普羅布考對血管性癡呆大鼠經(jīng)由JNK途徑的腦保護作用
發(fā)布時間:2018-05-13 23:35
本文選題:血管性癡呆 + 普羅布考; 參考:《河北醫(yī)科大學》2014年碩士論文
【摘要】:目的:血管性癡呆(vascular dementia, VD)指腦血管病變引起的腦損害所致的癡呆。是在Alzheimer。ˋD)之后第二常見的癡呆。發(fā)病機制一般認為是腦血管病的病灶涉及額葉、顳葉及邊緣系統(tǒng),或病灶損害了足夠容量的腦組織,導致高級認知功能的嚴重受損。目前對于VD的分子機制研究已日漸成為科學家們研究的熱點問題。主要有興奮性氨基酸毒性、膽堿能缺陷、自由基損傷、炎癥反應(yīng)、神經(jīng)細胞凋亡等。近年來,神經(jīng)細胞凋亡與VD的關(guān)系越來越受到科學家們的關(guān)注。 c-Jun氨基末端激酶(JNK)又稱應(yīng)激激活蛋白激酶(SAPK),是絲裂原激活的蛋白激酶(MAPKs)超家族的一員。大量實驗提示,JNK信號通路在細胞增殖、細胞凋亡、氧化應(yīng)激及多種人類疾病的發(fā)生發(fā)展中扮演著重要角色。已有研究表明,應(yīng)用特異性JNK抑制劑可有效地阻斷JNK信號通路從而有效地調(diào)控細胞凋亡。 普羅布考是一種非他汀類血脂調(diào)節(jié)藥物。目前國內(nèi)外研究表明,普羅布考在AD大鼠中具有顯著的腦保護作用,而其在VD中的治療鮮有報道。本實驗通過觀察VD大鼠海馬組織神經(jīng)細胞的凋亡情況及JNK及P-JNK水平的變化,探討JNK信號通路在VD中的作用及普羅布考對VD大鼠的腦保護作用機制,為VD的臨床治療及普羅布考的臨床應(yīng)用提供依據(jù)。 方法:選取健康雄性Sprague-Dawley (SD)大鼠,隨機分為假手術(shù)組、模型組、普羅布考組,每組10只,采用永久性結(jié)扎雙側(cè)頸總動脈的方法建立血管性癡呆大鼠模型。普羅布考組灌胃給予普羅布考500mg/kg/d,假手術(shù)組和模型組給予等量溶劑。給藥8周后,行Morris水迷宮實驗,對各組大鼠學習記憶能力進行測試,,行為學測試完畢后取材,采用流式細胞術(shù)評估海馬區(qū)神經(jīng)細胞凋亡程度,用免疫組織化學方法和免疫印跡法(westernblot)測定海馬區(qū)JNK和p-JNK蛋白的表達水平。 結(jié)果: 1行為學測定 1.1逃避潛伏期結(jié)果 水迷宮定位航行實驗表明,從訓練的第2天開始至結(jié)束,三組大鼠逃避潛伏期均有下降的趨勢,說明訓練可以增強學習能力。各組大鼠間學習記憶能力存在差異(F=15.34,P<0.05),與假手術(shù)組相比,模型組與普羅布考組大鼠第1-4天的逃避潛伏期時間均明顯延長(P<0.05);與模型組相比,普羅布考組大鼠第2-4天的逃避潛伏期時間明顯縮短(P<0.05),第1天無顯著差異(P>0.05)。 1.2穿越平臺次數(shù)結(jié)果 第5天測定的穿越平臺次數(shù)表示大鼠的空間記憶能力,穿越平臺次數(shù)越多記憶能力越強。與假手術(shù)組相比,模型組大鼠穿越平臺次數(shù)明顯減少(P<0.05);與模型組相比,普羅布考組大鼠穿越平臺次數(shù)明顯增多(P<0.05);普羅布考組與假手術(shù)組相比,大鼠穿越平臺次數(shù)無顯著差異(P>0.05)。各組大鼠隨著訓練時間的推移,訓練次數(shù)的增多,尋找平臺的方式在不斷變化,尋找平臺的時間都在縮短,說明學習鍛煉可以增強空間記憶能力。 2普羅布考對大鼠海馬CA1區(qū)神經(jīng)細胞凋亡的影響 流式細胞術(shù)細胞周期定量分析表明,假手術(shù)組未見明顯的凋亡峰,雖也有自發(fā)性細胞凋亡發(fā)生,但細胞凋亡百分率很低,僅為(5.06±2.52)%;模型組細胞凋亡率為(11.27±2.67)%,較假手術(shù)組顯著增高(P<0.05);普羅布考組細胞凋亡率為(6.57±1.47)%,較模型組顯著降低(P<0.05);普羅布考組與假手術(shù)組相比較雖然也有一定程度的增高,但無統(tǒng)計學意義(P>0.05)。 3普羅布考對大鼠海馬CA1區(qū)JNK及p-JNK蛋白表達結(jié)果的影響 3.1免疫組織化學染色結(jié)果 大鼠海馬CA1區(qū)p-JNK、JNK蛋白表達的陽性細胞情況:假手術(shù)組和普羅布考組大鼠海馬區(qū)僅見很少的p-JNK陽性神經(jīng)元。模型組部分海馬細胞體積縮小,細胞帶不連貫,可見較多的p-JNK陽性神經(jīng)元。模型組與假手術(shù)組相比,模型組大鼠海馬CA1區(qū)p-JNK蛋白表達的陽性細胞數(shù)明顯增多(P㩳0.05);與模型組相比,普羅布考組大鼠海馬CA1區(qū)p-JNK蛋白表達的陽性細胞數(shù)明顯減少(P㩳0.05);普羅布考組與假手術(shù)組相比,大鼠海馬CA1區(qū)p-JNK蛋白表達的陽性細胞數(shù)無明顯差異(P>0.05)。三組間比較,JNK蛋白表達的陽性細胞數(shù)均無明顯差異(F=0.54,P>0.05)。 3.2western blot結(jié)果 大鼠海馬p-JNK、JNK蛋白的表達水平情況:模型組與假手術(shù)組相比,模型組大鼠海馬區(qū)p-JNK蛋白表達水平明顯增高(P<0.05);普羅布考組與模型組相比,普羅布考組大鼠海馬區(qū)p-JNK蛋白表達水平明顯降低(P<0.05);普羅布考組與假手術(shù)組相比,大鼠海馬區(qū)p-JNK蛋白的表達水平也有差異,普羅布考組顯著高于假手術(shù)組(P<0.05)。三組間比較,大鼠海馬區(qū)JNK蛋白的表達水平均無明顯差異(P>0.05)。 三組間p-JNK/JNK值的比較:模型組與假手術(shù)組相比,模型組大鼠海馬區(qū)p-JNK/JNK值明顯增高(P<0.05);普羅布考組與模型組相比,普羅布考組大鼠海馬區(qū)p-JNK/JNK值明顯降低(P<0.05);普羅布考組與假手術(shù)組相比,大鼠海馬區(qū)p-JNK/JNK值略增高,但差異無統(tǒng)計學意義(P>0.05)。 結(jié)論: 1.普羅布考可以減輕VD大鼠海馬區(qū)神經(jīng)元凋亡,改善其學習記憶能力。 2.VD大鼠海馬區(qū)p-JNK/JNK值明顯增加,說明JNK信號通路參與了VD的發(fā)病過程。 3.普羅布考可以降低VD大鼠海馬區(qū)p-JNK/JNK值,提示抑制氧化應(yīng)激所致的凋亡可能是普羅布考改善VD大鼠空間學習記憶障礙的作用機制之一。
