| Yak?Bos grunniens?lives on Qinghai-Tibet Plateau and adjacent,where few other animals survive.Yaks are important to the local herders for their production and life.However,rates of in vitro maturation?IVM?of oocytes and embryo development in yak are low,which largely limited the extension of yak embryo transfer.Platelet activating factor?PAF?plays an important role in reproductive and developmental processes.Therefore,the objectives of this study were to investigate the effects of PAF on oocye maturation and early embryonic development of yak and its molecular mechanism.A total of 1 025 yak cumulus-oocyte complexes?COCs?were matured in IVM medium contained different concentrations of PAF(0,10-8,10-7,10-6 mol/L),followed by in vitro fertilization?IVF?with cattle sperm and in vitro culture?IVC?.Rates of oocyte maturation,cleavage and blastocyst were compared between oocytes matured in IVM medium contained different concentrations of PAF.The relative expression levels of BAX,BCL-2,EGF,EGFR,C-fos,OCT-4 and NANOG genes were detected by qPCR.The results were shown as followings.?1?When IVM medium contained 10-7 mol/L PAF,the rates of oocyte maturation?92.16±0.19%?,cleavage?77.±0.85%?and blastocyst?46.71±0.68%?were significantly higher than that in the other groups?P<0.05?.?2?IVM medium contained 10-7 mol/L PAF increased expression levels of BCL-2,EGF,EGFR,C-fos and NANOG genes in matured oocytes,but decreased the expression levels of BAX and OCT-4 genes.?3?Embryos at 2-,4-,8-cell,morula and blastocyst stages derived from oocytes matured in different concentrations of PAF were not different in expression levels of BCL-2 and BAX genes.PAF concentrations did not affect the expression levels of EGF and EGFR genes at 2-,4-,8-cell and morula stages,but blastocyst derived from oocytes matured in IVM medium contained 10-7 mol/L PAF had higher expression of EGF and EGFR than from 10-6 mol/L PAF?P<0.05?.The expression level of OCT-4 gene in 10-7 mol/L PAF was significantly higher than that in10-6 and 10-8 mol/L PAF?P<0.05?.The expression level of NANOG gene of embryos derived from oocytes matured in IVM medium contained various concentrations were not significant different in all developmental stages?P>0.05?.In summary,the IVM medium contained 10-7 mol/L PAF could improve the rates of oocyte maturation,cleavage and blastocyst,which might regulate the expression of BAX,BCL-2,EGF,EGFR,C-fos,OCT-4 and NANOG genes. |
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