Jiangsu Kanion Pharmaceutical Co., Ltd., Lianyungang, 222001, Jiangsu, China.
State Key Laboratory of New-tech for Chinese Medicine Pharmaceutical Process, Lianyungang, 222001, Jiangsu, China.
Cell Stress Chaperones. 2019 Mar;24(2):441-452. doi: 10.1007/s12192-019-00977-1. Epub 2019 Feb 27.
Ginkgolide terpenoid lactones, including ginkgolides and bilobalide, are two crucial bioactive constituents of extract of Ginkgo biloba (EGb) which was used in the treatment of cardiovascular and cerebrovascular diseases. The aims of this study were to investigate the antioxidant effects and mechanism of ginkgolides (ginkgolide A (GA), ginkgolide B (GB), ginkgolide K (GK)) and bilobalide (BB) against oxidative stress induced by transient focal cerebral ischemia. In vitro, SH-SY5Y cells were exposed to oxygen-glucose deprivation (OGD) for 4 h followed by reoxygenation with ginkgolides and BB treatments for 6 h, and then cell viability, superoxide dismutase (SOD), and ROS were respectively detected using kit. Western blot was used to confirm the protein levels of hemeoxygenase-1 (HO-1), quinone oxidoreductase l (Nqo1), Akt, phosphorylated Akt (p-Akt), nuclear factor-E2-related factor2 (Nrf2), and phosphorylated Nrf2 (p-Nrf2). GB combined with different concentrations of LY294002 (PI3K inhibitor) were administrated to SH-SY5Y cells for 1 h after OGD, and then p-Akt and p-Nrf2 levels were detected by western blot. In vivo, 2 h of middle cerebral artery occlusion (MCAO) model was established, followed with reperfusion and GB treatments for 24 and 72 h. The infarct volume ratios were confirmed by TTC staining. The protein levels of HO-1, Nqo1, SOD1, Akt, p-Akt, Nrf2, and p-Nrf2 were detected using western blot and immunohistochemistry (IHC). Experimental data in vitro confirm that GA, GB, GK, and BB resulted in significant decrease of ROS and increase of SOD activities and protein levels of HO-1 and Nqo1; however, GB group had a significant advantage in comparison with the GA and GK groups. Moreover, after ginkgolides and BB treatments, p-Akt and p-Nrf2 were significantly upregulated, which could be inhibited by LY294002 in a dose-dependent manner, meanwhile, GB exhibited more effective than GA and GK. In vivo, TTC staining indicated that the infarct volume ratios in MCAO rats were dramatically decreased by GB in a dose-dependent manner. Furthermore, GB significantly upregulated the protein levels of HO-1, Nqo1, SOD, p-Akt, p-Nrf2, and Nrf2. In conclusion, GA, GB, GK, and BB significantly inhibited oxidative stress damage caused by cerebral ischemia reperfusion. Compared with GA, GK, and BB, GB exerts the strongest antioxidant stress effects against ischemic stroke. Moreover, ginkgolides and BB upregulated the levels of antioxidant proteins through mediating the Akt/Nrf2 signaling pathway to protect neurons from oxidative stress injury.
银杏萜类内酯,包括银杏内酯和白果内酯,是银杏叶提取物(EGb)中两种重要的生物活性成分,用于治疗心脑血管疾病。本研究旨在探讨银杏内酯(银杏内酯 A(GA)、银杏内酯 B(GB)、银杏内酯 K(GK))和白果内酯(BB)对短暂性局灶性脑缺血诱导的氧化应激的抗氧化作用及其机制。在体外,将 SH-SY5Y 细胞暴露于氧葡萄糖剥夺(OGD)4 h 后,用银杏内酯和 BB 处理 6 h,然后分别用试剂盒检测细胞活力、超氧化物歧化酶(SOD)和 ROS。Western blot 用于确认血红素加氧酶-1(HO-1)、醌氧化还原酶 l(Nqo1)、Akt、磷酸化 Akt(p-Akt)、核因子-E2 相关因子 2(Nrf2)和磷酸化 Nrf2(p-Nrf2)的蛋白水平。GB 与不同浓度的 LY294002(PI3K 抑制剂)联合作用于 OGD 后 1 h 的 SH-SY5Y 细胞,然后用 Western blot 检测 p-Akt 和 p-Nrf2 水平。在体内,建立 2 h 的大脑中动脉闭塞(MCAO)模型,随后进行再灌注和 GB 治疗 24 和 72 h。TTC 染色证实梗死体积比。Western blot 和免疫组织化学(IHC)检测 HO-1、Nqo1、SOD1、Akt、p-Akt、Nrf2 和 p-Nrf2 的蛋白水平。体外实验数据证实 GA、GB、GK 和 BB 显著降低 ROS,增加 SOD 活性和 HO-1 和 Nqo1 的蛋白水平;然而,GB 组与 GA 和 GK 组相比具有显著优势。此外,银杏内酯和 BB 处理后,p-Akt 和 p-Nrf2 显著上调,LY294002 呈剂量依赖性抑制,同时,GB 比 GA 和 GK 更有效。在体内,TTC 染色表明,GB 呈剂量依赖性显著降低 MCAO 大鼠的梗死体积比。此外,GB 还显著上调 HO-1、Nqo1、SOD、p-Akt、p-Nrf2 和 Nrf2 的蛋白水平。综上所述,GA、GB、GK 和 BB 可显著抑制脑缺血再灌注引起的氧化应激损伤。与 GA、GK 和 BB 相比,GB 对缺血性中风的抗氧化应激作用最强。此外,银杏内酯和 BB 通过介导 Akt/Nrf2 信号通路上调抗氧化蛋白水平,从而保护神经元免受氧化应激损伤。