【摘要】：骨骼肌(skeletal muscle,SKM)正常結(jié)構(gòu)和功能的維持是保證人體正常運動狀態(tài)的最基本條件,蛋白合成和降解平衡的穩(wěn)定維持著SKM的正常結(jié)構(gòu)和功能,而這一平衡狀態(tài)的維持有賴于正常的神經(jīng)支配。當(dāng)失神經(jīng)支配時SKM蛋白合成與降解的平衡被打破,導(dǎo)致肌萎縮,并伴有一系列嚴(yán)重的臨床癥狀,如運動功能的喪失。在運動神經(jīng)損毀嚴(yán)重等特殊情況下,SKM的神經(jīng)支配無法及時恢復(fù),長時間的運動神經(jīng)支配缺失會導(dǎo)致SKM收縮功能的喪失,即使SKM再次得到運動神經(jīng)支配,其運動功能也無法恢復(fù)。因此,盡快恢復(fù)失神經(jīng)SKM的神經(jīng)支配至關(guān)重要。將感覺神經(jīng)近側(cè)端與運動神經(jīng)遠(yuǎn)側(cè)殘端連接的感覺保護(hù)成為保護(hù)無法及時恢復(fù)運動神經(jīng)支配SKM的一種方案,但感覺保護(hù)的作用較弱,其治療效果有待進(jìn)一步加強(qiáng)。體內(nèi)和體外的實驗均證實胰島素樣生長因子-1(insulin-like growth factor-1,IGF-1)作為一種多功能的多肽類生長因子,可通過激活磷脂酸肌醇3激酶(phosphatidylinositol3-kinase,PI3K)/Akt信號通路延緩多種病理性肌萎縮并維持和促進(jìn)神經(jīng)系統(tǒng)的生長及存活,但I(xiàn)GF-1對SKM感覺保護(hù)是否有增強(qiáng)作用尚有待證實。已有研究表明,Akt激活能夠影響線粒體的功能狀態(tài),而線粒體的功能與其形態(tài)密切相關(guān),線粒體在分裂和融合狀態(tài)之間持續(xù)轉(zhuǎn)換,線粒體的異常形態(tài)會導(dǎo)致多種疾病。但I(xiàn)GF-1對SKM感覺保護(hù)模型中線粒體的影響尚無相關(guān)研究。本課題通過建立在體感覺神經(jīng)支配動物模型和具有感覺神經(jīng)支配的SKM細(xì)胞體外聯(lián)合培養(yǎng)模型,研究IGF-1對SKM感覺保護(hù)的作用及相關(guān)機(jī)制,本課題的研究結(jié)果將會為延緩失神經(jīng)肌萎縮的治療提供新的理論基礎(chǔ)和實驗依據(jù)。第一部分IGF-1增強(qiáng)在體感覺神經(jīng)再支配對骨骼肌的保護(hù)作用如果SKM失去運動神經(jīng)支配的時間過長,即使SKM再次獲得神經(jīng)支配,其運動功能也將無法恢復(fù)。在運動神經(jīng)損傷嚴(yán)重,無法及時恢復(fù)SKM神經(jīng)支配時,可將感覺神經(jīng)與運動神經(jīng)殘端連接進(jìn)行修復(fù),使失神經(jīng)支配SKM得到臨時的感覺神經(jīng)支配,這種技術(shù)手段被稱為感覺保護(hù)。雖然運動功能仍無法恢復(fù),但感覺保護(hù)可保護(hù)SKM的收縮功能及重要結(jié)構(gòu),待運動神經(jīng)恢復(fù)至能夠正常修復(fù)后,再將運動神經(jīng)近側(cè)與遠(yuǎn)側(cè)殘端連接,使SKM運動功能逐步恢復(fù)。但感覺保護(hù)對失神經(jīng)SKM的作用程度有限,效果有待加強(qiáng)。IGF-1作為一種多功能多肽類因子,對SKM和神經(jīng)系統(tǒng)均具有保護(hù)作用,但I(xiàn)GF-1能否增強(qiáng)SKM感覺保護(hù)的作用尚有待于進(jìn)一步研究。mtDNA數(shù)量的變化與線粒體正常功能的維持密切相關(guān),而這種變化與SKM的功能有密切的關(guān)系,而這些變化過程中IGF-1所扮演的角色,目前也不清楚�；谝陨涎芯勘尘�,本課題設(shè)計如下實驗進(jìn)行研究。取25只260 ± 10 g的Wistar雄性大鼠,采用隨機(jī)分組的方法分為:(1)假手術(shù)組:在大鼠后肢作縱行切口,顯露坐骨神經(jīng)分叉部后縫合;(2)失神經(jīng)組:做同樣切口后離斷脛神經(jīng),近側(cè)殘端結(jié)扎并縫入塑料帽后縫合;(3)IGF-1組:手術(shù)操作同失神經(jīng)組,脛神經(jīng)離斷后縫合刀口,術(shù)后8 w時間內(nèi)每3d向腓腸肌多點注射10 μgIGF-1;(4)感覺保護(hù)組:作縱行切口后離斷脛神經(jīng)和腓腸神經(jīng),將腓腸神經(jīng)的近側(cè)殘端和脛神經(jīng)的遠(yuǎn)側(cè)殘端縫合,脛神經(jīng)的近側(cè)殘端同樣縫合到塑料帽中,縫合刀口;(5)IGF-1+感覺保護(hù)組,手術(shù)操作同感覺保護(hù)組,IGF-1應(yīng)用時間、部位及劑量同IGF-1組。術(shù)后8 w收集腓腸肌組織樣本進(jìn)行相關(guān)檢測。結(jié)果表明,對肌萎縮最為直觀反映為肌濕重和肌橫截面積(cross-sectional area,CSA),在失神經(jīng)組出現(xiàn)顯著下降,IGF-1組和感覺保護(hù)組增加,而IGF-1 +感覺保護(hù)組增加的幅度最大。SKM關(guān)鍵收縮蛋白肌球蛋白重鏈1(myosin heavy chain 1,MyHC1)變化趨勢與腓腸肌肌濕重和肌橫截面積相一致,失神經(jīng)組下降最明顯,而IGF-1增強(qiáng)了 SKM感覺保護(hù)的作用,使IGF-1 +感覺保護(hù)組的MyHC1表達(dá)量較感覺保護(hù)組進(jìn)一步提高。同時,IGF-1不僅能夠直接提升失神經(jīng)SKM線粒體含量,而且IGF-1還可進(jìn)一步增強(qiáng)感覺神經(jīng)再支配對線粒體含量的上調(diào)作用。以上結(jié)果表明,感覺神經(jīng)保護(hù)可延緩大鼠失神經(jīng)肌萎縮和線粒體數(shù)量的減少,在感覺神經(jīng)保護(hù)的基礎(chǔ)上應(yīng)用IGF-1后,可使感覺神經(jīng)保護(hù)延緩肌萎縮和線粒體數(shù)量減少的作用得到明顯增強(qiáng)。上述實驗結(jié)果為進(jìn)一步探討IGF-1對SKM感覺保護(hù)的增強(qiáng)作用提供了實驗依據(jù)和新的思路。第二部分IGF-1對具有感覺神經(jīng)支配的骨骼肌細(xì)胞保護(hù)作用的體外培養(yǎng)研究維持SKM正常運動功能的神經(jīng)支配的發(fā)生、發(fā)展和作用過程是極其復(fù)雜的。失神經(jīng)支配的SKM會即刻喪失其應(yīng)有的運動功能,而且還由于神經(jīng)營養(yǎng)作用的缺失而導(dǎo)致SKM很快就會出現(xiàn)萎縮。