A Model Of ASNR In Guinea Pigs

Objective:To establish a model of ASNR in guinea pigs by verifying consistency of appearance of ASNR and VEMP.in Other words,a model of profound hearing loss with normal saccular founction.Methods:27 healthy guinea pigs were employed in experiment and divided into two groups randomly,normal group(16 subjects)and deafened group(11 subjects).Each animal experienced auditory and vestibular tests including ABR,VEMP and caloric test.For defened animals a quick treatment was employed consisting in one subcutaneous injection of kanamycin at a dose of 400mg/kg followed one hour later by an Jugular vein injection of ethacrynic acid at a dose of 40mg/kg.Animals were left for at least one week after the treatment to allow complete recovery and then received ABR,VEMP and caloric test.The deafened group were divided two groups including ASNR group and non-ASNR group by presence of ASNR.Results:In 11 deafen animals(22 ears),ASNR was elicited in 8 ears(36.4 %),the threshold of ASNR was 120—130dB SPL,the mean of threshold was 124.4±4.96dB SPL.It's latency was 1.75-2.60 ms,the mean was 2.15±0.27 ms.The mean latency of threshold was 2.34±0.18ms.8 ASNR ears presented VEMP,the threshold,positive and negative potential latency of VEMP in ASNR group comparing to that of normal group showed no statistical significance (p＜0.05).Absent VEMP in 10 ears demonstrated parallel absence of ASNR. There was no statistically significant correlation between VEMP and caloric test or ASNR and caloric test in deafened group.Conclusions:According to literatures up to date,animal model of ASNR was first established by ototoxicity means.The presence of ASNR was consistent with VEMP and not correlated with caloric test,suggesting that ASNR and VEMP are both origin from saccule.This study evoked ASNR in the modle of guinea pigs which was profound hearing loss but had normal saccular founction.