脉络丛对铅镉的屏护作用及其机理探讨

Sequestering Effect of Choroid Plexus on Lead and Cadmium and Exploration on Its Mechanism

目的 研究急性染铅或镉后其在中枢神经系统的分布和GSH、巯基含量的变化。方法 分别给兔腹腔注射不同剂量的醋酸铅或静脉注射不同剂量的氯化镉溶液 ,于 4h和 2 4h后处死动物。采集脑脊液、血液、侧脑室脉络丛、大脑皮质 ,肝脏和肾皮质样品 ,测定其中铅或镉含量以及GSH和巯基的含量。结果 发现脉络丛中的铅或镉含量明显增高 ,高于脑脊液、大脑皮质和血液。染铅后 4h脉络丛中GSH升高 ,但染铅后 2 4h明显降低。血液、大脑皮质 ,肝脏和肾皮质GSH含量在高剂量染铅后 2 4h也明显降低。染铅后巯基含量的变化不明显。低剂量染镉后 4hGSH的变化不明显 ,2 4h降低 ,高剂量染镉后随时间延长GSH明显降低 ;低剂量染镉后 2 4h ,脉络丛、血液、大脑皮质和肾皮质巯基含量与对照组相比明显增高 ;高剂量染镉后 2 4h ,脉络丛和血液的巯基含量与对照组相比明显降低。结论 侧脑室脉络丛对铅或镉有屏护作用 ,保持脑脊液成分的相对稳定 ,使脑组织免受来自血液的重金属的损伤。脉络丛的屏护作用机制与GSH和重金属的结合有关。

Objective The study was performed to investigate the distribution of lead or cadmium,and the variation in contents of glutathione(GSH) and sulhydryl groups in central nervous system.Methods Rabbits were given different doses of lead or cadmium respectively.4 and 24 hours after lead or cadmium administration,animals were sacrificed.Samples of cerebrospinal fluid(CSF),blood,choroid plexus of lateral ventricle,cerebral cortex,liver and kidney were collected,and concentrations of lead or cadmium in these tissues were measured.Contents of GSH and sulhydryl groups were also determined in these tissues.Results The results showed that concentrations of lead or cadmium in choroid plexus were significantly higher than those in CSF,brain and blood.4 hours after lead injection,the content of GSH in choroid plexus increased significantly.However,it was obviously decreased 24 hours after lead injection.Contents of GSH in blood,cerebral cortex,liver and kidney decreased also in animals given high dose of lead 24 hours after lead injection.Contents of total sulhydryl groups in tissues after lead administration did not differ from the control group.In the group of low dose cadmium,contents of GSH did not differ from the control group 4 hours after cadmium injection,and decreased 24 hours after cadmium injection.In the group of high dose cadmium,contents of GSH decreased significantly with the time.Contents of sulhydryl groups in choroid plexus of lateral ventricle,blood,cerebral cortex and kidney increased obviously in the group of low dose cadmium 24 hours after cadminm injection.However,contents of sulhydryl groups in choroid plexus of lateral ventricle and blood decreased significantly in the group of high dose cadmium as compared with the control group.Conclusions The results indicated that choroid plexus of lateral ventricle could sequester lead or cadmium maintaining the balance of CSF and protecting the brain from damage of the heavy metal.The mechanism,by which the sequestered lead or cadmium may involve,might be associated with the binding of GSH with the heavy metal.