Detection of apoptotic alterations in sperm in subfertile patients and their correlations with sperm quality.
BACKGROUND
The aim of the present study was to define the effect of apoptosis on sperm quality and function.


METHODS
The apoptotic features in sperm were assessed in 60 subfertile subjects, using Annexin-V staining for phosphatidylserine (PS) externalization and Tdt-mediated dUTP nick end labelling (TUNEL) assay for DNA fragmentation.


RESULTS
On average, about 45% of the sperm were found to be apoptotic based on the results from Annexin-V staining, including both early (Annexin-V-positive, PI-negative) and late apoptosis (Annexin-V-positive, PI-positive). TUNEL-positive cells (median value 15%) significantly correlated to late apoptosis but not early apoptosis, indicating that DNA fragmentation only occurs at the later stage of sperm apoptosis. TUNEL-positive and late apoptotic cells (Annexin-V-positive, PI-positive) were found to be inversely correlated to sperm motility and vitality, and positively to abnormal sperm morphology. On the other hand, it is surprising to note that the apoptotic alterations in sperm positively correlated to sperm concentration or total sperm counts.


CONCLUSIONS
Overall results from this study support the abortive apoptosis theory; apoptosis in mature sperm is initiated during spermatogenesis, after which some cells earmarked for elimination via apoptosis may escape the removal mechanism and contribute to poor sperm quality.
Shen
Han-Ming
HM
Department of Community, Occupational and Family Medicine, Faculty of Medicine, National University of Singapore, Republic of Singapore.
Dai
Jun
J
Chia
Sin-Eng
SE
Lim
Alvin
A
Ong
Choon-Nam
CN
D000328:Adult; D017209:Apoptosis / Q000502:physiology*; D002470:Cell Survival / Q000502:physiology; D053938:DNA Fragmentation; D006801:Humans; D007248:Infertility, Male / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010718:Phosphatidylserines / Q000378:metabolism; D013076:Sperm Count; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000473:pathology / Q000502:physiology*
D010718:Phosphatidylserines