Fluctuation of Aquaporin 1, 5, and 9 Expression in the Pig Oviduct during the Estrous Cycle and Early Pregnancy

Abstract

Thirteen mammalian aquaporin (AQPs) isoforms with a unique tissue-specific pattern of expression have been identified. To date, 11 isoforms of AQP have been reported to be expressed in female and male reproductive systems. The purpose of our study was to determine the localization and quantitative changes in the expression of AQP1, 5 and 9 within the pig oviduct during different stages of the estrous cycle and early pregnancy. The results demonstrated that AQP1, 5, and 9 were clearly detected in all studied stages of the estrous cycle and pregnancy. AQP1 was localized within oviductal blood vessels. In cyclic gilts, the expression of AQP1 protein did not change significantly between days 10–12 and 14–16 but increased on days 2–4 and 18–20. AQP5 was localized in smooth muscle cells and oviductal epithelial cells. The expression of AQP5 protein did not change significantly between days 10–12 and 14–16 of the estrous cycle but increased on days 2–4 and 18–20. The anti-AQP9 antibody labeled epithelial cells of the oviduct. The expression of AQP9 did not change significantly between days 10–12 and 14–16 of the estrous cycle but increased on days 2–4 and 18–20. In pregnant gilts, expression of AQP1, 5, and 9 did not change significantly in comparison with the estrous cycle. Therefore, a functional and distinctive collaboration seems to exist among diverse AQPs in water handling during the different oviductal phases in the estrous cycle and early pregnancy.

Expression of 3β-hydroxysteroid dehydrogenase and P450 aromatase in porcine oviduct during the oestrous cycle

“…Chen et al (2013) have demonstrated that E2 and P4 regulate different ultrastructural features of porcine oviduct epithelium cells, expression of selected genes, sperm-binding capacity and probably fluid movement patterns along the epithelium lining. Furthermore, aquaporins expression in oviduct (Skowronski et al, 2011) and spontaneous motility of organ (Rodriguez-Martinez et al, 1982) changes in the course of oestrous cycle in pigs, indicating regulation by steroid hormones. Hence, it can be suggested that, besides ovarian steroids, also locally produced oviductal steroids may be involved in the regulation of oviductal functions.…”

“…These steroids affect gene expression, cells ultrastructure and differentiation, motility of oviduct, as well as the composition and volume of oviductal fluid during the oestrous cycle (Rodriguez-Martinez et al, 1982;Buhi, 2002;Yaniz et al, 2006;Carrasco et al, 2008;Skowronski et al, 2011;Hunter, 2012). Thus, steroids regulate oviductal microenvironment and support maturation of gametes, fertilization and early embryonic development (Hunter et al, 1999;Wollenhaupt et al, 2001;Buhi, 2002;Georgiou et al, 2005;Brüssow et al, 2008;Chen et al, 2013).…”

Glycan profile of oviductal isthmus epithelium in normal and superovulated ewes

“…Not all the oviductal NCs are secretory cells because some of them contain microvilli, which are covered with well-developed glycocalyx [11,60]. This suggests that NCs [61,62], which can be glycosylated [63][64][65]. AQPs take part not only in water transport but also in absorption or secretion of luminal fluid metabolites, thus maintaining a suitable environment for the reproductive functions.…”

Modifications of carbohydrate residues in the sheep oviductal ampulla after superovulation

“…This suggests that non-ciliated cells could be involved in absorptive phenomena which lead to the optimization of the luminal fluid for fertilization and embryonic development. As in other tissues, the absorptive activity of the intraluminal fluids occurring in the mammalian oviduct luminal surface is regulated by the aquaporins [67,68].…”

“…Therefore, it is possible that altered resorptive phenomena may take place in the oviductal ampulla of superovulated ewes. It has been demonstrated that sex-steroid hormones regulate the expression of some aquaporins during the estrous cycle in rat [67] and pig [68] oviduct. The physical properties of the mucus within the oviduct change during the sexual cycle.…”