RESUMO
PURPOSE: Mefenamic acid (MEF) as a non-steroidal anti-inflammatory drug is used as a medication for relieving of pain and inflammation. Radiation-induced inflammation process is involved in DNA damage and cell death. In this study, the radioprotective effect of MEF was investigated against genotoxicity induced by ionizing radiation in human blood lymphocytes. MATERIALS AND METHODS: Peripheral blood samples were collected from human volunteers and incubated with MEF at different concentrations (5, 10, 50, or 100 microM) for two hours. The whole blood was exposed to ionizing radiation at a dose 1.5 Gy. Lymphocytes were cultured with mitogenic stimulation to determine the micronuclei in cytokinesis blocked binucleated lymphocyte. RESULTS: A significant decreasing in the frequency of micronuclei was observed in human lymphocytes irradiated with MEF as compared to irradiated lymphocytes without MEF. The maximum decreasing in frequency of micronuclei was observed at 100 microM of MEF (38% decrease), providing maximal protection against ionizing radiation. CONCLUSION: The radioprotective effect of MEF is probably related to anti-inflammatory property of MEF on human lymphocytes.