Effects of Porcine Relaxin Hormone on Motility Characteristics of Boar Spermatozoa during Storage

First, a preliminary study was conducted looking for the optimum sperm concentration to be used for analysis with the Computer-Assisted Sperm Analysis (CASA). Results showed that 75x106 sperm cells/mL is the optimum one. Then, the actions of relaxin on sperm motility were evaluated by determining the effect of relaxin on full motility characteristics of spermatozoa during storage, using CASA; then identifying the relaxin receptors on spermatozoa, and finally establishing actions of relaxin in intraspermatic cAMP content. Motile spermatozoa were selected through percoll gradient and incubated for 1 hour with 4 relaxin concentrations at 37°C, during four days. Relaxin affected sperm motility (P\u3c0.05). This action appears associated with the presence of relaxin receptors RXFP1 and RXFP2 that were found in spermatozoa. However, the cAMP levels were not affected by relaxin (P\u3c0.05). This study indicates a beneficial action of relaxin on sperm motility; however, its mechanism of action requires further research