THE EFFECT OF TAXIFOLIN ON CISPLATIN INDUCED OXIDATIVE COCHLEAR DAMAGE IN RATS: BIOCHEMICAL AND HISTOPATHOLOGICAL EXAMINATION

Ototoxicity of cisplatin is one of the major dose limiting side effects. Cisplatin-dependent ototoxicity is known to be associated with reactive oxygen species. Protective effect of taxifolin, being a flavanone found in onions, milk thistle, French maritime, and Douglas fir bark, against cisplatin-associated ototoxicity will be examined in this study. There are no studies in the literature examining the protective effect of taxifolin against cisplatin-induced ototoxicity. 50 mg/kg taxifolin was orally administered to TXC group rats (n-6), and distilled water was orally administered as solvent to CG (n-6) and HG (n-6) groups. One hour later, 5 mg/kg cisplatin was administered intraperitoneally (i.p) to TXC and CG groups. This procedure was repeated once a day for 7 days. At the end of this period, all animals were sacrificed by high-dose anesthesia (50 mg/kg thiopental sodium) and biochemical and histopathological examinations were performed on the dissected cochlea tissue. Our biochemical test results showed that oxidant parameters were significantly increased whereas antioxidant parameters were significantly decreased in the cisplatin group (CG) compared to taxifolin (TXC) and healthy (HG) groups (P <0.0001 for both parameters). Histopathological results showed that severe cochlear vestibular membrane degeneration, dilated conjunctival blood vessels, edema and destruction developed in the cisplatin group. However, no pathological findings were found in the taxifolin-treated group except for mild degeneration and edema. This information suggests that taxifolin may be useful in the treatment of cisplatin-associated oxidative cochlear damage.