Interleukin‐4 Supplementation During In Vitro Culture Modulates the Expression of Stress‐ and Immune‐Related Genes During Porcine Blastocyst Development

The aim of this study was to evaluate the effect of supplementing in vitro culture medium of porcine zygotes with interleukin-4 (IL-4) on their developmental competence and quality. Cumulus-oocyte complexes (COCs) were matured and fertilized in vitro. The presumptive zygotes were then cultured in vitro for 7 days with different concentrations of IL-4 (25 pg/mL, 100 pg/mL, 25 ng/mL and 100 ng/mL) or without IL-4 (control). Cleavage and blastocyst formation rates were evaluated on days 2 and 7 of culture, respectively. On day 7 of IVC, some control and 25 pg/mL blastocysts were used to assess the expression of a panel of genes related to embryo quality by real-time quantitative PCR (RT-qPCR). The results did not show any positive effect of IL-4 on embryo developmental competence, regardless of its concentration. RT-qPCR revealed a significant downregulation of genes involved in cell cycle regulation (PCNA), DNA damage response and immune pathways (STAT6 and GATA3) in blastocysts treated with IL-4. In conclusion, supplementation of IVC medium with IL-4 did not improve the developmental competence of IVP embryos; however, IL-4 modulated the expression of stress- and immune-related genes in blastocysts.