孕鼠铅暴露对仔鼠血铅水平及听力影响的研究

Study on effect of lead exposure to blood lead level and hearing in young offspring through gestation-rat

目的：探讨孕鼠铅暴露对仔鼠血铅水平和听力的影响。方法：Wistar大鼠42只，按雌、雄配对分为5组（A、B、C、D、E组）。A组为正常对照组，进食正常饲料，B、c、D、E组每公斤饲料分别添加醋酸铅0．3、0．9、2．7、8．1g，产仔后恢复正常饲料。大鼠及仔鼠于出生后1、3周分别进行畸变产物耳声发射（DPOAE）、听性脑干反应（ABR）和血铅测定。结果：仔鼠与大鼠血铅水平呈正相关（r=0．5817）；DPOAE测试：大鼠和仔鼠均为一般正常耳蜗反馈曲线；ABR测试：大鼠D组Ⅰ～Ⅲ、Ⅲ～Ⅴ波间期与正常对照组比较，差异有统计学意义（P〈0．05）。仔鼠c1、c3组反应阈大于正常对照组（均P〈0．05）；仔鼠b1、c1、e1组Ⅰ波潜伏期短于正常对照组（均P〈0．05）。结论：仔鼠血铅水平与母鼠孕期铅暴露的程度相关；孕期低水平的宫内铅暴露对仔鼠听神经中枢段及听觉传导等特别敏感，易造成损伤。

Objective：To study the effect of lead exposure to the blood lead level and the hearing in young offspring through gestation-rat. Method：Experiments were carried out on 42 Wistar rats, half female and half male, randomly divided into five couple groups （A, B, C, D, E）. The group A, as a normal control group, was fed with a standard diet. The group B, C, D and E were fed with a standard diet, additionally with 0. 03%, 0. 09%, 0. 27% and 0. 81% lead acetate added respectively, and then fed with standard diet after birth. DPOAE, ABR and blood lead measurement were conducted on the parents rats and the neonatal offspring rats at first week and at the third week respectively. Result： The blood lead level of neonatal rat reported positively related with that of the parent rats（ r =0. 5817）. DPOAE test result; Both parent rats and neonatal rats presented a normal cochlea feedback curve. ABR test result： The period of the group D showed a significant difference from that of the normal control group A. Reaction threshold （dBpeSPL） of the neonatal rat group cl （at the first week） and group c3 （at the third week） showed a notable difference from that of the normal control group al and a3 （c〉a）. Conclusion：The blood lead level of a fetus rat is related with the exposure degree to lead during the pregnant period of mother rat. Low level lead exposure inside uterus during pregnant period will result easily in damage on the hearing nerve center segment and hearing conduct of a fetus rat for they are very sensitive.