A safety investigation into topical effects of naproxen sodium on nasal epithelial cells and potential toxicity in local application

We examined how topically-applied naproxen sodium affects human nasal epitheliocytes in culture. Samples of healthy human primary nasal epithelium (NE) harvested during septoplasty from volunteers without rhinosinusitis were incubated in cell culture. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays may be utilised when assessing cellular damage (toxicity), as evidenced by DNA fragmentation, nuclear condensation, alteration in the outer plasma membrane and cytoskeletal alteration. This was the method used in the study. Cultured epitheliocytes were incubated with naproxen sodium for 24 h at 37 °C. The MTT assay was then performed and the cells' morphology was examined by confocal microscopy. Additionally, cellular proliferation was assessed by the artificial scratch method followed by light microscopy. The results indicated that naproxen sodium does not cause any cytotoxic effects upon nasal epithelial cells when applied topically. There was no evidence indicating cytotoxicity on the nasal epitheliocytes in culture for the 24 h period over which the drug was applied. In particular, there was no alteration in cellular morphology, damage to the intracellular organelles structure or the cytoskeleton secondary to naproxen sodium. Furthermore, cellular proliferation occurred normally in these conditions, as on scratch test. Topical naproxen sodium may be used on nasal epithelial cells without inducing toxicity. This agent is therefore suitable, given its known anti-inflammatory effects, for use in patients suffering from diseases involving nasal and paranasal sinusal inflammation, including rhinosinusitis (both chronic and acute) and nasal polyposis which should be investigated. In the future, topical medication forms for nasal usage should be developed.