Objective: To investigate the antagonistic cell injury effect and molecular mechanism of scutellarin(SCU)in hypoxia reoxygenation(HR) treated human cardiac microvascular endothelial cells(HCMECs).Methods: The method of 12 h hypoxia following by 12 h reoxygenation was used to culture HCMECs in vitro to built cell injury model. The groups were divided into control group, model(HR) group, and HR + SCU(0.1 μmol/L, 1 μmol/L, and 10 μmol/L) group. The cell viability was determined by MTT, and oxidative stress was detected by malondialdehyde(MDA) levels by biochemical assay kit. Protein expression of JAK2/p-JAK2 and STAT3/p-STAT3 were evaluated by Western blot.Results: The results of MTT and MDA showed that HR decreased the cell viability(P < 0.05) and increased MDA level significantly(P < 0.05), SCU played a contrary role in these processes. Western blot analysis indicates that, the expression of JAK2 and p-JAK2, STAT3, and p-STAT3 were increased in model group when compared with control group(P < 0.05); Compared with model group, their expression were reduced by SCU(P < 0.05).Conclusion: SCU took a protective effect on HR-treated HCMECs, and the molecular mechanism may be associated with the inhibition of JAK2/STAT3 signal transduction pathway.
Flavonoid glycoside scutellarin(SCU)has been widely applied in the treatment of cerebral ischemic diseases in China.In this article,we conducted research on the working mechanisms of SCU in hypoxia reoxygenation(HR)injury of isolated cerebral basilar artery(BA)and erebral ischemia reperfusion(CIR)injury in rat models.In isolated rat BA rings,HR causes endothelial dysfunction(ED)and acetylcholine(ACh)induces endothelium-dependent vasodilation.The myography result showed that SCU(100μM)was able to significantly improve the endothelium-dependent vasodilation induced by Ach.However,SCU did not affect the ACh-induced relaxation in normal BA.Further studies suggested that SCU(10-1000μM)dose-dependently induced relaxation in isolated BA rings which were significantly blocked by the cGMP dependent protein kinase(PKG)inhibitor Rp-8-Br-cGMPs(PKGI-rp,4μM).Pre-incubation with SCU(500μM)reversed the impairment of endothelium-dependent vasodilation induced by HR,but the reversing effect was blocked if PKGI-rp(4μM)was added.The brain slice staining test in rats’model of middle cerebral artery occlusion(MCAO)induced CIR proved that the administration of SCU(45,90 mg/kg,iv)significantly reduced the area of cerebral infarction.The Western blot assay result showed that SCU(45 mg/kg,iv)increased brain PKG activity and PKG protein level after CIR surgery.In conclusion,our findings suggested that SCU possesses the ability of protecting brain cells against CIR injury through vascular endothelium protection and PKG signal.
Scutellarin(SCU), a flavonoid from a traditional Chinese medicinal plant. Our previous study has demonstrated that SCU relaxes mouse aortic arteries mainly in an endothelium-depend-ent manner. In the present study, we investigated the vasoprotective effects of SCU against HR-induced endothelial dysfunction(ED) in isolated rat CA and the possible mechanisms involving cyclic guanosine monophosphate(c GMP) dependent protein kinase(PKG). The isolated endothelium-intact and endothelium-denuded rat CA rings were treated with HR injury. Evaluation of endothelium-dependent and-independent vasodilation relaxation of the CA rings were performed using wire myography and the protein expressions were assayed by Western blotting. SCU(10–1 000 μmol·L-1) could relax the endothelium-intact CA rings but not endothelium-denuded ones. In the intact CA rings, the PKG inhibitor, Rp-8-Br-c GMPS(PKGI-rp, 4 μmol·L-1), significantly blocked SCU(10–1 000 μmol·L-1)-induced relaxation. The NO synthase(NOS) inhibitor, NO-nitro-L-arginine methylester(L-NAME, 100 μmol·L-1), did not significantly change the effects of SCU(10–1 000 μmol·L-1). HR treatment significantly impaired ACh-induced relaxation, which was reversed by pre-incubation with SCU(500 μmol·L-1), while HR treatment did not altered NTG-induced vasodilation. PKGI-rp(4 μmol·L-1) blocked the protective effects of SCU in HR-treated CA rings. Additionally, HR treatment reduced phosphorylated vasodilator-stimulated phosphoprotein(p-VASP,phosphorylated product of PKG), which was reversed by SCU pre-incubation, suggesting that SCU activated PKG phosphorylation against HR injury. SCU induces CA vasodilation in an endothelium-dependent manner to and repairs HR-induced impairment via activation of PKG signaling pathway.
OBJECTIVE To investigate the effect of scutellarin(SCU),which is the main effective component of Erigeron breviscapus(Vant.)Hand-Mazz native to Yunnan in China,on vascular dysfunction(VD)of cardiac coronary artery(CA)and cerebral basilar artery(BA)caused by hypertension in SHR rats.METHODS 1.BA and CA vesselsrings from 40 weeks of SHR rats were isolated and equilibrated in organ bath with MOPS-PSS buffer and ring tension was recorded,comparing with a normal control of WKY rats.SCU was treated accumulatively after pre-contracted with vasoconstrictor U46619(1μmol·L-1).2.ACH and SNP were treated accumulatively after pre-incubation with SCU(300μmol·L-1,100μmol·L-1)and pre-contracted by U46619(1μmol·L-1),K+60mmol·L-1,respectively.While U46619 was added accumulatively to BA/CA rings pre-incubated with SCU(300and 100μmol·L-1).ACH-induced relaxation rate was to evaluate endothelium-dependent relaxation,and SNP-induced relaxation rate to evaluate the artery non-endothelium-dependent relaxation.RESULTS SCU significantly dilated both BA and CA rings pre-contracted by U46619 in old rats.EC50 value of SCU in WKY ratswas less than that in SHR(P<0.05),which showing VD of CA and BA in SHR rats.Compared with WKY group,ACH relaxation curve of SHR group shifted to the right,suggesting that hypertension induced VD.When SCU 300μmol·L-1 pre-treated CA groups and SCU 100μmol·L-1 pre-treated BA groups,EC50 to ACH was significantly lower(P<0.05).Likewise,the vasodilatation of CA/BA rings to SNP was also improved obviously when pre-treated with SCU,and Emax to SNP was decreased significantly(P<0.05).Moreover,EC50 to U46619was significantly lower when pre-treated by SCU.CONCLUSION In SHR rats,SCU antagonized U46619 on CA/BA rings in a noncompetitive manner.Furthermore,SCU should appear to protect VD induced by hypertension.
OBJECTIVE This study discusses the effects of scutellarin(SCU),which is one of effective component of Erigeron breviscapus(Vant.)Hand-Mazz,on cGMP dependent protein kinase(PKG)in human cardiac microvascular endothelial cells(HCMECs)after hypoxia roxygenation(HR).METHODS Based on a model of HCMECs cells with HR injury,cell viability is examined by MTT assay.Protein expression of PKG is analyzed by Western blotting and its enzyme activity is investigated by ELISA technology.RESULTS The results of MTT assay- indicate that SCU(1,10μmol·L1)could protect HCMECs against HR injury.SCU(0.1,1 and 10μmol·L-1)canenhance PKG-I expression in control and HR injury cells.Furthermore,SCU(1,10μmol·L-1 significantly increase PKG activity in control cells(P<0.01),and also SCU(100μmol·L-1)appears similar on enzyme activity in HR injury cells(P <0.05).CONCLUSION SCU appears protective effects on endothelial cells against HR damage.While its mechanisms may be related to the influence of SCU on PKG activity in HCMECs.
