Novel stage classification of human spermatogenesis based on acrosome development.
To date, in the human seminiferous epithelium, only six associations of cell types have been distinguished, subdividing the epithelial cycle into six stages of very different duration. This hampers comparisons between studies on human and laboratory animals in which the cycle is usually subdivided into 12 stages. We now propose a new stage classification on basis of acrosomal development made visible by immunohistochemistry (IHC) for (pro)acrosin. IHC for acrosin gives results that are comparable to periodic acid Schiff staining. In the human too, we now distinguish 12 stages that differ from each other in duration by a factor of two at most. B spermatogonia are first apparent in stage I, preleptotene spermatocytes are formed in stage V, leptonema starts in stage VII, and spermiation takes place at the end of stage VI. A similar timing was previously observed in several monkeys. Stage identification by way of IHC for acrosin appeared possible for tissue fixed in formalin, Bouin fixative, diluted Bouin fixative, Cleland fluid, and modified Davidson fixative, indicating a wide applicability. In addition, it is also possible to distinguish the 12 stages in glutaraldehyde/osmium-tetroxide fixed/plastic embedded testis material without IHC for acrosin. The new stage classification will greatly facilitate research on human spermatogenesis and enable a much better comparison with results from work on experimental animals than hitherto possible. In addition, it will enable a highly focused approach to evaluate spermatogenic impairments, such as germ cell maturation arrests or defects, and to study details of germ cell differentiation.
Fondazione Pasteur Cenci Bolognetti, Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Section of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy.
Barbara
B
Muciaccia
Carla
C
Boitani
B Pasquale
BP
Berloco
Francesco
F
Nudo
Gustavo
G
Spadetta
Mario
M
Stefanini
Dirk G
DG
de Rooij
Elena
E
Vicini
D000177:Acrosome / Q000145:classification* / Q000502:physiology*; D000328:Adult; D000368:Aged; D000818:Animals; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D013087:Spermatids / Q000502:physiology; D013091:Spermatogenesis / Q000502:physiology*; D013093:Spermatogonia / Q000145:classification* / Q000166:cytology / Q000502:physiology; D055815:Young Adult
acrosome; cycle of the seminiferous epithelium; human reproduction; spermatid; spermatogenesis