| Traditional Chinese medicine(TCM) with a long history, has played an irreplaceable role in the prevention and treatment of serious diseases. Its efficacy is currently recognized internationally. TCM such as Compound Salvia pills, ginaton and Xiaochaihu Tang was used widely and developed rapidly in China, Germany, Japan and India. Cardiac-cerebral vascular disease seriously damages health and quality of life. Atherosclerosis(AS) is a common cardiovascular and cerebrovascular disease and a main cause of stroke. Unfortunately, for these disease, western medicine which focuses on a single target or single aspect in research has entered a bottleneck. In the TCM research, both of stroke and AS belong to the category of “Blood-Stasis Syndrome”. TCM of “resolving stasis and relieving toxin” for treating “Blood-Stasis Syndrome” prove their advantages such as good treatment effects, little side-effects, and no drug dependence. Further study on new drugs against cardiac-cerebral vascular disease and mechanisms of traditional drugs become hotspots in recent years. These studies will provide theoretical basis and clinical treatment for cardiaccerebral vascular disease.According to the previous research reports, boswellic acids and ellagic acid are two kinds of material basis of the herb for removing blood stasis and relieving toxin. Both of them have antioxidant activity and a possible role in Nrf2 induction. Boswellic acid which is present in blood circulation and pain medicine frankincense. Ellagic acid is widely present in herb, such as garnet, radix paeoniae rubra, gallnut. In the traditional prescription frankincense and herb containing ellagic acid is often combined in TCM.Oxidative stress is well known to play a pivotal role in cerebral ischemia-reperfusion injury. The nuclear factor erythroid-2-related factor 2(Nrf2)/ heme oxygenase-1(HO-1) pathway has been considered a potential target for treatment in stroke and pathogenesis of atherosclerosis. Cells exposed to oxygen-glucose deprivation(OGD), cerebral ischemia model, neurological behavior, immunohistochemistry, and western blot techniques were used in this study to investigate the short-term neuroprotective effects of AKBA and KBA. Besides, the study was to investigate the effects of EA on endothelial dysfunction and atherosclerosis in two mice model and HVUECV. The present study is aimed to explore a promising therapeutic target and candidate drug for treatment of cardiac-cerebral vascular disease, and provide novel evidence and insights on the protective effect of Nrf2/ HO-1 in cardiovascular and cerebrovascular disease.Study 1: Neuroprotection by Acetyl-11-Keto-β-Boswellic Acid and 11-Keto-β-Boswellic Acid, in Ischemic Brain Injury Involves the Nrf2/HO-1 defense PathwayAcetyl-11-Keto-b-Boswellic Acid(AKBA) and 11-Keto-β-Boswellic Acid(KBA) is active triterpenoid compound from the extract of Boswellia serrate, which is herb of removing blood stasis and relieving toxin. The purpose of this experiment is to study the effects of novel Nrf2 inducer AKBA and KBA in cerebral ischemia-reperfusion injury and multi-dimensional mechanism with levels of organs, cells and molecules.The present study was to determine whether AKBA can protect against cerebral ischemic injury. All rats were divided randomly into the following 3 groups using a random number table generated by SPSS 16.0: sham-operated group(Sham), Vehicle-treated I/R group(Vehicle+ I/R), and AKBA-treated I/R group(AKBA+I/R). The stroke model was produced in Sprague-Dawley rats via middle cerebral artery occlusion(MCAO). Transient OGD were conducted for primary cultured cortical neurons to model ischemia-like conditions in vitro. Treatment of AKBA significantly reduced infarct volumes and apoptotic cells, and also increased neurologic scores by elevating the Nrf2 and HO-1 expression in brain tissues in MCAO rats at 48 hours post reperfusion. In primary cultured neurons, AKBA increased the Nrf2 and HO-1 expression, which provided protection against OGDinduced oxidative insult. Additionally, AKBA treatment increased Nrf2 binding activity to antioxidant-response elements(ARE). The protective effect of AKBA was attenuated by knockdown of Nrf2 or HO-1. In conclusion, these findings provide evidence that AKBA protects neurons against ischemic injury, and this neuroprotective effect involves the Nrf2/HO-1 pathway.In this study, we also determine whether another bioactive component of Boswellia serrate KBA can protect against cerebral ischemic injury. MCAO was operated on male Sprague-Dawley rats. KBA(25 mg/kg) applied 1 h after reperfusion, reduced infarct volumes and apoptotic cells, as well as increased neurologic scores at 48 hours after reperfusion significantly. Meanwhile, post treatment with KBA significantly decreased MDA levels, improved SOD activity and increased the protein Nrf2 and HO-1 expression in brain tissues. In primary cultured astrocytes, KBA increased the Nrf2 and HO-1 expression, which provided protection against OGD-induced oxidative insult. But, knockdown of Nrf2 or HO-1 attenuated the protective effect of KBA. In conclusion, these findings provide evidence that the neuroprotection of KBA against oxidative stress-induced ischemic injury involves the Nrf2/HO-1 pathway.Study2: Dietary Ellagic Acid Improves Oxidant-induced Endothelial Dysfunctionand Atherosclerosis: Role of Nrf2 ActivationIn this study, we aimed to investigate the effects of EA on endothelial dysfunction and atherosclerosis via antioxidant-related mechanisms. In animal studies, wild-type(WT) C57BL/6 mice and apolipoprotein E-deficient mice(Apo E-/-) mice were fed a high-fat(21%) diet(HFD) or a HFD plus with EA(HFD+EA), for 14 weeks. Vascular reactivity was studied in mice aortas. The effect of EA in human umbilical vein endothelial cells(HVUECV) exposed to hypochlorous acid(HOCl) was also investigated.In experiment 1, compared with animals on HFD alone, EA attenuated atherosclerosis in WT mice. In aortic rings from two mice models during experiment 2, EA significantly improved endothelium-dependent relaxation and attenuated HOCl-induced endothelial dysfunction. Besides, EA significantly improved nitric oxide synthase activity, antioxidant capacity and markers of endothelial dysfunction in plasma. Western blot analysis showed that EA increased Nrf2 and HO-1 expression in the aortas(P < 0.05). In a separate study in experiment 2, EA did not protect against HOCl-induced endothelial dysfunction in arteries obtained from Nrf2 gene knockout mice compared with WT mice. In experiment 3, EA prevented HOCl-induced cellular damage and induced HO-1 protein expression in HVUECV, and these effects were disappeared by the si RNA of Nrf2. Our results provide further support for the protective effects of dietary EA particularly oxidant-induced endothelial dysfunction and atherosclerosis partly via Nrf2 activation.This study(No.81373947) focus on “Blood-Stasis Syndrome” and effective substance of herb with “resolving stasis and detox” effect, which aims to explore the basic pathogenesis of “Blood-Stasis Syndrome” and mechanisms of “resolving stasis and detox” effect. Our study will contribute to a wealth of information in resolving stasis and detox treatment for “Blood-Stasis Syndrome” and secondary development of TCM. In this study, we firstly demonstrated the protective effects of BA in brain IR and effects of EA on endothelial dysfunction in atherosclerosis. Based on the results obtained, in future we will study on the synergistic action of two effective substance and optimization of their formulations to contribute to the development of TCM. |
PDF Full Text Request