Raman spectroscopy of human neuronal and epidermal cells exposed to an insecticide mixture of chlorpyrifos and deltamethrin

Many pesticides are increasingly used in combinations for crop protection. Their chemical stability ensures the presence of such mixtures, both in the workspaces of the operators involved in agricultural activities and in foodstuffs, thus making probable human exposure to such chemicals in the environment. This investigation, performed by means of Raman microspectroscopy and principal component analysis, concerns the effects of in vitro cellular exposure to a commercial insecticide based on a chlorpyrifos and deltamethrin mixture. The investigated cells belong to the SHSY-5Y and human keratinocyte (HUKE) cell lines, which can be considered representative of neuronal and epidermal cells, respectively. After 24 h exposure at a concentration one-tenth of that usually used by operators, about 50% of the investigated cells were dead and the relative content of the biochemical components of both types of cells that were still alive had been affected by the exposure. A statistically significant decrease in the protein and nucleic acid content occurred in the SHSY-5Y cells, and a lowering of the lipid and carbohydrate content was observed in the HUKE cells. This study shows the utility of Raman microspectroscopy and principal component analysis for the investigation of the effects on human cells of environmental exposure to any chemicals.