低剂量毒死蜱和氯氰菊酯联合染毒对雌性大鼠生殖发育的影响

目的 观察低剂量毒死蜱(氯吡硫磷)和氯氰菊酯联合染毒对雌性大鼠生育功能的影响。 方法 健康Wistar大鼠雌雄按2∶1合笼,将孕鼠分为对照组、毒死蜱组、氯氰菊酯组和联合染毒组等4组,每组8只。按照1 ml/kg量灌胃,毒死蜱组剂量为1.6 mg/kg,氯氰菊酯组剂量为2.5 mg/kg,联合染毒组给药毒死蜱1.6 mg/kg+氯氰菊酯2.5 mg/kg。从孕1~孕8 d染毒,孕19 d,处死孕鼠,记录黄体数和总着床数,活胎的体重和身长,并观察活胎外观是否有畸形。分离胎盘并记录胎盘重量,测定大鼠全血的乙酰胆碱酯酶(AchE)的活力,免疫组织化学检测P450aromA。 结果 孕第19 d,联合染毒组孕鼠体质量与对照组比较明显降低(P<0.05);各组孕鼠黄体数、总着床数、死胎率、胎仔性别比例和胎仔身长与对照组比较差异无统计学意义(P>0.05)。联合染毒组胎盘质量较对照组显著降低(P<0.05)。染毒各组活胎仔体质量较对照组明显降低(P<0.05)。联合染毒组孕鼠全血中AChE活力较对照组显著降低(P<0.05)。单独染毒组胎盘P450aromA蛋白表达与对照组相似,联合染毒组胎盘P450aromA蛋白表达显著高于对照组(P<0.05)。 结论 低剂量毒死蜱和氯氰菊酯联合染毒产生一定的胚胎毒性,造成仔鼠发育迟缓,并引起了孕鼠AchE的下降和胎盘P450aromA蛋白表达的增强。

Effects of mixed exposure to low-dose chlorpyrifos and cypermethrin on reproductive function in female rats

Objective To observe the effects of mixed exposure to low-dose chlorpyrifos and cypermethrin on reproductive function in female rats. Methods Female and male healthy Wistar rats were mixed in a 2:1 ratio in the cage. The pregnant rats were divided into the control group, the chlorpyrifos group, the cypermethrin group and the chlorpyrifos and cypermethrin group (each n=8). Gastric perfusion was performed according to the weight of the 1 ml/kg calculation. The chlorpyrifos group, the cypermethrin group and the chlorpyrifos and cypermethrin group were given chlorpyrifos 1.6 mg/kg, cypermethrin 2.5 mg/kg and chlorpyrifos 1.6 mg/kg combined with cypermethrin 2.5 mg/kg from gestation day 1 to 8 respectively by gavage. All pregnant rats were sacrificed on the 19th day of pregnancy. The number of ovulated corpus luteum, the total number of implantation, and the weight and length of live fetuses were recorded, and surface deformity of live fetuses was observed. The placentae were separated, and the weight of placentae was recorded. Acetylcholinesterase (AchE) activity in rat whole blood was detected, and P450aromA was detected by immune histochemical method. Results On the 19th day of pregnancy, body mass of pregnant rats in the chlorpyrifos and cypermethrin group was decreased obviously as compared with that of the control group (P<0.05). No statistically significant differences were observed in the number of ovulated corpus luteum, the total number of implantation, stillbirth rate, sex ratio of fetuses and length of fetuses between each exposure group and the control group (P>0.05). The weight of placentae was significantly lower in the chlorpyrifos and cypermethrin group than in the control group (P<0.05). Body mass of live fetuses in each exposure group was decreased significantly as compared with that of the control group (P<0.05). AchE activity in whole blood of pregnant rats in the chlorpyrifos and cypermethrin group was significantly reduced than that in the control group (P<0.05). P450aromA protein expression in placentae in the chlorpyrifos group and the cypermethrin group was similar to that in the control group (P<0.05), while P450aromA protein expression in placentae in the chlorpyrifos and cypermethrin group was significantly higher than that in the control group (P<0.05). Conclusions Mixed exposure to low-dose chlorpyrifos and cypermethrin in female rats produces certain embryo toxicity, and results in the delayed development of offspring, the decreased AchE activity in pregnant rats and the enhanced expression of P450aromA protein in placentae.