Protamine1, 2 and Catsper1: sperm quality and fertility indicators in Stallions

The genes identification involved in male reproduction and the evaluation of its functions improve the comprehension about spermatogenesis molecular bases, fertilization, embryos early cleavage, spermatic quality and male infertility. The present study aimed to verify the Protamine1 (PRM1), Protamine2 (PRM2) and Cation Channel Sperm Associated 1 (Catsper1) genes expression into the equine sperm and their relations with the stallions' spermatic quality and fertility. Semen collections were performed in eighteen stallions, which were divided in two groups, based on fertility rates: fertile (with pregnancy rate per cycle ≥ 70%) and subfertile (with pregnancy rate per cycle ≤ 40%). The semen analysis was performed by Computer Assisted Sperm Analysis AndroVision®. The mRNA was extracted from the spermatozoa and the PRM1, PRM2 and Catsper1 gene expression verification in the spermatic cell was conducted by the qPCR technique. The results present a higher expression of PRM1 and Catsper1 in the fertile stallions' group than subfertile group; there was no correlation of PRM1 and PRM2 expression with spermatic quality parameters; there was correlation of the Catsper1 expression with morphology and motility parameters. Negative correlation was found between the PRM1/PRM2 ratio, fertility and motility parameters. The present research demonstrates that the PRM1 and Catsper1 genes are related to stallions' fertility and spermatic quality, and they may work as biomarkers.