Freezing and thawing alter chromatin stability of ejaculated human spermatozoa: fluorescence acridine orange staining and Feulgen-DNA cytophotometric studies.
Cryopreservation and freezing-thawing effects on the fertilizing ability of human spermatozoa commonly are evaluated by post-thaw motility. Various studies have depicted the ultrastructural changes caused by freezing-thawing, yet the chromatin alterations have been studied very limitedly. Our aim was to determine the extent to which freezing-thawing alters the chromatin of human spermatozoa, using two analytical methods: acridine orange staining and Feulgen-DNA cytophotometric studies. Both methods revealed a dramatic effect of freezing-thawing on sperm chromatin: the native DNA content decreased as did the Feulgen-DNA content, and sperm surface area was reduced. These results indicate an effect on DNA, diminished accessibility for Feulgen, and a decrease in nuclear surface area and prompt us to hypothesize a relationship between an "overcondensation" state for sperm chromatin after freezing-thawing and a lower conception rate for human semen after cryostorage.
Royere
D
D
Unité de Reproduction Cecos/Fiv, Gynécologie, CHU Tours, France.
Hamamah
S
S
Nicolle
J C
JC
Barthelemy
C
C
Lansac
J
J
D000165:Acridine Orange; D000328:Adult; D002843:Chromatin / Q000002:abnormalities*; D003592:Cytophotometry / Q000379:methods; D004247:DNA / Q000032:analysis; D005615:Freezing; D006801:Humans; D008297:Male; D013094:Spermatozoa / Q000002:abnormalities*; D013194:Staining and Labeling / Q000379:methods
D002843:Chromatin; D004247:DNA; D000165:Acridine Orange