Objective assessment of spermatogenesis in men with functional and anatomic obstruction of the genital tract.

Experimental rodent models simulating the condition of neurogenic infertility have drawn attention to the role of potential epididymal dysfunction as an underlying cause. This functional obstruction of the genital tract is comparable to the outcome of genital tract obstruction after vasectomy, and may explain the common finding of asthenospermia in both groups following either stimulated semen recovery or vasovasostomy, respectively. Since spermatogenic dysfunction has been reported in spinal cord injury, the relative roles of defective sperm production and sperm transport remain to be determined in men with neurogenic infertility. The objective of this study was to compare the levels of spermatogenesis in groups of vasectomized men and those with spinal cord injury, using objective measurement criteria for spermatogenesis. Groups of 10 spinal cord-injured and six vasectomized men matched for age and duration of disease, underwent incisional testicular biopsy. The specimens were divided equally for parallel quantitation of spermatogenesis by both quantitative cytometry and DNA flow cytometric analysis. Quantitative parameters showed similar values for both groups with reference to mean tubular wall thickness, mean tubular concentration of spermatids and Sertoli cells, as well as the mean spermatid: Sertoli cell ratio per tubule. Additionally, similar percentages of 1N, 2N and 4N cells, were found in both groups. Based on these preliminary findings this study provides a clinical correlation supporting the experimental observation that both anatomical and functional obstruction of the male genital tract exert a similar although minor spermatogenic insult, and that in both the putative cause for neurogenic infertility is more likely to be at the post-testicular level.