Novel sustainable strategies to mitigate toxicity of emerging contaminants: cellular and physiological insights from CMIT-exposed mussels treated with insect-based protein hydrolysates

The present interest in developing sustainable strategies to mitigate or prevent toxicity of emerging contaminants is attributable to their increasing occurrence in natural ecosystems. Beyond their established roles in the agri-food, feed, and biotechnology sectors, insects are emerging as valuable sources of bioactive compounds, highlighting their recognition as sustainable solutions in nutraceutical and pharmaceutical research. Therefore, the effects of protein hydrolysates from the black soldier fly, Hermetia illucens (BPHs) were evaluated against the toxicity induced by the methylchloroisothiazolinone (CMIT), a widely used biocides belonging to the isothiazolinones class of the biocides. Analyses focused on the modulation of key cellular and physiological parameters in Mytilus galloprovincialis exposed to CMIT (0.01 mg/L), BPHs (0.5 mg/mL), and their mix. Changes in haemocyte functions were assessed through cell viability assays and phagocytosis assay along with the expression of γ-actin; investigation into digestive gland (DG) functionality was carried out by measuring the viability of DG cells and their ability to perform osmoregulation after a hypotonic shock through the Regulatory Volume Decrease video-metric assay (RVD); antioxidant and cytoprotective responses were evaluated through the Cu/ZnSOD, MnSOD, Hsp70, and CYP4Y1 gene expression analysis. Our findings showed that BPHs play a significant protective role against toxicity induced by CMIT in exposed mussels. Significant differences emerged between the control and the CMIT-treated groups, whereas a similar trend was observed between the CTRL and BSPHs-exposed groups. Groups exposed to the combinations (BPHs + CMIT) showed a recovery, suggesting the protective effect of this compound.