【摘要】：研究背景及目的：腹主動脈瘤(AAA)是老齡化社會的常見病,發(fā)病隱匿,一旦破裂,死亡率達60～80%。炎癥、細胞外基質降解、平滑肌細胞(SMC)凋亡及表型轉化、和氧化應激等均是AAA發(fā)生的關鍵環(huán)節(jié)。巨噬細胞浸潤是腹主動脈瘤(AAA)進展的關鍵環(huán)節(jié),趨化因子受體CXCR2及配體對巨噬細胞在組織的浸潤起重要調節(jié)作用。但在AAA進展過程中,CXCR2如何調節(jié)巨噬細胞浸潤,進而降解細胞外基質、引起氧化應激,機制尚不清楚。因此,本實驗采用CXCR2特異性抑制劑SB265610抑制CXCR2表達,明確CXCR2對小鼠AAA形成的調節(jié)作用,闡明CXCR2促進AAA進展的具體分子機制。其次本實驗收集AAA病人和正常人血漿,檢測血管生成素相關生長因子并探討其與腹主動脈瘤直徑之間的關系。實驗方法：(1)通過對雄性缺陷小鼠(ApoE-/-)皮下埋植血管緊張素Ⅱ (Ang Ⅱ)緩釋泵(1,000 ng/min/kg)的方法,復制動物AAA模型； (2)通過腹腔注射SB265610 (2mg/kg·d)抑制CXCR2,因此小鼠分成四組：Control, SB265610, Ang Ⅱ, AngⅡ+SB265610。通過測量血管超聲、鼠尾監(jiān)測血壓及大體解剖觀察各組小鼠體內動脈大體形態(tài)及血壓變化；通過HE染色、Elastin染色和免疫組織化學染色法觀察各組小鼠組織結構的變化和炎癥細胞浸潤；通過細胞流式技術分析各組小鼠組織和血中炎癥細胞的表達；通過PCR分析各組小鼠動脈壁內炎癥因子表達水平；通過DHE染色確定主動脈壁內氧化應激的情況,通過免疫組織染色、Western Blot和明膠酶譜方法分析各組小鼠動脈壁內基質金屬蛋白酶的表達及活性變化； (3)收集AAA病人及對照組血漿,通過ELISA方法檢測不同組血漿中AGF表達水平,并分析不同直徑腹主動脈瘤血漿AGF之間的差異。結果：1.Ang Ⅱ刺激誘導ApoE-/-小鼠建立成功誘導建立AAA動物模型；2.SB265610抑制CXCR2后顯著抑制Ang Ⅱ誘導的ApoE-/-小鼠AAA形成(發(fā)生率及直徑)；3. CXCR2被抑制后抑制Ang Ⅱ誘導的①動脈壁內巨噬細胞浸潤；②基質金屬蛋白酶的表達及活性；③氧化應激；4.腹主動脈瘤患者的血漿AGF水平升高,且直徑較大的腹主動脈瘤升高程度更明顯。結論：我們證明了CXCR2的激活可以促進腹主動脈瘤形成。其作用機制可能與血管緊張素Ⅱ誘導的巨噬細胞浸潤,MMP表達和活性增加,氧化應激激活相關。CXCR2抑制劑SB265610可以抑制這些改變。而且,我們發(fā)現腹主動脈瘤患者的血漿AGF水平升高,且升高的程度可以反映腹主動脈瘤的大小。這些發(fā)現闡明了CXCR2參與AAA發(fā)生的病理生理學機制,為AAA治療提供了一個新的治療靶點；同時本研究還發(fā)現AGF在腹主動脈瘤患者血漿中的變化,有一定的診斷及隨訪價值。
[Abstract]:Background and objective: abdominal aortic aneurysm (AAA) is a common disease in aging society. Inflammation, degradation of extracellular matrix, apoptosis and phenotypic transformation of smooth muscle cells (SMC), and oxidative stress are the key links of AAA. Macrophage infiltration is the key to the progression of (AAA) in abdominal aortic aneurysms. Chemokine receptor CXCR2 and ligand play an important role in regulating macrophage infiltration in the tissues. However, during the progress of AAA, it is unclear how CXCR2 regulates macrophage infiltration and degrades extracellular matrix and causes oxidative stress. Therefore, SB265610, a specific inhibitor of CXCR2, was used to inhibit the expression of CXCR2, to clarify the regulatory effect of CXCR2 on the formation of AAA in mice, and to elucidate the specific molecular mechanism of CXCR2 promoting the progression of AAA. Secondly, plasma samples were collected from AAA patients and normal subjects to detect angiopoietin related growth factors and to explore the relationship between angiopoietin and the diameter of abdominal aortic aneurysms. Methods: (1) Animal AAA model was established by subcutaneous implantation of angiotensin 鈪，

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