為了研究延緩失神經(jīng)支配SKM的策略,本課題利用具有背根神經(jīng)節(jié)(dorsal root ganglion,DRG)神經(jīng)元感覺神經(jīng)支配的SKM細(xì)胞模型,研究外源性IGF-1對SKM細(xì)胞直接作用或通過作用于支配SKM細(xì)胞的感覺神經(jīng)而改善SKM細(xì)胞狀態(tài)的新的治療策略。在Wistar新生鼠后肢SKM細(xì)胞培養(yǎng)2 d后,取15 d胎鼠器官型DRG來建立DRG組織塊和分散SKM細(xì)胞的聯(lián)合培養(yǎng)體系,此培養(yǎng)體系將繼續(xù)培養(yǎng)4 d。本課題的實驗分組為:(1)對照組(SKM組),SKM細(xì)胞在SKM培養(yǎng)液中培養(yǎng)2d后更換為共培養(yǎng)體系培養(yǎng)液繼續(xù)培養(yǎng)4d;(2)聯(lián)合培養(yǎng)組,單純SKM細(xì)胞培養(yǎng)2 d后加入DRG組織塊繼續(xù)共培養(yǎng)4d;(3)SKM + IGF-1組,SKM細(xì)胞在培養(yǎng)2d后,更換為共培養(yǎng)體系使用的培養(yǎng)液培養(yǎng)2d,然后在共培養(yǎng)培養(yǎng)液中加入IGF-1(20nmol/L)繼續(xù)培養(yǎng)2d;(4)聯(lián)合培養(yǎng)+IGF-1組,單純SKM細(xì)胞培養(yǎng)2 d后,與DRG組織塊共培養(yǎng)2 d,此后在聯(lián)合培養(yǎng)培養(yǎng)液中加入IGF-1繼續(xù)培養(yǎng)2 d。通過免疫熒光標(biāo)記檢測SKM細(xì)胞的長度和表面積以衡量細(xì)胞生長狀態(tài),通過檢測SKM關(guān)鍵收縮蛋白MyHC1的表達(dá)量以間接反映SKM細(xì)胞的收縮潛能,檢測mtDNA/nuDNA比值代表線粒體數(shù)量的變化,用MitoTracker Red活體染料標(biāo)定線粒體的形態(tài),檢測胞漿細(xì)胞色素C(Cytochrome C,CytC)表達(dá)量衡量線粒體完整性。結(jié)果顯示,IGF-1可直接作用于SKM細(xì)胞或通過作用于DRG感覺神經(jīng)元而間接影響SKM細(xì)胞的生長狀態(tài);IGF-1可通過影響SKM細(xì)胞收縮性蛋白MyHC1的表達(dá)來改善SKM細(xì)胞的功能狀態(tài);IGF-1對SKM細(xì)胞線粒體數(shù)量、線粒體分裂/融合的動態(tài)平衡以及線粒體完整性的維持等多個方面具有重要的促進(jìn)作用。以上結(jié)果表明,作為單因素作用的感覺神經(jīng)支配或IGF-1可對培養(yǎng)的SKM細(xì)胞狀態(tài)具有一定的影響作用,聯(lián)合應(yīng)用感覺神經(jīng)保護(hù)和IGF-1對SKM細(xì)胞的效果更為明顯。本課題的研究結(jié)果為IGF-1對感覺保護(hù)的作用提供新的資料和觀點,為SKM細(xì)胞狀態(tài)和線粒體之間的關(guān)系補(bǔ)充了新的實驗資料和依據(jù)。第三部分IGF-1保護(hù)具有感覺神經(jīng)支配的骨骼肌細(xì)胞的線粒體信號途徑IGF-1和感覺神經(jīng)支配對失神經(jīng)SKM具有確定的保護(hù)作用,對于長時間失神經(jīng)支配SKM運動功能的恢復(fù)具有重要的指導(dǎo)意義,尤其是IGF-1通過增強(qiáng)感覺神經(jīng)支配信號而對SKM細(xì)胞的間接作用研究策略是本研究領(lǐng)域的一個重要發(fā)展方向,但I(xiàn)GF-1的這種保護(hù)作用機(jī)制仍不清楚。但由于失神經(jīng)支配SKM狀態(tài)變化和功能喪失的嚴(yán)重性表現(xiàn)在多個方面,又由于IGF-1信號通路對SKM細(xì)胞作用靶點的不確定性,致使IGF-1通過增強(qiáng)感覺神經(jīng)支配信號改善SKM細(xì)胞狀態(tài)的機(jī)制探索帶來了一定的難度。本課題利用具有DRG神經(jīng)元感覺神經(jīng)支配的SKM細(xì)胞模型,通過檢測IGF-1激活的Akt通路及下游的相關(guān)靶點,并運用相應(yīng)的激活/抑制劑和過表達(dá)載體研究相應(yīng)的機(jī)制。結(jié)果表明,感覺神經(jīng)支配并沒有激活SKM細(xì)胞的Akt通路,感覺神經(jīng)保護(hù)對SKM細(xì)胞的改善可能是通過其他途徑來實現(xiàn)的。但I(xiàn)GF-1對感覺神經(jīng)-肌聯(lián)合培養(yǎng)的SKM細(xì)胞Akt磷酸化水平則有顯著的上調(diào)作用。通過用LY294002抑制Akt磷酸化,進(jìn)一步確認(rèn)Akt磷酸化水平的上調(diào)是IGF-1誘導(dǎo)的線粒體數(shù)量增加、線粒體融合增多、線粒體完整性改善、蛋白水解泛素蛋白酶體途徑(ubiquitin-proteasome system,UPS)中泛素連接酶 atrogin-1 和肌環(huán)指蛋白 1(muscle RING finger 1,MuRF1)抑制、MyHC1蛋白表達(dá)量上升的關(guān)鍵步驟。與未給予IGF-1的感覺保護(hù)組相比,應(yīng)用IGF-1的感覺保護(hù)組SKM的Akt磷酸化水平的上調(diào)抑制了線粒體外膜蛋白線粒體E3泛素蛋白連接酶1(mitochondrial E3 ubiquitin protein ligase 1,Mull)的表達(dá)。為進(jìn)一步確認(rèn)Mull在Akt對線粒體及下游改變中發(fā)揮的作用,通過構(gòu)建Mull過表達(dá)載體,應(yīng)用于IGF-1孵育的聯(lián)合培養(yǎng)體系內(nèi),證實了 Mull過表達(dá)可抑制SKM細(xì)胞的Akt磷酸化水平升高誘導(dǎo)的線粒體狀態(tài)的改善、蛋白降解途徑抑制和SKM收縮蛋白表達(dá)的上調(diào),確認(rèn)了 Mull可能為IGF-1下游作用于線粒體的重要靶點。IGF-1抑制Mull,使SKM細(xì)胞線粒體狀態(tài)改善,能量產(chǎn)生增多,從而抑制了線粒體下游能量感受器5-磷酸腺苷依賴的蛋白激酶 α(adenosine 5'-monophosphate-activated protein kinase α,AMPKΩ)的活化。通過應(yīng)用1 mmol/LAMPKα激活劑5-氨基咪唑-4-甲酰胺-1-D-核糖核苷酸(5-aminoimidazole-4-carbox-amide-1-D-ribonucleoside,AICAR),進(jìn)一步確認(rèn)IGF-1改善線粒體能量產(chǎn)生后,抑制AMPKα活化,進(jìn)而減少atrogin-1 mRNA、MuRF1 mRNA表達(dá)和促進(jìn)MyHCl蛋白表達(dá)。本課題的研究結(jié)果明確了在神經(jīng)-肌聯(lián)合培養(yǎng)體系中IGF-1對線粒體功能形態(tài)和SKM細(xì)胞狀態(tài)的進(jìn)一步促進(jìn)作用的機(jī)制。IGF-1通過對其下游靶點Akt、Mull以及AMPKα的調(diào)控來改善感覺神經(jīng)再支配SKM細(xì)胞的狀態(tài)。該途徑的主要調(diào)控機(jī)制為IGF-1誘導(dǎo)Akt磷酸化和抑制Mull的表達(dá),從而改善線粒體形態(tài)及功能狀態(tài),最終通過抑制UPS關(guān)鍵分子atrogin-1和MuRF1的表達(dá)來增加收縮性蛋白MyHC1的合成。這些數(shù)據(jù)為通過調(diào)控IGF-1信號通路及線粒體改善長期失神經(jīng)SKM細(xì)胞的功能狀態(tài)提供了全新的實驗依據(jù),同時也為該途徑的關(guān)鍵分子的研究開拓了全新的領(lǐng)域。
