[Effect of poloxamer 407 on the cochlear morphology and hearing function after perfusion in round window: experiment with guinea pigs].

Objective: To observe the effect of sustained-release vehicle-Poloxamer 407 on the function and morphology of the cochlear after perfusion in round window.

Methods: The right ears of 16 guinea pigs as experimental group were perfusion with 20% Poloxamer 407 solusion 100 microl in round window, the left ears as control group with normal saline. Another 4 animals without treatment were in negative control group. Auditory function was investigated before and immediate, 7, 14, 28, 49 days after perfusion, and the cochlear basilar membranes were stained by silver nitrate after ABR examinations. The stained basilar membranes were examined under light microscopy.

Results: The ABR threshold to filtered clicks were elevated after perfusion, and were recovered to normal at 49 days after perfusion. The morphology of cochlear hair cells were not significantly damaged after perfusion.

Conclusion: Poloxamer 407 after topical perfusion in round window can cause temporary changes on auditory function of inner ear, but no inreversible damage on function and morphology of cochlear. Therefore, Polomamer 407 can be used as sustained-release vehicle in middle and inner ear diseases.