In Vivo Effects of <i>N</i> , <i>N</i> ‐Diethyl‐ <i>Meta</i> ‐Toluamide (DEET) Exposure on Sinonasal Epithelia in a Murine Model

Environmental factors, including airborne toxicants, are thought to contribute to the pathogenesis of chronic rhinosinusitis, although the exact mechanism is not fully understood. The purpose of this pilot study is to assess the impact of pesticide, N,N-diethyl-meta-toluamide (DEET), on the sinonasal epithelium using an in vivo murine model. Sixteen mice were exposed for a 2-week period to intranasal solutions containing either saline/50% dimethylsulfoxide (controls, n = 4) or two different concentrations of DEET (0.6 mg: n = 6, 1.0 mg: n = 6). Sinonasal tissue was harvested after the exposure period, and histopathologic analysis was performed. Eleven of the 12 DEET-exposed mice demonstrated inflammatory changes, including increased mucinous cells in the stroma, mucus extravasation, and inflammatory cell infiltrates. All four control mice showed normal respiratory epithelia with no evidence of inflammation. These findings suggest that short-term DEET exposure has pro-inflammatory effects on sinonasal epithelia in an in vivo murine model.