title: DNA integrity of fresh and frozen canine epididymal spermatozoa.
abstract: The aims of this study were to evaluate: (1) the effect of cryopreservation on DNA fragmentation of canine epididymal spermatozoa, and (2) the potential protective effect of melatonin on post-thaw sperm quality (motility, morphology, acrosomal and DNA integrity). Epididymal spermatozoa were collected after orchiectomy of ten dogs. Sperm samples were frozen in the presence or absence of melatonin (1mM). DNA fragmentation index (percentage of spermatozoa with fragmented DNA) was similar in fresh samples (3.3±3.6) and samples frozen with (4.2±3.8) or without (3.6±3.7) melatonin. Sperm motility was significantly (p<0.0001) higher in fresh compared to frozen samples. The presence of melatonin in the freezing extender did not affect the sperm motility. Proportions of spermatozoa with normal morphology were similar in fresh and frozen samples, irrespective of the presence of melatonin in the extender. Acrosome integrity was significantly decreased (p<0.01) by cryopreservation, and melatonin did not exert any beneficial effects. In conclusion, DNA fragmentation of canine epididymal spermatozoa was not affected by the freezing procedure, and the presence of melatonin did not preserve motility and acrosome integrity which were adversely affected by cryopreservation. The evaluation of DNA status of thawed gametes is particularly relevant for epididymal spermatozoa since these spermatozoa are usually stored and used in assisted reproductive techniques.
authors.affiliation: Dipartimento di Scienze Veterinarie per la Salute, la Produzione Animale e la Sicurezza Alimentare - Università degli Studi di Milano, Via Celoria 10, 20133 Milano, Italy. Electronic address: sara.varesi@unimi.it.
authors.forename: Sara
authors.initials: S
authors.lastname: Varesi
authors.affiliation: Dipartimento di Scienze Veterinarie per la Salute, la Produzione Animale e la Sicurezza Alimentare - Università degli Studi di Milano, Via Celoria 10, 20133 Milano, Italy. Electronic address: valentina.vernocchi@unimi.it.
authors.forename: Valentina
authors.initials: V
authors.lastname: Vernocchi
authors.affiliation: Dipartimento di Scienze Veterinarie per la Salute, la Produzione Animale e la Sicurezza Alimentare - Università degli Studi di Milano, Via Celoria 10, 20133 Milano, Italy. Electronic address: mariagiorgia.morselli@unimi.it.
authors.forename: Maria Giorgia
authors.initials: MG
authors.lastname: Morselli
authors.affiliation: Dipartimento di Scienze Veterinarie per la Salute, la Produzione Animale e la Sicurezza Alimentare - Università degli Studi di Milano, Via Celoria 10, 20133 Milano, Italy. Electronic address: cecilia.luvoni@unimi.it.
authors.forename: Gaia Cecilia
authors.initials: GC
authors.lastname: Luvoni
mesh_terms: D000177:Acrosome / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D015925:Cryopreservation / Q000379:methods*; D004247:DNA / Q000235:genetics*; D053938:DNA Fragmentation / Q000187:drug effects; D004285:Dogs; D004822:Epididymis / Q000166:cytology*; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D009919:Orchiectomy; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000737:chemistry* / Q000166:cytology
chemical_list: D004247:DNA; D008550:Melatonin
keywords: DNA integrity; Dog; Epididymal semen; Freezing