甲状腺素对缺血-再灌注肠黏膜屏障功能的保护作用

目的：探讨肠缺血-再灌注24h时甲状腺素代谢异常和肠黏膜屏障破坏之间的关系，阐明外源性甲状腺素对肠黏膜屏障功能的保护作用。方法：将39只Wistar大鼠随机分为4组：假手术组（S，n=12）；肠缺血-再灌注组（G，n=8）；肠缺血-再灌注＋生理盐水组（N，n=9）；肠缺血-再灌注＋甲状腺素组（T，n=10）。利用肠系膜上动脉夹闭法制作大鼠肠缺血-再灌注模型，并补充外源性甲状腺素。24h后测定外周血游离甲状腺素、促甲状腺素、磷酸肌酸激酶和门静脉血内毒素水平，同时做肠黏膜病理形态学检查。结果：再灌注24h后，G组和N组的血清甲状腺素水平明显低于S组、T组，两者有显著差异（P〈0.01），但T组和S组之间无显著差异（P〉0．05）；磷酸肌酸激酶水平G组和～组明显高于S组、T组，（P〈0．01），但T组和S组之间无显著差异（P〉0．05）；门静脉血内毒素水平G组和N组明显高于S组、T组，（P〈0．01）；肠黏膜组织结构以G组和N组破坏最为严重，T组变化轻微。结论：肠缺血-再灌注时，肠黏膜屏障功能受到破坏；外周血甲状腺素代谢异常，血清甲状腺素水平降低；补充外源性甲状腺素可以保护肠缺血-再灌注时肠黏膜屏障功能。

Protective Effect of Thyroid Hormone on Intestinal Mucosal Barrier Function in Ischemia-reperfusion Rats

Objective: To observe the relationship between metabolic abnormalities of thyroid hormone and intestinal barrier dysfunction and the protective effect of thyroid hormone on intestinal mucosal barrier in ischemia-reperfusion rats . Methods: Thirty nine Wistar rats were randomly divided into 4 groups:sham group(S,n=12),gut ischemia-reperfusion group (G, n= 8),gut ischemia-reperfusion plus normal saline group (N,n=9) and gut ischemia-reperfusion plus thyroid hormone group (T, n=10). First, ischemia-reperfusion rat model were established by clamping the superior mesehteric artery for 60 minutes and followed by reperfusion for 24 hours. After 24 hours,blood was collected to examine serum free T3, free T, TSH, isoenzyme of creatine kinase (CK-MB) and levels of portal vein blood endotoxin.intestinal mucosal mechanical barrier was observed under microscope. Results: 24 hours After ischemia-reperfusion,comparison of serum FT3 ,FT4 demonstrated a siginificant decrease in the G and N groups,and there was no obvious different between T and S groups . N and G groups had a increase in CK-MB and levels of endotoxin compared with T and S groups. The severity of damage to the intestinal mucosal mechanical barrier in the T group was milder.histological structures were much improved 24 hours after reperfusion in group T than in the other groups Conclusion: Thyroid hormone can protect the intestinal mucosal barrier and improve the prognosis in ischemia-reperfusion rats .