葛根素对豚鼠耳蜗缺血再灌注损伤时听功能和iNOS的影响

Protective effect of Puerain on the auditory function and the expression of iNOS after vertebrobasilar artery ischemia reperfusion in guinea pigs

目的探讨葛根素在豚鼠椎基底动脉缺血再灌注耳蜗损伤中的保护作用及分子机制,为葛根素治疗耳蜗缺血再灌注损伤提供理论依据。方法纯白雄性豚鼠3 2只随机分为4组:正常对照组、缺血再灌注7 d组、生理盐水组(即缺血再灌注7 d加生理盐水对照组)和用药组(即缺血再灌注7 d加葛根素保护组)。除正常对照组外的所有豚鼠均进行手术造模,用药组在缺血再灌注开始时,腹腔注射葛根素1 5 0 mg/(kg.d)-1,每日1次,连用6 d,于再灌注7 d时处死。生理盐水组操作同用药组,但以等容量生理盐水代替葛根素。应用听觉脑干反应(ABR)评价听功能。采用免疫组织化学技术,观察诱导型一氧化碳合酶(iNOS)在各组Cortis器、螺旋神经节及血管纹的表达。结果缺血再灌注7 d组、生理盐水组与正常对照组比较各波潜伏期、Ⅰ～Ⅲ波间期明显延长,阈值升高(P<0.0 5)。用药组与缺血再灌注7 d组、生理盐水组相比Ⅰ、Ⅲ、Ⅳ波潜伏期、Ⅰ～Ⅲ波间期缩短和阈值降低(P<0.0 5)。正常对照组与用药组Ⅲ、Ⅳ波潜伏期、Ⅰ～Ⅲ波间期和阈值比较无统计学意义(P>0.0 5)。用药组iNOS表达与缺血再灌注7 d组比较明显下调(P<0.0 5)。结论葛根素具有一定保护耳蜗缺血再灌注损伤的作用,其保护作用的机制之一可能与下调iNOS表达有关。

Objective To investigate the protective effect of Puerain on vertebrobasilar artery ischemia reperfusion injury of guinea pigs cochlea and its molecular mechanism.Methods Thirty-two healthy male guinea pigs with normal Preyer＇s reflex were randomly divided into four groups： normal control group（NC）,reperfusion 7 days group（RG）,Puerain group（PG）,and normal saline group（NS）.Animal model of vertebrobasilar artery ischemia reperfusion was established via the skull base approach.In PG,after ischemia Puerain of 150 mg/（kg·d）-1 was injected intraabdominally every day for 6 days.In NS,normal saline of the same volume as Puerain was used for 6 days too.The auditory function was evaluated with evoked auditory brainstem response（ABR）.The changes of inducible nitronic oxide synthase（iNOS） caused by Puerain were studied with paraffin embedded immunohistochemistry.Results Compared with the NC,the latency of all waves and interphases between waveⅠⅢ in RG and NS got elongated,and their thresholds got elevated in ABR（P〈0.05）.Compared with the RG and NS,latency of waveⅠ,Ⅲ,Ⅳ and interphases between waveⅠⅢ in PG got shortened,and the threshold got reduced（P〈0.05）.The differences of lantency of wave Ⅲ,Ⅳ,the interphases（waveⅠⅢ）,and the threshold between PG and NC were statistically insignificant（P〉0.05）.The expression of iNOS in PG was much lower than that in RG（P〈0.05）.Conclusion Puerain can protect the cochlea from ischemia reperfusion injury.The protective mechanism might be related to the down-regulating of the expression of iNOS.