齐墩果酸对铅致血脑屏障紧密连接损伤的保护作用

Protective Effect of Oleanolic Acid on Lead-induced Blood-brain Barrier Tight Junctional Injury

目的探讨生长发育期铅暴露对大鼠血脑屏障损伤的作用以及齐墩果酸的拮抗作用,并探讨铅对血脑屏障损害的分子机制.方法用醋酸铅饮水法建立生长发育期大鼠铅中毒模型,在铅暴露同时给予齐墩果酸进行干预.实验分为4组:对照组、齐墩果酸组、齐墩果酸+Pb组和Pb组.染毒结束后,应用Morris水迷宫法和旷场实验检测大鼠的神经行为变化,原子吸收光谱法检测血液和脑铅含量,蛋白免疫印迹法检测血脑屏障TJ相关蛋白ZO-1,Claudin-5,JAM-A的表达.结果染铅鼠血铅和脑铅含量明显高于对照组(P<0. 05),染铅组大鼠空间探索和学习记忆能力明显低于对照组(P<0. 05),ZO-1,Claudin-5,JAM-A蛋白表达水平低于对照组(P<0. 05).而齐墩果酸可明显改善染铅鼠的血脑屏障损伤效应,与单独染铅组比较,齐墩果酸+Pb组大鼠血铅和脑铅含量升高,大鼠空间探索和学习记忆能力增强,但差异不显著(P>0. 05); ZO-1,Claudin-5,JAM-A蛋白表达水平升高,与染铅组比较差异显著(P<0. 05).结论生长发育期铅暴露可损害大鼠血脑屏障的紧密连接,使铅蓄积于脑组织,产生神经毒效应,齐墩果酸对铅的神经毒效应具有一定保护作用,能改善血脑屏障功能.

Objective To investigate the effect of lead exposure on blood-brain barrier in rats during growth and development and the antagonism of oleanolic acid,and to explore the molecular mechanism of lead damage to blood-brain barrier.Method The lead poisoning rat model was established during the growth and development period of drinking lead acetate,and the oleanolic acid was also given to the lead exposure.The experiment was divided into 4 groups:control group,oleanolic acid group,oleanolic acid+Pb group and Pb group.After the end of the poison,Morris water maze test and open field test were used to detect the neurobehavioral changes in rats.Atomic absorption spectroscopy was used to detect blood and brain lead content.Western blot was used to detect the expression of blood-brain barrier TJ-related proteins ZO-1,Claudin-5,JAM-A.Results Compared with the control group,the blood and brain lead levels of lead-exposed rats were significantly higher(P<0.05).The spatial exploration and learning and memory ability of lead-exposed rats were significantly lower(P<0.05).ZO-1,Claudin-5,JAM-A protein expression level was lower(P<0.05).Oleanolic acid significantly improved the blood-brain barrier damage in lead-exposed mice.Compared with the lead-exposed group alone,the blood lead and brain lead levels in the oleanolic acid+Pb group increased,and the spatial exploration and learning and memory abilities were increased,but the difference was not significant(P>0.05).ZO-1,Claudin-5,JAM-A protein expression levels also increased in OA+Pb group,the difference was significant compared with Pb group(P<0.05).Conclusion Exposure to lead during growth and development may impair the tight junction of the blood-brain barrier in rats,causing lead accumulation in the brain and producing neurotoxic effects.Oleanolic acid has a protective effect on the neurotoxicity of lead and improves blood-brain barrier function.