甲基汞在脑组织中的积累和脂质过氧化作用

Methylmercury Accumulation in Brain and Lipid Peroxidation in Rats

[目的]通过对SD大鼠进行腹腔注射氯化甲基汞 ,研究不同时间、不同剂量氯化甲基汞在大鼠脑组织中的积累情况和对大鼠脑组织的脂质过氧化作用及两者之间可能存在的关系。[方法]将SD大鼠在不同剂量 (0 ,0.05 ,0.5 ,5mg/kg)下分别暴露20min和24h。处死后测定脑组织汞含量、谷胱甘肽过氧化物酶 (GSH_Px)、超氧化物歧化酶 (SOD)活性和丙二醛 (MDA)含量。[结果]20min时 ,0.5mg/kg剂量下脑组织汞含量为 (0.0173±0.0230) μg/g,表明甲基汞已到达脑组织 ;20min时 ,各剂量下各脂质过氧化指标与对照组相比均未见显著差异。24h时 ,5mg/kg剂量下 ,GSH_Px活性为 (19.13±4.49)U/mgprot,SOD活性为 (89.09±13.55)U/ml,MDA含量为 (3.53±0.70)nmol/ml,与对照相比差异显著 ,表明已有脂质过氧化发生。[结论]甲基汞对脑组织有极大的亲合性 ,在0.5mg/kg剂量下 ,20min即可迅速穿过血脑屏障进入脑组织并逐渐积累。脂质过氧化作用是在甲基汞积累到一定程度后发生的 。

In order to study effects of methymercury chloride on lipid peroxidation in rats,the accumulation of merˉcury in brain,and the relationship between them in rats given by ip injection of methylmercury chloride. The rats were exˉposed to methylmercury at different doses(0,0.05,0.5,5mg/kg)for20minutes and24hours,and then mercury was determined in the brain,the activity of SOD,GSH_Px and the content of MDA were also determined.The results showed that after exposure for20minutes,in the group of0.5mg/kg,0.0173±0.0230μg Hg/g wet organ was accumulated in the brain,but all lipid peroxidation indexes at all doses haven't shown any changes distinctively.After exposure to methylmercury for24hours,the activity of GSH_Px was19.31±4.49U/mg protein,the activity of SOD was80.09±13.55U/ml,and the content of MDA was3.53±0.70nmol/ml in5mg/kg dose group,the results showed distinctive changes,compared with the control group.[Conclusion]Methylmercury can easily peneˉtrate through the brain_blood barrier and accumulate in the brain.Lipid peroxidation may occure after mercury reached brain to some exˉtent.Lipid peroxidation is perhaps related to the accumulation of mercury in brain.