Chronic scrotal hyperthermia induces azoospermia and severe damage to testicular tissue in mice

Scrotal hyperthermia leads to altered spermatogenesis due to heat-related oxidative stress. One of the main causes of infertility in men is oxidative stress, which refers to an imbalance in the levels of reactive oxygen species (ROS) and antioxidants. Therefore, this study aimed to evaluate the effects of chronic scrotal hyperthermia on testicular tissue structure, sperm parameters, and oxidative stress in adult mice. Thirty adult NMRI male mice were divided into three groups: Control (n = 10), Sham (n = 10), and Hyperthermia (n = 10). At the end of the study animals were sacrificed for evaluations of biochemical, cellular and histological analysis. The Hyperthermia group revealed a significant reduction in sperm count and weight of testis when compared to the control and sham groups. Also, succinate dehydrogenase (SDH) activity, ROS, ATP production, glutathione disulfide (GSH), tiols metabolism and stereological parameters in the hyperthermia group showed a significant reduction compared to the control and sham groups. Our results also revealed that scrotal hyperthermia significantly increases ROS production, mitochondrial membrane permeability (MMP), malondialdehyde (MDA), oxidized glutathione (GSSG) and apoptotic cells in testicular tissue in the hyperthermia groups in comparison with the control and sham groups. Overall, our result indicated that chronic scrotal hyperthermia causes complete spermatogenic arrest, probably mainly throughout the induction of oxidative stress.