CXCL12 improves the developmental potential of bovine oocytes by activating SHP2 during maturation

In vitro maturation (IVM) of mammalian oocytes is an important means in assisted reproductive technology. Most bovine immature oocytes complete nuclear maturation, but less than half develop to the blastocyst stage after fertilization. Thus, inefficient in vitro production (IVP) is mainly caused by a suboptimal in vitro culture process, in which oocyte quality appears to be the limiting factor. In our study, a potential maternal regulator, C-X-C motif chemokine ligand 12 (CXCL12), was identified by analyzing transcriptome data. CXCL12 supplementation promoted the developmental potential of oocytes by improving protein synthesis and reorganizing cortical granules and mitochondria during IVM, which eventually increased blastocyst formation efficiency and cell number after parthenogenesis, fertilization, and cloning. All these promoting effects by CXCL12 were achieved by activating SHP2, thereby promoting the MAPK signaling pathway. These findings provide an IVM system that closely resembles the maternal environment to provide high-quality oocytes for IVP.