Oxidative Stress and Genotoxicity Biomarker Responses in Grey Mullet (Mugil cephalus) From a Polluted Environment in Saronikos Gulf, Greece

Abstract

This study aimed to assess oxidative stress and genotoxicity biomarkers in grey mullet Mugil cephalus from a site receiving discharges from industrial and harbor activities and a reference site in Saronikos Gulf, Greece. Cellular antioxidant defenses, i.e., antioxidant enzyme activities (catalase, selenium [Se]-dependent glutathione peroxidase, glutathione-S-transferase) and oxidative damage, i.e., lipid peroxidation (measured as thiobarbituric acid reactive substances) were used as biomarkers of oxidative stress. The micronucleus test was used for evaluation of chromosome damage, and the frequency of cells with double nuclei was used as an indication of damage to cell divisions. Antioxidant enzyme activities were lower in fish from the polluted site compared with fish from the reference site, suggesting deficiency of the antioxidant system to compensate for oxidative stress. This is further supported by the higher lipid peroxidation levels in fish from the polluted site, which represent oxidative damage. Micronuclei and double-nuclei frequencies were higher in fish from the polluted site compared with fish from the reference site, indicating genotoxic effects. Correlations between biomarkers suggest that observed effects were due to contaminants exhibiting oxidative stress potential that can also induce genotoxicity. Results suggest that the selected biomarkers in M. cephalus are useful for the assessment of pollution impacts in coastal environments influenced by multiple pollution sources.

Frequency of micronuclei and of other nuclear abnormalities in erythrocytes of the grey mullet from the Mondego, Douro and Ave estuaries—Portugal

“…For example, in a study made in the Goksu Delta (Turkey), grey mullets from the reference areas (upstream of the polluted zones) had an average MN rate of 1.26‰; the value rose to up an impressive 3.86‰ in the considered polluted areas (Ergene et al 2007). A similar trend was found also in grey mullets, but now from the Saronikos Gulf, Greece (Tsangaris et al 2011). The above considerations also apply to all the other ENMAs, and therefore warn that significantly lower values of a particular ENMA in a supposedly less polluted area should not be simplistic viewed as synonymous of having an environment that is free from genotoxicity.…”

A protocol for identifying suitable biomarkers to assess fish health: A systematic review

“…Additionally, in one study different responses were reported when the same fish population were exposed to the same sediment but under either laboratory or field conditions [112]. This variability is likely due to species-specific responses [83, 101], tissue-specific responses [113], seasonal and annual variations [114] and responses to contaminants other than metals (e.g. organics [97, 98]).…”

“…In M . cephalus , hepatic CAT activity showed a significant negative response to contaminated water [72], but was also shown to be influenced by season [114]. In addition to season, the variability in CAT responses documented in field studies is likely due to salinity, location, and species [98, 102, 103, 121, 122].…”

Modulatory effects of Thymbra spicata L. different extracts against the mercury induced genotoxicity in human lymphocytes in vitro

“…In addition, some authors have suggested that ROS may be implicated in the production of high basal SCE frequencies in chromosome instability syndromes (Lee et al 1990;Therman and Susman 1993;Cinkilic et al 2009). Similarly, oxidative stress could lead to MN formations (Tsangaris et al 2010). Thus, the increases of SCE and MN rates after HgCl 2 exposure could be explained by possible prooxidant effect of this compound.…”