铅镉联合急性中毒对大鼠脏器病理组织学和超微结构的影响

按照等毒性配比法混合硝酸铅与氯化镉溶液进行急性毒性试验，采用Bliss法和Keplinger标准进行毒性评价，并应用光镜和电镜观察大鼠染毒后各脏器的显微与超微结构变化。探讨硝酸铅（Pb（NO3）2）与氯化镉（CdCl2·2．5H2O）溶液联合经口灌胃对SD大鼠的急性毒性效应。结果显示，铅镉联合作用下大鼠的绝对致死量（LD100）为5062．00mg／kg，最大耐受浓度（MTD）为1436．00mg／kg，半数致死量（LD50）为2696．54mg／kg，95％可信区间是2162．00～3362．89mg／kg。铅镉联合急性中毒的靶器官为肝脏、肾脏和脾脏，光镜下，主要表现为血管发生不同程度的充血和溶血、实质细胞发生不同程度的变性（水泡变性和颗粒变性）和坏死。电镜下，主要表现为细胞器结构破坏。结果表明，硝酸铅和氯化镉联合急性毒性为相加作用，对大鼠肝脏、肾脏和脾脏均有不同程度的急性毒性损伤。

The acute combined exposure effects of lead and cadmium on histopathology and ultrastructure of rats

In order to study the acute oral toxicity of lead nitrate（Pb（NO3）2 ） and cadmium chloride （CdCl2 · 2.5H2O）combined to Sprague Dawley（SD） rats,lead nitrate and cadmium chloride were mixed according the method of equal toxic ratio mixing, and the effect of combinative toxicity were tested by Bliss method. The results were evaluated with Keplinger evaluation system; also the optical and electron microscopic were used to display the lesions differences between the groups that were administrated orally with or without different dose of lead nitrate and cadmium chloride. The results showed that absolutely lethal dose （LD100） of combined exposure of lead and cadmium was 5 062.00 mg/kg;the maximum tolerance concentration （MTD） was 1 436.00 rag/ kg;median lethal dose （LD50,） is 2 696.54 mg/kg,with the 95% confidence interval of 2 162.00- 3 362.89 mg/kg. Histopathological test and electron microscope results showed that the target organs of combined acute toxicity of lead nitrate and cadmium chloride were liver, kidney and spleen. Different degree of congestion and hemolysis of blood vessel,degeneration and necrosis of parenchyma cell （such as blister degeneration and particle degeneration） was observed in these target organs. Cell structure damages of the target organs were also observed in the electron mi- crographs. In conclusion,the acute toxicity oral of lead and cadmium had an additive effect and the liver,kidney and spleen of test rats showed the different level of acute toxicity injuries; the three organs may be the potential target organs for toxicity.