Expression of testicular androgen receptor in non-obstructive azoospermia and its change after hormonal therapy.

Several trials aimed at improving the sperm retrieval from men with non-obstructive azoospermia (NOA) by optimizing intratesticular testosterone (ITT) have reported partial responses, however, an appropriate level of ITT has not been identified. In this study, we examined the expression of the testicular androgen receptor (AR) in NOA and investigated its correlation with clinical and pathological parameters. Expression of the testicular AR was investigated in 52 men with NOA and 22 men with obstructive azoospermia (OA). Twenty-two patients for whom sperm retrieval failed during microdissection testicular sperm extraction (micro-TESE) were enrolled in hormonal therapy using hCG with or without recombinant human follicle stimulating hormone (rhFSH) prior to a second micro-TESE. Sertoli cells were identified by vimentin immunostaining, and positivity in Sertoli cells was used as the AR index. AR immunostaining was robust in the nuclei of Sertoli cells [Sertoli cell androgen receptor (SCAR)] in both OA and NOA. The mean AR index in NOA was significantly higher than that in OA (p < 0.05). In NOA patients, there was no correlation between the AR index and the clinical parameters, whereas the AR index of early maturation arrest (MA) was significantly lower than that of Sertoli cell only, late MA and hypospermatogenesis (p < 0.05). A significant increase in the AR index after salvage hormonal therapy was shown, particularly when using rhFSH. The AR index in patients from whom spermatozoa could be retrieved at the second micro-TESE increased significantly after hormonal therapy. In human testes, the expression of AR is dominant in Sertoli cells, and the expression of SCAR is upregulated by FSH. Germ cell maturation, especially during spermatogonia to spermatocyte stage, has been shown to be SCAR-dependent. Taken together, the results indicate that SCAR elevation is closely associated with sperm retrieval after hormonal therapy and that FSH-based hormonal therapy is potentially effective in NOA men with MA.