[Abstract]:The maintenance of normal structure and function of skeletal muscle (SKM) is the basic condition to ensure the normal movement of human body. The stability of protein synthesis and degradation balance maintains the normal structure and function of SKM. The maintenance of this balance depends on the normal innervation. When denervation occurs, the synthesis and degradation of SKM protein are smooth. The balance is broken, resulting in muscular atrophy, and accompanied by a series of serious clinical symptoms, such as loss of motor function. In special cases such as severe motor nerve damage, the nerve innervation of SKM can not be restored in time. Long-term loss of motor innervation can lead to the loss of contraction function of SKM, even if SKM is reinnervated by motor nerve, its motor function will be lost. Therefore, it is very important to restore the innervation of the denervated SKM as soon as possible. The sensory protection of the proximal end of the sensory nerve connected with the distal stump of the motor nerve is a scheme that can not restore the innervation of the motor nerve in time. Insulin-like growth factor-1 (IGF-1), as a multifunctional polypeptide growth factor, has been demonstrated to delay various pathological muscular atrophy and maintain and promote the growth and survival of the nervous system by activating phosphatidylinositol 3-kinase (PI3K) / Akt signaling pathway. Whether IGF-1 enhances the sensory protection of SKM remains to be confirmed. Studies have shown that Akt activation can affect the functional state of mitochondria, and the function of mitochondria is closely related to its morphology. Mitochondria continue to change between splitting and fusion states. Abnormal morphology of mitochondria can lead to many diseases. However, IGF-1 can affect the sensory protection mode of SKM. In this study, the effects of IGF-1 on sensory protection of SKM and its related mechanisms were studied by establishing the animal model of somatosensory innervation and the SKM cell model with sensory innervation in vitro. The results of this study will provide a new theory for delaying the treatment of denervated muscular atrophy. The first part is about the protective effect of IGF-1 on skeletal muscle by sensory nerve reinnervation in vivo. If SKM loses its motor nerve reinnervation for too long, its motor function will not be restored even if SKM is reinnervation again. This technique is called sensory protection. Although motor function can not be restored, sensory protection can protect the contractile function and important structure of the motor nerve. After the motor nerve can be restored to normal, the motor nerve can be closed to the motor nerve. However, the effect of sensory