基于SIRT1/VEGFA信号通路探讨川芎嗪调节缺血性脑卒中损伤后血管内皮细胞的新生作用研究

Tetramethylpyrazine regulates angiogenesis of endothelial cells in cerebral ischemic stroke injury via SIRT1/VEGFA signaling pathway

该文研究川芎嗪(tetramethylpyrazine, TMP)能否通过刺激脑微血管内皮细胞促进血管新生,缓解缺血性脑卒中(cerebral ischemic stroke, CIS)并探讨其作用机制。体内实验:成年sprague-dawley(SD)大鼠,假手术(sham)组、大脑中动脉闭塞再灌注(middle cerebral artery occlusion/reperfusion, MCAO/R)组、MCAO/R+TMP组(腹腔注射20 mg·kg^(-1))。采用Z-Longa法评估神经功能;TTC染色检测脑梗死体积,酶联免疫吸附法(enzyme-linked immunosorbent assay, ELISA)检测血管内皮生长因子(vascular endothelial growth factor, VEGF)、血管生成素(angiopoietin, Ang)和血小板衍生生长因子(platelet-derived growth factor, PDGF);免疫荧光检测Ki67、血管内皮生长因子A(vascular endothelial growth factor A,VEGFA)、沉默信息调节因子1(slient information regulator 1,SIRT1);蛋白免疫印迹法(Western blot)检测VEGFA、SIRT1、血管生成素-2(angiopoietin-2,Ang-2)和血小板衍生生长因子B(platelet-derived growth factor B,PDGFB)。体外实验:培养小鼠脑微血管内皮细胞(brain-derived endothelial cells.3,Bend.3),确定TMP的最佳药物浓度;加入血管新生抑制剂卡博替尼(cabozantinib, BMS),ELISA检测VEGF、Ang和PDGF;Western blot检测VEGFA、Ang-2和PDGFB;免疫荧光染色检测CD31、CD34、Ki67;成管实验观察Bend.3细胞增殖、迁移和管腔形成的能力。加入SIRT1特异性抑制剂selisistat (EX-527)检测SIRT1和VEGFA的蛋白和免疫荧光,观察TMP对SIRT1/VEGFA通路的调控。结果显示,在体内实验中与sham组相比,MCAO/R组神经功能受损严重,脑梗死体积增大,VEGF、VEGFA、Ang、Ang-2、PDGF和PDGFB表达上升,Ki67和SIRT1表达下降(P<0.01)。与MCAO/R组相比,MCAO/R+TMP组神经功能受损症状改善、脑梗死体积明显缩小,激活了VEGF、VEGFA、Ang、Ang-2、PDGF和PDGFB、Ki67和SIRT1表达(P<0.01)。体外实验中发现与sham组相比,Bend.3细胞经糖氧剥夺复糖氧(oxygen glucose deprivation/reoxygenation, OGD/R)处理后被激活(P<0.05,P<0.01)。与OGD/R组相比,OGD/R+TMP组VEGF、VEGFA、Ang、Ang-2、PDGF、PDGFB、SIRT1、Ki67、CD31和CD34的表达水平上调,Bend.3细胞的成管能力增强,同时不受BMS和EX-527的抑制作用(P<0.05,P<0.01,P<0.001)。由此表明,TMP能通过激活SIRT1/VEGFA通路,刺激血管新生,缓解CIS损伤。

This study aims to investigate whether tetramethylpyrazine(TMP) can stimulate angiogenesis in cerebral microvascular endothelial cells and alleviate cerebral ischemic stroke(CIS) and to explore the underlying mechanisms. In the animal study, adult Sprague-Dawley rats(n=15) were assigned into sham surgery(sham), middle cerebral artery occlusion/reperfusion(MCAO/R), and MCAO/R+TMP(intraperitoneal injection of 20 mg·kg~(-1)) groups. The neurological function was evaluated by the Z-Longa method. The cerebral infarction volume was detected by TTC staining. Enzyme-linked immunosorbent assay(ELISA) was employed to detect the expression of vascular endothelial growth factor(VEGF), angiopoietin(Ang), and platelet-derived growth factor(PDGF). Immunofluorescence staining was employed to detect Ki67 and the expression of vascular endothelial growth factor A(VEGFA) and slient information regulator 1(SIRT1). Western blot was employed to determine the expression levels of VEGFA, SIRT1, angiopoietin-2(Ang-2), and platelet-derived growth factor B(PDGFB). In the cell study, mouse brain-derived endothelial cells(Bend.3) were cultured, and the optimal concentration of TMP was determined. Then, VEGF, Ang, and PDGF were detected by ELISA after the addition of cabozantinib. Western blot was employed to measure the expression of VEGFA, Ang-2, and PDGFB. Immunofluorescence staining was used to detect CD31, CD34, and Ki67, and the proliferation, migration, and tube formation ability of Bend.3 cells were observed in vitro. Western blot and immunofluorescence staining were performed to measure the expression of SIRT1 and VEGFA after addition of the SIRT1-specific inhibitor selisistat(EX-527). The results showed that compared with the sham group, the MCAO/R group had severe neurological function damage, increased infarction volume, up-regulated expression of VEGF, VEGFA, Ang, Ang-2, PDGF, and PDGFB, and down-regulated expression of Ki67 and SIRT1(P<0.01). Compared with the MCAO/R group, the MCAO/R+TMP group presented alleviated neurological function damage, reduced infarction volume, and activated expression of VEGF, VEGFA, Ang, Ang-2, PDGF, PDGFB, Ki67, and SIRT1(P<0.01). The cell experiments showed that compared with the normal group, Bend.3 cells were activated by oxygen glucose deprivation/reoxygenation(OGD/R) treatment(P<0.05, P<0.01). Compared with the OGD/R group, the OGD/R+TMP group upregulated the expression levels of VEGF, VEGFA, Ang, Ang-2, PDGF, PDGFB, SIRT1, Ki67, CD31, and CD34, enhanced the angiogenic ability of Bend.3 cells without being inhibited by BMS or EX-527(P<0.05, P<0.01, P<0.001). The results suggest that TMP can activate the SIRT1/VEGFA signaling pathway to stimulate angiogenesis and alleviate CIS injury.