Human semen cryopreservation: a sperm DNA fragmentation study with alkaline and neutral Comet assay

Human semen cryopreservation: a sperm DNA fragmentation study with alkaline and neutral Comet assay

J. Ribas-Maynou, A. Fernandez-Encinas, A. Garcıa-Peiro, E. Prada, C. Abad, M. J. Amengual, J. Navarro and J. Benet

Departament de Biologia Cel
lular, Fisiologia i Immunologia, Universitat Aut
onoma de Barcelona, Bellaterra, Catalunya, Spain, Centro de Infertilidad Masculina y Analisis de Barcelona (CIMAB), Edifici Eureka, PBM5, Parc de Recerca de la UAB (PRUAB), Bellaterra, Spain, Servei de Ginecologia, Hospital Universitari Mutua de Terrassa, Terrassa, Spain, Servei d’Urologia, Corporacio Sanit
aria Parc Taulı, Institut Universitari Parc Taulı – UAB, Sabadell, Spain, and UDIAT, Centre Diagn
ostic, Corporacio Sanit
aria Parc Taulı, Institut Universitari Parc Taulı – UAB, Sabadell, Spain

Sperm cryopreservation is widely used for both research and reproduction purposes, but its effect on sperm DNA damage remains controversial. Sperm DNA fragmentation (SDF) has become an important biomarker to assess male infertility. In particular, the differentiation between single- and double-stranded DNA fragmentation (ssSDF and dsSDF) has clinical implications for male infertility where ssSDF is associated with reduced fertility, whereas dsSDF is associated with increased risk of miscarriage. In this study, semen samples from 30 human males have been analysed in both fresh and cryopreserved using the alkaline and neutral Comet assays.
Results show an increase of about 10% of ssSDF, assessed by the alkaline Comet assay, regardless of the male fertility status. Neutral Comet analysis of dsSDF does not show any statistical increase when comparing fresh and cryopreserved samples in any of the patient groups. Results support previous reports that oxidative stress is the major effector in DNA damage during sample cryopreservation, as, on one hand, ssSDF has previously been related to oxidative damage and, on the other hand, we have not found any effect on dsSDF. Therefore, there might be a slight risk of decreased fertility after using a freezed sample, but no evidence for increased miscarriage risk from cryopreserved spermatozoa should be expected.

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