基于Nrf2-Notch1信号轴探讨黄芩苷对帕金森病大鼠黑质多巴胺能神经元氧化应激的影响

Effect of Baicalin on the Oxidative Stress of Dopaminergic Neurons in Substantia Nigra of Rats with Parkinson’s Disease Based on Nrf2-Notch1 Signal Axis

[目的]基于核因子E2相关因子2(nuclear factor E2 related factor 2,Nrf2)-Notch1信号轴探讨黄芩苷(baicalin,BA)对帕金森病(Parkinson's disease,PD)大鼠黑质多巴胺能神经元(dopaminergic neurons,DN)氧化应激的作用机制。[方法]将PD大鼠分为模型组、BA组、BA-Nrf2抑制剂组及BA-Notch1抑制剂组,以健康大鼠为对照组。BA组以78mg·kg^(-1)的BA 0.9%氯化钠溶液灌胃;模型组和对照组以等量0.9%氯化钠溶液灌胃,同时均以0.9%氯化钠溶液2mL·kg^(-1)腹腔注射;BA-Nrf2抑制剂组在BA组基础上腹腔注射Brusatol 2mg·kg^(-1);BA-Notch1抑制剂组在BA组基础上腹腔注射DAPT 10mg·kg^(-1),1次/d,连续2周。给药2周后检测脑黑质中丙二醛(malondialdehyde,MDA)水平、谷胱甘肽过氧化物酶(glutathione peroxidase,GSHPx)和超氧化物歧化酶(superoxide dismutase,SOD)活力、DN细胞凋亡率及Nrf2、血红素加氧酶1(heme oxygenase 1,Hmox1)、Notch1、Split多毛增强子1(hairy and enhancer of Split 1,Hes1)mRNA和蛋白的表达。[结果]与对照组比较,模型组脑黑质中MDA水平及DN细胞凋亡率升高(P<0.05),脑黑质中SOD和GSH-Px活力及Nrf2、Hmox1、Notch1、Hes1 mRNA和蛋白相对表达量降低(P<0.05)。与模型组比较,BA组、BA-Nrf2抑制剂组及BA-Notch1抑制剂组脑黑质中MDA水平及DN细胞凋亡率降低,BA-Nrf2抑制剂组和BA-Notch1抑制剂组高于BA组(P<0.05)。与模型组比较,BA组、BA-Nrf2抑制剂组及BA-Notch1抑制剂组脑黑质中SOD和GSH-Px活力及Nrf2、Hmox1、Notch1、Hes1 m RNA和蛋白相对表达量升高,BA-Nrf2抑制剂组和BA-Notch1抑制剂组低于BA组(P<0.05)。[结论]BA可有效改善PD大鼠脑黑质DN氧化应激损伤,其机制可能与激活Nrf2-Notch1信号轴有关。

[Objective]To explore the mechanism of baicalin(BA)on oxidative stress in substantia nigra dopaminergic neurons(DN)in Parkinson's disease(PD)rats based on the nuclear factor E2 related factor 2(Nrf2)-Notch1 signal axis.[Methods]The PD rats were divided into model group,BA group,BA-Nrf2 inhibitor group and BA-Notch1 inhibitor group,with healthy rats as control group.Rats in BA group were given 78mg·kg^(-1) BA 0.9%sodium chloride solution by gavage,while model group and control group were given the same amount of 0.9%sodium chloride solution by gavage,and both were injected intraperitoneally with 0.9%sodium chloride solution 2mL·kg^(-1).BA-Nrf2 inhibitor group was intraperitoneally injected with Brusatol 2mg·kg^(-1) on the basis of BA group.In BA-Notch1 inhibitor group,DAPT 10mg·kg^(-1) was intraperitoneally injected on the basis of BA group,once a day,for 2 consecutive weeks.After 2 weeks of administration,malondialdehyde(MDA)level,superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)activity,DN apoptosis rate,Nrf2,heme oxygenase 1(Hmox1),Notch1,hairy and enhancer of Split 1(Hes1)mRNA and protein expression in the substantia nigra were detected.[Results]Compared with control group,the level of MDA and the apoptosis rate of DN in the substantia nigra of model group increased(P<0.05),while the activities of SOD and GSH-Px and the relative expression of Nrf2,Hmox1,Notch1,Hes1 mRNA and protein in the substantia nigra decreased(P<0.05).Compared with model group,the levels of MDA and DN apoptosis rate in the substantia nigra of BA group,BA-Nrf2 inhibitor group and BA-Notch1 inhibitor group were reduced,and above indicators in BA-Nrf2 inhibitor group and BA-Notch1 inhibitor group were higher than that in BA group(P<0.05).Compared with model group,the activity of SOD,GSH-Px and the relative expressions of Nrf2,Hmox1,Notch1,Hes1 mRNA and protein in the substantia nigra increased in BA group,BA-Nrf2 inhibitor group and BA-Notch1 inhibitor group,and above indicators in BA-Nrf2 inhibitor group and BA-Notch1 inhibitor group were lower than that in BA group(P<0.05).[Conclusion]BA can effectively relieve the oxidative stress damage of DN in the substantia nigra of PD rats,and its mechanism may be related to the activation of the Nrf2-Notch1 signal axis.