Antioxidant defenses of flame scallop Ctenoides scaber (Born, 1778) exposed to the water-soluble fraction of used vehicle crankcase oils

Abstract

Used vehicle crankcase oils are a source of contamination in Caribbean marine environments and may alter the oxidative balance of organism that inhabiting coastal ecosystems. This paper aims to evaluate effects of a water-soluble fraction of used vehicle crankcase oils (WSF-UVCO) on the antioxidant responses of the flame scallop Ctenoides scaber. The organisms were exposed to ascending sublethal concentrations 0, 0.001, 0.01 and 0.1 % of WSF-UVCO in a static system of aquaria during one week. Subsequently activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) as well as concentrations of reduced glutathione (GSH) and thiobarbituric acid reactive substances (TBARS) were determined in the digestive gland, adductor muscle and gills. SOD, CAT, GST and TBARS increased in digestive gland of organisms exposed to WSF-UVCO at medium and highest concentrations, with a concomitant decrease in GPX and GR activities. In adductor muscle CAT decreased, but GR rose with exposure to 0.01 and 0.1 % WSF-UVCO; in gills, GST rose through all WSF-UVCO concentrations, and SOD, CAT and GR increased only at 0.1 %. The fluctuations in antioxidant enzymes and GST activities point out possible adjustments to control ROS production and detoxification of xenobiotics. These biochemical responses may guarantee the oxidative balance in flame scallop during short term exposure to low concentrations of WSF-UVCO. C. scaber appears suitable as an experimental organism for evaluating biological risks of sublethal exposure to hazardous xenobiotics in tropical marine environments.

Keywords: Antioxidant enzymes; Catalase; Oxidative damage; Reduced glutathione; Water-soluble fraction.

Graphical abstract

Fig. 1

Activity of superoxide dismutase (A) and catalase (B) from control and WSF-UVCO treated flame scallop during 7 d. Results are expressed as the mean ± SD (N = 8). The enzyme activity was expressed in terms U units (μmoles substrate converted to product min⁻¹ per mg of protein). Letters are shown above bars when there was significant statistical difference between groups.

Fig. 2

Activities of and glutathione peroxidase (A) y glutathione reductase (B) and glutathione-S-transferase (B) from control and crankcase oil treated flame scallop during one week. Results are expressed as the mean ± SD (N = 8). The enzyme activity was expressed in terms U units (μmoles substrate converted to product min⁻¹ per mg of protein). Letters are shown above bars when there was significant statistical difference between groups.

Fig. 3

Activities of glutathione-S-transferase from control and crankcase oil treated flame scallop during one week. Results are expressed as the mean ± SD (N = 8). The enzyme activity was expressed in terms U units (μmoles substrate converted to product min⁻¹ per mg of protein). Letters are shown above bars when there was significant statistical difference between groups.

Fig. 4

Reduce glutathione (A) and thiobarbituric acid reactive substances (B) in control and crankcase oil treated flame scallop during one week. Letters are shown above bars when there was significant statistical difference between groups (p < 0.05).