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目的探讨汽车尾气暴露对孕鼠胎盘的毒性作用及对其子代的影响。方法 40只120日龄雌性Wistar大鼠经适应性饲养并受孕后随机分为4组(对照组及低、中、高剂量组),每组10只。对照组给予吸入新鲜空气,低、中、高剂量组分别于妊娠第3~19天通过动式染毒装置按汽车尾气与新鲜空气比例1∶30、1∶20、1∶10吸入染毒,每日2 h。末次染毒24 h后取材,观察汽车尾气对妊娠结局及胎鼠的影响;光学显微镜下观察胎盘组织形态学改变;免疫组织化学法测定胎盘碱性磷酸酶(AKP)的水平;观察胎鼠肝脏中嗜多染红细胞微核率的改变。结果与其他3组比较,高剂量组仔鼠体重[(3.96±0.45)g]、身长[(3.76±0.43)cm]、窝重[(50.34±9.45)g]均降低,差异有统计学意义。高剂量组的不良妊娠结局(死胎、吸收胎)增多、活胎数减少,但差异无统计学意义。高剂量组胎盘海绵带空泡化细胞增多,滋养叶细胞稀疏,绒毛肿胀增粗、间隙变窄,绒毛周围纤维蛋白沉积增多;其他剂量组胎盘结构无明显改变。低、中剂量组AKP水平较对照组无明显改变,高剂量组AKP水平较对照组明显下降(P<0.05)。低剂量组与对照组比较,微核细胞率无明显改变;中、高剂量组与对照组比较,微核细胞率明显增加,差异有统计学意义(P<0.01)。结论汽车尾气具有胚胎毒性和遗传毒性。
Objective To investigate the toxic effects of vehicle tail gas exposure on placenta of pregnant rats and its effect on its offspring. Methods Forty 120-day-old female Wistar rats were randomly divided into 4 groups (control group, low, medium and high dose groups), 10 mice in each group. The control group was given inhaled fresh air, and the low, medium and high dose groups were respectively exposed to the vehicle exhaust and fresh air ratio of 1:30, 1:20 and 1:10 by means of a dynamic exposure device on the 3rd to 19th days of pregnancy, 2 h daily Twenty-four hours after the last exposure, the effects of vehicle exhaust on pregnancy outcome and fetus were observed. The morphology of placenta was observed under optical microscope. The level of placental alkaline phosphatase (AKP) was measured by immunohistochemistry. The change of micronucleus rate of multi-cochlear erythrocytes. Results Compared with the other three groups, the body weight, [(3.96 ± 0.45) g], length [(3.76 ± 0.43) cm] and litter weight [(50.34 ± 9.45) g] . High-dose group of adverse pregnancy outcomes (stillbirth, aborted fetus) increased, live births decreased, but the difference was not statistically significant. High-dose group of placental sponge with vacuolized cells increased, trophoblast cells sparse, thick chorionic villi, narrowing the gap, fibrin deposition around the villi increased; other dose group no significant changes in placental structure. The levels of AKP in the low and middle dose groups had no significant changes compared with the control group, while the AKP levels in the high dose group were significantly lower than those in the control group (P <0.05). Compared with the control group, the rate of micronucleated cells in the low-dose group did not change significantly. The rates of micronucleated cells in medium-dose and high-dose groups were significantly increased compared with the control group (P <0.01). Conclusion Automobile exhaust has embryotoxicity and genotoxicity.