Genotoxic effects of the insect repellent n, n-diethyl-meta-toluamide (DEET) and detection of retinoblastoma gene expression in human lymphocytes: A pilot study

N, N-diethyl-meta-toluamide (DEET), has been used as the active ingredient in the majority of the commercial insect repellents for decades. Its extensive usage is related to the total protection that provides against a broad spectrum of biting insects. In the last few years, residues of DEET have been detected all over the world in various aquatic environments including drinking water. Consequently, DEET has become an emerging contaminant and the evaluation of its potential effects on human genetic material -presents major scientific interest. The genotoxic and cytotoxic activity of DEET at different concentrations (i.e. 50, 100, 200 and 300 μg/ml) was evaluated by employing the Cytokinesis Block MicroNucleus (CBMN) assay in cultured human lymphocytes. DNA was extracted from all samples, and DNA methylation was performed. The expression of retinoblastoma (RB) gene was assessed by real-time RT-PCR. The obtained results showed low gene expression irrespective of DEET concentration, therefore, further studies are required to draw definite conclusions. It is worth noting that there are no previous studies correlating DEET and its influence on RB gene expression. Our findings on the genotoxic and cytotoxic effects of DEET in cultured human lymphocytes suggest the potential human health risks of DEET. It is proposed that DEET should be handled with care, in order to minimize its environmental and human risk.