The Study Of Regulation Of AQP8 Expression In HT-29 By VIP

Objective:To investigate the expression of AQP8 in human colonic epithelial cells line,HT-29,and to characterize the regulation of AQP8 expression by VIP.To explore the molecular biology mechanisms of intestinal water metabolism and the regulatory mechanisms, and to provides the theory basis for the clinical treatment of water metabolism disorder correlation intestinal disease.Method:Human colonic epithelial cells,HT-29,were incubated with VIP(10^-8M).The expression of AQP8 mRNA and the protein was determined by Fluorogenic probe quantitative reverse transcription-polymerase chain reaction,(FQ-RT-PCR)and Immunocytochemical, respectively.Results:AQP8 mRNA and protein was expression in the human colonic epidermis cell line,HT-29 cell.The level of AQP8 mRNA expression at 3h after addition of VIP was remarkably higher than that of other time groups and the control(P＜0.001).The level of AQP8mRNA expression was no significantly difference in the control and the groups of 6h,12h,24h after addition of VIP(P＞0.05).The level of AQP8 mRNA expression was no significantly difference in the groups of 6h,12h,24h after addition of VIP(P＞0.05).The level of AQP8 protein expression at 3h after addition of VIP was remarkably higher than that of other time groups and the control(P＜0.001).The level of AQP8 protein expression was no significantly difference in the control and the groups of 6h,12h,24h after addition of VIP(P＞0.05).The level of AQP8 protein expression was no significantly difference in the groups of 6h,12h,24h after addition of VIP(P＞0.05).Conclusion:1.AQP8 is expressed in the human colonic surface epithelial cell abundantly, whereas less extent in intracytoplasm 2.AQP8mRNA expression in HT-29 cells was up-regulated by VIP.3.The peak enhancement of AQP8 was obserbed at 3h after incubation, after this time its expression was decrease gradually,these result indicated that the regulation of AQP8 expression by VIP is short-term.AQP8 is a membrane protein that transport water bidirectionaly.In our experiment we found that AQP8 expression was enhanced in VIP stimulated water and electrolytes secretion process and facilitated the water transported into enteric cavity,this may contributing to the onset of diarrhea.Therefore we can conclude that AQP maybe one of the target molecules in VIP caused diarrhea.