Leukemia inhibitory factor supplementation during in vitro maturation enhances bovine oocyte maturation and somatic cloned embryo development.

Somatic cell nuclear transfer (SCNT) plays a crucial role in animal reproduction and genetic engineering, especially in the breeding of high-yield dairy cows. However, the application of SCNT technology faces numerous challenges, particularly the low efficiency and high abortion rates during the in vitro maturation phase. These issues lead to reduced implantation rates of cloned embryos, affecting overall reproductive efficiency. Therefore, enhancing the quality of in vitro maturation media has become an essential approach to improve in vitro production efficiency. This study aimed to investigate the effects of leukemia inhibitory factor (LIF) on bovine oocyte maturation and cloned embryo implantation rates. We observed a significant increase in oocyte maturation rates by supplementing 25 ng/mL LIF into the maturation medium. Subsequently, we generated SCNT embryos using LIF-treated oocytes and conducted activation and culture experiments. The results indicated that LIF could enhance the differentiation capabilities of SCNT embryos and exert an anti-apoptotic effect during early embryonic development. Specifically, the supplementation of LIF not only improved the nuclear maturation rates of oocytes but also enhanced cytoplasmic maturation characteristics, such as mitochondrial membrane potential and endoplasmic reticulum distribution. Furthermore, LIF-treated oocytes exhibited higher cell numbers and lower apoptosis rates in SCNT embryos, indicating its crucial role in embryo quality control. Ultimately, we found that LIF significantly improved the implantation efficiency of cloned embryos, particularly during the early stages of pregnancy following embryo transfer. This finding provides new insights into improving the success rates of SCNT technology and lays the groundwork for future research, especially in exploring the effects of other growth factors and cytokines on oocyte maturation and embryo development.