Scaffold-Mediated Sustained,Non-viral Delivery of miR-219/miR-338 Promotes CNS Remyelination

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Disruption of KATP Channel Expression in Skeletal Muscle by Targeted Oligonucleotide Delivery Promotes Activity-linked Thermogenesis

Despite the medical, social, and economic impact of obesity, only a few therapeutic options, focused largely on reducing caloric intake, are currently available and these have limited success rates. A major impediment is that any challenge by caloric restriction is counterbalanced by activation of systems that conserve energy to prevent body weight loss. Therefore, targeting energy-conserving mechanisms to promote energy expenditure is an attractive strategy for obesity treatment. Here, in order to suppress muscle energy efficiency, we target sarcolemmal ATP-sensitive potassium (K_ATP) channels which have previously been shown to be important in maintaining muscle energy economy. Specifically, we employ intramuscular injections of cell-penetrating vivo-morpholinos to prevent translation of the channel pore-forming subunit. This intervention results in significant reduction of K_ATP channel expression and function in treated areas, without affecting the channel expression in nontargeted tissues. Furthermore, suppression of K_ATP channel function in a group of hind limb muscles causes a substantial increase in activity-related energy consumption, with little effect on exercise tolerance. These findings establish a proof-of-principle that selective skeletal muscle targeting of sarcolemmal K_ATP channel function is possible and that this intervention can alter overall bodily energetics without a disabling impact on muscle mechanical function.     

VEGF/VEGFR在脑缺血再灌注损伤中的神经保护作用

目的:研究VEGF/VEGFR在脑缺血再灌注损伤中的神经保护作用。方法:SD大鼠108只,随机分为假手术组、对照组与VEGFR抗体组,每组36只,制备大脑中动脉缺血再灌注损伤(MCAO)模型,假手术组不造成缺血。VEGFR抗体组在造模前20 min侧脑室注射VEGF抗体,假手术组、对照组侧脑室注射等量生理盐水。比较3组在造模后1、3、7 d Bederson评分、VEGFR及缺血半暗带VEGFR2的变化。结果:VEGFR抗体组的Bederson评分在第1、3天高于对照组(P<0.05),VEGFR的表达在第1、3天低于对照组(P<0.01),但较假手术组高;VEGFR抗体组VEGFR2表达在第1、3天低于对照组(P<0.01)。结论:脑缺血再灌注损伤时,VEGF活化刺激VEGFR表达上调,促进血管内皮细胞增殖,加速新生血管形成。     

川芎嗪对大鼠脑缺血再灌注损伤的作用

目的探讨中药川芎嗪对大鼠脑缺血再灌注损伤的作用机制。方法选用雄性Wistar大鼠25只,随机分为正常对照组(n=5)、脑缺血再灌注组(n=6)、尼莫地平组(n=7)及川芎嗪组(n=7)。正常对照组不做任何处理;余3组采用改良Zea Longa线栓法建立可再通脑缺血模型,模型成功建立后,各组大鼠腹腔分别注射0.9%氯化钠注射液、尼莫地平、川芎嗪;于脑缺血3 h和再灌注后48 h分别行神经功能评分。再灌注后48 h后测定各组大鼠脑血流。处死后对脑缺血再灌注组、尼莫地平组及川芎嗪组大鼠进行TTC染色计算脑梗死体积,并测定缺血区线粒体超氧化物歧化酶(SOD)活性。结果缺血再灌注48 h后4组脑血流值两两比较差异均有统计学意义(P<0.01);尼莫地平组与川芎嗪组脑梗死神经功能恢复评分均低于给药前和缺血再灌注组,差异均有统计学意义(P<0.01),且川芎嗪组改善情况优于尼莫地平组(P<0.01);缺血再灌注各组大鼠脑梗死区相对体积组间两两比较差异均有统计学意义(P<0.05,P<0.01)。川芎嗪组大鼠脑组织线粒体SOD活性与其他缺血再灌注组比较差异均有统计学意义(P<0.01)。结论川芎嗪具有抗氧自由基作用,可修复脑缺血再灌注损伤。     

