IN VITRO PROTECTIVE EFFECTS OF DEXAMETHASONE AGAINST CISPLATIN OTOTOXICITY IN OCK3 MOUSE CELL LINE.

Present therapies of malignant tumours are still based on cytotoxic drugs that damage DNA or inhibit cell division, causing death of cancerous cells and tissues. However, most chemiotherapeutic drugs are non-specific, thus their cytoxic action also affects healthy cells and tissues. One of the most widely employed chemiotherapic drug, cisplatin, shows serious ototoxic effects leading to more or less profound hearing loss. To counteract these effects, several strategies have been devised, such as the administration of antioxidants and glucocorticoids. Dexamethasone, a glucocorticoid widely employed as anti-inflammatory drug, is known to exert some protective effects against cisplatin toxicity. This study was aimed to test by cytofluorimetry the time/dose effects of dexamethasone and cisplatin, administered separately and in co-treatment, in an inner ear mouse cell line (OCK3). The results showed that, in the experimental conditions tested, dexamethasone had no cytotoxic effects at any concentration, while cisplatin had time/dose dependent cytotoxicity. Concerning the co-treatment, when OCK3 cells were pre-treated with dexamethasone before cisplatin administration, a lower cell mortality was observed at 48 h incubation time and concentrations between 50 and 250 nM. Thus dexamethasone apparently exerts in vitro protective effects against cisplatin-induced ototoxicity.