Telomerase activity in the testis of infertile patients with selected causes

In human testes, stem cells such as spermatogonia need to produce progeny cells continually. Telomere length is maintained throughout spermatogenesis, i.e. from spermatogonia to spermatozoon, and telomerase is reported to be present in the testes. In this study, we measured the activity of telomerase in the human testes of 16 cases of idiopathic azoospermia, 10 of obstructive azoospermia, and 17 of oligozoospermia in order to understand the role of telomerase in spermatogenesis. Telomerase activity in the testes with Sertoli cell-only and in testes with maturation arrest were 0.08 +/- 0.05 optical density (OD) (mean +/- SD) and 1.96 +/- 0.98 OD, respectively (P < 0.05). Classifying those testes with maturation arrest into two groups, the telomerase activity of those with early maturation arrest (arrest at spermatocyte) and of those with late maturation arrest (arrest at round spermatid) was 1.82 +/- 0.82 OD and 2.10 +/- 1.14 OD respectively. There was no significant difference between the two groups. The telomerase activity in the testes showing hypospermatogenesis in obstructive azoospermia and in those of oligozoospermia with hypospermatogenesis was 1.89 +/- 1.06 OD and 1.92 +/- 1.02 OD respectively. No difference in telomerase activity existed between the testes with maturation arrest and those with hypospermatogenesis in obstructive azoospermia or oligozoospermia. Sertoli cell-only testes without germ cells showed no telomerase activity. The source of the telomerase activity was likely to be germ cells. The telomerase activity in the testes (n = 63) was related to the histology of the testes. The activity of telomerase showed no significant correlation with the sperm concentration in each patient. Only serum oestradiol level significantly correlated with telomerase activity (P < 0.05). The concentrations of follicle stimulating hormone, luteinizing hormone, or testosterone had no significant relationship with the telomerase activity. Therefore similar levels of telomerase activity were detected in the testes of infertile men with azoospermia and oligozoospermia and in testes showing maturation arrest.