Influence of fluoroquinolones on viability of Balb/c 3T3 and HepG2 cells

The cytotoxic potential of fluoroquinolones (enrofloxacin, ciprofloxacin, difloxacin, sarafloxacin, danofloxacin, norfloxacin a nd marbofloxacin) was investigated using mouse fibroblasts Balb/c 3T3 and human hepatoma HepG2 cell lines. The cells were exposed for 24, 48, and 72 h to drugs at eight concentrations ranged from 0.78 to 100 µg/mL. Four independent cytotoxicity assays were applied, in which various endpoints were assessed: mitochondrial activity - MTT reduction, lysosomal activity - neutral red uptake, total protein content, and cellular membrane integrity - lactate dehydrogenase release. Mean effective cytotoxic concentrations (EC50) calculated at different time points from concentration-response curves ranged from 10 to 100 µg/mL. The most a ffected endpoint in both cell lines was mitochondrial activity. The EC50-MTT-72 h <10 µg/mL was found for difloxacin, marbofloxacin ( fibroblasts), sarafloxacin, and norfloxacin (HepG2). The data shows that cytotoxicity of the fluoroquinolones appears after longer exposure of both cell cultures to these compounds.