Effect of captivity and cryopreservation on ROS production in Solea senegalensis spermatozoa

Abstract

Reactive oxygen species have a great impact on spermatozoa function. Gametes from sole males born in captivity (F1) display lower quality than those from wild individuals. In this paper, the percentage of cells positive for dichlorofluorescein (DCF+) was determined by flow cytometry in wild and F1 animals, the effect of cryopreservation on DCF+cells was evaluated in both groups and the distribution of H2O2within the cell was studied by confocal microscopy. Our results indicated that there are no differences in either viability or DCF+cells between wild and F1 animals when fresh samples were evaluated. However, when data were analyzed considering two different sperm populations in terms of motility, a significant decrease in viability and DCF+cells was reported in low-motile F1 spermatozoa. Cryopreservation did not alter the viability or the presence of DCF+cells in sperm samples from wild animals, but significantly decreased the viability in F1 samples. Distribution patterns of H2O2have been established by confocal microscopy inSolea senegalensisspermatozoa: co-localization of H2O2with active mitochondria (MitoTracker+) and co-localization with nuclear DNA (DAPI). Compared with H2O2distribution in other marine species such asScophthalmus maximus,Solea senegalensisspermatozoa showed widespread presence of H2O2particularly in the nuclei, which could potentially compromise DNA integrity.