Effects of mercury on oxidative stress and gene expression of potential biomarkers in larvae of the Chinese rare minnow Gobiocypris rarus.
Mercury levels have increased in aquatic food webs throughout the world and can be found at toxic levels in some biota. However, the molecular mechanisms and effects of mercuric chloride (Hg(2+)) remain poorly understood. In the present study, antioxidant parameters (superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde)-as well as a series of gene expressions, including cortisol receptor (cr), Na(+)/K(+)-ATPase (aptase), and prolactin (prl) genes involved in ion-regulatory process, insulin-like growth factor I (igf1) and growth hormone (gh) related to growth rate, as well as heat shock protein70 (hsp70) and metallothionein (mt) used as physiological stress identification-were measured in whole body of Chinese rare minnow larvae (Gobiocypris rarus) after exposure to Hg(2+) (0, 0.1, and 0.3 mg/L) for 4 days. Results show that oxidative stress was generated in fish exposed to Hg(2+) and that the transcription levels of cr, atpase, gh, hsp70, and mt genes increased in a dose-dependent manner, but expression levels of prl and igf1 genes were showed to be decreased in the treated groups. Based on principal component analysis, the correlation between gh and igf1 genes and cr and prl genes was negative. In conclusion, exposure to Hg(2+) could alter multiple physiological and molecular indices in fish; however, before those parameters are used as special biomarkers for monitoring Hg(2+) in aquatic environment, more detailed experiments in laboratory must be performed in the future.
Key Laboratory of Freshwater Biodiversity Conservation (Ministry of Agriculture), Key Field Station for Fishery Resource and Environment in Upper-Middle Reaches of Yangtze River (Ministry of Agriculture), Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, 430223, China, zhihuali06@yahoo.com.
Zhi-Hua
ZH
Li
Lu
L
Chen
Yan-Hua
YH
Wu
Ping
P
Li
Yun-Feng
YF
Li
Zhao-Hui
ZH
Ni
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D003530:Cyprinidae / Q000502:physiology*; D015870:Gene Expression / Q000187:drug effects*; D008628:Mercury / Q000633:toxicity*; D018384:Oxidative Stress; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D015415:Biomarkers; D014874:Water Pollutants, Chemical; D000254:Sodium-Potassium-Exchanging ATPase; D008628:Mercury