Oxidative damage in unfertilized eggs of Chinese rare minnow (Gobiocypris rarus) exposed to nonylphenol

• Published in: Environmental toxicology and chemistry 2008-01, Vol.27 (1), p.213-219
• Main Authors: Zhang, Xian, Yang, Fangxing, Cai, Ya Q., Xu, Ying
• Format: Article
• Language: English
• Subjects: Amino acids; Animals; Antioxidants; Biomarkers - analysis; Carbonyl compounds; Cell Survival; Chemicals; Chinese rare minnow; Chorion - drug effects; Cyprinidae; Danio rerio; Eggs; Environmental Pollutants - adverse effects; Exposure; Female; Females; Fertility; Fish; Gobiocypris rarus; Lipids; Lipids - analysis; Mortality; Nonylphenol; Ovum - drug effects; Ovum - metabolism; Ovum - pathology; Oxidative damage; Oxidative stress; Oxidative Stress - drug effects; Peroxidation; Phenols - adverse effects; Proteins; Proteins - analysis; Reactive Oxygen Species - metabolism; Reproductive system; Rodents; Thinning; Unfertilized egg
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1897/07-074.1

In the present study, female Chinese rare minnows (Gobiocypris rarus) were used as in vivo models and exposed to nonylphenol (NP) at concentrations of 1 to 200 μg/L for 21 d under semistatic conditions. Molecular biomarkers of oxidative stress were measured in unfertilized eggs and included reactive oxygen species (ROS), lipid peroxidation products (thiobarbituric acid‐reactive substances [TBARS] and protein carbonyl), superoxide dismutase activity, and glutathione. Cathepsin D activity as an indicator of egg viability also was assayed. Nonylphenol induced ROS formation in unfertilized eggs in all exposed groups compared to the controls. The levels of protein carbonyl and TBARS in unfertilized eggs were significantly increased (p < 0.05) at 10 to 200 and 100 to 200 μg/L, respectively. Good positive correlations were shown between ROS induction and levels of TBARS and protein carbonyl in eggs (R = 0.918, p < 0.05 and R = 0.784, p < 0.05, respectively). Superoxide dismutase activity in eggs was significantly inhibited (p < 0.05) in the 50 to 200 μg/L exposure groups. Glutathione levels in eggs were significantly depleted (p < 0.05) at 100 to 200 μg/L concentrations. In addition, ROS induction resulted in oxidative damage to lipid and protein in chorions. Significant reductions (p < 0.05) of the protein and lipid contents in chorions were both found in the 50 to 200 μg/L exposure groups. A previous study found that NP exposure could lead to chorion thinning in zebra fish. Thus, the reductions in protein and lipid contents in chorion could be the reason for chorion thinning by NP exposure. Meanwhile, cathepsin D activity was significantly inhibited (p < 0.05) in all exposure groups. The results demonstrated that NP‐induced oxidative stress could damage the chorion of unfertilized eggs and lead to a decline in gamete quality in female Chinese rare minnow.