Objective: To observe the effects of Tongbian granules on the regulation of aquaporin 3 (AQP3) and aquaporin 8 (AQP8) in rats with slow transit constipation (STC)

and to clarify its possible mechanism. Method: A slow constipation rat mode was induced by compound phenylethyl piperidine. The 50 model rats were randomly divided into model group

low-

medium-and high-dose Tongbian granules groups (9.3

18.7

37.3 g·kg-1)

and polyethylene glycol powder group (2.1 g·kg-1). The another 10 normal rats were assigned to normal control group. All rats were ig adiminstrated with the corresponding medicines for 30 days.The body weight

24-hour stool weight

the carbon powder propulsion in the colon of rats were recorded and measured. The distribution and relative content of AQP3 and AQP8 in rat colon were detected. Result: Compared with model group

the body weight

24-hour stool weight

the carbon powder propulsion rate in the colon were decreased in model group. The above indexes were improved in the Tongbian granules groups (P<0.05). Immunohistochemistry results showed that the number of AQP3 and AQP8 were remarkably decreased in all dose Tongbian granules groups and polyethylene glycol powder group. Tongbian granules group of high dose had the best results (P<0.05). Conclusion: Tongbian granules has excellent curative effects in improving constipation defecation function of STC rats

which may be involved with the regulation of absorption and secretion of moisture achieved by depressing AQP3 and AQP8 in rat colon.