protection on denervated SKM is limited and needs to be strengthened. As a multifunctional polypeptide factor, IGF-1 has protective effects on both SKM and nervous system, but whether IGF-1 can enhance the sensory protection of SKM remains to be further studied. Changes in mitochondrial function are closely related to the maintenance of normal mitochondrial function, and this change is closely related to the function of SKM. The role of IGF-1 in these changes is not clear at present. Based on the above research background, the following experiments were designed to study. 25 Wistar male rats of 260 + 10 g were randomly divided into two groups. Methods: (1) Sham operation group: longitudinal incision was made in the hind limbs of rats, sciatic nerve bifurcation was exposed and sutured; (2) denervation group: tibial nerve was severed after the same incision, proximal stump ligation and suture into plastic cap after suture; (3) IGF-1 group: the operation was the same as denervation group, tibial nerve was severed after suture knife mouth, 8 weeks after the operation more gastrocnemius muscle every 3 days. (4) Sensory protection group: the tibial nerve and sural nerve were severed after longitudinal incision, the proximal stump of the sural nerve and the distal stump of the tibial nerve were sutured, and the proximal stump of the tibial nerve was also sutured into the plastic cap to suture the knife edge; (5) IGF-1 + sensory protection group, the operation was the same as sensory protection group, the application time and location of IGF-1. The results showed that muscle atrophy was most intuitively reflected as muscle wet weight and cross-sectional area (CSA). In denervated group, there was a significant decrease, while in IGF-1 group and sensory protection group increased, while in IGF-1 + sensory protection group the increase was the greatest. The change trend of myosin heavy chain 1 (MyHC1) was consistent with the wet weight and cross-sectional area of gastrocnemius muscle. In denervated group, the decrease was most obvious. IGF-1 enhanced the sensory protective effect of SKM, and further increased the expression of MyHC1 in the sensory protective group compared with the sensory protective group. These results suggest that sensory nerve protection can delay denervated muscle atrophy and mitochondrial decrease in rats, and sensory nerve protection can be delayed by the application of IGF-1 on the basis of sensory nerve protection. Muscle atrophy and mitochondrial decrease were significantly enhanced. These results provide experimental evidence and new ideas for further exploring the sensory protective effect of IGF-1 on SKM. Part II In vitro study of the protective effect of IGF-1 on skeletal muscle cells with sensory innervation to maintain normal motor function of SKM The occurrence, development and action of denervation are extremely complex. The denervated SKM immediately loses its motor function and soon atrophies due to the absence of neurotrophic function. In order to study the strategy of delaying denervation of