The Mechanism Of Danofloxacin Induced LLC-PK1Cell Injure Mediated By Oxidative Stress

Fluoroquinolone antimicrobial agents (FQs) are widely used in the treatment of systemic infections,expecially in the treatment of respiratory and urinary tract infections, because of their broader spectrum of antimicrobial activity as well as their good tissue penetrations. The adverse events of FQs,such as central nervous system reactions, gastrointestinal tract, phototoxicity, tendinitis and nephrotoxicity.are encountered in clinical practice. Oxidative stress play a rol in the mechanism of the adverse events induced by fluoroquinolones, but whether the mechanisms of the nephrotoxicity is also connected with oxidative stress remains completely unknown.In this study, the LLC-PK1cell was used as study model to investigate the mechanisms of nephrotoxicity which was induced by danofloxacin. So that it will provide some advice for reducing the adverse reaction of FQs in clinical practice.The cytotoxicity of LLC-PK1cells induced by danofloxacin was studied through detecting the chang of morphology, cell viability and the extent of apoptosis..Furthermore,through detecting the level of the intracellular reactive oxygen species,the lipid peroxidation, the activity of antioxidant enzymes.including SOD,CAT and GSH-PX,the influence of danofloxacin on oxidation reduction system in LLC-PK1cells was investigated. Moreover, through Pre-incubating with GSH and NAC,the protective effect of antioxidant(GSH,NAC) against the toxicity induced by danofloxacin was also examined.The results showed the viability of LLC-PK1cells was decreased in a concentration-and time-dependent manner. The total apoptotic cells was22.7%at400μM of danofloxacin for48h,but all the rest groups’are under5%. After incubating LLC-PK1cells with different danofloxacin for24h,the intracellular ROS was increased in ime-dependent manner. After treatment with12.5μM danofloxacin for6,12,24,48,72h, the level of the intracellular ROS in LLC-PK1was highest at24h.Danofloxacin caused about4.1-fold increase in the MDA level at the concentration of400μM for24h but it did not induce apoptosis. Furthermore, antioxidant enzymes activities, such as superoxide dismutase (SOD) and catalase (CAT), were rapidly decreased after treatment with25μM of danofloxacin for24h. However, the activities of SOD and CAT were increased after treatment with100,200and400μM of danofloxacin for24h. The activity of glutathione peroxidase (GSH-PX) was significantly decreased in a concentration-dependent manner. In the experiments with the antioxidants, Pretreatment with GSH and NAC inhibited ROS production, lipid peroxidation and GSH-PX decline.These data suggest that the possible mechanisms of danofloxacin-induced nephrotoxicity might be related to oxidative damage due to excess accumulation of ROS. However, in some extent, the increase activity of SOD and CAT decreased the oxidative damage induced by danofloxacin...