THE HUMAN BLOOD-TESTIS BARRIER IN IMPAIRED SPERMATOGENESIS

The aim of this study was to explore the competence of the blood-testi s barrier (BTB) using electron opaque tracers in diverse human testicu lar pathologies associated with Sertoli cell only syndrome. Two groups of patients were studied: (1) those with complete depletion (absence) of germ cells, and (2) those with severe germ cell depletion but with some germ cells left in the seminiferous epithelium. The first situat ion was associated with cryptorchidism with absence of germinal cells, idiopathic cases of aplasia of germ cells, peritumoral areas surround ing small seminomas where the seminiferous tubules were observed to co ntain a predominant population of Sertoli cells, or long estrogen trea tment. The second was found also in cryptorchidism with early germ cel ls, idiopathic azoospermia, and oligospermia associated with sterility . In the first situation, seminiferous tubules lacked lumen and Sertol i cells had immature morphological characteristics, i.e., oval nuclei with smooth profiles, even heterochromatin distribution and a single, small nucleolus. Inter-Sertoli tight junctions were tortuous, interrup ted, and mostly perpendicular to the basal lamina. Lanthanum hydroxide or nickel nitrate permeated most of the inter-Sertoli spaces, indicat ing disruption of the BTB. In the second situation, seminiferous tubul es had a lumen, and Sertoli cells exhibited a mature appearance with l arge tripartite nucleoli and irregular, highly infolded nucleo-lemma. Only spermatogonia or primary spermatocytes showing diverse degrees of cell involution were found. Numerous inter-Sertoli tight junctions, u ninterrupted and parallel to the basal lamina, stopped the electron op aque intercellular tracers close to it; this meant the assembly of a c ompetent BTB. Therefore, a close correlation was found between morphol ogical parameters of Sertoli cell maturity, including their tight junc tion organization, and BTB integrity.