Abstract

Water channels play important role in colon, and might be involved in constipation disease. To understand the mRNA expression changes of aquaporin protein 1 and 7 (AQP1, AQP7) in a rat model of slow transit constipation (STC), a rat model of slow transit constipation was designed, and the correlated changes of aquaporin protein 1 and 7 at the mRNA level were examined. The rat model of slow transit constipation was produced with diphenoxylate administration. The mRNA expression of AQP1 and 7 from STC rats and control rats were examined with reverse transcription polymerase chain reaction (RT-PCR). AQP1 was expressed in ascending and descending colon of both control and STC rats. For the ascending colon, the AQP1 grayscale ratio in control and STC rats were 0.602 ± 0.239 and 0.344 ± 0.212 (P < 0.05), respectively; these were 0.509 ± 0.308 and 0.419 ± 0.309 (P > 0.05), respectively in descending colon. AQP7 was also expressed in ascending and descending colon of both control and STC rats, with 0.776 ± 0.642 and 0.764 ± 0.147 in ascending colon (P > 0.05), and 0.736 ± 0.42 and 0.759 ± 0.629 in descending colon (P > 0.05), respectively. We did not examine the changes of the AQPs at the protein level. The downregulation of AQP1 rather than AQP7 might be involved in the development and progression of STC.

Key words: Aquaporin protein, AQP1, AQP7, slow transit constipation, mRNA.