title: Accumulation and effects of Cr(VI) in Japanese medaka (Oryzias latipes) during chronic dissolved and dietary exposures.
abstract: Chromium (Cr) is an essential metal and a nutritional supplement for both human and agricultural uses. It is also a pollutant from a variety of industrial uses. These uses can lead to elevated Cr levels in aquatic environments, where it can enter and affect aquatic organisms. Its accumulation and subsequent effects in fish have received relatively little attention, especially for chronic exposure. In the present study, Japanese medaka were chronically exposed to dissolved or dietary Cr(VI) for 3 months. Cr accumulation in liver, gills, intestine, and brain was evaluated. Effects on the antioxidant system, nervous system (acetylcholinesterase, AChE), digestive system (α-glucosidase, α-Glu), and tissue histology (liver and gills) were also assessed. Cr accumulation was observed in the intestine and liver of fish exposed to Cr-contaminated brine shrimp. However, chronic dissolved Cr exposure led to significant Cr accumulation in all organs tested. Analysis of the subcellular distribution of Cr in medaka livers revealed that 37% of the Cr was present in the heat stable protein fraction. The dissolved Cr exposure had pronounced effects on the antioxidant system in the liver, with an elevated ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) and decreases in GSH and glutathione S-transferase (GST). The α-Glu activity in the intestine was significantly inhibited. In addition, Cr exposure caused histopathological alterations in the gills and liver. In general, the effects of dietary Cr were relatively minor, possible due to the much lower accumulation in the fish. Our results imply that Japanese medaka accumulate Cr mainly via uptake of dissolved Cr(VI).
authors.affiliation: Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Liaoning 110016, China.
authors.forename: Hongxing
authors.initials: H
authors.lastname: Chen
authors.affiliation: Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Liaoning 110016, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Mu
authors.affiliation: State Key Laboratory of Ecological Animal Husbandry and Environmental Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi 030801, China.
authors.forename: Jinling
authors.initials: J
authors.lastname: Cao
authors.affiliation: Division of Marine Chemistry, National Marine Environmental Monitoring Center, Dalian, Liaoning 116023, China.
authors.forename: Jingli
authors.initials: J
authors.lastname: Mu
authors.affiliation: Department of Biology, University of Louisiana at Lafayette, P. O. Box 43602, Lafayette, LA 70504-3602, USA.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Klerks
authors.affiliation: Guangxi Academy of Fishery Sciences, Nanning, Guangxi 530021, China. Electronic address: lfylzc123@163.com.
authors.forename: Yongju
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Guangxi Academy of Fishery Sciences, Nanning, Guangxi 530021, China.
authors.forename: Zhongbao
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Liaoning 110016, China. Electronic address: xielt@iae.ac.cn.
authors.forename: Lingtian
authors.initials: L
authors.lastname: Xie
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002857:Chromium / Q000493:pharmacokinetics* / Q000633:toxicity*; D004032:Diet; D005260:Female; D005880:Gills / Q000187:drug effects / Q000473:pathology; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D009990:Oryzias / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics* / Q000633:toxicity*; D000520:alpha-Glucosidases / Q000378:metabolism
chemical_list: D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D005982:Glutathione Transferase; D000110:Acetylcholinesterase; D000520:alpha-Glucosidases; D005978:Glutathione
keywords: Accumulation; Antioxidants; Cr(VI); Histopathology; Japanese medaka