重组生长激素预处理对大鼠肝脏热缺血再灌注损伤的作用

目的观察重组生长激素（rGH）预处理对大鼠肝脏热缺血再灌注损伤的作用。方法建立大鼠肝脏热缺血再灌注损伤模型，设立实验组，对照组和假手术组，每组10只。实验组术前连续7天皮下注射rGH，1U／Kg／d，对照组给予同体积生理盐水作为对照。实验组和对照组均予阻断第一肛门40分钟后恢复再灌注。假手术组仅作开关腹手术。分别在恢复再灌注后2小时和24小时后检测各组血清TNF-α、IL-1β水平及肝组织匀浆MDA、SOD含量。同时电镜下观察各组肝组织超微结构的变化以及应用TUNEL染色方法比较各组间细胞凋亡指数。结果实验组TNF-α水平在再灌注后2小时和24小时均低于对照组（P〈0．05），而IL-1β水平在两组之间差异无显著性。MDA水平实验组在再灌注后2小时和24小时均明显低于对照组（P〈0．05），而SOD水平在两组之间无显著性差异。对照组肝组织细胞凋亡指数明显高于实验组（P〈0．05）。电镜观察发现对照组肝细胞线粒体结构紊乱，嵴消失，细胞核染色质出现断裂，染色体碎片外溢，凋亡小体形成等现象，而实验组没有发现上述征象。结论重组生长激素预处理对大鼠肝脏热缺血再灌注损伤具有保护作用。     

康复训练介导NGF/VEGF/CD34表达对脑缺血再灌注大鼠血管再生的影响

目的：观察康复训练对脑缺血再灌注大鼠神经功能的影响，探讨康复训练调节血管再生的机制。方法：将SD大鼠适应性喂养1周后，进行脑缺血再灌注手术造模，24h后挑选神经功能评分2~3分的大鼠和假手术大鼠分为假手术组（8只），康复组（16只）和脑缺血组（24只），康复组每天按计划进行跑步训练，分别于康复训练的第7天、第14天对大鼠进行神经行为学评分并随机挑选部分大鼠进行取材进行TTC染色、免疫组化及免疫印迹实验。结果：脑缺血再灌注造成大鼠神经功能损伤，7d和14d的康复训练有效提高了大鼠神经行为学评分（P＜0.05）。此外，脑缺血再灌注诱导了大鼠脑中血管内皮生长因子（VEGF）与神经生长因子（NGF）蛋白表达增加，促进脑中血管微循环的建立；与脑缺血组相比，7d和14d康复训练显著增加了大鼠脑中VEGF与NGF表达（P＜0.05），加速了缺血区血管微循环的建立（P＜0.05）。结论：康复训练对于脑缺血再灌注有良好的治疗效果，其机制可能是增加了VEGF与NGF表达，加速了缺血区血管微循环的建立。     

肢体缺血再灌注时炎性介质的表达和临床意义

目的　研究肢体缺血再灌注炎性介质血栓素B2 (TXB2 )、白细胞介素- 8(IL -8)、过氧化脂质(LPO)和一氧化氮(NO)的变化。方法　2 1例择期手术病人随机分非缺血对照组、缺血再灌注组,以放射免疫法、ELISA法、硫代巴比妥法和硝酸还原酶法分别测定TXB2、IL- 8、LPO和NO的值。结果　肢体缺血的灌注后10min ,LPO显著升高。再灌注后18minTXB2、IL -8和LPO均显著增高;NO显著降低。结论　肢体缺血再灌注的病理过程是一种炎症反应,肢体缺血再灌注损伤是由炎症反应引起的自身免疫损伤。     

Influence of Different Conditioning Methods on Force and Fatigue Resistance in Chronically Stimulated Skeletal Muscles

A study was undertaken to compare different conditioning methods for the transformation of latissimus dorsi muscle into a fatigue resistant one for application in circulatory assist. In ten sheep four electrodes were sutured to the epineurium of the left thoracodorsal nerve for indirect electrical stimulation of the latissimus dorsi muscle. In six sheep a "carousel stimulation, " a special multichannel stimulation, in combination with a recently developed conditioning protocol was used for muscle conditioning ( multichannel method ). In four sheep, a conventional stimulation protocol using single channel stimulation was applied for transformation of the muscle (single channel method). The final experiments were carried out when fatigue resistance was obtained. The maximum tetanic forces at different preloads were determined and fatigue resistance was tested during 20 minutes of continuous stimulation. Both conditioning patterns led to fatigue-free chronic stimulation. Muscles conditioned by multichannel stimulation exhibited between 20% and 33% less force than the contralateral unconditioned muscles, whereas in the single channel group this loss was between 32% and 43%. Thus, the multichannel method revealed relatively superior in preserving muscle force for chronic stimulation.     

