Spatial arrangement of testicular cells disrupted by transient scrotal hyperthermia and subsequent impairment of spermatogenesis.

The spermatogenesis is temperature-dependent and heat stress have destructive effects on spermatogenesis and reduces sperm quality. Sixteen adult mice were allocated to two groups: hyperthermia and control groups. Scrotal hyperthermia was induced by water bath with 43°C for 30 min. Then, the spermatozoon was isolated through the tail region of epididymis for sperm parameters analysis. The testicular tissues were taken for stereological studies, hormonal assay, TUNEL assay and molecular studies. We found a marked decrease in sperm parameters and serum testosterone level in mice induced by scrotal hyperthermia as well as stereological analysis indicated a significant reduction in testicular cells and changes in the spatial arrangement of testicular cells in the scrotal hyperthermia groups compared to the control groups. Moreover, the TUNEL assay results showed that apoptotic cells were enhanced significantly in the group of scrotal hyperthermia compared to the control groups. Furthermore, scrotal hyperthermia caused a reduction in the expression of retinoic acid 8 (STRA8), c-kit and proliferating cell nuclear antigen (PCNA) genes in the scrotal hyperthermia groups compared to the control. According to results, induction of transient scrotal hyperthermia leads to a fluctuation in the spatial arrangement of testicular cells, which finally influences the normal function of spermatogenesis.