Caspase-dependent and -independent DNA fragmentation in Sertoli and germ cells from men with primary testicular failure: relationship with histological diagnosis.
BACKGROUND
Germ cell elimination and sperm DNA fragmentation in men with primary testiculopathies involve apoptosis-related processes whose mechanisms are poorly understood. This study examines the participation of typical (caspase-dependent) and atypical (caspase-independent) pathways in these processes.


METHODS
Caspase activity and DNA fragmentation were evaluated in Sertoli and germ cells from 63 men with non-obstructive azoospermia and with different histological diagnoses who were undergoing testicular biopsy for an assisted reproduction attempt. In eight of these men, phosphatidylserine externalization was also examined.


RESULTS
The percentage of Sertoli cells showing caspase activity and DNA fragmentation was low and uniform in all diagnoses. In germ cells that remained tightly associated with Sertoli cells despite vigorous mechanical treatment, the incidence of both caspase activity and DNA fragmentation was high, particularly in men with maturation arrest. In Sertoli cell-free germ cells, high incidence of DNA fragmentation contrasted with low incidence of caspase activity and phosphatidylserine externalization.


CONCLUSIONS
In men with primary testicular failure, apoptosis of Sertoli cells is insignificant. Some germ cells undergo caspase-dependent apoptosis, show phosphatidylserine externalization and are tightly associated with Sertoli cells. Other germ cells show caspase-independent DNA fragmentation, do not externalize phosphatidylserine and lack a tight association with Sertoli cells.
Tesarik
Jan
J
Molecular Assisted Reproduction & Genetics, Gracia 36, 18002 Granada, Spain. cmendoza@ugr.es
Ubaldi
Filippo
F
Rienzi
Laura
L
Martinez
Francisco
F
Iacobelli
Marcello
M
Mendoza
Carmen
C
Greco
Ermanno
E
D017209:Apoptosis; D001706:Biopsy; D020169:Caspases / Q000378:metabolism*; D053938:DNA Fragmentation; D006801:Humans; D020287:In Situ Nick-End Labeling; D008297:Male; D008856:Microscopy, Fluorescence; D010718:Phosphatidylserines / Q000378:metabolism; D012708:Sertoli Cells / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D013094:Spermatozoa / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D013733:Testicular Diseases / Q000201:enzymology / Q000473:pathology*
D010718:Phosphatidylserines; D020169:Caspases