Compare two methods of measuring DNA damage induced by photogenotoxicity of fluoroquinolones

AIM: To compare two methods of measuring DNA damage induced by photogenotoxicity of fluoroquinolones(FQ). METHODS: Lomefloxacin (LFLX), sparfloxacin (SPFX), ciprofloxacin (CPFX), and levofloxacin (LELX)were tested by comet assay and photodynamic DNA strand breaking activity under the different conditions of UVA irradiation. RESULTS: In comet assay, photogenotoxicity was evident at SPFX 1mg/L, LFLX 5mg/L, and CPFX 5mg/L, and LELX 10mg/L. In photodynamic DNA srand-breaking activity, SPFX and LFLX induced the conver sion of the supercoiled form into the nicked relaxed form at 10-50μmol/L, while CPFX at 25μmol/L and LELX at 50μmol/L. CONCLUSION: There were good correlations between the two methods to detect DNA damage induced by phototoxicity of fluoroquinolones. Photodynamic DNA strand breaking activity was a good method to detect DNA damage induced by photogenotoxicity of fluoroquinolones as well as comet assay.