饮水铅暴露对大鼠不同脑区铁、锌、锰和铜含量的影响

Effects of Lead Exposure through Drinking Water on Content of Iron,Zinc,Manganese and Copper in Differen Encephalic Regions of Rats

目的探讨不同时间和不同浓度铅暴露对SD大鼠不同脑区铁、锌、锰和铜含量的影响。方法将36只健康初断乳(21d龄)清洁级SD大鼠随机分成3组,分别为低(400mg/L)、高(800mg/L)浓度铅染毒组和对照(去离子水)组,每组12只,雌雄各半。采用自由饮水方式进行染毒,日饮水量为100ml/kg,连续染毒8周。分别于染毒4、8周,取脑,测定额叶、颞叶、顶叶、海马四个脑区铅、铁、锌、锰和铜的含量。结果染毒4、8周时,各脑区铅含量高于对照组;与染毒4周比较,染毒8周时大鼠额叶和颞叶两脑区铅含量较高(P<0.05)。染毒4周时高浓度染毒组顶叶和海马铅含量高于低浓度染毒组,差异有统计学意义(P<0.05);染毒8周时高浓度铅染毒组顶叶和海马两脑区铅含量虽高于低浓度铅染毒组,但差异无统计学意义。脑铁含量随铅染毒浓度的增加而升高,脑铁含量与脑铅含量呈正相关(r=0.452,P<0.01);脑锌含量随着铅染毒浓度的增加而降低,脑锌含量与脑铅含量呈负相关(r=-0.357,P<0.05)。顶叶和海马铁含量随染铅时间的延长而呈统计学意义的增加,而额叶和颞叶锌随染铅时间的延长而呈统计学意义的降低。铅染毒大鼠脑锰、脑铜含量无变化,差异无统计学意义。结论铅染毒使SD大鼠脑铅和脑铁含量升高,脑锌含量降低,对脑锰、脑铜含量无影响。

Objective To explore the effects of different time and dosage lead exposure through drinking water on the content of iron, zinc, manganese and copper in different encephalic regions of SD rats. Methods Thirty-six SD rats of clean grade, aged 21 days, were randomly divided into three groups, 12 in each and treated with lead acetate at the doses of 0, 400 mg/L and 800 mg/L respectively through drinking water. After 4 or 8 weeks of treatment with lead, rats were sacrificed and the brains were removed, and four encephalic regions （the frontal lobe, temporal lobe, parietal lobe and hippocampus） were separated. Coupled plasma-atomic emission spectrophotometry （ICP-AES） was employed to determine the contents of leacl （Pb）, Fe, Mn, Cu, Zn in four encephalie regions respectively. Results After the rats were exposed to lead for 4 or 8 weeks,lead contents in four encephalic regions were higher compared with the control. In 8 weeks group, lead contents in the frontal lobe, temporal lobe were higher compared with that in 4 weeks group, with a time-dependent manner, while lead contents in parietal lobe and hippocampus did not increase. The iron contents in the brain increased and the zinc contents decreased as the lead exposure dose increased. In different encephalie regions, the changes of the iron and zinc contents were not the same. Iron contents of parietal lobe and hippoeampus increased, while zinc contents of frontal lobe, temporal lobe decreased with time. Lead-exposure had no significant effects on manganese and copper contents in rat brain. Conclusion Lead exposure may increase the contents of lead and iron in the brain of SD rats, meanwhile decrease the content of zinc in degrees in different encephalic regions.