SKM, dorsal root ganglion (DRG) is used in this study. NGlion, DRG) neuron sensory innervation of SKM cell model, to study exogenous IGF-1 on SKM cells directly or through the role of sensory nerve innervation of SKM cells to improve the state of SKM cells new treatment strategies. Wistar newborn rat hindlimb SKM cells cultured for 2 days, take 15 days fetal rat organotype DRG to establish DRG tissue blocks and disperse SKM cells. The experimental groups of this subject are: (1) control group (SKM group), SKM cells were cultured in SKM medium for 2 days and then replaced by co-culture medium for 4 days; (2) co-culture group, SKM cells were cultured in DRG tissue block for 4 days after 2 days; (3) SKM + IGF-1 group, SKM + IGF-1 group M cells were cultured in co-culture medium for 2 days, then added with IGF-1 (20 nmol/L) for 2 days; (4) co-culture + IGF-1 group, SKM cells were co-cultured with DRG tissue block for 2 days after 2 days, and then co-cultured with IGF-1 in co-culture medium for 2 days. The length and surface area of SKM cells were measured by labeling. The contractile potential of SKM cells was indirectly reflected by detecting the expression of MyHC1, the ratio of mtDNA to nuDNA, the number of mitochondria, the morphology of mitochondria and cytochrome C (Cytochrome C) were measured by MitoTracker Red dye in vivo. The results showed that IGF-1 could directly affect SKM cells or indirectly affect the growth of SKM cells by acting on DRG sensory neurons; IGF-1 could improve the functional status of SKM cells by affecting the expression of contractile protein MyHC 1; and IGF-1 could improve the mitochondrial number and mitochondria of SKM cells. These results suggest that sensory innervation or IGF-1, as a single factor, can affect the state of cultured SKM cells to some extent, and the combination of sensory nerve protection and IGF-1 is more effective in SKM cells. The results of this study provide new data and viewpoints for the role of IGF-1 in sensory protection, and provide new experimental data and evidence for the relationship between SKM cell state and mitochondria. Part III The protective effect of IGF-1 on the mitochondrial signaling pathway of skeletal muscle cells with sensory innervation and the loss of sensory innervation. Neural SKM has a definite protective effect, which is of great significance to the recovery of motor function of long-term denervated SKM. In particular, the indirect effect of IGF-1 on SKM cells by enhancing sensory innervation signal is an important research direction in this field, but the protective mechanism of IGF-1 is still not clear. However, the severity of the changes of denervated SKM state and the loss of function is manifested in many aspects, and the uncertainty of the target of IGF-1 signaling pathway on SKM cells leads to the difficulty of exploring the mechanism of IGF-1 improving SKM cell state by enhancing sensory innervation signals. The results showed that sensory innervation did not activate the Akt pathway of SKM cells, and the improvement of sensory nerve