胚胎期暴露DEHP对子代大鼠神经行为的影响

Effect of embryonic exposure to DEHP on nervous behavior of offspring rats

目的通过邻苯二甲酸二(2-乙基己基)酯(DEHP)胚胎期暴露,评价其对子代大鼠神经行为的影响,初步探讨DEHP所致子鼠神经毒性的机制。方法雌性Wistar大鼠从妊娠日起用10、100、500 mg/(kg.d)DEHP连续灌胃染毒19 d,观察子代大鼠的神经行为学指标。于子鼠出生第7天和第21天测定海马神经细胞凋亡率,不同剂量的DEHP染毒对海马组织bcl-2、bax基因的表达的影响。结果于子鼠出生6周后,进行水迷宫测试。结果显示,随着DEHP剂量增加,中、高剂量组错误次数增加和潜伏期延长十分明显(F=8.058,P<0.05;F=11.221,P<0.05)。电穿梭测试显示,中、高剂量组电击次数增加和主动逃避时间延长较为明显(F=6.984,P<0.05;F=9.841,P<0.05)。出生后7 d子代大鼠海马神经元的细胞凋亡率高于出生21 d,高剂量组尤为显著。RT-PCR检测表明,与对照组相比,bcl-2和bax基因表达增高(F=253.78,P<0.05;F=66.67,P<0.05),且随着DEHP暴露剂量的升高,表达亦增加。结论 DEHP对子代大鼠神经系统具有明显的毒性作用,存在着剂量-反应关系,其可能通过干扰bcl-2和bax基因的表达而影响子代大鼠神经系统发育。

Objective The purpose of this s tudy is to observe the effect of embryon ic exposure to DEHP on nervous behavior in offspring rats,and explore the primar y mechanism of neurotoxicity induced by DEHP.Methods The mature female Wistar ra ts were consecutively lavaged with 10 mg /（kg·d）,100 mg/（kg·d） and 500 mg/（kg·d） of DEH P respectively from the first day until t he 19 th day of pregnancy,and observation was made on the nervous beh avior of offspring rats.The apoptosis rates in hippocampus of the offspring rats at the 7 th and 2 1 st postnatal day（PND）were detecte d respectively by flow cytometer（FCM）.Me antime,the influence of different doses of DEHP on gene expression of bcl-2 an d bax were also analysed.Results The water maze test showed that both false time and latency were increased in DEHP groups and was dose-dependent,especially in the 100 mg/（kg·d） an d 500 mg/（kg·d） groups（F=8.058,P〈0.05;F=11.221,P〈0.05）.Meanwhile,electricity shutt led test also showed that both shocked t ime and active elusion time were inc reased in DEHP groups,especially 100 mg/（kg·d） and 500 mg/（kg·d） groups（F=6.984,P〈0. 05;F=9.841,P〈0.05）.While the apoptosis r ate in hippocampus of PND7 was higher th an that of PND21,especially in 500 mg/（k g·d）group.In addition,there were statist ical significance between DEHP groups an d the controls in gene expression of bcl-2 and bax（F=253.78,P〈0.05;F=66.67,P〈0.0 5）, and the increase of bcl-2 and bax gene e xpressions were dose dependent.Conclusio n DEHP shows obvious toxicity on the of fspring nervous system of DEHP exposed r ats,the possible mechanism might be the interference on the expression of bcl-2 and bax,thereby affecting nervous system development.