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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IMMCⅢ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IMMCⅢ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。
Objective To analyze the effects and possible mechanisms of congenital lead poisoning on gastrointestinal, duodenal and jejunal intercostal migrating complex motility (IMMC) in offspring. Methods Pregnant mice were exposed to 0.1% lead and 0.2% lead acetate solution to establish a model of congenital lead exposure. Their offspring were exposed to low dose lead exposure (LG) and high dose lead exposure (HG), and normal control (NG) . The IMMC in the antrum, duodenum and jejunum of male offspring were detected. The expression of CCK-8 and MTL in the gastrointestinal mucosa and plasma were detected by immunohistochemistry and radioimmunoassay. Results Lead exposure during embryogenesis led to an increase in the amplitude of IM phase III in the gastric antrum, duodenum and jejunum of the offspring. The phase Ⅱ phase shortened, the phase Ⅲ phase prolonged and the total time course increased. The time course and amplitude of IMMC Ⅲ in gastric antrum, duodenum and jejunum in NG, LG and HG groups were significantly different (P <0.01). The expression of CCK-8 in gastric mucosa of NG, LG and HG groups increased in turn followed by the decrease of MTL expression (P <0.01), while the expressions of MTL and CCK-8 in proximal duodenal mucosa increased. The levels of CCK and MTL in plasma increased in lead exposure group, while the levels of CCK and MTL in NG, LG and HG groups were highly statistically significant (P <0.01). Conclusions Congenital lead exposure may lead to impaired gastrointestinal motility in the offspring. The different distribution and changes of CCK and MTL in gastrointestinal tract and blood may be the important reasons.