Background: Aquaporins (AQPs), the family of water-selective channels, are localized in various organs and tissues, including the gastrointestinal (GI) tract. However, the roles of AQPs in the GI tract remain unclear. Materials and Methods: Male SD rats were subjected to subtotal colectomy (Group C, n = 22) or a sham operation (Group S, n = 16) and were sacri-ficed on postoperative days 7, 14, and 28. Total RNAs from the distal ileum and rectum were extracted. Quantitative RT-PCR was performed to measure AQP8 mRNA expression. For light-microscopy or immunohistochemistry, paraffin-embedded sections of 4 μm were prepared with H-E staining or anti-AQP8 antibody reaction. Mann-Whitney U-test was performed to compare the AQP8 distributions between the two groups, and the statistical significance was defined as p < 0.05. Results: AQP8 mRNA expression was enhanced in both the ileum and rectum in Group C at day 7. AQP8 protein expression was consistently observed in the ileum and rectum. The villus length in the ileum of Group C was significantly greater than that of Group S at days 7 and 14. Conclusion: Enhanced AQP8 mRNA expression in the subtotal colectomy model suggests that AQP8 plays an important role in maintaining the intestinal fluid balance.
King, L.S. and Agre, P. (1996) Pathophysiology of the aquaporin water channels. Annual Review of Physiology, 58, 619-648. doi:10.1146/annurev.ph.58.030196.003155
Preston, G.M., Carrol, T.P., Guggino, W.B. and Agre, P. (1992) Appearance of water channels in Xenopus oocytes expressing red cell CHIP28 protein. Science, 256, 385-387. doi:10.1126/science.256.5055.385
Fushimi, K., Uchida, S., Hara, Y., Hirata, Y., Marumo, F. and Sasaki, S. (1993) Cloning and expression of apical membrane water channel of rat kidney collecting tubule. Nature, 361, 549-552. doi:10.1038/361549a0
Ishibashi, K., Sasaki, S., Fushimi, K., Uchida, S., Kuwahara, M., Saito, H., Furukawa, T., Nakajima, K., Yamaguchi, Y. and Marumo, F. (1994) Molecular cloning and expression of a member of the aquaporin family with permeability to glycerol and urea in addition to water expressed at the basolateral membrane of kidney collecting duct cells. Proceeding of the National Academy of Sciences of the United States of America, 91, 6269-6273.
Jung, J.S., Bhat, R.V., Preston, G.M., Guggino, W.B., Baraban, J.M. and Agre, P. (1994) Molecular characterization of an aquaporin cDNA from brain candidate osmoreceptor and regulator of water balance. Proceeding of the National Academy of Sciences of the United States of America, 91, 13052-13056.
Raina, S., Preston, G.M., Guggino, W.B. and Agre, P. (1995) Molecular cloning and characterization of an aquaporin cDNA from salivary, lacrimal and respiratory tissues. Journal Biological Chemistry, 270, 1908-1912. doi:10.1074/jbc.270.4.1908
Ma, T., Yang, B., Kuo, W.L. and Verkman, A.S. (1996) cDNA cloning and gene structure of a novel water channel expressed exclusively in human kidney: Evidence for a gene cluster of aquaporins at chromosome locus 12q13. Genomics, 35, 543-550. doi:10.1006/geno.1996.0396
Ishibashi, K., Kuwahara, M., Gu, Y., Kageyama, Y., Tohsaka, A., Suzuki, F., Marumo, F. and Sasaki, S. (1997) Cloning and functional expression of a new water channel abundantly expressed in the testis permeable to water, glycerol and urea. Journal Biological Chemistry, 272, 20782-20786. doi:10.1074/jbc.272.33.20782
Koyama, Y., Yamamoto, T., Kondo, D., Funaki, H., Yaoita, E., Kawasaki, K., Sato, N., Hatakeyama, K. and Kihara, I. (1997) Molecular cloning of a new aquaporin from rat pancreas and liver. Journal Biological Chemistry, 272, 30329-30333. doi:10.1074/jbc.272.48.30329
Ishibashi, K., Kuwahara, M., Gu, Y., Tanaka, Y., Marumo, F. and Sasaki, S. (1998) Cloning and functional expression of a new aquaporin (AQP9) abundantly expressed in the peripheral leukocytes permeable to water and urea, but not to glycerol. Biochemical and Biophysical Research Communications, 244, 268-274. doi:10.1006/bbrc.1998.8252
Hatakeyama, S., Yoshida, Y., Tani, T., Koyama, Y., Nihei, K., Ohshiro, K., Kamiie, J.I., Yaoita, E., Suda, T., Hatakeyama, K. and Yamamoto T. (2001) Cloning of a new aquaporin (aqp10) abundantly expressed in duodenum and jejunum. Biochemical and Biophysical Research Communications, 287, 814-819. doi:10.1006/bbrc.2001.5661
Koyama, Y., Yamamoto, T., Tani, T., Nihei, K., Kondo, D., Funaki, H., Yaoita, E., Kawasaki, K., Sato, N., Hatakeyama, K. and Kihara I. (1999) Expression and localization of aquaporins in rat gastrointestinal tract. American Journal of Physiology, 276, C621-C627.
