银杏叶提取物注射液对噪音性听力损失的保护机制研究

Research on the protective effect and mechanism of EGB injection on NIHL rats by regulating PI3K/MAPK pathway

目的研究银杏叶提取物注射液(EGB)调控磷脂酰肌醇3激酶(PI3K)/丝裂原活化蛋白激酶(MAPK)信号通路对噪音性听力损失(NIHL)的保护作用及机制。方法将SD大鼠随机分为对照组(Control组)、NIHL模型组(Model组)、低剂量EGB组(EGB-L组,0.7 mg·kg^(-1))、高剂量EGB组(EGB-H组,1.4 mg·kg^(-1))和高剂量EGB+PI3K激活剂740Y-P组(EGB-H+740Y-P组,1.4 mg·kg^(-1)EGB+0.02 mg·kg^(-1)740Y-P)。听觉脑干反应(ABR)评估各组大鼠的听力;HE染色观察大鼠耳蜗组织病理学与螺旋神经节细胞数量;RT-qPCR法测定大鼠耳蜗组织PI3K、MAPK mRNA表达;免疫印迹试验(Western Blot)法检测大鼠耳蜗组织PI3K/MAPK信号通路相关蛋白表达。CCK-8法测定耳蜗毛细胞增殖活性。结果与Control组相比,Model组大鼠在2、4、8 kHz处左、右耳的听力阈值、耳蜗组织PI3K、MAPK mRNA表达、耳蜗组织PI3K、MAPK、AKT磷酸化水平显著升高(P<0.05),耳蜗组织螺旋神经节细胞和毛细胞数量显著减少(P<0.05);与Model组相比,EGB-H组大鼠相关指标变化与上述相反(P<0.05)。PI3K激活剂740Y-P减弱EGB对大鼠NIHL保护作用。结论EGB可能通过下调PI3K/MAPK信号通路保护大鼠NIHL。

Objective To research the protective effect and mechanism of extract of ginkgo biloba(EGB)injection on noise induced hearing loss(NIHL)rats by regulating phosphatidylinositol 3-kinase(PI3K)/mitogen activated protein kinase(MAPK)signaling pathway.Methods Sprague dawley(SD)rats were randomly divided into control group,NIHL model group,low-dose EGB group(EGB-L group,0.7 mg·kg^(-1)),high-dose EGB group(EGB-H group,1.4 mg·kg^(-1)),and high-dose EGB+740Y-P group-1-1(EGB-H+740Y-P group,1.4 mg·kg^(-1) EGB+0.02 mg·kg^(-1)740Y-P).Auditory brainstem response(ABR)was used to evaluate the hearing of rats in each group.Hematoxylin eosin(HE)staining was used to observe the histopathological changes of rat cochlea tissue and the number of spiral ganglion cells.The mRNA expression of PI3K and MAPK in rat cochlea tissue was detected by reverse transcription quantitative polymerase chain reaction(RT-qPCR).Western blot method was used to detect the related protein expression on PI3K/MAPK signaling pathway in rat cochlea tissue.The proliferative activity of cochlear hair cells was determined by cell counting kit-8(CCK-8)method.Results Compared with the control group,the hearing threshold of each ear at 2,4 and 8 kHz,the mRNA expression of PI3K and MAPK in cochlea tissue,the phosphorylation level of MAPK,PI3K and protein kinase B(AKT)in cochlea tissue in the model group significantly increased(P<0.05),and the number of spiral ganglion cells and hair cells in cochlea tissue significantly decreased(P<0.05).Compared with the model group,the changes of the same indicators in the EGB-H group were contrary to those above(P<0.05).740Y-P,a PI3K activator,reduced the protective effect of EGB on NIHL rats.Conclusion EGB might protect NIHL rats by down-regulating PI3K/MAPK signaling pathway.