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目的通过观察孕期不同时段铅暴露对妊娠结局及胎盘MMP-9的表达影响,评价孕早期、孕后期及孕全程铅暴露的毒性特点及毒性机制。方法采用原子吸收光谱仪测定孕期不同阶段低水平铅暴露后的大鼠孕末期血铅水平。0.025%醋酸铅对实验组孕鼠染毒,根据大鼠孕期3周推算足月剖宫产,观察统计异常分娩情况,记录胎盘质量、仔鼠数、仔鼠质量。免疫组化法测定胎盘滋养细胞MMP-9的表达。结果孕早期染铅对孕末期血铅水平及胎盘质量的影响较大,孕晚期染铅对仔鼠重量的影响较明显,孕全程染铅对孕末期血铅水平、胎盘质量及仔鼠质量均有明显影响,孕全程染铅组其胎盘MMP-9表达下降。结论铅具有生殖毒性及胚盘毒性,孕期不同时段铅暴露导致不同的妊娠结局。胎盘MMP-9表达下降可能是铅致胎盘损伤的病理机制之一。
Objective To observe the effects of lead exposure on the outcome of pregnancy and the expression of MMP-9 in placenta during different periods of pregnancy and to evaluate the toxicity and toxic mechanism of lead exposure during early pregnancy, during pregnancy and after pregnancy. Methods The level of blood lead in pregnant rats during the second trimester of pregnancy was determined by atomic absorption spectrometry. 0.025% lead acetate was exposed to the experimental group pregnant rats, cesarean section was calculated according to the 3 weeks of pregnancy, statistical abnormal delivery was observed, and the placenta quality, the number of offspring and the quality of offspring were recorded. The expression of MMP-9 in placental trophoblast cells was detected by immunohistochemistry. Results Lead exposure in the first trimester had a significant effect on blood lead level and placenta quality during the first trimester of pregnancy. The effect of lead exposure on the weight of the offspring was more obvious in the third trimester. The level of lead in the whole pregnancy, the level of the placenta and the quality of the pups Significantly affect the placenta MMP-9 expression in the whole lead exposure group decreased. Conclusion Lead has reproductive toxicity and embryo toxicity, lead exposure during different periods of pregnancy lead to different pregnancy outcomes. Decreased expression of placenta MMP-9 may be one of the pathological mechanisms of lead-induced placental injury.