Effect of Lead Graded Doses in <i>Mactra Corallina</i> Gills: Antioxidants Status, Cholinergic Function and Histopathological Studies

Abstract

Lead is non-essential toxic metal used in the industrial process causes severe risk to aquatic organisms. This study aimed (aims) to evaluate the effect of Pb on oxidative stress in gills of Mactra corallina. During the experiment, bivalves were randomly divided into four groups, control served as control and D1, D2 and D3 groups were exposed to Pb graded doses (1mg/L, 2.5mg/L and 5mg/L) during 5 days, respectively. Pb accumulation was significantly increased in all treated gills with doses dependent manner. The exposure of M. corallina to PbCl 2 promoted oxidative stress in gills with an increase in malondialdehyde (MDA) and in metallothionein (MTs) levels. Moreover, a decline in glutathione (GSH), non-protein-SH (NPSH) and ascorbic acid (Vit C) levels were detected in all treated groups. Thus, alterations of enzymatic antioxidants systems were confirmed by a significant increase of catalase (CAT) and decreases of glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in doses dependent manner. The cholinergic function was confirmed by a significant decrease of acetylcholinesterase (AChE) activity in the highest exposure dose. The impairment of the gill function was confirmed by the histological study.

Assessment of stress biomarkers responses in mantle and adductor muscles of Mactra stultorum following lead exposure

“…Besides, these high MT's induction in the mantle than in the adductor muscles in our study can probably be firstly by the possibility of that tissue to accumulate more quantity of metals than the adductor muscle [29,51,52]and secondly by the activation of their main role in metal detoxification when the lipid peroxidation and protein oxidation reached the maximum. Our results are therefore in agreement with previous studies carried out on Mytilus galloprovincialis mantle and M. corallina tissues after lead exposure [15,16,29].…”

“…Moreover, due to their benthic and sedentary mode of life; suspension-feeding mode and high filtration rate, it is easily exposed to environmental pollution [13]. M. stultorum can accrued a enormous number and high concentration of heavy metals in their tissues [14,15,16]. Therefore, similar to other species of Mactra, Mussels and Oysters, M stultorum can be used as a good bioindicator of heavy metal pollution in marine environments [17].…”

“…Even though there are investigations about the impact of PbCl 2 on M. stultorum gills and digestive gland [15,16], still information are lacking about the impact of this metal on the metabolism and redox status of other organs. Thus, in this study, we focused on identifying the metabolic and redox strategies developed by M. stultorum adductor muscles and mantle to cope with graded PbCl 2 concentrations.…”

The Cortisol Levels, Histology, and Fine Structure of Various Tissues of Fish Gambusia affinis (Baird and Girard, 1853) after Exposure to Lead

“…Due to bioaccumulation, exposure to Pb can be lethal for aquatic organisms, even at low concentrations [12][13][14]. Pb can disrupt antioxidant equilibrium, cause oxidative stress disorders, and change behavior [15][16][17][18]. In vivo experiments on the efects of Pb exposure in fsh have examined the augmentation of antioxidant responses by inducing reactive oxygen stress (ROS), the toxic efects on membrane structure and function due to Pb's high afnity for red blood cells, and the changes in fsh immune systems [5,[19][20][21].…”