Assessment of the Impact of Cadmium on the Redox Status and Metabolic Profile of the Sea Urchin Paracentrotus lividus.

Cadmium (Cd) is one of the most harmful heavy metals to aquatic organisms and a widespread pollutant in marine biota. Because of its high bioavailability, persistence, and ability to bioaccumulate, cadmium (Cd), a toxic heavy metal discharged by mining runoff, industrial discharge, and agricultural inputs, is one of the most detrimental pollutants to aquatic organisms and a common pollutant in marine biota. The current study assessed the potentially toxic effects of cadmium on oxidative stress biomarkers and metabolite profiles in Paracentrotuslividus gonads exposed to a range of concentrations (0.0183, 0.183, and 1.83 mg/L) over 96 h. The results showed that Cd induced oxidative stress by increasing malondialdehyde, hydrogen peroxide, and lipid hydroperoxide levels compared to the control group, as well as increasing antioxidant activities (reduced glutathione and catalase). In addition, based on the gas chromatography-mass spectrometry analysis, 74 metabolites were identified in the gonadal extracts of both treated sea urchins and the control. The Partial Least Squares Discriminant Analysis revealed a clear class separation and discriminated nine relevant metabolites through the VIP scores. The performed heatmap analysis highlighted disturbance in the levels of sterols and fatty acid compounds such as Cholest-5-en-3-ol(3.beta.)-, Desmosterol, and (23S)-ethylcholest-5-en-3.beta.-ol and eicosapentaenoic acid (EPA), as well as the antioxidant defenses such as retinoic acid, and steroid regulation such as Pregna-5-en-20-one, 3-hydroxy-,(3β). Overall, our data revealed the high sensitivity of gonads to Cd, even at relatively low concentrations.