Correlation of Adiponectin mRNA Abundance and Its Receptors with Quantitative Parameters of Sperm Motility in Rams

BACKGROUND Adiponectin and its receptors (AdipoR1 and AdipoR2), known as adiponectin system, have some proven roles in the fat and glucose metabolisms. Several studies have shown that adiponectin can be considered as a candidate in linking metabolism to testicular function. In this regard, we evaluated the correlation between sperm mRNA abundance of adiponectin and its receptors, with sperm motility indices in the present study. MATERIALS AND METHODS In this completely randomized design study, semen samples from 6 adult rams were fractionated on a two layer discontinuous percoll gradient into high and low motile sperm cells, then quantitative parameters of sperm motility were determined by computer-assisted sperm analyzer (CASA). The mRNA abundance levels of Adiponectin, AdipoR1 and AdipoR2 were measured quantitatively using real-time reverse transcriptase polymerase chain reaction (qRT-PCR) in the high and low motile groups. RESULTS Firstly, we showed that adiponectin and its receptors (AdipoR1 and AdipoR2) were transcriptionally expressed in the ram sperm cells. Using Pfaff based method qRT- PCR, these levels of transcription were significantly higher in the high motile rather than low motile samples. This increase was 3.5, 3.6 and 2.5 fold change rate for Adiponectin, AdipoR1 and AdipoR2, respectively. Some of sperm motility indices [curvilinear velocity (VCL), straight-line velocity (VSL), average path velocity (VAP), linearity (LIN), wobble (WOB) and straightness (STR)] were also significantly correlated with Adiponectin and AdipoR1 relative expression. The correlation of AdipoR2 was also significant with the mentioned parameters, although this correlation was not comparable with adiponectin and AdipoR1. CONCLUSION This study revealed the novel association of adiponectin system with sperm motility. The results of our study suggested that adiponectin is one of the possible factors which can be evaluated and studied in male infertility disorders.