Photobiomodulation is more effective than long-term scrotal hyperthermia in improving testis tissue and spermatogenesis in mice with busulfan-induced azoospermia.

Objective: The use of photobiomodulation (PBM) for tissue repair has gained acceptance. This study investigated and compared the effects of PBM on mice exposed to scrotal hyperthermia and busulfan.

Methods: Forty 8-week-old adult mice were divided into five groups: I) control, II) hyperthermia, III) busulfan, IV) hyperthermia+PBM, and V) busulfan+PBM. To induce azoospermia in groups II and IV, the scrotum of the mice was exposed to water at 43 °C every other day for 5 weeks. In groups III and V, a single dose of busulfan (45 mg/kg) was administered intraperitoneally. Mice in groups IV and V received laser irradiation (0.03 J/cm2/sec) every other day for 35 days.

Results: Molecular data analysis revealed that the levels of glutathione and the expression of proliferating cell nuclear antigen (Pcna) and stimulated by retinoic acid gene 8 (Stra8) genes were significantly higher in the busulfan+PBM group than in the hyperthermia+PBM group. Additionally, the number of testicular cells, tissue volume, and sperm parameters were also markedly higher in the busulfan+PBM group. Furthermore, this group exhibited a notable increase in serum testosterone levels.

Conclusion: The results demonstrated that laser therapy enhances testicular function and spermatogenesis by reducing the formation of reactive oxygen species and increasing the expression of mitotic genes following the induction of scrotal hyperthermia and busulfan injection. However, the effectiveness of PBM was greater in the busulfan+PBM group.