Effects of cryopreservation on human sperm deoxyribonucleic acid integrity.
OBJECTIVE
To evaluate the effect of cryopreservation on sperm motility and viability and to assess sperm DNA fragmentation and oxidation in men undergoing infertility investigation before and after cryopreservation in liquid nitrogen.


METHODS
Analysis of cryopreservation effects on sperm DNA integrity.


METHODS
Laboratory of Histology-Embryology of medicine faculty, Sfax, Tunisia.


METHODS
Fifteen semen samples from men undergoing infertility investigation.


METHODS
Neat semen samples were cryopreserved in liquid nitrogen using a commercial freezing medium (SpermFreeze, Fertipro, Belgium) according to the manufacturer's instructions. Samples were thawed at room temperature.


METHODS
Sperm DNA fragmentation was assessed using terminal deoxynucleotidyl transferase (Tdt) mediated dUTP nick end labeling and sperm DNA oxidation was determined using a fluorescent assay (OxyDNA test) for the detection of 8-oxoguanine. Evaluation of DNA fragmentation and oxidation rates was carried out before and after cryopreservation using flow cytometry.


RESULTS
A significant decrease in sperm motility and viability was observed after cryostorage. In addition, sperm DNA fragmentation and DNA oxidative damage increased significantly after cryopreservation/thaw.


CONCLUSIONS
Cryopreservation has deleterious effects on sperm DNA by inducing DNA fragmentation and oxidation but the mechanisms underlying such damages need to be elucidated by further investigations.
Zribi
Nassira
N
Laboratory of Histology-Embryology, Medicine Faculty of Sfax, Sfax, Tunisia. nacira.zribi@gmail.com
Feki Chakroun
Nozha
N
El Euch
Henda
H
Gargouri
Jalel
J
Bahloul
Ali
A
Ammar Keskes
Leila
L
D000328:Adult; D015925:Cryopreservation; D053938:DNA Fragmentation; D005434:Flow Cytometry; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D020287:In Situ Nick-End Labeling; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D013076:Sperm Count; D013081:Sperm Motility; D013094:Spermatozoa / Q000378:metabolism / Q000473:pathology*; D014416:Tunisia
C024829:8-hydroxyguanine; D006147:Guanine