An ultrastructural study on the presence of various types of crystals in the infertile human testis.

Testicular biopsies obtained from 23 infertile outpatients, found to be normal except for oligospermia, were investigated using a Zeiss electron microscope. Ultrastructural changes in the Sertoli cells were encountered frequently, whilst most of the spermatogenic cells were degenerative. Sertoli cells exhibited abundant microfilaments which were seen to form small clusters leading to the formation of Charcot-Böttcher crystals, whilst the Leydig cells of the same specimens revealed the presence of small microtubular arrays and numerous small sized crystals. Fusion of small sized crystals resulted in the formation of typical Reinke crystals in the Leydig cells. Crystalloid structures similar to those seen in the Sertoli cells were also observed in the cytoplasm of type-A-spermatogonia and in a number of multinucleated cells with cytoplasmic characteristics of spermatogonia and Sertoli cells. Similar crystallization processes in both Sertoli and Leydig cells imply a close relationship between crystallization processes and impairment of spermatogenesis.