The Protective Effects of Intratympanic Dexamethasone to Prevent Cisplatin Ototoxicity / 听力学及言语疾病杂志

ABSTRACT

Objective To investigate the effectiveness of intratympanic dexamethasone injection as a protec-tion agent against cisplatin ototoxicity.Methods Fifty five healthy guinea pigs were randomly divided into four groups.The guinea pigs groups received (group I)0.9% NaCl solution(16 ml/kg)intraperitoneally (IP),(group II)dexamethasone (10 mg/ml)intratympanically(IT),(group III)cisplatin (16 mg/kg)only intraperitoneally(IP) and (group IV)dexamethasone (10 mg/ml)IT followed after 1h by 16 mg/kg cisplatin.Before and 7 days following injections,the ototoxic effect was measured with auditory brainstem response(ABR).The contents of malondiade-hyde(MDA)and activities of superoxide dismutase(SOD)were also measured.Results ABR thresholds before and after dosing were 28.50±4.74,29.00±3.94 dB nHL and 28.67±5.82,31.33±5.81 dB nHL in group I and group II,respectively,with no significant differences (P>0.05).The contents of MDA and activities of SOD were 2.01 ±0.07 mmol/L ,234.10±13.09 U/ml and 2.06±0.09 mmol/L,233.20±13.24 U/ml in the group I and group II, respectively,with no significant differences (P>0.05).ABR thresholds after dosing were 55.33±4.81,and 40.67 ±3.72 dB nHL in the group III and group IV,which were significantly increased,but ABR thresholds in the group IV were significantly lower than that in the group III (P<0.05).The contents of MDA were 5.74±0.17,3.51± 0.18 mmol/L in the group III and group IV,which were significantly increased.SOD activities were 107.90 ± 14.21,and 162.70±11.25 U/ml,which significantly decreased.Nevertheless,in the group IV dexamethasone rela-tively reduced the contents of MDA(P<0.001)while increased the activities of SOD(P<0.001)compared with group III.Conclusion Intratympanic dexamethasone injection presents as an effective treatment modality to prevent cisplatin ototoxicity without any ototoxic effect.