天麻素对噪声性耳聋听觉脑干诱发电位及耳蜗毛细胞的影响

摘要

Objective To study the preventive and treating effects of Gastrodia elata B1 on noise-induced hearing loss (NIHL) in guinea pigs and to explore its probable mechanisms of effects.Methods Fifty healthy guinea pigs with normal tympanic membrane and auricle reflex were randomly divided into five groups:normal group,prevention group with Gastrodia elata B1 (Ⅰ 1),prevention group with normal saline (Ⅰ 2),treatment group with Gastrodia elata B1 (Ⅱ 1),treatment group with normal saline (Ⅱ 2).All of animals except normal controls were simultaneously exposed to steady white noise at 105dBSPL for 4 h/day,and lasted for 7 days.Guinea pigs of Ⅰ1 began to be injected by Gastrodia elata B1 (100mg/kg,celiac injection) three days before noise exposure,and lasted for 10 days,whereas those in Ⅰ 2 had been given normal saline instead of Gastrodia elata B1.Guinea pigs in Ⅱ 1 began to use Gastrodia elata B1 in the second day after noise exposure and lasted for 10 days,whereas those in Ⅱ 2 had been given normal saline instead of Gastrodia elata B1.Auditory brainstem response (ABR) was used to study the variation of the auditory function.The morphological changes of hair cells were observed on the stretched preparation of basilar membrane.The variety of succinate dehydrogenase (SDH) of hair cells was observed by light microscope.Results Guinea pigs of Ⅰ1 showed significantly lower ABR threshold (P ＜ 0.01),less loss rate of out hair cells (P＜0.01),and more SDH-staining hair cells,as compared with Ⅰ2.There was no significant difference between animals of Ⅱ 1 and Ⅱ2 on the above parameters.Conclusion Gastrodia elata B1 has prevention effect on NIHL.But this experiment showed no significant effect about its treatment.The mechanisms of the preventive effect of Gastrodia elata B1 may be stabling hair cell memberane and ameliorating the activities of SDH in the hair cells,then increaseing cell to gain ATP,and improving the microcirculation of the cochlea.%目的 观察天麻素对豚鼠噪声性耳聋听觉脑干诱发电位(ABR)及耳蜗外毛细胞的影响,同时探讨预防及治疗的作用机制.方法 雄性纯白豚鼠共50只,随机分5组:正常组、预防实验组及预防对照组,治疗实验组及治疗对照组.将除正常组以外4组动物置于隔音室,暴露于105dB SPL稳态白噪声,噪声持续时间4h/d并且连续7天.预防实验组暴露噪声前3天开始腹腔注射天麻素100mg/kg,连续每日注射至噪声结束当天,预防对照组同条件下使用注射用水；治疗实验组于噪声结束后次日给予天麻素100mg/kg腹腔注射,每日注射连续10天,治疗对照组同条件下予注射用水.记录ABR听阈值变化；采用耳蜗基膜铺片技术观察耳蜗毛细胞形态学改变同时计算外毛细胞损伤率；观察外毛细胞琥珀酸脱氢酶蓝染沉淀的活性改变.结果 预防实验组ABR听阈值和耳蜗外毛细胞缺失率均低于预防对照组(P＜0.05)；预防实验组耳蜗外毛细胞琥珀酸脱氢酶蓝染细胞明显优于预防对照组.治疗实验组与治疗对照组各项观察指标均无统计学差异.结论 进一步证实了天麻提取液天麻素对噪声性耳聋的预防作用,但其治疗作用在本实验不明显.天麻素能保护细胞膜稳定并增加耳蜗毛细胞琥珀酸脱氢酶活性,从而增加细胞能量供应改善耳蜗微循环.