[Ultrastructural analysis of anionic sites of the basal membrane of the seminiferous tubules of subjects with severe oligospermia].

Several morphological alterations of the basement membrane of the seminiferous tubules have been reported in the patients presenting with a testicular sterility. The proteoglycans are one of the major components of the basal membrane and may be ultrastructurally defined by the use of the cationic marker polyethyleneimine (PEI). In comparaison to the normal distribution of the anionic sites labelled by PEI which is characterized by a regular pattern of distribution along both the epithelial and the interstitial faces of the lamina densa, the pattern of distribution of the sites is largely altered in 6 patients, 27 to 40 years of age, with oligo- or azoospermia. Several types of alterations are reported: parallel thickening of the lamina densa with an abnormal distribution of the anionic sites inside the lamina densa, stratifications of the basal membrane depressing the seminiferous epithelium with anionic sites labelled on both faces of the lamina densa-like layers, massive expansions of the lamina densa with either a regularly circumferential labelling of the sites or a random type of distribution. The digestion of the sites by the enzyme heparitinase is highly suggestive of the presence of proteo-heparan-sulfate. The analysis of the distribution of the anionic sites may represent a usefull tool for studying the pathogenesis of testicular sterility.