protection on SKM cells might be through the detection of the Akt pathway activated by IGF-1 and related downstream targets, and the corresponding activation/inhibitor and overexpression vector. However, IGF-1 can significantly up-regulate the phosphorylation of Akt in SKM cells co-cultured with sensory nerves and muscles. By inhibiting Akt phosphorylation with LY294002, it is further confirmed that the up-regulation of Akt phosphorylation is due to the increase of mitochondrial number, mitochondrial fusion, mitochondrial integrity and ubiquitous protein hydrolysis induced by IGF-1. Inhibition of ubiquitin-proteasome system (UPS) ubiquitin-ligase Atrogin-1 and myRING finger-1 (MuRF1) is a key step in the increase of MyHC1 protein expression. The up-regulation of Akt phosphorylation in SKM treated with IGF-1 inhibited mitochondria compared with the sensory protection group without IGF-1. Expression of mitochondrial E3 ubiquitin protein ligase 1 (Mull) in vitro. To further confirm the role of Mull in mitochondrial and downstream alterations induced by Akt, Mull overexpression vector was constructed and applied to the co-culture system incubated with IGF-1. It was confirmed that Mull overexpression could inhibit SKM fineness. Mull may be an important target for downstream action of IGF-1 on mitochondria. IGF-1 inhibits Mull, improves mitochondrial state and increases energy production in SKM cells, thus inhibiting downstream energy perception in mitochondria. Activation of adenosine 5'-monophosphate-activated protein kinase alpha (AMPK_) by receptor 5-adenosine 5'-monophosphate-activated protein kinase alpha (AMPK_). Improvement of mitochondrial energy by using 1 mmol/LAMPK alpha activator 5-aminoimidazole-4-formamide-1-D-ribonucleoside (AICAR) was further confirmed. After production, it inhibits the activation of AMPK alpha, thereby reducing the expression of Atrogin-1 mRNA, MuRF1 mRNA and promoting the expression of MyHCl protein.The results of this study clarify the further mechanism of IGF-1 in promoting the functional morphology of mitochondria and the state of SKM cells in the neuromuscular co-culture system. The main regulatory mechanism of this pathway is that IGF-1 induces Akt phosphorylation and inhibits Mull expression, thereby improving mitochondrial morphology and functional status, and ultimately increasing the synthesis of contractile protein MyHC 1 by inhibiting the expression of the key UPS molecules Atrogin-1 and MuRF 1. Controlling the IGF-1 signaling pathway and mitochondria to improve the functional status of long-term denervated SKM cells provides a new experimental basis, but also for this
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：R685

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1 Gang Li;Qing-shan Li;Wen-bin Li;Jian Wei;Wen-kai Chang;Zhi Chen;Hu-yun Qiao;Ying-wei Jia;Jiang-hua Tian;Bing-sheng Liang;;miRNA targeted signaling pathway in the early stage of denervated fast and slow muscle atrophy[J];Neural Regeneration Research;2016年08期

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