Role Of Thyroid Hormone In Protecting Gut Barrier In Septic Rats

AIM: To investigate the role of exogenous thyroid hormone supplement in protecting gut barrier in septic rats.METHODS: Twenty-two rats were randomized into three groups: sham group (n=6), sepsis group(n=8), and sepsis plus tri- iodothyronine (T3) group(n=8). Septic rat model was established through cecal ligation and puncture(CLP). After 5h, sham and sepsis groups received saline, and the remaining group received T3 intraperitoneally. Twenty-one hrs After CLP, intestinal permeability and serum free T3 and T4 were measured with fluorescence spectrophotometer and by radioimmunoassay, respectively. Intestinal ultrastructure and histologic morphology were observed under transmission electron microscopy (TEM) and light microscopy, respectively.RESULTS: After 21h, septic symptoms and signs in sepsis plus T3 group were milder than those in sepsis group. Serum FT3 or FT4 concentration in sepsis group was lower than that in sham group(1.59± 0.20,3.41±2.14 pmol/L vs 3.44±1.40,9.53 ±3.39pmol/L, P<0.05), and FT3 concentration in sepsis plus T3 group(3.40±1.65 pmol/L, P<0.05) was corrected. Portal concentration of fluorescein isothiocyanate ?dextran (FITC-D) in sepsis group(2.51±0.56mg/L) was higher than that in sham group(1.22±0.21mg/L)(P<0.0l), and in sepsis plus T3 group(1.68±0.38mg/L) it was decreased significantly(P<0.0l). It wasshown that T3 supplementation in sepsis resulted in a significant diminution of granular FITC-dextran in cellular gaps and capillary of intestinal mucosa under TEM.TEM and light microscopy showed that T3 supplement preserved well ultrastructure and morphology of intetinal mucosa in septic rats.CONCLUSION: There is euthyroid sick syndrome in septic rats, exogenous thyroid hormone can be beneficial to the general condition of the bodies, and decrease gut permeability in rats ,and protect from the structural and functional damages of gut barrier in septic rats.