Embryo quality and production efficiency of porcine parthenotes is improved by phytohemagglutinin

Abstract

In vitro production of porcine embryos has become routine in most laboratories but the yield and quality of the resultant blastocysts remain suboptimal. Phytohemagglutinin (PHA) is an N-acetylgalactosamine/galactose sugar-specific lectin with a wide variety of biological activities including mitogenesis, mediation of cell recognition, and agglutination of cells. This study was therefore, designed to investigate the effect of PHA on the preimplantation embryo development and quality of in vitro produced porcine parthenotes. Parthenogenetic presumptive diploid zygotes were produced in vitro by electrical activation and cultured in the absence or presence of PHA at different concentrations (0, 5, 10, 15, 20 microg/ml). There were no significant differences in the cleavage rate of porcine parthenotes in control and treatment groups at all tested concentrations of PHA (P < 0.05). However, supplementation of PHA at the concentration of 15 microg/ml significantly improved the blastocyst rate (68.9 +/- 1.5% vs. 43.1 +/- 4.1%), hatching rate (25.8 +/- 3.1% vs. 8.9 +/- 2.0%), and total nuclei number (95.5 +/- 9.3 vs. 63.4 +/- 4.3) when compared to control group (P > 0.05). TUNEL labeling revealed that blastocysts in PHA group were less predisposed to biochemical apoptosis than in control group while total apoptosis and nuclear fragmentation remained unaltered. Real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis further revealed that PHA decreased the expression ratio of BAX/BCL-XL and enhanced the relative abundance of IGF2 transcripts. Therefore, our study suggests that PHA improves the blastocyst yield and quality by enhancing blastocyst expansion, hatching, and total cell number and decreasing the apoptosis by positively modulating the expression of embryo survival related genes.