COMBINATIONAL ADMINISTRATION OF AMINOGLYCOSIDES AND LOOP DIURETICS AS AN EFFICIENT STRATEGY TO ESTABLISH DEAFNESS MODELS IN RATS

It is known that aminoglycoside antibiotics can damage the vestibular and auditory sensory epithelia, and the loop diuretics can enhance the ototoxic effect of aminoglycosides. Previous studies on the synergistic effect of these two types of drugs have used mice, guinea pigs and cats, but not rats. The aim of this study was to determine this synergistic effects in rat cochleae. Rats received intravenous injections of different doses of furosemide and/or intramuscular injections of kanamycin sulfate. Au- ditory brainstem response （ABR）, scanning electron microscopy （SEM） and immunocytochemistry were used to determine the effects of drug administration. In the group receiving combined administration of furosemide and kanamycin, the ABR thresh- old showed significant elevation 3 days after drug administration, greater than single drug administration. The hair cells showed various degrees of injury from the apical turn to the basal turn of the cochlea and from the outer hair cells to the inner hair cells. Neuron fibers of the hair cells showed significant loss 7 days after the drug administration, but the number of spiral ganglia did not decrease and supporting cells showed no signs of injury. Our study suggest that combined administration of fu- rosemide and kanamycin has an synergistic ototoxic effect, and can result in hair cell loss and hearing loss in rats.

Effects of combined administration of furosemide and kanamycin on rat auditory nerve

Objective To determine the effects of combined administration of furosemide and kanamycin on inner ear structures and the auditory nerve in rats. Methods The rats in the treatment group received intravenous injections of combined furosemide and kanamycin sulfate, and the rats in the normal control group received no treatment. The auditory brainstem response （ABR） test was carried out 7 days after drug administration to determine the effects of drug administration on hearing. Cochlear slice and cochlear wholcmount were prepared after 7 days of drug treatment. Results After 7 days of drug administration, ABR thresholds were significantly higher in the treatment group than in the control group and neurofilaments were significantly reduced, although the number of spiral ganglia showed no decrease and there were no signs of supporting cell injury. Conclusions Combined administration of furosemide and kanamyein sulfate has an apparent synergistic ototoxic effect. Although spiral ganglion damage may not be apparent within a short time period of drug administration, damage to auditory nerve fibers is obvious.

Clinical and Experimental Observation on Treatment of Sensorineural Deafness with Bushen Conger Tablet (补肾聪耳片)

Objective: To observe the effect of Bushen Conger （BSCE） tablet, a pure Chinese herbal medicine for reinforcing Kidney, removing blood stasis and opening apertures, in treating sensorineural deafness. Methods: Three hundred and ten patients were treated by BSCE tablet and the effects were observed. At the same time the effects of BSCE tablet on hearing, SOD, LPO, etc. were also assayed in guinea pigs. Results: The clinical total effective rate of BSCE tablet was 71.9 %. Animal experiment proved that the drug was effective in preventing and treating toxic deafness induced by aminoglycoside antibiotics. Conclusion: BSCE tablet could cure sensorineural deafness through adjusting the cochlear cyclic neucleotides as well as its SOD level, reducing the LPO level, and raising the thyroid and sexual glandular functions.