Author(s): Zubkova EV, Wade M, Robaire B
Abstract Share this page
Abstract OBJECTIVE: Our goal was to test the hypothesis that spermatozoal chromatin packaging changes with age and that aging affects the susceptibility of spermatozoal DNA to oxidative damage. DESIGN: Laboratory study. SETTING: Academic facility. PATIENT(S): Young (4 months) and old (21 months) Brown Norway rats. INTERVENTION(S): Spermatozoa were collected from the cauda epididymidis and were incubated in saline or H2O2. MAIN OUTCOME MEASUREMENT(S): Thiols levels, chromatin condensation, DNA susceptibility to acid-induced DNA denaturation, and DNA damage were evaluated using monobromobimane, chromomycin A3 (CMA3), acridine orange, and polymerase chain reaction, respectively. RESULT(S): Spermatozoa from old rats had 25\% fewer disulfides but similar levels of free thiols as compared with young. The CMA3 staining was decreased by 13\% with age. Levels of chromatin denaturation and DNA damage were similar in control groups. After exposure to oxidant, free thiols became oxidized by about 20\% irrespective of age, but CMA3 staining changed little. The acridine orange assay, however, showed a trend for greater chromatin denaturation in spermatozoa from old rats after oxidant treatment. Furthermore, the DNA from spermatozoa of old rats was significantly more susceptible to developing DNA breaks and modification after oxidative challenge. CONCLUSION(S): Spermatozoal chromatin packaging changes with aging and vulnerability to oxidative damage increases.
This article was published in Fertil Steril
and referenced in Journal of Gerontology & Geriatric Research