Enzymatic activity of mouse group X-sPLA2 improves in vitro production of preimplantation bovine embryos.

Assisted reproductive technologies (ART) are widely used for both humans and domestic animals. In bovine species, in vitro embryo production is increasingly used and significant efforts are being made to optimize media and culture conditions. Phospholipase A2 (PLA2) are lipolytic enzymes that hydrolyze glycerophospholipids to produce free fatty acids and lysophospholipids that have been found to be critical for many biological processes. Mouse group X secreted PLA ₂ (mGX) is abundant in the male reproductive tract and its use during sperm capacitation has been shown to improve in vitro production of viable embryos in a mouse model. Here, we examined its effect in the bovine species, testing the impact of mGX on the three steps involved in vitro production of preimplantation embryos: oocyte maturation, fertilization and preimplantation development. We found that incubating cumulus oocyte complexes (COC) or gametes with mGX resulted in increased blastocyst hatching and blastocyst production, respectively. The increases of embryo production induced by the phospholipase mGX were not observed for the catalytically inactive mutant H48Q-mGX, suggesting that these effects require the enzymatic activity of mGX. We also tested bGIB, a bovine homolog of mGX. bGIB failed to improve blastocyst production, underlining the high specificity of mGX. In conclusion, the results presented show that the effects of mGX are not restricted to the mouse model and that it is potent in the bovine species as well. This result strengthens the potential of mGX as a "pro-fertility drug" for mammalian reproduction.
(Copyright © 2019 Elsevier Inc. All rights reserved.)