Tissue testicular inhibin-B as a marker of spermatogenesis

Abstract

Inhibin-B is one of the most important serum markers of spermatogenesis, but its testicular expression has been studied to a relatively low extent. Moreover, its sensitivity as well as our ability to forecast the level of its intensity in spermatogenesis of elderly males are still subject to discussion. Objective: to study the role of inhibin-B in normal spermatogenesis, with Sertoli-cell syndrome and focal spermatogenesis (nonobstructive azoospermia). Methods. In a retrospective study were analyzed biopsies of testicular, in patients (n = 82) with non-obstructive azoospermia. In addition, we studied the effect of inhibin-B in the germ cells in healthy men aged 22—35 years (n = 10) and 64—75 years (n = 10). Inhibin-B was determined by immunolabeling immunohistochemistry. The level of inhibin-B was assessed by the number of the immunolabeling cells, which was calculated as a percentage of total cells in the sample. Results. When focal damage of spermatogenesis (mixed atrophy) is observed a pronounced accumulation of inhibin-B in Sertoli cells (98.0 ± 2.7%) and in Leydig cells (94.0 ± 1.5%) compared to young healthy men (65.9 ± 0.4% and 12.0 ± 0.4%, respectively). Number of immunolabeling cells for inhibin-B into spermatogonia was similar in young and elderly men (4.0 ± 0.2% and 5.0 ± 0.3%), and in patients with azoospermia sharply increased and was 45.0 ± 0.4%. In older men positive reaction for antibodies against inhibin-B in Sertoli cells was 83.0 ± 0.8%. Conclusion. The results of the study indicate accumulation of inhibin-B in Sertoli and Leydig cells in non-obstructive azoospermia, which eliminates the possibility of a compensatory effect on germ cells by a negative feedback loop. Expression levels of inhibin-B depend on the options syndrome of Sertoli cells associated with the Sertoli cell morphology. Indicators of the degree of tissue expression of inhibin-B can be used as a differential diagnostic marker of azoospermia and in the other forms of infertility.