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.