Effects of Pharmacological and Agrochemical Endocrine Disruptors on Human Sperm Mitochondrial Respiration: Evidence from Ex Vivo Bioenergetic Profiling

Background: Human exposure to endocrine-disrupting chemicals (EDCs) is increasingly linked to male reproductive dysfunction, but underlying mechanisms remain unclear. This study aimed to evaluate how selected pharmacological (dihydroxyflutamide, 2OH-FTA; bicalutamide, BIC) and agrochemical (lindane, βHCH; permethrin, PERM; mancozeb, MNZ; tributyltin oxide, TBTO) EDCs affect mitochondrial function in human spermatozoa with parameters within World Health Organization (WHO) reference ranges. Methods: Human sperm cells were exposed ex vivo to 0.1–1000 nM of each compound. Mitochondrial respiration was measured using polarography, assessing oxygen consumption in active (V3) and resting (V4) states, and the respiratory control ratio (RCR) was calculated as an index of mitochondrial coupling. Results: Both 2OH-FTA and BIC reduced RCR in a concentration-dependent manner, mainly due to increases in V4, with BIC showing the strongest effect. βHCH produced a similar pattern, elevating V4 and decreasing RCR. In contrast, PERM, MNZ, and TBTO caused near-complete collapse of both V3 and V4 even at sub-nanomolar concentrations, indicating severe, concentration-independent mitochondrial toxicity. Conclusions: Sperm mitochondria are highly sensitive to EDCs, and distinct compounds exert different bioenergetic effects. Mitochondrial respiration assays provide a useful tool for ex vivo toxicological screening and risk assessment.