先天性铅中毒对子代大鼠胃、十二指肠及空肠IMMC的影响及可能机制

目的 分析先天性铅中毒对仔鼠胃、十二指肠及空肠消化间期移行性复合运动(IMMC)的影响及可能机制。方法 孕鼠自由饮用0.1%及0.2%醋酸铅溶液建立先天性铅暴露模型,其子代分别为低剂量铅暴露组(LG)及高剂量铅暴露组(HG),同时设立正常对照组(NG)。监测雄性仔鼠胃窦、十二指肠及空肠部位IMMC,应用免疫组化及放射免疫法检测胃肠黏膜及血浆CCK-8、MTL的表达或水平变化。结果 胚胎期铅暴露可导致仔鼠胃窦部、十二指肠及空肠IMMC Ⅲ相波幅增加,Ⅱ相时程缩短,Ⅲ相时程延长并导致总时程增长。NG、LG、HG组仔鼠胃窦、十二指肠、空肠部IMMC Ⅲ相时程与波幅差异有显著的统计学意义(P＜0.01)。NG、LG、HG组仔鼠胃窦部黏膜CCK-8表达依次增加而MTL表达逐渐减少(P＜0.01),而十二指肠近端黏膜MTL、CCK-8表达均增加。铅暴露组仔鼠血浆CCK与MTL水平均升高,NG、LG、HG组CCK与MTL的水平比较差异有高度统计学意义(P＜0.01)。结论 先天性铅暴露可导致仔鼠胃肠动力受损,CCK及MTL在胃肠及血液中不同分布和变化可能是其重要原因。

Effects and potential mechanisms of congenital lead exposure on interdigestie migrating motor complex changes of stomach,duodenum and jejunum in offspring rats

Objective To analyze the effect and potential mechanisms of congenital lead poisoning on interdigestove migrating motor complex (IMMC) changes of stomach,duodenum and jejunum in offspring rats.Method The animal model of congenital lead exposure was established with pregnant rats drinking freely 0.1% (low-dose group,LG) and 0.2% (high-dose group,HG) lead acetate solution.The normal control group (NG) was also established.IMMC changes of stomach,duodenum and jejunum of male offspring rats were observed in technique of electrophysiological monitor.The methods of immunohistochemistry and radioimmunoassay were also applied to elucidate the potential mechanism of gastrointestinal (GI) motility disorders in the plasma levels and GI tissue expressions of CCK-8 and MTL.Results Compared with group NG,the periods and amplitudes of GI IMMC Ⅲ phase increased (P<0.01) in the offspring rats with lead exposure in embryo period.Furthermore,the increase of CCK-8 expressions and decreasing MTL expressions in gastric antrum mucosa (P<0.01),increasing expressions of CCK-8 and MTL in proximal duodenal mucosa (P<0.01),and as well as increasing levels of plasma CCK and MTL (P<0.01) were observed in groups LG and HG.The differences among these three groups were of statistical significance (P<0.01).Conclusions The abnormal changes of GI motility are observed in offspring rats with lead exposure in embryo period.It is possible that the different expressions or distribution of CCK and MTL in the peripheral tissue and blood are the important mechanisms for these pathological changes.