Inhibition of mRNA expression of glucose transporters in the small intestine in Iodoacetamide-Induced Colitis in Rats

Abstract

Previous studies have shown that ulcerative colitis (UC) decreases fluid and alanine absorption in the small intestine. However, the effect of UC on glucose absorption in the small intestine has not been yet fully characterized. We have examined the effect of iodoacetamide-induced colitis on glucose absorption and the mRNA expression of glucose transporters in the small intestinE. colitis was induced by instillation of 6% iodoacetamide intrarectally in anesthetized Sprague-Dawley rats (N=6). Sham rats were treated with the vehicle. Rats were then allowed to recover for 7 days. Glucose (20 mM) absorption measured In-Vivo by the single pass perfusion technique in the jejunum showed a significant decrease in rats treated with iodoacetamide 40 minutes post-perfusion as compared to normal/sham rats. mRNA expressions of SGLT1, GLUT2, and GLUT5 were determined in duodenal, jejunal, and ileal samples by real-time PCR with actin as the housekeeping gene in normal, sham, and rats with colitis. Colitis was assessed by the mRNA expression level of Tumor Necrosis Factor alpha (TNFα). A significant increase in TNFα mRNA was detected in the colon of rats treated with iodoacetamide (3.9±0.56 vs 0.7±0.07 in normal/sham) (p<0.01), however, no variation was noted in the small intestine. SGLT1 mRNA significantly decreased in the jejunum (3.30±1.25 vs 31.56±7.25 in normal/sham) and duodenum (4.25±2 vs 35±4.83 in normal/sham) (p<0.01) in rats with colitis. A significant decrease in GLUT2 mRNA was also noted in the jejunum (50.14±16.4 vs 251.9±68 in normal/sham) and duodenum (51.6±18.63 vs 323.79±77.9 in normal/sham) (p<0.01) in rats with colitis. However, no significant variation in GLUT5 mRNA expression was noted in the small intestine in rats with colitis and in any mRNA glucose transporters in the ileum of iodoacetamide-treated rats. Our results show that the noted decrease in glucose absorption may be due to the decrease in mRNA expression of glucose transporters in the small intest.