Ultrastructural integrity of mouse testicular cells separated by velocity sedimentation

Mouse testicular cells were examined ultrastructurally to determine whether the cells are damaged during the preparation of single-cell suspensions or during cell separation. The testicular cells were dissociated from seminiferous tubules by trypsinization and were fixed immediatley; fixed after being held in suspension for 4 h at 4 degrees C; or fixed after being separated into enriched fractions by sedimentation velocity either at unit gravity or by centrifugal elutriation. In general, the ultrastructural integrity of the cells, compared with that of corresponding testicular cells fixed in situ, was maintained during the dissociation and separation procedures. Ultrastructural abnormalities were most frequently produced in Sertoli cells and were occasionally observed in the acrosomes and nuclei of round spermatids. The cytoplasmic matrix of the midpiece of mature elongated spermatids or spermatozoa and the acrosomes of these cells were often disrupted. It is suggested that the dissociation procedures were responsible for most of the observed alterations of ultrastructural integrity.