脉络丛对铅的屏障作用及其病理形态学观察

The effect of choroid plexus on sequestering cadmium and its patho-morphological chage

目的 观察脉络丛对铅的屏障作用及其病理形态学改变。方法 给 3个实验组兔子每公斤体重分别腹腔注射含 5、2 5或 50mg的Pb的醋酸铅溶液 ,对照组注射生理盐水。注射后 4和 2 4h处死动物 ,采集脑脊液、大脑皮质、侧脑室脉络丛、血液、肝脏和肾皮质样品。经浓硝酸和过氧化氢湿式消化后 ,用原子吸收分光光度计测定组织样品中铅浓度。脉络丛样品经冲洗、固定后 ,制成组织切片 ,用光镜、电镜观察脉络丛的病理形态学改变。结果 组织铅浓度从高到低依次为肝、肾皮质、侧脑室脉络丛、血液、大脑皮质和脑脊液。脑脊液中铅浓度最低 ;3个剂量组的脉络丛铅浓度都明显地高于大脑皮质和脑脊液铅浓度。光镜见脉络丛上皮细胞肿胀 ,颗粒变性 ,严重的呈坏死性改变。电镜见脉络丛上皮细胞溶酶体增加 ,线粒体肿胀。结论 侧脑室脉络丛对铅有屏障作用 ,能阻止铅从血液进入脑脊液和脑组织。但当染铅达到一定剂量时 。

Objective The study was performed to investigate whether choroid plexus can sequester lead (Pb) and its patho\|morphological change.Methods The rabbits in three experimental groups were given intraperitoneal injection of 5,25 or 50 mg Pb/kg body weight and thc control group was given normal saline.Four and 24 hours after lead administration,animals were separately sacrificed and the liver,kidney,blood,brain,cerebrospinal fluid (CSF) and choroid plexus of lateral ventricle samples were collected.The concentrations of lead in the tissue samples were determined by AAS.Samples of choroid plexus were rushed in saline thoroughly,then fixed.Patho\\morphological changes of choroidal epithelial cells were observed in light microscopy and electron microsocopy.Results\ The order from high to low concentration of lead in the tissues was liver,renal cortex,choroid plexus,blood,cerebral cortex,and CSF.The experimental results indicated that the choroid plexus had definite effects as barrier and storage to lead and prevent lead from entering the CSF and brain.Choroidal epithelial cells appeared vacuolation and granular degeneration in light microscope.The choroidal epithelial cells showed that the number of lysosome was increased and mitochondria were swellen in the transmission electron microscope Conclusion Choroid plexus could accumulate and sequester Pb to protect cerebral cortex from the fluxes of Pb in blood lead.When concentration of Pb gain to a certain level,sequestering action of choroid plexus was weak,or disappeared and the lead resulted in certain pathological changes in the choroid plexus of lateral ventricle.