The role of heat shock protein 70 (Hsp 70) in male infertility: is it a line of defense against sperm DNA fragmentation?
OBJECTIVE
To clarify the role of heat shock protein 70 (Hsp 70) and its relation with DNA damage in male infertility.


METHODS
Prospective study.


METHODS
Andrology laboratory of Istanbul Medical Faculty.


METHODS
Semen samples from 37 infertile men and 13 fertile men (as controls).


METHODS
The percentage of DNA fragmentation was assayed with the use of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL). Sperm Hsp 70 expression was determined by using Western blot analysis.


METHODS
Both the percentages of sperm DNA fragmentation and Hsp 70 expression were correlated with semen analysis parameters.


RESULTS
TUNEL-positive spermatozoa in the infertile group (18.7% for asthenospermics and 13.0% for oligoasthenospermics) were higher than the fertile group (4.9%). Significant inverse correlations were detected between percentage of TUNEL-positive cells and both concentration (r = -0.487) and motility (r = -0.377) of spermatozoa. No expression of Hsp 70 was observed in azospermic group, whereas Hsp 70 levels were found increased significantly in infertile group (U = 62 for asthenospermics and U = 38 for oligoasthenospermics) compared to fertile group as analyzed by using Mann-Whitney U Wilcoxon rank sum test. Furthermore, significant positive correlation was found between percentage of TUNEL-positive cells and Hsp 70 expression (r = 0.357).


CONCLUSIONS
Hsp 70 expression may have been increased as a protective mechanism against apoptosis in spermatozoa of infertile men.
Erata
Gül Ozdemirler
GO
Department of Biochemistry, Istanbul Medical Faculty, University of Istanbul, Capa, Istanbul, Turkey. gul_erata@yahoo.com
Koçak Toker
Necla
N
Durlanik
Ozgür
O
Kadioğlu
Ateş
A
Aktan
Gülşen
G
Aykaç Toker
Gülçin
G
D015153:Blotting, Western; D053938:DNA Fragmentation / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000502:physiology*; D006801:Humans; D020287:In Situ Nick-End Labeling; D007248:Infertility, Male / Q000503:physiopathology*; D008297:Male; D011446:Prospective Studies; D013094:Spermatozoa / Q000166:cytology*
D018840:HSP70 Heat-Shock Proteins