Protective Effect Of Thyroid Hormone On Intestinal Mucosal Barrier Runction In Ischemia-reperfusion Rats

Serious infection and trauma can cause multiple organ dysfunction syndrome, and its mortality is very high .Present experiments show that MODS has relation with intestinal barrier dysfunction. The objective of this study is to investigate the relationship between metabolic abnormalities of thyroid hormone and intestinal barrier dysfunction and to prove the protective effect of thyroid hormone on intestinal mucosal barrier in ischemia-reperfiision rats .This study can provide theoretical basis to clinical prevention from multiple organ dysfunction syndrome. Methods: Thirty - nine Wistar rats were randomly divided into 4 groups: sham group(S. n=12),gut ischemia-reperfiision group (G n=8),gut ischemia-reperfiision plus normal saline group (N. n=9) and gut ischemia-reperfiision plus thyroid hormone group (T. n=10). First, ischemia-reperfusion rat model were established by clamping the superior mesenteric artery (SMA) for 60 minutes and followed by reperfiision for 24 hours. In group S, SMA was separated without occlusion. In groups G, N and T, SMA was separated and occluded for 60 minutes, then, released for reperfiision for 24 hours. Triiodothyronine T₃ was administered intraperitoneally to correct the low T₃ syndrome of ischemia-reperfusionrats in group T. After 24hours,the animals were sacrificed and blood and tissue samples were collected to examine serum free T₃, free T₄, TSH, isoenzyme of creatine kinase (CK-MB) and levels of portal vein blood endotoxin. Intestinal mucosal mechanical barrier was observed under light microscopy respectively. Results : 24 hours after ischemia-reperfusion ,comparison of serum FT₃, FT₄ demonstrated a significant decrease in the G and N groups. At the same time,there was no significant difference between T and S groups . N and G groups had an increase in CK-MB and endotoxin compared with T and S groups. The severity of damage to the intestinal mucosal mechanical barrier in the T group was milder while G and N groups were badly damaged. Histological structures of intestinal mucosa were much improved 24 hours after reperfusion in group T than in the other groups. Conclusions : There were significant correlation between the metabolic abnormalities of thyroid hormone and intestinal barrier dysfunction. Thyroid hormone can protect the intestinal mucosal barrier and improve the prognosis in ischemia-reperfusion rats.