Integrated Effect of Metal Accumulation, Oxidative Stress Responses and DNA Damage in Venerupis Decussata Gills Collected From Two Coast Tunisian Lagoons

The bivalve Venerupis decussata has been proposed as a sentinel species for assessment of lagoon water. Our study aimed to evaluate the spatial and temporal variation of oxidative stress biomarkers, metal content and DNA damage in Venerupis decussata digestive gland collected seasonally from contaminated (BOUGHRARA “L2”) and comparatively cleaner ( GHAR EL MELH “L1”) lagoons. Trace metal contents (Cu, Pb and Cd) in Venerupis decussata collected at polluted site were 1-2 folds higher compared to the control site and showed maximum variation especially during summer and spring seasons. The current findings indicate a seasonal increase of malondialdehyde (MDA), protein carbonyl (PCO), glutathione (GSH) and metallothioneins (MT) levels in relation to trace element accumulation in Venerupis decussata digestive gland from BOUGHRARA sampling lagoon compared to those from GHAR EL MELH. We found an increase in glutathione-S-transfers (GST) and glutathione peroxides (GPx) activities in clams collected from BOUGHRARA lagoon. A random DNA degradation was observed mostly in digestive gland from the polluted site. The principal component examination of the physiological parameters showed a clear separation between Venerupis decussata collected from the polluted lagoon (L2) and those from the clean one (L1). Our study delivers basic information on the toxicological effects of environmental pollutants in clam through the combination of metabolic and physiological methodologies