Peroxisome proliferator-activated receptor delta-PPARδ agonist (L-165041) enhances bovine embryo survival and post vitrification viability

The effect of L-165041 (PPARδ-agonist) on decreasing apoptosis and intracellular lipid content was assessed in fresh and vitrified-warmed in vitro-produced bovine embryos. It was hypothesised that the addition of L-165041 to the culture medium enhances development and cryopreservation. Oocytes were allocated to one of two treatments: control-standard culture medium, or L-165041 added to the medium on day 1 with no media change. Ultrastructure, cleavage, and blastocyst rates were evaluated in fresh, and in post-vitrification cultured embryos by optical and electronic microscopy. A subset of fresh embryos were fixed for TUNEL assay and for Sudan-Black-B histochemical staining. Vitrified-warmed embryos were assessed using MALDI-MS technique. Cleavage and blastocyst rates (control 49.4 ± 5.2, L-165041 51.8 ± 4.3) were not influenced by L-165041. The proportion of inner cell mass cells (ICM) was higher in fresh embryos, and the rate of total and ICM apoptosis was lower in L-165041. In warmed-embryos, total and ICM apoptosis was lower in L-165041. The overall hatching rate was higher in L-165041 (66.62 ± 2.83% vs 53.19 ± 2.90%). There was less lipid accumulation in fresh L-165041-embryos. In conclusion, the use of L-165041 is recommended to improve the viability of in vitro-derived bovine embryos.