[Abstract]:Objective: vascular dementia (VD) refers to dementia caused by brain damage caused by cerebrovascular disease. It is the second common dementia after Alzheimer disease (AD). The pathogenesis is generally thought to be cerebral vascular disease involving frontal lobe, temporal lobe and marginal system, or lesions that damage the brain tissue of sufficient capacity, leading to advanced cognitive function. The study of molecular mechanism of VD has become a hot topic of scientists' research. It mainly includes excitatory amino acid toxicity, cholinergic defect, free radical damage, inflammatory reaction, and nerve cell apoptosis. In recent years, the relationship between neuronal apoptosis and VD has attracted more and more scientists' attention.
C-Jun amino terminal kinase (JNK), also known as stress activated protein kinase (SAPK), is a member of the mitogen activated protein kinase (MAPKs) superfamily. A large number of experiments suggest that the JNK signaling pathway plays an important role in cell proliferation, apoptosis, oxidative stress and the development of various human diseases. Inhibitors can effectively block the JNK signaling pathway and effectively regulate apoptosis.
Probucol is a non statin lipid regulating drug. Current research at home and abroad has shown that probucol has significant brain protection in AD rats, and its treatment in VD is rarely reported. By observing the apoptosis and the changes of JNK and P-JNK levels in the hippocampal neurons of VD rats, this study explored the JNK signaling pathway in VD. The role of probucol in the brain protection of VD rats provides evidence for the clinical treatment of VD and the clinical application of probucol.
Methods: healthy male Sprague-Dawley (SD) rats were randomly divided into sham operation group, model group and probucol group, with 10 rats in each group. The model of vascular dementia rats was established by permanent ligature of bilateral common carotid artery. The probucol group was given 500mg/kg/d, the sham operation group and the model group were given the same amount of solvent. The drug was given 8. After week, the Morris water maze test was carried out to test the learning and memory ability of rats in each group. After the behavior test was completed, flow cytometry was used to evaluate the degree of neuronal apoptosis in the hippocampus. The expression level of JNK and p-JNK protein in the hippocampus was measured by immunohistochemistry and immunoblotting (Westernblot).
Result錛
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