Furosemide induces dose-dependent testicular toxicity via disrupting blood-testis barrier, inflammation, and apoptosis: A comprehensive biochemical, hormonal, and histopathological study.

Furosemide (FSD) is a widely prescribed loop diuretic; however, its potential reproductive toxicity and its underlying mechanism have not been explored yet. The current study assessed the dose-dependent effects of FSD on testicular function in Sprague Dawley rats. Thirty-two male Sprague Dawley rats were apportioned into four groups i.e., control, FSD (10 mg/kg), FSD (20 mg/kg), and FSD (30 mg/kg) treated group. FSD exposure significantly downregulated the expression of blood-testis barrier genes (CLDN11, OCLN, TJP1, F11R, CDH2, GJA1), as well as upregulated pro-inflammatory mediators (NF-κB, TNF-α, IL-1β, IL-6, COX-2) in a dose-dependent manner, which indicates disruption of intercellular junctions and testicular inflammation. Oxidative stress was significantly increased, as revealed by increased ROS and MDA concentrations and decreased antioxidant enzymes (CAT, SOD, GPx, GSR, HO-1) after FSD exposure. Moreover, FSD intoxication suppressed the levels of reproductive hormones (LH and FSH, testosterone), indicating the impairment of the hypothalamic-gonadal axis. Apoptotic indices showed increased Bax, Caspase-3, Caspase-9 and decreased Bcl-2 after FSD administration, confirming activation of mitochondrial-mediated germ cell death. Similarly, semen analysis showed FSD exposure reduced the number, motility, sperm membrane integrity, and viability while increasing sperm abnormalities. Steroidogenic enzymes (StAR, 3β-HSD, 17β-HSD) were suppressed, which may indicate impaired biosynthesis of testosterone and spermatogenesis. Histopathological evaluations revealed severe degree of seminiferous tubule degeneration, reduction of germ cell population, and structure change of testicular architecture following the administration of FSD. Collectively, these findings demonstrate the multifaceted testicular toxicity of FSD, via disruption of BTB, oxidative stress, hormonal dysregulation, apoptosis and structural degeneration, leading to eventual consequences on male reproductive health. These results distinguish the potential reproductive risk caused by FSD exposure, warranting clinical trials for validation in humans.