title: Exposure of spermatozoa to duroquinone may impair reproduction of the common carp (Cyprinus carpio) through oxidative stress.
abstract: Toxicity of many waterborne organic contaminants to aquatic organisms is mediated through oxidative damages resulting from the production of reactive oxygen species (ROS). Using duroquinone as a model ROS inducer, we carried out in vitro and in vivo experiments to test the hypothesis that reproduction in common carp (Cyprinus carpio) can be impaired through oxidative damage of their spermatozoa. In vitro exposure of fish spermatozoa to 0, 12.5, 25, 50, 100 and 200 microM duroquinone for 2 h showed a significant increase in the level of ROS in a dose-dependant manner. Sperm motility was significantly reduced in all exposure groups, but lipid peroxidation (LPO) and DNA strand break (measured by comet assay) were only enhanced at 50 microM and above. A significant decrease in subsequent hatching rate was recorded in all the exposure groups, despite fertilization rate was not affected. In the in vivo experiment, spermatozoa were collected 24 and 72 h after fish received intra-peritoneal injections of 1.0 and 10 mg kg(-1) body weight duroquinone. DNA damage was clearly evident in spermatozoa of all treatment groups after 72 h exposure, and ROS was significantly enhanced in the high concentration group. LPO however, remained unchanged in both treatment groups. The overall results of both our in vitro and in vivo experiments demonstrated that duroquinone can induce ROS production in spermatozoa, which may impair sperm quality and subsequently reproductive success through oxidative stress.
authors.affiliation: Center for Coastal Pollution and Conservation, City University of Hong Kong, Kowloon, PR China.
authors.forename: Bingsheng
authors.initials: B
authors.lastname: Zhou
authors.forename: Wenhua
authors.initials: W
authors.lastname: Liu
authors.forename: William H L
authors.initials: WH
authors.lastname: Siu
authors.forename: Desmond
authors.initials: D
authors.lastname: O'Toole
authors.forename: Paul K S
authors.initials: PK
authors.lastname: Lam
authors.forename: Rudolf S S
authors.initials: RS
authors.lastname: Wu
mesh_terms: D000818:Animals; D016227:Benzoquinones / Q000008:administration & dosage / Q000633:toxicity*; D002347:Carps / Q000502:physiology*; D020552:Comet Assay / Q000662:veterinary; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D007274:Injections, Intraperitoneal / Q000662:veterinary; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D018384:Oxidative Stress; D011897:Random Allocation; D017382:Reactive Oxygen Species / Q000032:analysis; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects*; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D016227:Benzoquinones; D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D014874:Water Pollutants, Chemical; C034257:duroquinone