Regeneration of spermatogenesis in a mouse model of azoospermia by follicle-stimulating hormone and oestradiol

Summary Busulfan is a chemotherapeutic drug that induces sterility, azoospermia and testicular atrophy. To induce degeneration of spermatogenesis, we used different amounts of busulfan. Adult male C57Bl/6 mice were treated with 15, 30 and 45 mg kg−1 of busulfan. After 5 weeks, animals had daily injections of 7.5 IU human follicle‐stimulating hormone (hFSH) and 12.5 μg kg−1 oestradiol benzoate (EB), separately or simultaneously. After this time, the animals were killed and blood samples were taken through cardiac puncture. Testes were used for histopathology experiments, DNA flow cytometry and RNA extraction for expression of c‐kit and cyclin B1 genes. EB unlike FSH has induced stimulatory effects on spermatogenesis, increased the level of serum testosterone 2‐fold and caused a 2‐fold increase in the number of haploid cells. The result showed that hFSH with EB multiplied EB stimulatory effects on spermatogenesis up to four times. Expression of c‐kit and cyclin B1 genes increased in EB and hFSH+EB groups. These findings suggest that EB regulates spermatogonial stem cells via hFSH. hFSH with EB had synergistic effect on regeneration of spermatogenesis.