CNP Regulates Mitochondrial Biosynthesis And Function Of Bovine Cunulus Cells And Oocytes

C-type natriuretic peptide(CNP)is one of the members of the natriuretic peptide family.Studies have shown that CNP improves oocyte development while maintaining the blocking of bovine oocyte meiosis in vitro,but the specific mechanism remains unclear Hence,this paper investigated the effect of CNP on mitochondrial biosynthesis and function of cumulus cells(CCs)and bovine oocytes,which provides a new insight into understanding the role of CNP in regulating oocyte developmental competence.In this study,bovine cumulus oocyte complexes(COCs)were collected and treated in the pre-in vitro maturation medium without(Control pre-IVM)or with CNP(CNP pre-IVM)for 6 hours,and then were subjected to routinely in vitro maturation culture(Control no pre-IVM)for 24 h,at the same time,the no pre-treated COCs were directly matured in vitro as a control(Control no pre-IVM).JC-1,Mito-Green,ROS kit,qPCR and immunofluorescence assay were used to detect membrane potential,mitochondrial distribution and density,reactive oxygen species,antioxidant factors,biosynthesis key factors,mitochondrial coding protein gene,nuclear coding protein gene and SIRT1 protein gene.The results showed that compared with the pre-mature control(Control no pre-IVM)and the pre-mature treatment without CNP(Control pre-IVM),the COCs of CNP pre-IVM(CNP pre-IVM)were significantly matured in vitro at 0 h.The ratio of semi-extended distribution of mitochondria in bovine oocytes increased,and the proportion of mitochondria evenly distributed in bovine oocytes was significantly increased after 24 hours in vitro(P<0.05),it also significantly increased the mitochondrial membrane potential and mitochondrial density of bovine cumulus cells and oocytes(P<0.05),thereby enhancing mitochondrial function;significantly improving the key regulatory factors of mitochondrial biosynthesis,nuclear genome coding and mitochondrial genome coding mitochondrial protein genes and SIRT1 gene expression(P<0.05),by affecting the expression of related genes to regulate mitochondrial biosynthesis;significantly increased the expression of antioxidant genes(P<0.05),significantly reduced the level of reactive oxygen species(P<0.05),and activate the antioxidant function of mitochondria.In summary,the pre-mature CNP treatment not only enhanced the biosynthesis and function of bovine oocytes and cumulus granulosa cells,but also improved the antioxidant function.