Metals as a cause of oxidative stress in fish: a review

Abstract

ABSTRACT:This review summarizes the current knowledge on the contribution of metals to the development of oxidative stress in fish. Metals are important inducers of oxidative stress in aquatic organisms, promoting formation of reactive oxygen species through two mechanisms. Redox active metals generate reactive oxygen species through redox cycling, while metals without redox potential impair antioxidant defences, especially that of thiol-containing antioxidants and enzymes. Elevated levels of reactive oxygen species lead to oxidative damage including lipid peroxidation, protein and DNA oxidation, and enzyme inactivation. Antioxidant defences include the enzyme system and low molecular weight antioxidants. Metal-binding proteins, such as ferritin, ceruloplasmin and metallothioneins, have special functions in the detoxification of toxic metals and also play a role in the metabolism and homeostasis of essential metals. Recent studies of metallothioneins as biomarkers indicate that quantitative analysis of mRNA expression of metallothionein genes can be appropriate in cases with elevated levels of metals and no evidence of oxidative damage in fish tissue. Components of the antioxidant defence are used as biochemical markers of oxidative stress. These markers may be manifested differently in the field than in results found in laboratory studies. A complex approach should be taken in field studies of metal contamination of the aquatic environment. Keywords: ROS; metallothioneins; glutathion; superoxide dismutase; antioxidant defenceList of abbreviations ALA-D = aminolevulinic acid dehydratase; BNF = β-naphthoflavone; CAT = catalase; GPx = glutathione peroxidise; GR = glutathione reductase; GSH = glutathione; GSSG = glutathione disulphide; GST = glutathione S-transferase; LPO = lipid peroxidation; MDA = malondialdehyde; MTs = metallothioneins; NADPH = nicotinamidadeninedinucleotide phosphate (reduced); ROS = reactive oxygen species; SOD = superoxide dismutase

Effect of Silver Nanoparticles On Energy Metabolism In Selected Tissues Of Aeromonas Hydrophila Infected Indian Major Carp, Catla Catla

“…On the other hand, no significant change in LPx levels in the selected tissues of fishes exposed to 1/10 th concentration of 100µg/L AgNPs might indicate a counter active mechanism of intrinsic antioxidant system. Though, antioxidant enzymes were not determined in the present study, it is well known that antioxidant enzymes play an important role during alterations in pro-oxidant and/or redox changes (22). One of the important findings of the present study (see section 2.4.2) suggests that 1/10 th concentration of 100µg/L AgNPs reversed the changes induced by A. hydrophila on activity levels of oxidative enzymes in the selected tissues of fishes.…”

Ca2+ and caspases are involved in hydroxyl radical-induced apoptosis in erythrocytes of Jian carp (Cyprinus carpio var. Jian)

“…ROS released from neutrophils, macrophages and endothelial cells in the vasculature are taken up by mammal erythrocytes (Aoshiba et al 1999;Nagababu and Rifkind 1998;Rifkind et al 1997). Moreover, studies have shown that the pollutants can stimulate ROS production in aquatic organisms (Kaptaner et al 2014;Sevcikova et al 2011;Xu et al 2012). This pool of ROS could impair the function of erythrocytes.…”

Heavy Metals Content in Paraphilometroides nemipteri from South China Sea may Influence Level of Glutathione and P38 Protein Expression

“…The antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferases (GSTs) are involved in defense mechanism against xenobiotics and heavy metals (Stohs & Bagchi 1995). There are two types of heavy metals which are redox active metals and metals without redox (Sevcikova et al 2011). Redox active metals induced oxidative stress by altering redox cycling in the cells, which leads to glutathione reduction and elevation of antioxidant enzymes such as SOD, CAT and GPx.…”