Role of follicle-stimulating hormone and estradiol benzoate in recovering spermatogenesis in tamoxifen-injured rats

Objective: To evaluate the effects of follicle-stimulating hormone (FSH) and estradiol benzoate (EB) on the recovery of spermatogenesis, histology, sexual hormones levels and testicular gene expression in testes of tamoxifen-injured rats. Methods: Forty adult rats were divided into eight groups in a factorial arrangement of tamoxifen and hormonal treatments. Half of the groups orally received 0.6 mg/kg tamoxifen, and 30 d later tamoxifen and notamoxifen groups (controls) were paired and assigned into four hormonal treatments with daily intramuscular injections for 10 consecutive days: 1 mL saline (control); 7.5 IU FSH; 12 μg/kg EB; and 7.5 IU FSH+12 μg/kg EB. One day after the last treatment, spermatozoa were recovered from epididymis, blood was processed for sex hormones concentration (testosterone, FSH and luteinizing hormone) and testes were processed for histology and RNA extraction for expression of genes related to apoptosis [caspase 3, inducible nitric oxide synthase (iNOS) and B-cell lymphoma-2 (Bcl-2)]. Results: Control groups did not show significant changes in most parameters, but hormonal treatments decreased caspase 3 and iNOS and increased Bcl-2 expression. Tamoxifen significantly decreased counts, motility and viability of spermatozoa, Bcl-2 expression and sex hormones. It increased intertubular space, caspase 3 and iNOS expression, and induced seminiferous tubular atrophy. The hormonal treatments reverted spermatogenesis, hormonal levels and histology compared with controls, however not attaining the same sperm quality as controls. Conclusions: Tamoxifen is clearly detrimental to spermatogenesis and overall testicular structure and function, whereas hormonal therapy with FSH and EB can improve testicular function and revert tamoxifen-induced azoospermia