Aquaporin-3 (AQP3), one isoform of water channel family, has been found to be expressed in mouse oocytes. The present study aimed to investigate whether functional AQP3 was expressed in oocytes induced by controlled ovarian hyperstimulation (COH), and whether altered oocyte AQP3 expression was associated with changes in fertilization rate.
Sixty ICR female mice were divided into two groups: COH and control. AQP3 mRNA expression of mouse metaphase II (MII) oocytes was quantified by real-time RT-PCR. The water permeability of oocytes was assessed with cell swelling test. The fertilization profiles of oocytes were generated via in vitro fertilization.
AQP3 mRNA was expressed in both natural and COH-induced mouse oocytes. COH significantly reduced AQP3 mRNA expression. The volume of oocytes was significantly increased after exposure to hypotonic medium and pretreatment with HgCl(2) attenuated hypotonic medium-induced increase in oocyte volume and water permeability coefficient (Pf). Furthermore, the expression of AQP3, Pf and the fertilization rate were significantly lower in COH oocytes than those in control.
AQP3 might play an important role in controlling oocyte quality and a low in vitro fertilization rate of COH mice might, in part, result from reduced AQP3 expression and water permeability in mouse oocytes.
"In the present study, we demonstrated for the first time that Aqp3 mRNA is also present in immature and in vitro matured mouse oocytes. In addition, we confirmed that Aqp3 mRNA is present in in vivo matured mouse oocytes but not in cumulus cells, which is in good agreement with previous studies (Edashige et al., 2000; Meng et al., 2008). We employed a mouse model designed specifically to approximate the cytoplasmic maturity. "
[Show abstract][Hide abstract] ABSTRACT: This study aimed to investigate whether aquaporin 3 (Aqp3) mRNAs are expressed in immature oocytes and altered during in vitro maturation process. Five- to 6-week-old female ICR mice were primed by gonadotropin for 24 and 48 h. Immature oocytes obtained 48 h after priming were also matured in vitro for 17 to 18 h. In vivo matured oocytes were obtained after 48 h priming followed by hCG injection. Total RNAs were extracted from 80 to 150 oocytes in each experimental group, and the levels of Aqp3 mRNA were quantified by real-time reverse transcriptase polymerase chain reaction. The experiments were repeated twice using different oocytes. The Aqp3 mRNA was expressed in immature oocytes, as well as in in vitro and in vivo matured oocytes. The expression level was higher in immature oocytes obtained 48 h after priming (17.2 ± 8.6, mean ± SD) than those with no priming (5.7 ± 0.8) or obtained 24 h after priming (2.5 ± 0.8). The expression of Aqp3 mRNA decreased after in vitro maturation (1.2 ± 0.5), which was similar to in vivo matured oocytes (1.0 ± 0.0). Our work demonstrated that Aqp3 mRNA expression increased during the development of immature oocyte but decreased after completion of in vitro maturation. The results indicate that AQP3 is certainly needed for the acquisition of immature oocytes' full growing potential within antral follicles.
"Edashige et al.  showed the expression of AQP3 and AQP7 mRNA in mouse oocytes. The presence of AQP3 mRNA in mouse oocytes was recently confirmed by Meng et al. . AQP7, 8 and/or 9 have been shown to participate in water influx across the ovarian follicle wall primarily through transcellular transport mechanisms in the rat . "
[Show abstract][Hide abstract] ABSTRACT: Aquaporins (AQPs) are a family of membrane channel proteins that facilitate bulk water transport. To date, 11 isoforms of AQPs have been reported to be expressed in the 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 uterus during different stages of the estrous cycle and early pregnancy.
Immunoperoxidase and semi-quantitative immunoblotting techniques were used to examine the distribution and changes in amounts of AQP1, AQP5 and AQP9 in uteral cells of pigs at the early (Days 2-4), middle (10-12), late (14-16) stage of the luteal phase and late (18-20) stage of the follicular phase of the estrous cycle as well as on Days 14-16 and 30-32 of gestation (the onset and the end of implantation process).
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 uterine blood vessels. In cyclic gilts, endometrial and myometrial expression of AQP1 protein did not change significantly but increased during gestation. AQP5 was localized in smooth muscle cells and uterine epithelial cells. Endometrial expression of AQP5 protein did not change significantly between Days 2-4 and 10-12 of the estrous cycle but increased on Days 14-16 and 18-20 as well as during early pregnancy. Myometrial expression of AQP5 did not differ significantly during the estrous cycle but increased in the pregnancy. The anti-AQP9 antibody labeled uterine epithelial cells of uterus. Endometrial expression of AQP9 did not change significantly between Days 2-4 and 10-12 of the estrous cycle but increased on Days 14-16 and 18-20 as well as during early pregnancy.
The results suggest that a functional and distinctive collaboration exists among diverse AQPs in water handling during the different uterine phases in the estrous cycle and early pregnancy.
"These channels are widely distributed in all kingdoms of life, including bacteria, plants, and mammals (Tait et al. 2008). Thirteen isoforms, aquaporin 0 (AQP0) to aquaporin 12 (AQP12) have been found in mammals to date (Meng et al. 2008), and several diseases, such as congenital cataracts and nephrogenic diabetes insipidus, are associated with the impaired function of these channels (Francis et al. 2000 ; Ma et al. 2000). AQP4 is the principal AQP in mammalian brain (Manley et al. 2000), and its expression is polarized in astrocyte foot process adjacent to endothelial cells (Tait et al. 2008). "
[Show abstract][Hide abstract] ABSTRACT: Our previous study revealed that aquaporin 4 (AQP4) knockout attenuated locomotor activity in cocaine exposure mice and reduced the extracellular dopamine levels in the nucleus accumbens, suggesting that AQP4 might participate in cocaine addiction. The aim of the present study was to investigate the impact of AQP4 on cell proliferation of dentate gyrus in the mouse hippocampus after repeated cocaine treatment and withdrawal. The immunohistochemistry results showed that repeated cocaine administration significantly decreased cellular proliferation in the subgranular zone, which was followed by a rebound increase after 2-wk withdrawal and a return to normal level after 3-wk withdrawal. AQP4 knockout resisted cocaine-induced reductions of neural cell proliferation. Further studies through immunohistochemistry and immunoblot analysis showed that AQP4 knockout sustained the levels of glial fibrillary acidic protein in the hippocampus, and suppressed the enhancement of extracellular signal-regulated kinase phosphorylation induced by repeated cocaine administration. Notably, AQP4 knockout increased protein kinase C activity examined by substrate protein phosphorylation method, which was not affected by cocaine administration or withdrawal. We also found that repeated cocaine administration could elevate the expression of AQP4 in wild-type mice. In conclusion, it is reported for the first time that AQP4 knockout resisted cocaine-mediated inhibition of neural cell proliferation via up-regulating PKC-mediated signal transduction, suggesting that AQP4 might regulate neurogenesis during drug addiction. Our findings may have helpful implications in the cell biology of neurogenesis.
The International Journal of Neuropsychopharmacology 03/2009; 12(6):843-50. DOI:10.1017/S1461145709009900 · 4.01 Impact Factor
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