The effect of total colectomy on water absorption and aquaporin expression in the rat jejunum

Abstract

The main role of the colon is electrolyte and water absorption. Total colectomy eliminates this colonic function and may alter the absorptive capacity if the small intestine for nutrients and fluid. The purpose of the present study was to investigate the effect of total colectomy on water absorption in the jejunum in colectomized rats that were allowed to recover for 3 days, 15 days and 30 days post-colectomy. mRNA and protein expression of the genes coding for water transporters AQP1, AQP4, AQP7 and AQP8 were analyzed by RT-PCR and Western Blot. The results have revealed no significant changed in mRNA expression of aquaporins whereas a significant decrease in protein expression of AQP1, 4, 7 and 8 was seen at 15 days post-colectomy when compared to normal/sham rats before returning to normal at 30 days post-colectomy. However, no significant change in water absorption was detected in the jejunum post-colectomy when compared to normal/sham rats. These results indicate that a functional adaptation occurs in the small intestine following total colectomy, through the ability of the small intestine to modulate its absorptive capacity for water absorption following the loss of the colon.