Changes in membrane lipids of ram spermatozoa after cryopreservation

CARRO, M.M.; PEÑALVA, D.A.; AVELDAÑO, M.I.; HOZBOR, F.A.; FURLAND, N.E.

Rosario

Congreso; L Reunión de la Sociedad Argentina de de Investigación Bioquímica y Biología Molecular (SAIB); 2014

SAIB

Cryopreservation is known to affect spermatozoa structure and functions. Ram spermatozoa are among the most highly sensitive mammalian gametes to freezing, with frozen-thawed ram semen producing very low pregnancy rates. The aim of this study was to find, in ram spermatozoa, possible correlations between effects of cryopreservation on sperm functionality on the one hand, and quantifiable changes in lipid profile and membrane properties on the other. As expected, freeze-thawing decreased sperm quality, as indicated by post-thaw parameters related to membrane integrity and functionality, mitochondrial viability and sperm motility. Chlortetracycline staining revealed that the percentage of capacitated spermatozoa increased in cryopreserved versus control fresh semen. The most relevant lipid change after cryopreservation was a remarkable increase of lysophosphatidylcholine (LPC) and free fatty acid (FFA) levels, suggesting that a form of phospholipase A2 is activated during this process. Interestingly, in fresh spermatozoa the LPC content was very low in autumn (the reproductive period) and far higher in summer and spring time. Since LPC and FFA display inhibitory effects on sperm motility, in addition to inducing acrosomal damage, our data suggest that low LPC levels may be useful as markers of sperm quality and potential predictors of sperm suitability to cryopreservation