Keratinocyte cellular damage induced by pesticide doses below the cytotoxic level evidenced by electrical impedance and broadband dielectric spectroscopy

Cellular response of a normal human keratinocyte cell line exposed to non-cytotoxic doses of a deltamethrin-based pesticide was investigated by means of two different electrical impedance data spectroscopy approaches: Nyquist plot and broadband dielectric spectroscopy. The measurements have shown that the membrane capacity increases with pesticide concentration and this facilitates the electric current through cell membranes. Furthermore, the impedance of the extracellular matrix also increases with pesticide concentration, thus reducing the electric current outside the cell. Dielectric permittivity changes in the cellular samples at frequency larger than 100 Hz. Fluorescence measurements emphasized an increase of neutral membrane lipids as consequence of the pesticide exposure. Comparison of fluorescence response of pesticide exposed cells with the control ones showed a time increase of the emission intensity, suggesting the existence of a membrane lipid response aimed at repairing of the cell damage due to pesticide exposure. Therefore, both the spectroscopic techniques have demonstrated to be potential means to investigate the response to cell stress and damage. This opens up new possibilities in the early diagnosis of cellular modifications related to pesticides exposure of cells.