December 2014 (No. 4) Volume 14
DNA integrity of fresh and frozen canine epididymal spermatozoa
Sara Varesi, Valentina Vernocchi, Maria Giorgia Morselli, Gaia Cecilia Luvoni *
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
The aims of this study were to evaluate: (1) the effect of cryopreservation on DNA fragmen-tation 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 (1 mM). 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.
Reproductive Biology, 2014 14 (4): 257-261.
* Corresponding author at: Department of Health, Animal Science and Food Safety, University of Milan, Via Celoria 10, 20133 Milan, Italy. E-mail addresses: firstname.lastname@example.org (S. Varesi), email@example.com (V. Vernocchi), firstname.lastname@example.org (M. G. Morselli), email@example.com (G.C. Luvoni)