Induction to oxidative stress by saxitoxin investigated through lipid peroxidation in Neuro 2A cells and Chlamydomonas reinhardtii alga

Abstract

Saxitoxin (STX) is a cyanotoxin, which can cause neurotoxic effects and induce ecological changes in aquatic environments, a potential risk to public and environmental health. Many studies of cytotoxicity on animal cells and algae have been performed, although few compare the toxic effects between the two models. In this sense, we investigated the oxidative stress induced by STX (0.4-3.0 nM) in two different cellular models: Neuro-2A (N2A) cells and Chlamydomonas reinhardtii alga by quantification of malondialdehyde (MDA) levels as indicative of lipid peroxidation (LPO). Also was evaluated the antioxidant defense of these cells systems after exposure to STX by the addition of antioxidants in N2A cells culture, and by the measure of antioxidants enzymes activity in C. reinhardtii cells. The MDA levels of N2A cells increased from 15% to 113% for 0.4 and 3.0 nM of STX, respectively, as compared to control. Superoxide-dismutase and catalase did not appear to protect the cell from STX effect while, in cells treated with vitamin E, the rates of MDA production decreased significantly, except for higher concentrations of STX. No MDA productions were observed in algal cells however some effects on antioxidant enzymes activity were observed when algae were exposed to 3.0 nM STX. Our results indicate that the concentrations of STX that may induce oxidative stress through LPO are different in animal and phytoplankton communities. A combination of algal and animal bioassays should be conducted for reliable assessment of oxidative stress induced by STX.

Lipid peroxidation and antioxidant responses in zebrafish brain induced by Aphanizomenon flos-aquae DC-1 aphantoxins

“…Several recent studies have demonstrated that extracted saxitoxin (STX) or PSPs from Cylindrospermopsis raciborskii may induce oxidative stress, lipid peroxidation in cultured neuro-2A cells and in brains of the fish Hoplias malabaricus, and antioxidative responses in the hepatopancreas of clams (da Silva et al, 2011;Melegari et al, 2012). These results also show that PSPs could induce oxidative stress, lipid peroxidation and antioxidant defense responses in both nervous cells and the nervous system, as well as in other non-nervous organs.…”

“…The spectrum of ROS includes superoxide radicals, hydrogen peroxide, and hydroxyl radicals. The main protective system against ROS and their toxic by-products includes enzymes such as SOD, CAT, GPx and GST, as well as non-enzymatic systems such as GSH (Halliwell and Gutteridge, 2007;Melegari et al, 2012).…”

Changes in metabolites, antioxidant system, and gene expression in Microcystis aeruginosa under sodium chloride stress

“…Elevated NaCl concentration leads to membrane lipid peroxidation in M. aeruginosa that can cause the cytomembrane damage . Meanwhile, membrane lipid peroxidation in turn aggravates cellular stress condition and causes more MC production since MC may act as a defense mechanism against stress condition (Melegari et al, 2012). Consequently, membrane lipid peroxidation can facilitate the production of MC and the release of MC into culture medium.…”

Toxicological risk assessment of complex mixtures through the Wtox model

“…Each level corresponds to a particular risk classification. For each parameter, ranges of toxicological effect were established from outcome evaluations of researches already undertaken by LABTOX team members (Matias et al, 1998a;Matias et al, 1998b;Carvalho Pinto-Silva et al, 2003Perreault et al, 2011;Melegari et al, 2012;Flohr et al, 2012a;Flohr et al, 2012b),and studies in the available literature (Lambolez et al, 1994;Villegas-Navarro et al, 1999;Knops et al, 2001;Backhaus et al, 1997;Lappaleinen et al, 2001;Ç avas and Ergene-Gozucara, 2003;Rodriguez et al, 2006;Picado et al, 2008;Kang et al, 2010;Kostamo and Kukkonen, 2003;Grinevicius et al, 2009;Ç avas and Ergene-Gözükara, 2005;Avci et al, 2005;Huang et al, 2007).…”