Quantitative analysis of sperm mRNA in the pig: relationship with early embryo development and capacitation

Abstract

Although it is well known that mRNA is present in mammalian spermatozoa, the relevance of mRNA to capacitation and early embryo development in the pig remains unclear. In the present study, we investigated differences in the abundance of selected mRNAs coding for MYC, CYP19, ADAM2, PRM1 and PRM2 in purified porcine spermatozoa depending on embryo cleavage rate and capacitation (n = 20 semen samples). Semen samples were used in IVF procedures, with subsequent embryo development classified into one of two groups based on cleavage rate (i.e. high (>75%) and low (<75%) cleavage groups) and mRNA abundance in purified spermatozoa compared between these two groups. In addition, mRNA abundance was compared between capacitated and non-capacitated spermatozoa. Comparison of mRNA levels between porcine spermatozoa revealed that the abundance of MYC, CYP19, ADAM2, PRM1 and PRM2 mRNA was significantly greater in the high cleavage group (n = 10 high cleavage group semen samples) than in the low cleavage group (n = 10; P < 0.05). Significant downregulation of MYC mRNA was observed in capacitated spermatozoa (n = 12; P < 0.05). The results of the present study suggest that the amount of specific mRNAs could be used for estimating the quality of spermatozoa in the pig.