Effects of betahistine on guinea pig model of ischemic inner ear / 第三军医大学学报

ABSTRACT

Objective To investigate the improving effect of betahistine hydrochloride (BH) on the cochlear blood supply in guinea pig and the potential use in cochlear ischemia. Methods The guinea pig model of ischemic inner ear was established by ferromagnetic embolization of the target microvessels of the cochlea. A total of 10 model guinea pigs were divided into BH group and control group ( n =5 in each group). Guinea pigs in BH group were treated with 0.1% BH through gastric canal, and those in the control group with the identical volume of saline. At 24 h after treatment, the cochlear blood flow (CBF), auditory brainstem responses (ABR), ferromagnetic emboli in the microvessels of cochlear lateral wall, and the hair cell succinic dehydrogenase (SDH) activity were detected. Results CBF in 10 ears in the control group was (50?7)%, and the elevated ABR threshold was found in 7 ears (70%). Ferromagnetic emboli confirmed by carbonyl iron spheres were extensively distributed in the microvessels in the cochlear lateral wall. Spot like lesion of the outer hair cells was found in SDH stained basic membrane. However, in BH group, CBF was (81?11)%. Elevated threshold of ABR was found in only 3 ears, and the ferromagnetic emboli in the microvessles in the cochlear lateral wall were less than those in the control group. Scattered lesions of the outer hair cells were found in SDH stained basic membrane. There was significant difference in the number of deleted hair cells between the BH group and the control group. Conclusion The preliminary results indicated that BH may increase CBF and attenuate the cochlear lesion due to ischemia, resulting in partial protection of hearing.