妊娠期大鼠汽车尾气暴露对仔鼠生殖毒性及遗传毒性研究

Productive Toxicity and Genotoxicity of Automobile Exhaust

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2h。末次染毒24h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）gl、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 automobile exhaust exposure on the placenta of pregnant rats and their offspring during gestation periods. Methods Forty 120-day-old female Wistar rats, after adaptive feeding and pregnancy, were randomly divided into 4 groups, 10 in each. In the dynamic device, pregnant rats were exposed to the mix of ear exhaust and fresh air by the proportion of 1：30,1：20,1：10 continually from 3rd to 19th days of pregnancy, 2 h per day and the ones inhaling the fresh air was made the control group. After 24 h of the last exposure, the effects of automobile exhaust on pregnancy outcome and offspring were observed, the optical mieroseope observation of morphological changes of placenta was performed. Results The offspring＇s body weight/（3.96±0.45）g], length [（3.76±0.43）em], litter weight [（50.34±9.45）g] in high close group were significantly lower（P〈0.05）. The abnormal pregnancy outcomes （stillbirth, fetal absorption） increased and live births reduced in high dose group. In the high-dose group, placenta spongiosa trophoblast giant cells and cell vacuolation increased and the labyrinth trophoblast degenerated. The villi swelled and enlarged, with the intercellular gaps got narrow and the fibrous proteins around villi increased and accumulated. There was no significant change of placental structure in other dose groups. The alkaline phosphatase （AKP） level in low dose group had no significantly change compared with the control group, the alkaline phosphatase level in high dose group （P 〈0.05） decreased more significantly than the control group. The frequencies of mieronueleus had no significantly change compared with the control group, the frequencies of micronueleus in high dose group increased more significantly than the control group（P〈0.01）. Conclusion Automobile exhaust has embryotoxicity and genotoxieity.