Year: 2008
Type: article
Abstract: Many toxic xenobiotics entering into the aquatic environment exert their effects through redox cycling. Oxidative stress, incorporating both antioxidant defences as well as oxidative damage, is a common effect in organisms exposed to xenobiotics in their environment. The studies included in this dissertation evaluate the effects of different types of environmental pollution on oxidative stress biomarkers in teleost fishes. Effects of aging, alone or in combination with oxidative stress, on protein carbonylation were also addressed.\nAntioxidant enzyme activities were measured in rainbow trout (Oncorhynchus mykiss)\ncaged in a river polluted by sewage treatment plant (STP) effluent as well as highly\ncontaminated sediment, and in corkwing wrasse (Symphodus melops) collected at heavy\nmetal contaminated and PAH contaminated sites. Antioxidant enzymes showed very few\nchanges in these fish. Glutathione levels were affected by STP effluent exposure in rainbow\ntrout and by PAH exposure in corkwing wrasse.\nProtein carbonylation was elevated in plasma of the corkwing wrasse captured at the\nheavy metal site and in plasma of rainbow trout caged near the STP effluent. Lipid\nperoxidation was elevated in the livers of these rainbow trout. Oxidative damage\nbiomarkers were also measured in eelpout (Zoarces viviparus) captured in a polluted\nharbor, before, during and after a dredging campaign, as well as following an oil spill.\nProtein carbonyl levels in livers of eelpout were affected by exposure to pollution in the\nharbor, though this was measured both as increases and as decreases, indicating a\ncomplicated relationship between prooxidant exposure and protein carbonyl accumulation.\nLipid peroxidation in eelpout was unaffected by pollutant exposure. Western blot analyses\nof protein carbonylation in corkwing wrasse exposed to heavy metals and in rainbow trout\nexposed to paraquat (PQ) suggest that albumin may be the plasma protein most likely to\nundergo carbonylation in these fish.\nBrown trout (Salmo trutta) were used in a laboratory study to investigate the effects of\naging on oxidative stress parameters, i.e. protein carbonylation, 20S proteosome activity\nand glutathione levels. All parameters were affected by aging, as was the response to PQ\nexposure, where 1 year old fish were more sensitive than 0+ fish.\nTo conclude, the results presented here indicate that antioxidant enzymes may not\nprovide a good biomarker of exposure to xenobiotics in the field. However, oxidative\ndamage products, i.e. protein carbonyls and lipid peroxidation, seem to be useful as\nbiomarkers. Care should be taken to consider age of the exposed individuals. Oxidative\nstress is a complex phenomenon to measure in the field. Antioxidant enzyme activities may\nbe altered after an acute exposure and then return to normal levels but damage products can\npersist even after the initial stress has stabilized.
Author: Bethanie Carney Almroth
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2125240718