title: Effects of cryopreservation on sperm DNA integrity in normospermic and four categories of infertile males.
abstract: This study examined the effects of cryopreservation on DNA integrity of spermatozoa from 34 fertile subjects and 166 infertile subjects comprised of 80 teratospermic, 32 normospermic, 30 astheno-teratospermic, and 24 oligo-astheno-teratospermic individuals. Semen samples were prepared by swim-up and the Percoll density gradient centrifugation method (Pdgc) prior to freezing in liquid nitrogen. Neat and prepared samples were supplemented with cryoprotectant (SpermFreez) in cryoampoules and were frozen using the static phase vapor cooling procedure. Sperm DNA integrity of all thawed samples was determined using the alkaline comet assay. It was noticed that the sperm DNA integrity of frozen samples of fertile subjects was considerably higher than that of infertile subjects with greater catch-up integrity similar to the fresh samples. Freezing caused less chromatin damage to sperm of Pdgc samples from both fertile and infertile subjects as was compared to the neat and swim-up samples. It is concluded that the increase in comet frequency of frozen-thawed samples from infertile subjects was more prominent (8.25-22.78%; P<0.01) than in the fresh samples. Frozen-thawed samples from Ts (Teratospermic individuals) and ATs (Astheno-teratozoosspermic) showed higher level of OTM (Olive tail moment) indicating a higher level of chromatin fragmentation than fertile, Ns (Normospermics), and OATs (Oligo-astheno-teratozoospermics).
authors.affiliation: Department of Animal Sciences, Quid-i-Azam University, Islamabad, Pakistan. laeeq01@yahoo.com
authors.forename: Laiq
authors.initials: L
authors.lastname: Ahmad
authors.forename: Samina
authors.initials: S
authors.lastname: Jalali
authors.forename: Sajjad Aslam
authors.initials: SA
authors.lastname: Shami
authors.forename: Zertashia
authors.initials: Z
authors.lastname: Akram
authors.forename: Sajida
authors.initials: S
authors.lastname: Batool
authors.forename: Ommia
authors.initials: O
authors.lastname: Kalsoom
mesh_terms: D020552:Comet Assay / Q000379:methods; D015925:Cryopreservation; D004247:DNA / Q000032:analysis*; D004249:DNA Damage; D006801:Humans; D007248:Infertility, Male / Q000235:genetics* / Q000473:pathology; D008297:Male; D013094:Spermatozoa / Q000002:abnormalities* / Q000473:pathology* / Q000502:physiology
chemical_list: D004247:DNA