A model portraying experimental loss of hair cell: the use of distortion product otoacoustic emission in the assessment of rat's ear.

The use of rats in research academies to study deafness is widespread, meanwhile medicinal methods to eliminate hair cells is also increasing. Thus, aminoglycosides and loop diuretics have grasped more attention. This study aimed at establishing an animal model in which a rapid distortion of the hair cell of cochlea administering amikacin and furosemide and using distortion product otoacoustic emission (DPOAE) the functioning of rat's ear would be assessed. Forty-eight male Sprague-Dawley rats (mean weight 200-250g) were randomly divided into six equal groups. Except the control group the rest received 0.5mg/g, 0.75mg/g, 1mg/g, 1.25mg/g, and 1.5mg/g, of subcutaneous amikacin respectively. 30 minutes later every rat received 0.1mg/g of furosemide intrapritoneally. DPOAE of rats was measured before these injections and 72 hours later. Then tissue sections of the rat's cochlea were prepared. All the cases had a significant decrease in their DPOAE with the frequencies 2KHz-8KHz (p<0.05). The most change in DPOAE was in rats which had received 1mg/g - 1.5mg/g amikacin. Histological studies approved distortion of hair cell even the apical turn. To establish a deafness model due losing hair cells, it is possible to use a combination of 1mg/g amikacin and 0.1mg/g furosemide. Besides, to approve deafness DPOAE resulted can be used.