Live human germ cells in the context of their spermatogenic stages

BACKGROUND: Various types of live, dispersed, human testicular cells in vit ro were previously compared with the morphologic characteristics of human s permatogenic germ cells in situ within seminiferous tubules. The current st udy extends those observations by placing live human germ cells in the cont ext of their developmental steps and stages of the spermatogenic cycle. MET HODS: Live human testicular tissue was obtained from an organ-donating, bra in-dead person. A cell suspension was obtained by enzymatic digestion, and dispersed cells were observed live with Nomarski optics. Testes from 10 men were obtained at autopsy within ten hours of death, fixed in glutaraldehyd e, further fixed in osmium, embedded in Epon, sectioned at 20 mum, and obse rved unstained by Nomarski optics. RESULTS: In both live and fixed preparat ions, Sertoli cells have oval to pear-shaped nuclei with indented nuclear e nvelopes and large nucleoli, which makes their appearance distinctly differ ent from germ cells. For germ cells, size, shape, and chromatic pattern of nuclei, the presence of meiotic metaphase figures, acrosomic vesicles/struc tures, tails, and/or mitochondria in the middle piece are characteristicall y seen in live dispersed cells and those in the fixed seminiferous tubules. These lead to identification of live germ cells in man and placement of ea ch in the context of their developmental steps of spermatogenesis at corres ponding stages of the spermatogenic cycle. CONCLUSIONS: This comparative ap proach allows verification of the identity of individual germ cells seen in vitro and provides a checklist of distinguishing characteristics of live h uman germ cells to be used in clinical procedures or by scientists interest ed in studying live cells at known steps in spermatogenic development chara cteristic of germ cells in specific stages of the spermatogenic cycle.