(P<0.01),而肾皮质汞含量无明显改变;肾皮质Nrf2、HO-1、γ-GCS和GPx-1mRNA的表达水平均升高,差异有统计学意义(P<0.01);肾皮质γ-GCS、HO-1蛋白的表达水平均升高,而Nrf2、GPx-1蛋白的表达水平降低,差异有统计学意义(P<0.01)。结论姜黄素可通过激活Nrf2信号通路对汞致大鼠肾损伤产生一定的拮抗作用。

Objective To explore the protective effect of curcumin on renal damage induced by mercury in rats. Methods Thirty Wistar rats with equal numbers of male and female were randomly divided into five groups, including the control group,mercury treatment groups（2.2, 4.4, 8.8 μmol/kg HgCl_2 body weight）,and curcumin pre-treatment group（8.8 μmol/kg HgCl_2 body weight ＋100 mg/kg curcumin body weight）. The rats in control group and mercury treatment groups were treated with intraperitoneal injection with saline, and the rats in curcumin pre-treatment groups were subcutaneously injected with 100 mg/kg curcumin body weight. The volume of injection was 1 ml/kg. Two hours later,intraperitoneal injection of HgCl_2 was performed. The volume of injection was 5 ml/kg, curcumin pre-treatment or HgCl_2 exposure were given every day, for three consecutive days. Twenty-four hours after the last treatment, the mercury level in renal cortex, the intracellular ROS, apoptosis rate and the mRNA and protein expressions of Nrf2,HO-1,γ-GCS,GPx-1 were all determined. Results Compared with the control group,with the mercury exposure increased,the mercury level and apoptosis rate, and the ROS levels expression in renal cortex of 4.4 and 8.8 μmol/kg HgCl_2 groups and the curcumin pre-treatment group were all increased significantly（P〈0.05 or P〈0.01）. Compared with the control group, the mRNA expressions of Nrf2,HO-1 and γ-GCS were all increased, while the mRNA expression of Gpx-1 decreased significantly, except the mRNA of HO-1 and Gpx-1 expression in renal cortex of2.2 μmol/kg HgCl_2 group and the mRNA of Gpx-1 expression in renal cortex of incurcumin pre-treatment group（P〈0.01 or P〈0.05）. Compared with the control group, the protein expressions of Nrf2,HO-1 and γ-GCS were all increased,while the protein expression of Gpx-1 decreased significantly, except the protein of HO-1 and Gpx-1 expression in renal cortex of 2.2μmol/kg HgCl_2 group and the protein of Gpx-1 expression in renal cortex of curcumin pre-treatment group（P〈0.01 or P〈0.05）.Compared with the 8.8 μmol/kg HgCl_2 group,the ROS level,apoptosis rate,the protein expressions of Nrf2 and Gpx-1 significantly decreased, the mRNA expressions of Nrf2,HO-1,γ-GCS and Gpx-1, the protein expressions of HO-1 and γ-GCS significantly increased,the mercury level showed no significantly variation, in renal cortex of the curcumin pre-treatment group（P〈0.01）. Conclusion Curcumin has a protective effect on mercuric chloride-induced renal damage in rats.