低剂量无机汞宫内及哺乳期暴露对仔大鼠肝、肾和脑组织中谷胱甘肽抗氧化物酶系统的影响

Effects of low dose of inorganic mercury on glutathione antioxid ant enzyme system in liver, kidney and brain regions of infant rats after in utero and lactation exposure

目的 研究低剂量无机汞子宫内及哺乳期暴露对仔大鼠肝脏、肾脏及脑组织中谷胱甘肽抗氧化物酶系统的影响 ,探讨低剂量无机汞对子代发育潜在的毒性。方法 对怀孕d 0的母大鼠进行 0 .2mg·L- 1Hg2 +饮水染毒直至仔鼠出生后d 2 0断乳期。研究仔鼠肝脏、肾脏及脑区 (大脑、小脑、脑干、海马及其余脑组织 )中汞的分布及汞暴露对上述组织中总巯基含量、还原型谷胱甘肽 (GSH)水平及谷胱甘肽过氧化物酶 (GSH Px)活性的影响。结果汞暴露后仔鼠肾脏中汞的含量最高 ,其次是肝脏和脑组织。在所研究的仔鼠各脑区中 ,海马汞含量最高 ,其次是小脑和大脑。汞暴露组仔鼠肝脏和肾脏中巯基含量比对照组升高了 2倍 ,而脑区中汞暴露组巯基含量与对照组相比则降低至 1/ 2～ 1/ 3。汞暴露组仔鼠肝脏中GSH水平与对照组相比升高了6 5 % ,而在肾脏和脑组织中GSH的水平与对照组相比则显著降低 ,其中 ,汞暴露组仔鼠各脑区中GSH水平降低幅度与对照组相比均超过了 5 8%。除肝脏外 ,汞暴露组仔鼠肾脏和脑区中GSH Px活性明显下降。在脑组织中 ,除海马外 ,GSH Px活性在汞暴露组其他 4个脑区中的下降幅度均超过 80 %。结论 低剂量无机汞子宫内及哺乳期暴露对仔鼠肾脏 ,特别是对脑组织的正常发育造成了一定程度的危害 ;

AIM To investigate the effects of re- latively environmental l ow dose of inorganic mercury on glutathione antioxidant enzymes system in liver, kidney and brain regions of infant rats after their in utero and la ctation expo sure. METHODS The pregnant female rats were exposed to Hg 2+ at a dose of 0.2 mg·L -1 in drinking water from prenatal d 0 continued to po stnatal d 20. The distribution patterns of mercury contents in liver, kidney a nd brain regions of the offspring were analyzed and the total sulfhydryl content s, reduced glutathione(GSH) levels and activity of glutathione peroxidase(GSH-P x) were studied. RESULTS Mercury was accumulated mainly in infant k idney, and then followed by liver and brain regions after their in utero and lactation Hg 2+ exposure. As in the brain regions, the highest Hg content present in infant hippocampus, and then cerebellum and cerebrum. Mercury exposure induced total sulfhydryl content a 2-fold increase in the infant live r and kidneys compared with control group. On the contrary, total sulfhydryl in all the observed brain regions decreased. The level of GSH in liver of the Hg-e xposed group increased by 68% compared with control, while it reduced significan tly in kidney and brain regions. After such Hg exposure, the GSH level decreased more than 58% in the infant rat brain regions. The activity of GSH-Px in liver of the exposed group showed no substantial difference from the controls, howeve r, in kidney and brain regions, except in hippocampus, it decreased significantl y. In the brain regions, GSH-Px activities decreased by over 80% except in hipp ocampus. CONCLUSION Low dose inorganic mercury in utero and lactation exposure can significantly decrease the level of GSH and the acti vity of GSH-Px in kidney and brain regions, which suggest a potential risk to t he developing kidney and brain, however, the low level inorganic mercury exposur e seemed to have little oxidant effect on infant liver.