Osteopontin Concentration in Prostates Fractions: A Novel Marker of Sperm Quality in Dogs

SIMPLE SUMMARY: In our study, we investigate the relationship between sperm quality and osteopontin (OPN) in Malakli shepherd dogs, collecting sperm samples from 39 male dogs of various ages. We discovered significant differences in OPN levels between ejaculate fractions, with lower OPN concentrations being linked to poorer sperm motility and morphology. Our findings have the potential to significantly impact dog breeding and fertility practices, offering valuable insights to predict and enhance sperm quality for the future. This research not only advances animal reproduction science, but also benefits veterinary medicine and stud selection, ultimately contributing to the well-being of dog breeders’ society. ABSTRACT: This study aimed to investigate the relationship between the sperm quality and the osteopontin (OPN) concentration in the prostates of Malakli shepherd dogs. Ejaculates were collected once by digital manipulation from 39 male dogs aged between 2 and 4 years and older. The first and third fractions of the ejaculate were centrifuged at 5000× g for 30 min, and supernatants were stored at −80 °C for further analysis of OPN using a double-antibody sandwich method (SEA899CA, Cloude-Clone Corp, Houston, TX, USA). Meanwhile, the second fractions were evaluated for sperm motility, concentration, viability, and rate of abnormal spermatozoa (head, acrosome, midpiece and tail abnormalities). The average concentration of OPN was 8.7 ± 5.2 ng/mL, and it differed significantly between the 1st 10.4 ± 5.3 ng/mL and 3rd 7.4 ± 5 ng/mL fractions. According to ROC (receiver operating characteristic curve) analysis, the OPN concentration had a better diagnostic ability for sperm motility (p < 0.001) than for the rate of abnormal spermatozoa (p < 0.05). Additionally, the OPN concentration was negatively correlated with poor sperm morphology and motility. In conclusion, the OPN concentration in prostate-derived secretions may be a possible marker of sperm quality in dogs. Further research could explore the involvement of OPN in sperm motility during cryopreservation and in vivo fertility.