Spermatogonial proliferation patterns in men with azoospermia of different etiologies

To demonstrate the pattern(s) of spermatogonial proliferation in different spermatogenic disorders.

Retrospective case-control study. Teaching hospital.

Azoospermic men who underwent testicular biopsy for sperm recovery and preparation for intracytoplasmic sperm injection.

Testicular biopsy evaluation by quantitative immunohistochemistry for proliferating cell nuclear antigen (PCNA).

The expression of PCNA in spermatogonia as an index of proliferating activity in testes with focal spermatogenesis, spermatocyte maturation arrest, or normal spermatogenesis.

In biopsies with focal spermatogenesis (11 men), there was a statistically significant reduction of PCNA-labeled spermatogonia in seminiferous tubules showing spermatocyte arrest compared with the expression in adjacent tubules with advanced spermatogenic stage or in normal spermatogenesis (obstructive azoospermia, six men). However, PCNA expression in tubules of the group with complete maturation arrest (six men) was significantly higher compared with the same spermatogenic defect-spermatocyte arrest-within focal spermatogenesis biopsies.

Different causes underlie the spermatogenic disorders reported in this study. In focal spermatogenesis, the disorder is associated with the presence of mitotic inactive spermatogonia. The detection of normal active spermatogonia in the spermatocyte arrest group indicates that the spermatogenic defect, which is accompanied by meiosis impairment, is not related to a malfunction of spermatogonial proliferation.