Vitamin C enhances the <i>in vitro</i> development of early porcine embryos by improving mitochondrial function

Mammalian embryos often suffer from oxidative stress in vitro, as the oxygen in the atmosphere is higher than that in the oviductal environment. Vitamin C (Vc) has been proven to enhance early embryonic development <i>in vitro</i>, but the underlying mechanism remains unclear. In this study, we investigated the pathways of action by which Vc promotes the <i>in vitro</i> development of porcine embryos. Comparative analysis of <i>in vitro</i> and <i>in vivo</i> gene expression profiles of morula found that most of the differentially expressed genes were enriched in pathways related to mitochondrial function. The addition of 12.5 μg/mL Vc to the culture medium significantly increased blastocyst production in a dose- and duration-dependent manner. Moreover, ROS levels were significantly higher in embryos cultured in the air (21% oxygen) than cultured in a hypoxic condition (5% oxygen) and were reduced by Vc supplementation. Vc also significantly increased the mitochondrial membrane potential levels and the expression levels of mitochondrial function-related genes (<i>MFN1</i> and <i>OPA1</i>) and TCA cycle-related genes (<i>PDHA1</i> and <i>OGDH</i>) in embryos cultured <i>in vitro</i>. These results suggest that the addition of Vc to the <i>in vitro</i> culture medium can increase the developmental potential and improve the mitochondrial function of early porcine embryos.