血铅水平异常与呼吸道反复感染的关系及机制

Relationship between Abnormal Blood Lead Level and Recurrent Respiratory Tract Infection in Children and Its Mechanism

为了检测暴露于不同浓度铅(Pb)水平下的大鼠肝脏和肾脏细胞凋亡情况,以探讨Pb在儿童呼吸道反复感染中的作用机制。本研究设置3组Pb(NO3)2浓度实验组大鼠,每组包含10只雌性和10只雄性,每日分别消耗28.12 mg/kg、91.25 mg/kg、265.58 mg/kg的Pb(NO3)2混合饲料;对照组只饮用不含Pb(NO3)2的蒸馏水,连续饲喂至少90 d。随后对各组大鼠制备肝脏及肾脏生理切片,并进行TUNEL染色检测,以及Bax、Bcl-2和caspase-3蛋白免疫组织化学(IHC)检测。TUNEL染色结果显示,TUNEL阳性细胞主要位于肝脏肝细胞周围和肾脏肾小管上皮细胞周围,凋亡细胞数量随Pb(NO3)2浓度升高而增加。IHC检测显示,实验组Bax和caspase-3蛋白表达量升高,Bcl-2蛋白表达减少。肝脏和肾皮组织Bax、Bcl-2和caspase-3阳性细胞平均光密度(AOD)数据统计结果与IHC检测结果相吻合。机体Pb水平异常可诱导肝脏和肾皮细胞凋亡,损害其功能,这其中与Bcl-2、Bax和caspase-3等凋亡蛋白表达水平的变化有关。

To detect the apoptosis of rat liver and kidney cells exposed to different concentrations of lead(Pb),and to explore the mechanism of Pb in children with respiratory infection.Three groups of rats with Pb(NO3)2 concentration were set up.Each group contained 10 females and 10 males.The daily consumption of Pb(NO3)2 mixed feed was 28.12 mg/kg,91.25 mg/kg,265.58 mg/kg.The control group only drank distilled water without Pb(NO3)2 and fed continuously for at least 90 days.Liver and kidney sections were prepared from each group of rats,and subjected to TUNEL staining,as well as Bax,Bcl-2 and caspase-3 protein immunohistochemistry(IHC).TUNEL staining showed that TUNEL-positive cells were mainly located around liver hepatocytes and renal tubular epithelial cells,and the number of apoptotic cells increased with increasing Pb(NO3)2 concentration.IHC test showed that the expression of Bax and caspase-3 protein was increased and the expression of Bcl-2 protein was decreased in the experimental group.The average optical density(AOD)data of Bax,Bcl-2 and caspase-3 positive cells in liver and kidney skin tissues are consistent with the IHC test results.The abnormal level of Pb in the body can induce apoptosis of liver and kidney cells and impair its function,which is related to the changes of expression levels of apoptosis proteins such as Bcl-2,Bax and caspase-3.