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Impact of cryopreservation and reactive oxygen species on DNA integrity, lipid peroxidation, and functional parameters in ram sperm
Author(s) -
Peris Soliman I.,
Bilodeau JeanFrançois,
Dufour Maurice,
Bailey Janice L.
Publication year - 2007
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20686
Subject(s) - sperm , cryopreservation , biology , andrology , dna fragmentation , sperm motility , lipid peroxidation , semen , motility , reactive oxygen species , oxidative stress , endocrinology , anatomy , embryo , biochemistry , apoptosis , genetics , medicine , programmed cell death
Assisted reproduction using frozen‐thawed semen has practical advantages, although cryopreservation is detrimental to sperm fertility in most mammals. We examined the influence of cryopreservation and reactive oxygen species (ROS) on ram sperm DNA stability (using SCSA), lipid peroxidation (LPO), chlortetracycline fluorescence (CTC) patterns, motility and viability. In Experiment 1, DNA integrity, LPO, CTC, motility and viability tests were performed on fresh and cryopreserved sperm after 0, 6, and 24 hr in synthetic oviductal fluid (SOF). In Experiment 2, fresh sperm were incubated in serum‐free SOF (SOF‐S; 1, 4, and 24 hr) with 0, 50, 150, or 300 µM H 2 O 2 then assayed. Cryopreservation increased the percentage of sperm with a high DNA fragmentation index (%DFI), decreased the percentages of motile and viable sperm at thawing (0 hr), but did not affect LPO. H 2 O 2 (150 or 300 µM) increased %DFI after 24 hr. LPO or sperm viability were not affected by H 2 O 2 , although most motility parameters decreased. H 2 O 2 decreased the percentage of chlortetracycline pattern F sperm at 4 hr and increased the percentage of acrosome‐reacted sperm (pattern AR) after 1 hr. Pooled data of Experiment 2 showed LPO was positively correlated with SCSA (r = 0.29 to r = 0.59; P < 0.05 to P < 0.01), while most motility parameters and the percentage of viable sperm were negatively correlated with LPO (r = −0.30 to r = −0.38; P < 0.05 to P < 0.01). LPO was positively correlated with the percentage of pattern AR sperm (r = 0.33; P < 0.01). Cryopreservation and H 2 O 2 promote DNA instability in ram sperm, though motility is a more sensitive indicator of oxidative stress than the other parameters investigated. Mol. Reprod. Dev. 74: 878–892, 2007. © 2006 Wiley‐Liss, Inc.