Integrated multiple transcriptomes in oviductal tissue across the porcine oestrous cycle reveal functional roles in oocyte maturation and transport
Abstract Understanding the changes in the swine female reproductive system is important for solving issues related to reproductive failure and litter size. Elucidating the regulatory mechanisms of the natural oestrous cycle in the oviduct under non-fertilisation conditions can improve our understanding of its role in the reproductive system. Herein, whole transcriptome RNA sequencing of oviduct tissue samples was performed. The differentially expressed genes (DEGs) were identified for each time point relative to Day 0 and classified into three clusters based on their expression patterns. Clusters 1 and 2 included genes involved in the physiological changes through the oestrous cycle. Cluster 1 genes were mainly involved in PI3K-Akt signalling and steroid hormone biosynthesis pathways. Cluster 2 genes were involved in extracellular matrix-receptor interactions and protein digestion pathways. In Cluster 3, the DEGs were downregulated in the luteal phase; they were strongly associated with cell cycle, calcium signalling, and oocyte meiosis. The gene expression in the oviduct during the oestrous cycle influenced oocyte transport and fertilisation. Our findings provide a basis for successfully breeding pigs and elucidating the mechanisms underlying the changes in the pig oviduct during the oestrous cycle.