本文關(guān)鍵詞： 阿爾茨海默癥 聚乳酸羥基乙酸共聚物 CRT β淀粉樣蛋白　出處：《寧夏大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：阿爾茨海默癥(Alzheimer'sdisease,AD)作為一種目前致死率極高的疾病已經(jīng)嚴(yán)重威脅到了人們的公共健康問題,受到越來越多的關(guān)注。其常見的病理特征包括老年斑、神經(jīng)元纖維異常纏結(jié)和神經(jīng)元胞外高密度β淀粉樣蛋白(amyloid β,Aβ)的沉積。雖然目前已有多種治療藥物上市,但由于存在藥物可溶性差,生物可溶性低,難以穿越血腦屏障(blood-brain barrier,BBB)等問題,致使AD的治療現(xiàn)狀仍不容樂觀。納米顆粒載體因其在體內(nèi)體外實(shí)驗(yàn)中均易被檢測到因此用于AD的診斷治療日益受到重視。因此,我們希望設(shè)計(jì)出一種可以穿越BBB靶向腦部并積極發(fā)揮攜帶藥物功能的新型納米藥物載體。聚乳酸輕基乙酸共聚物(Poly(lactic-co-glycolicacid),PLGA)是一種生物可降解的高分子微球,具有良好的生物相容性,應(yīng)用前景廣闊,因此我們選擇PLGA為基礎(chǔ)納米顆粒藥物載體,并將姜黃素與環(huán)肽S1包裹進(jìn)納米顆粒內(nèi)腔,將制得的納米顆粒命名為NP-S1+Cur。姜黃素是一種可以抑制Aβ毒性的天然化合物,而S1可以通過影響APP的剪切過程有效降低Aβ生成,二者對AD的致病機(jī)制均有一定的積極影響。隨后我們選擇用穿膜肽CRT修飾在PLGA納米顆粒表面(CRT-NP-S1+Cur),因?yàn)镃RT是一種與鐵生物性能相似的多肽,可以靶向性結(jié)合轉(zhuǎn)鐵蛋白與轉(zhuǎn)鐵蛋白受體復(fù)合物,增強(qiáng)納米顆粒穿越BBB的能力。通過透射電鏡(Transmission electron microscope,TEM)觀察納米顆粒形態(tài),動態(tài)光散射法(Dynamic light scattering,DLS)確定耦連CRT前后納米顆粒的大小分別為128.6 nm and 139.8 nm,包封率分別為 23.2 ± 5.3%and 21.4 ± 6.9%,載藥量分別為 0.54 ± 0.04%and 0.42 ±0.06%;利用MTT毒性實(shí)驗(yàn)分析納米顆粒的生物毒性;同時,體外模擬血腦屏障實(shí)驗(yàn)和體內(nèi)活體成像實(shí)驗(yàn)表明,CRT-NP-Sl+Cur具有更強(qiáng)的穿越BBB的能力。動物行為學(xué)和病理學(xué)研究表明,經(jīng)過對AD轉(zhuǎn)基因小鼠21天腹腔注射PLGA納米顆粒后,能夠改善AD鼠的空間記憶能力,小鼠腦內(nèi)老年斑數(shù)量有所減少,小膠質(zhì)細(xì)胞和星型膠質(zhì)細(xì)胞活化水平、突觸素水平均有改善。用試劑盒對實(shí)驗(yàn)小鼠腦部進(jìn)行分析發(fā)現(xiàn),PLGA納米顆粒可以增強(qiáng)腦內(nèi)超氧化物歧化酶(SOD)的活性,降低Aβ和活性氧(ROS)水平,促炎性細(xì)胞因子(TNF-α和IL-6)的表達(dá),與NP-S1+Cur相比,CRT-NP-S1+Cur的作用效果更顯著。以上結(jié)果表明,本實(shí)驗(yàn)設(shè)計(jì)的新型納米藥物載體具有穿越BBB并靶向腦部,從而高效發(fā)揮姜黃素抗氧化、抗炎癥作用及S1抑制Aβ生成、降低Aβ毒性的作用,對AD的治療具有潛在的應(yīng)用價(jià)值。
[Abstract]:Alzheimer's disease (AD), a disease with a high mortality rate, has become a serious threat to public health and has attracted increasing attention. Its common pathological features include senile plaques. Abnormal tangles of neuron fibers and deposition of amyloid 尾 -A 尾 -amyloid 尾 -amyloid 尾 -amyloid 尾 -amyloid 尾 -amyloid 尾 -amyloid in neurons. It is difficult to cross the blood-brain barrier and BBB, so the current status of AD treatment is still not optimistic. The nanoparticles carrier is easy to be detected in vivo and in vitro, so the diagnosis and treatment of AD has been paid more and more attention. We hope to design a novel nano-drug carrier that can traverse the brain of BBB and play an active role in carrying drugs. Poly (lactic acid-co-glycolic acid) is a biodegradable polymer microsphere with good biocompatibility. Therefore, we chose PLGA as the base drug carrier and encapsulated curcumin and cyclic peptide S1 into the intracavity of nanoparticles. The prepared nanoparticles were named NP-S1 Cur.Curcumin is a natural compound that can inhibit the toxicity of A 尾, and S1 can effectively reduce A 尾 formation by affecting the shearing process of APP. Both of them have a positive effect on the pathogenesis of AD. Subsequently, we chose to modify CRT-NP-S1 Curan on the surface of PLGA nanoparticles with transmembrane peptide CRT, because CRT is a polypeptide similar to the biological properties of iron. It can target the complex of transferrin and transferrin receptor to enhance the ability of nanoparticles to cross BBB. The morphology of nanoparticles was observed by transmission electron microscopetem (TEM). The size of nanoparticles before and after coupling CRT was 128.6 nm and 139.8 nm, the entrapment efficiency was 23.2 鹵5.3 and 21.4 鹵6.9, and the drug loading was 0.54 鹵0.04 and 0.42 鹵0.06 respectively. The biotoxicity of nanoparticles was analyzed by MTT toxicity test. At the same time, in vitro and in vivo imaging experiments showed that CRT-NP-Sl Cur had a stronger ability to cross BBB. Animal behavioral and pathological studies showed that after 21 days of intraperitoneal injection of PLGA nanoparticles into AD transgenic mice, CRT-NP-Sl Cur had stronger ability to cross BBB. It could improve the spatial memory ability of AD mice. The number of senile plaques in the brain of AD mice was decreased, and the activation levels of microglia and astrocytes were decreased. The level of synaptophysin was improved. The results showed that PLGA nanoparticles could enhance the activity of superoxide dismutase (SOD), decrease the levels of A 尾 and reactive oxygen species (Ros), and promote the expression of inflammatory cytokines TNF- 偽 and IL-6. Compared with NP-S1 Cur, the effect of CRT-NP-S1 Cur was more significant. The results showed that the novel drug carrier could travel through BBB and target the brain, thus effectively exerting curcumin antioxidation, anti-inflammatory effect and S1 inhibiting A 尾 production. Reducing the toxicity of A 尾 has potential application value in the treatment of AD.
【學(xué)位授予單位】：寧夏大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：R749.16

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