Antioxidant enzymes responses of polychaete Perinereis aibuhitensis following chronic exposure to 17β-estradiol

Abstract

The occurrence of 17b-estradiol (E2) in the aquatic environment can lead to damage to the reproductive system, along with other adverse effects including oxidative stress, in aquatic organisms. In the present study, Perinereis aibuhitensis were treated with E2 at 0.1, 1, 10, 100 and 1000 lg/L for 205 d, after which the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST), and the concentrations of glutathione antioxidant biomarker responses were studied. Weight gain and specific growth rate of P. aibuhitensis were not significantly affected by E2 treatment. Although no significant differences in mortality were observed, the group receiving the highest dose of E2 (1000 lg/L) experienced the highest rate of mortality. Treatment with E2 enhanced the levels of total glutathione (T-GSH), but levels of glutathione reduced (GSH) were significantly decreased by 17.02, 20.55, 23.45, 31.91 and 56.08%, with a concomitant increase in the levels of glutathione disulphide (GSSG) by 148.58, 213.05, 232.62, 294.63 and 306.45%, at 0.1, 1, 10, 100 and 1000 lg/L E2, respectively. The redox ratio of GSH/GSSG was significantly decreased (p < 0.01). The results of this study suggest that long-term exposure of P. aibuhitensis to E2 may inhibit antioxidant enzyme activities, thereby reducing the capacity of its detoxification system. ARTICLE HISTORY

Assessment of trace element accumulation on the Tunisian coasts using biochemical biomarkers in Perinereis cultrifera

“…Our results showed a higher GSH level in S1 than in S2, which could be a result of increased synthesis and neutralization of ROS via the thiol group. Dissimilar studies on polychaetes have shown a decrease in GSH level in relation to trace metal accumulation (Lv et al 2016). According to the above results, the significant relationship between antioxidant biomarkers (mainly GSH, SOD and GST) and the concentrations of metals (mainly Cd and Zn) in P. cultrifera tissue suggest the activation of the mechanisms of detoxification due to the generation of ROS.…”

17β-Estradiol induces cyto-genotoxicity on blood cells of common carp (Cyprinus carpio)

“…Several types of indirect DNA damage are caused by estrogeninduced oxidants, such as oxidized DNA bases, DNA strand breakage, and adduct formation by reactive aldehydes derived from lipid hydroperoxides (Cavlieri et al, 2000). On the other hand, enzymes, such as glutathione, a major endogenous antioxidant, which plays a crucial role in protecting cells from exogenous and endogenous toxins, and which exists in the glutathione reduced (GSH) and glutathione disulphide (GSSG), was reported by Lv et al (2016) an increased dose dependent, specifically the activity of GSSG of P. aibuhitensis exposed to E2; in addition to this, Guti errez-G omez et al (2016) also found a significant increase in the activity of the antioxidant enzymes superoxide dismutase, the first defense and the main enzyme responsible for the conversion of superoxide anion to hydrogen peroxide, and glutathione peroxidase in blood of C. carpio exposed to concentration of 1 mg L À1 E2 at 96 h; the increase of these enzymes could explain the results in the comet assay that demonstrated less damage to concentration of 1 mg L À1 , evidencing a greater activity as a mechanism to counteract oxidative DNA damage induced by E2. However, occasionally, such damage is not effectively repaired or is erroneously repaired, eliciting changes in the original DNA sequence (Cavalieri and Rogan, 2014), for this reason, and to evidence the damage, the comet assay is often applied in conjunction with the MNi test, that due to its simplicity, is one of the most applicable techniques to identify genomic alterations in environmental animals.…”

“…Studies of aquatic wildlife that are directly exposed to contaminants, often provide early indications of potential environmental problems. A few studies report E2 can produce different harmful effects, for example, is an endocrine disrupter at concentrations above 200 ng L À1 in O. mykiss (Marlatt et al, 2006), affect the reproduction of O. javanicus at concentrations greater than 16 ng L À1 (Imai et al, 2005), can decrease the capacity of cellular antioxidant systems in P. aibuhitensis at concentrations greater than 0.1 mg L À1 (Lv et al, 2016) and can induce immunomodulatory changes and neurotoxicity in different organisms (Thilagam et al, 2014). On the other hand, in vitro assays have shown that at low concentrations (1e10 ng L À1 ) of E2 induce feminization in some species of male wild fishes (Routledge et al, 1998), and changes the hepatic gene expression of the vitellogenins and choriogenins in P. flesus (Williams et al, 2007).…”