Effects of microRNA-21-5p treatment of porcine sperm before and after capacitation on in vitro oocyte fertilization and embryo development

Context During in vitro fertilization (IVF), polyspermy occurs more frequently in pigs than in other species. Sperm function and embryo development are influenced by the paracrine effects of microRNAs. Aims In this study, we investigated the effects of microRNA-21-5p (miR-21-5p) treatment of porcine sperm on IVF efficiency and embryo development. Methods Porcine sperm were treated with no miR-21-5p (control group), 50 nM miR-21-5p (miRNA group) or 100 nM miR-21-5p inhibitor (inhibitor group) for 0–12 h. Key results Notably, miR-21-5p and its inhibitor exerted no significant effect on acrosome integrity or sperm viability. Sperm viability at different time points during treatment showed no significant change from 0 to 4 h, but decreased significantly by 12 h (P < 0.05). No significant difference in fertilization parameters was observed among sperm treated with miR-21-5p or its inhibitor during capacitation, those treated during IVF, or those treated during both capacitation and IVF. The rates of cleavage formation, two-cell stage development and blastocyst formation were significantly elevated (indicating accelerated development) for embryos derived from sperm treated with miR-21-5p inhibitor during IVF (P < 0.05). Conclusions The treatment of porcine sperm with miRNA-21-5p inhibitor at the stage of IVF could enhance the development of porcine embryos. Implications Our findings may inform interventions for enhancing embryo development during IVF in pigs.