Tani, T., Koyama, Y., Nihei, K., Hatakeyama, S., Ohshiro, K., Yoshida, Y., Yaoita, E., Sakai, Y., Hatakeyama, K. and Yamamoto, T. (2001) Immunolocalization of aquaporin-8 in rat digestive organs and testis. Archives of Histology and Cytology, 64, 159-168. doi:10.1679/aohc.64.159
Berry, V., Francis, P., Kaushal, S., Moore, A. and Bhattacharyta, S. (2000) Missense mutations in MIP underlie autosomal dominant polymorphic and lamellar cataracts linked to 12q. Nature Genetics, 25, 15-17. doi:10.1038/75538
King, L.S., Choi, M., Fernandez, P.C., Cartron, J.P. and Agre, P. (2001) Defective urinary-concentrating ability due to a complete deficiency of aquaporin-1. New England Journal of Medicine, 345, 175-179. doi:10.1056/NEJM200107193450304
King, L.S., Nielsen, S., Agre, P. and Brown, R.H. (2002) Decreased pulmonary vascular permeability in aquaporin1-null humans. Proceeding of the National Academy of Sciences of the United States of America, 99, 1059-1063.
Deen, P.M., Verdijk, M.A., Knoers, N.V., Wieringa, B., Monnens, L.A., van Os, C.H. and van Oost, B.A. (1994) Requirement of human renal water channel aquaporin-2 for vasopressin-dependent concentration of urine. Science, 264, 92-95. doi:10.1126/science.8140421
Ma, T., Song, Y., Yang, B., Gillespie, A., Carlson, E.J., Epstein, C.J. and Verkman, A.S. (2000) Nephrogenic diabetes inspidus in mice lacking aquaporin-3 water channels. Proceeding of the National Academy of Sciences of the United States of America, 97, 4386-4391.
Ma, T., Yang, B., Gillespie, A., Carison, E.J., Epstein, C.J. and Verkman, A.S. (1997) Generation and phenotype of a transgenic knockout mouse lacking the mercurialinsensitive water channel aquaporin-4. The Journal of Clinical Investigation, 100, 957-962. doi:10.1172/JCI231
Steinfeld, S., Cogan, E., King, L.S., Agre, P., Kiss, R. and Delporte, C. (2001) Abnormal distribution of aquaporin-5 water channel protein in salivary glands from Sjogren’s syndrome patients. Laboratory investigation, 81, 143-148. doi:10.1038/labinvest.3780221
Verkman, A.S., Yang, B., Song, Y., Manley, G.T. and Ma, T. (2000) Role of water channels in fluid transport studied by phenotype analysis of aquaporin knockout mice. Experimental physiology, 85, 233S-241S. doi:10.1111/j.1469-445X.2000.tb00028.x
Purdy, M.J., Cima, R.R., Doble, M.A., Klein, M.A., Zinner, M.J. and Soybel, D.J. (1999) Selective decrease in levels of mRNA encoding a water channel (AQP3) in ileal mucosa after ileostomy in the rat. Journal of Gastrointestinal Surgery, 3, 54-60. doi:10.1016/S1091-255X(99)80009-2
Willis, S., Kisielinski, K., Klosterhalfen, B. and Schumpelick, V. (2002) Morphological and functional adaptation of the small intestine after colectomy and ileal pouch-anal anastomosis in rats. International Journal of colorectal Disease, 17, 85-91. doi:10.1007/s003840100352