Supplementation of Forskolin and Linoleic Acid During IVC Improved the Developmental and Vitrification Efficiency of Bovine Embryos

The success of assisted reproductive technology is contingent upon the growth potential of embryos post-vitrification process. When compared to in vivo embryos, it has been found that the high intracellular lipid accumulation inside the in vitro-derived embryos results in poor survival during vitrification. Based on this finding, the present study assessed the impact of incorporating forskolin and linoleic acid (FL) entering in vitro culture (IVC) on the embryos' cryo-survival, lipid content, and viability throughout vitrification. Lipid metabolomics and single-cell RNA sequencing (scRNA-seq) techniques were used to determine the underlying mechanism that the therapies were mimicking. It was observed that out of 726 identified lipids, 26 were expressed differentially between the control and FL groups, with 12 lipids upregulated and 14 lipids downregulated. These lipids were classified as Triacylglycerol (TG), Diacylglycerol (DG), Phosphatidylcholine (PC), and so on. A total of 1079 DEGs were detected between the FL and control groups, consisting of 644 upregulated genes and 435 downregulated genes. These DEGs were significantly enhanced in the arachidonic acid metabolism, lipolysis, fatty acid metabolism, cAMP signaling pathway, and other critical developmental pathways. Based on the observation, it was concluded that forskolin and linoleic acid decreased the droplet content of embryos by modulating lipid metabolism, thus enhancing the vitrified bovine embryos' cryo-survival.