Evaluation of DNA damage in Dicentrarchus labrax sperm following cryopreservation

In this paper, DNA laddering analysis and single-cell gel electrophoresis (SCGE) or Comet assay, were used to detect DNA damage in response to a cryopreservation process in sea bass spermatozoa. The results obtained demonstrate that the cryopreservation protocol used to cryopreserve the sea bass sperm cause significantly damage at DNA level. In fact, the degree of DNA damage in frozen-thawed sperm (% DNA(T) = 38.2 +/- 11.2, M-T = 498.9 +/- 166.4, n = 3) was different (P < 0.01) from that measured in fresh sperm (% DNA(T) = 32.7 +/- 11.1, M-T 375.2 +/- 190.7, n = 3). Data here reported also demonstrated the fundamental role played by cryoprotectants (BSA and Me2SO) in reducing fish sperm DNA fragmentation. Finally, from our results, the ability of SCGE to reveal DNA fragmentation in fish sperm is also confirmed. (C) 2003 Elsevier Inc. All rights reserved.