镉中毒肾损害病理学及电子探针X-射线扫描分析

Pathological Obsevations and Electron Probe X-ray Scanninganalysis of Cadmium-induced Renal Damage in Rats

用氯化镉制成亚慢性镉中毒肾损害动物模型,系统地观察了肾脏组织学,超微结构及 Cd^(++),Ca^(++)变化。结果表明:近曲小管是镉中毒肾损害最早、最主要的部位,膜性细胞器受损是其超微结构病理改变的特点,胞浆多泡膜层体(MB)、暗黑颗粒及核内包涵体可能是镉中毒性肾损害的特征性病变。肾脏镉含量随染毒时间而进行性升高,但电子探针 X-射线波谱扫描分析肾组织细胞、亚细胞内却未发现游离镉的富集,而胞浆 Ca^(++)富集增多,提示以大分子结合形式存在,钙稳态失调与镉毒性肾损害机理有关。

Male Wistar rats were treated with cadmi- um chloride (CdCl,5.3μmol/kg body wt,,ip., 5 times a week up to 10 weeks).Dynamic obs- ervations of morphometry were conducted by light and electron microscopy.Early pathologi- cal alterations include mitochondria swelled, cristae of mitochondria ruptured,an increased number of small lysosomes and dark gra- nules (DG),“multivesicular lamellated body (MB)” appeared in cytoplasma in renal poximal tubular cells around the 2～4week period of exposure;then followed by tubular necrosis in some area,MB increased,organella disappeara- nce,brush border festered,infolder destroyed in plasmic membrane,inclusion body in the nucleus appeared in proximal tubular cells,de- generation of distal and collecting tubular cells, hypertrophy of glomerular epithelial cells,cap- sule and basal membrane thickened;finally collagen fibers proliferated and terminated in cirrhosis.Cadmium concentratrations in renal cortex were increased with the successive treat- ment and reached the highest plateaux at 9th week of the exposure,scanninganalysis of Cd ion and Ca ion by electron probe X-ray scannigan- alyze revealed that there was no concentrated points or areas of Cd ions in the kidney in this study,implied the possibility of Cd bound to metalloproteins and other biomacromolecular substances,and the concentrated points and areas of Ca ions in cytoplasms were increased,which suggested the disturbances in calcium homeost- asis asa mechanism of cadmium toxic effects.