Publication | Closed Access
Effect of transtympanic injection of steroids on cochlear blood flow, auditory sensitivity, and histology in the guinea pig.
136
Citations
0
References
1998
Year
Steroids are routinely used to treat inner ear disorders, and transtympanic delivery offers higher local concentrations while minimizing systemic exposure. The study aimed to assess the safety of transtympanic dexamethasone injection on cochlear blood flow, auditory sensitivity, and histology in guinea pigs. Cochlear blood flow was measured with laser Doppler flowmetry, auditory sensitivity with auditory brain‑stem responses, and inner ear tissue examined histologically after injection. Dexamethasone injection produced a rapid, sustained 29.26 % increase in cochlear blood flow without affecting auditory sensitivity or causing histologic damage, indicating it is unlikely to harm the inner ear and may enhance steroid efficacy through increased perfusion.
Transtympanic application of steroids is not harmful to the inner ear.Steroids are routinely used to treat inner ear pathologies, such as sudden sensorineural hearing loss and autoimmune inner ear disease. The transtympanic route has received increased attention as it can lead to higher levels in tissue and nearly eliminate systemic effects. There has been concern over the safety of applying these drugs directly to the inner ear.This study investigates the effects of transtympanic Dexamethasone injection on cochlear blood flow using laser Doppler flowmetry, auditory sensitivity using auditory brain stem responses, and histology in the guinea pig.Results show a significant increase in cochlear blood flow within 30 s to a mean of 29.26% without significant change in auditory sensitivity. The increase in cochlear blood flow was sustained and did not return to baseline for at least 1 hour after drug application. No histologic changes were observed.These results suggest that transtympanic steroid application is not likely to be detrimental to the inner ear. Additionally, the increase in blood flow may indicate a possible mechanism accounting for the pharmacologic effects of steroids in the inner ear.