Effects of freezing-thawing on the spermatozoon nucleus: a comparative chromatin cytophotometric study in the porcine and human species.
Freezing-thawing effects on the nuclei of porcine and human spermatozoa were studied by determining native DNA percentage from fluorescence after acridine orange (AO) staining and by analyzing chromatin structure by a quantitative microspectrophotometric study of Feulgen-DNA complexes before and after freezing. The study of boar spermatozoa revealed no alteration in native DNA percentage after freezing. However, native DNA percentage decreased significantly in human spermatozoa. Feulgen-DNA content and sperm nuclear surface area decreased in both species after freezing. These results prompted us to hypothesize an overcondensation of sperm chromatin after freezing-thawing. This overcondensation may be related to the lower conception rates obtained with human and porcine semen after cryostorage via defective decondensation.
Hamamah
S
S
Département de Gynécologie-Obstétrique, Hôpital Bretonneau, Tours, France.
Royère
D
D
Nicolle
J C
JC
Paquignon
M
M
Lansac
J
J
D000818:Animals; D002417:Cattle; D002467:Cell Nucleus / Q000648:ultrastructure; D002843:Chromatin / Q000648:ultrastructure*; D015925:Cryopreservation; D004247:DNA / Q000032:analysis; D006801:Humans; D008297:Male; D009691:Nucleic Acid Denaturation; D012662:Semen Preservation; D013045:Species Specificity; D013094:Spermatozoa / Q000032:analysis / Q000648:ultrastructure*; D013552:Swine / Q000502:physiology*
D002843:Chromatin; D004247:DNA