Zoledronic acid induces cytogenetic toxicity in male germline cells of Swiss albino mice.

This study mainly focuses on the cytogenetic toxicity induction by zoledronic acid (ZA), a nitrogen containing bisphosphonate (N-BPs) in the male germline cells of Swiss albino mice. A single intraperitoneal exposure with three different doses of ZA (2, 4, and 8 mg/kg body weight), toxicity was assessed by analyzing spermatogonial metaphase chromosome aberrations at 24 h, aberrant primary spermatocytes at week 4, and abnormal spermatozoa at week 8 posttreatment. Cyclophosphamide (40 mg/kg) and 0.9% NaCl were used as positive and vehicle controls respectively in the study. The results showed that there was a significant induction in the number of chromosomal aberrations especially at two doses of ZA (4 and 8 mg/kg) after 24 h in the spermatogonial cells (p < 0.001) compared to vehicle control. The transmission genetic damages were noticed as aberrant spermatocytes with atypical bivalents (X-Y/autosomal asynapsis) at 4 mg/kg of ZA (p < 0.01) and at 8 mg/kg of ZA (p < 0.001) at week 4 posttreatment. A statistically significant higher number of abnormal spermatozoa (sperm) were also noticed at week 8 posttreatment of both at 4 and 8 mg/kg of ZA (p < 0.001). Hence, from these genotoxicity studies, it can be concluded that ZA is genotoxic in male germline cells and has the potential of transmitting the genotoxic effects from spermatogonial cells to sperm in male Swiss mice.