Abstract
Abstract: :
Purpose: External bacterial ocular infections are usually treated with potent broad-spectrum antimicrobials, such as aminoglycosides and fluoroquinolones. One of the major concerns in using such agents is their potential epithelial toxic effect. The aim of this study was to investigate the possible in vitro cytotoxic effect of both netilmicin (an aminoglycoside agent) and ofloxacin (a fluoroquinolone agent) on human conjunctival epithelial cells. Methods: A continuous human conjunctival cell line (Wong-Kilbourne-derivative of Chang conjunctiva, ATCC) was exposed to a preservative-free solution containing either netilmicin or ofloxacin at various concentrations (up to 5 mg/mL). After 24 hours of treatment, cells were examined for cytotoxicity. Cell proliferation was assessed by measurement of BrdU incorporation during DNA synthesis in proliferating cells. Cell viability was also evaluated using MTT and neutral red assay (NR). MTT assesses viability based on the functional state of the cell mitochondria whereas NR uptake is directly proportional to the number of viable cells actively accumulating dye in lysosomes. Three separate experiments have been done for each end point and separate ID50 values were also calculated. Results: No cytotoxicity was observed after 24 hours netilmicin treatment. Accordingly, for this aminoglycoside no ID50 could be calculated. On the contrary, a dose-depend inhibition of proliferation and decrease of cell viability was detected with ofloxacin treatment. The ID50 of the ofloxacin ranged from 0.4 to 1.2 mg/mL, not varying markedly between different tests. A severe cytotoxicity (100% inhibition compared to control) was observed at the clinically used ofloxacin concentration (3 mg/mL). Conclusions: Our results suggest that, at clinically used concentrations, netilmicin is not cytotoxic, whereas ofloxacin has significant antiproliferative and cytotoxic effects for conjunctival cells. .
Keywords: 318 anterior segment • 319 antibiotics/antifungals/antiparasitics • 514 pharmacology