RESUMEN
In this study, we reported for the first time the dose-dependent dual effects of Alpha-Ketoglutarate (AKG) on cumulus oocyte complexes (COCs) during in vitro maturation (IVM). AKG at appropriate concentration (30 µM) has beneficial effects on IVM. This includes improved cumulus expansion, oocyte quality, and embryo development. These effects are mediated through multiple underlying mechanisms. AKG reduced the excessive accumulation of reactive oxygen species (ROS) in cumulus cells, reduced the consumption of GSH and NADPH. Cumulus GSH and NADPH were transported to oocytes via gap junctions, thereby reducing the oxidative stress, apoptosis and maintaining the redox balance in oocytes. In addition, AKG improved the mitochondrial function by regulating the mitochondrial complex 1 related gene expression in oocytes to maintain mitochondrial membrane potential and ATP production. On the other hand, oocyte generated GDF9 could also be transported to cumulus cells to promote cumulus expansion. Conversely, a high concentration of AKG (750 µM) exerted adverse effects on IVM and suppressed the cumulus expansion as well as reduced the oocyte quality. The suppression of the cumulus expansion caused by high concentration of AKG could be rescued with GDF9 supplementation in COCs, indicating the critical role of GDF9 in IVM. The results provide valuable information on the variable effects of AKG at different concentrations on reproductive physiology.
Asunto(s)
Células del Cúmulo , Técnicas de Maduración In Vitro de los Oocitos , Ácidos Cetoglutáricos , Oocitos , Especies Reactivas de Oxígeno , Ácidos Cetoglutáricos/farmacología , Ácidos Cetoglutáricos/metabolismo , Oocitos/efectos de los fármacos , Oocitos/metabolismo , Animales , Células del Cúmulo/efectos de los fármacos , Células del Cúmulo/metabolismo , Células del Cúmulo/citología , Técnicas de Maduración In Vitro de los Oocitos/métodos , Femenino , Especies Reactivas de Oxígeno/metabolismo , Ratones , Relación Dosis-Respuesta a Droga , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , Factor 9 de Diferenciación de Crecimiento/metabolismo , Factor 9 de Diferenciación de Crecimiento/genética , Glutatión/metabolismo , Estrés Oxidativo/efectos de los fármacos , NADP/metabolismo , Apoptosis/efectos de los fármacos , Potencial de la Membrana Mitocondrial/efectos de los fármacosRESUMEN
Embryonic mortality is considered to be one of the main reasons for reduced conception rates in the cattle industry. Insufficient endometrial receptivity is a major factor resulting in embryo implantation failure and losses. Apoptosis of endometrial epithelial cells is an important process during establishment of uterine receptivity and embryo implantation. The aim of this study was to explore the role of bta-miR-200b on endometrial epithelial cell apoptosis in cattle. Overexpression of bta-miR-200b upregulated the expression of proapoptotic gene BCL2 associated X, apoptosis regulator (BAX) and endometrial receptivity marker gene osteopontin (OPN) at mRNA and protein level in bovine endometrial epithelial cells. Moreover, overexpression of bta-miR-200b was able to inhibit proliferation and promote apoptosis of bovine endometrial epithelial cells by arresting the cell cycle at the G0/G1 phase. MYB Proto-Oncogene (MYB) was verified to be a target of bta-miR-200b in bovine endometrial epithelial cells using dual-luciferase reporter assay. Transfection of bta-miR-200b mimics decreased the mRNA and protein expression of MYB. Overexpression of MYB decreased the effect of bta-miR-200b on apoptosis of bovine endometrial epithelial cells. Our findings suggest that bta-miR-200b can affect the apoptosis of endometrial epithelial cells in cattle by targeting the MYB gene.