The Round Window Membrane Approach Of Antioxidant And/or Glutamate Receptor Antagonist Protect The Cochlea Against The Amikacin Ototoxicity

Objective: To test the effect of antioxidant L-NAC and/or glutamate receptor antagonist Caroverine to protect the cochlea against amikacin ototoxicity using round window membrane approach. Method: A total of 30 health guinea pigs were randomly divided into 3 groups, and every group included 10 guinea pigs. The animals were injection of 3% pentobarbital (1ml/mg), then underwent surgery. Opened the right bullar, and exposed the right round window niche, the gelfoam was placed into the round window niche, stick the bullar with binder, the skin sututed. After 30 minutes, all the animals received amikacin (400mg/kg/d, i.m) for five days. Through gelfoam 0.9% saline (1ml/kg) was given in group A; NAC (1ml/kg) was given in group B; Caroverine (12.8mg/ml, 60ul/kg) was given in group C. ABR thresholds of guinea pigs were measured respectively prior to amikacin injection and 2 weeks after amikacin injection. Two weeks after amikacin injection, guinea pigs were killed and right bullar were obtained. Count hair cells by using fluorescence microscope. We found morphological results. Results: We use SPSS10.0 statistics. By analyzing ABR thresholds of the total animals and comparing the results of every two groups, P<0.05, the difference was significant, indicating differences between each two groups at different frequencies. By analyzing ABR threshold shifts and comparing the results of every two groups, P< 0.05, the difference was significant, indicating differences between each two groups at different frequencies. Morphological finding: the mean outer hair cell (OHC) loss rate was 85% in group A, and its mean inner hair cell (IHC) loss rate was 70%. The mean outer hair cell (OHC) loss rate was 65% in group B, and its mean inner hair cell (IHC) loss rate was 60%. The mean outer hair cell (OHC) loss rate was 55% in group C, and its mean inner hair cell (IHC) loss rate was 50%.