SERUM AND SEMINAL FLUID (RANKL) AND OSTEOPROTEGERIN LEVELS IN THE DIFFERENTIATION OF MALES WITH ASTHENOZOOSPERMIA
Asthenozoospermia is defined as diminished sperm motility and is frequently observed in infertile males. This study was designed to examine the potential roles of receptor activator of nuclear factor of kappa-beta ligand (RANKL) and osteoprotegerin (OPG) in the development of asthenozoospermia, a subtype of male infertility. This case-control study was conducted at the infertility center of Al-Batool Teaching Hospital in Diyala Governorate, Iraq, in collaboration with the Department of Biochemistry, College of Medicine, University of Baghdad, between April 2024 and January 2025. The study enrolled 59 male subjects aged 20-55 years, who were categorized into two groups based on seminal fluid analysis: a normozoospermic group (n=29), which served as the control, and an asthenozoospermic group (n=30). Investigations included serum and seminal fluid measurements of parameters using enzyme-linked immunosorbent assays. The results showed that RANKL levels in both seminal plasma and serum were significantly increased, whereas OPG levels in both fluids were significantly decreased in the asthenozoospermic group compared with the normozoospermic group (p < 0.001 for all comparisons). The reservoir operating characteristics analysis revealed that seminal fluid and serum OPG demonstrated excellent diagnostic capability in distinguishing asthenozoospermic infertile subjects. The study suggests that seminal and serum OPG levels, and, to a lesser extent, serum RANKL, could serve as a new biomarker for differentiating asthenozoospermic subjects and could be used as a confirmatory (or alternative) test to seminal fluid analysis in such patients.