Synergistic Effects of GDNF and VEGF on Lifespan and Disease Progression in a Familial ALS Rat Model

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive loss of motor neurons in the brain and spinal cord. We have recently shown that human mesenchymal stem cells (hMSCs) modified to release glial cell line-derived neurotrophic factor (GDNF) decrease disease progression in a rat model of ALS when delivered to skeletal muscle. In the current study, we determined whether or not this effect could be enhanced by delivering GDNF in concert with other trophic factors. hMSC engineered to secrete GDNF (hMSC-GDNF), vascular endothelial growth factor (hMSC-VEGF), insulin-like growth factor-I (hMSC-IGF-I), or brain-derived neurotrophic factor (hMSC-BDNF), were prepared and transplanted bilaterally into three muscle groups. hMSC-GDNF and hMSC-VEGF prolonged survival and slowed the loss of motor function, but hMSC-IGF-I and hMSC-BDNF did not have any effect. We then tested the efficacy of a combined ex vivo delivery of GDNF and VEGF in extending survival and protecting neuromuscular junctions (NMJs) and motor neurons. Interestingly, the combined delivery of these neurotrophic factors showed a strong synergistic effect. These studies further support ex vivo gene therapy approaches for ALS that target skeletal muscle.     

PI3K/PKB信号途径在远程肢体缺血后处理减轻 脑缺血再灌注损伤中的作用

目的：通过观察肢体缺血后处理（LIP）后p-Akt、Caspase-9 及Bcl-2 蛋白的表达,探讨PI3K/PKB信号途 径在远程LIP 减轻脑缺血再灌注损伤中的作用。方法：42 只大鼠随机分成对照组、缺血再灌注（IR）组和LIP 组各14 只,后2 组采用线栓法制备局灶性脑缺血再灌注模型,LIP 组在缺血2 h 后再灌注前实施3 个循环健 侧股动脉缺血5 min再灌注5 min的LIP。采用TTC染色测定脑梗死体积,免疫组化法检测p-Akt、Caspase-9、 Bcl-2蛋白的表达。结果：LIP组大鼠脑梗死体积较IR组明显减小（P＜0.05）。LIP组p-Akt、Bcl-2蛋白表达较 IR 组明显增高（P＜0.05）,LIP 组Caspase-9 蛋白表达较IR 组明显降低（P＜0.05）。结论：LIP 可上调p-Akt、 Bcl-2表达,下调Caspase-9表达,并减轻脑梗死体积,PI3K/PKB信号通路在LIP减轻脑缺血再灌注损伤中可能 发挥重要保护作用。     

缺血预处理对高血脂大鼠心肌再灌注损伤和氧自由基代谢的影响

目的研究缺血预处理 (IP)对缺血再灌注 (I/R)高血脂大鼠离体心脏功能、心肌酶、氧自由基的影响。方法采用大鼠离体心脏灌注模型 ,以左室收缩峰压 (LVSP)和心室内瞬间最大变化速率 (dp/dtmax)估价心功能。以心肌酶 (CK)反应心肌损伤 ,以心肌组织丙二醛 (MDA)含量、超氧化物歧化酶 (SOD)活性、心肌细胞线粒体中谷胱甘肽过氧化酶 (GRH PX)活性反映心肌自由基代谢。将IP和I/R情况进行比较。结果IP使高血脂大鼠心脏再灌注后LVSP、dp/dtmax增高、CK降低、MDA减少、SOD和GSH PX增高 (均P <0 .0 5 ) ,且与正常大鼠无显著性差异 (均P >0 .0 5 )。结论IP对高血脂大鼠心肌缺血再灌注损伤有保护作用。高血脂可能不参与心肌缺血再灌注损伤的机制。     

高血压大鼠脑缺血再灌注后IGF-Ⅰ的表达及意义

目的 观察高血压大鼠脑缺血再灌注后胰岛素样生长因子-Ⅰ(IGF-Ⅰ)的表达及意义.方法 用线栓法将肾性高血压与正常血压大鼠制备成脑缺血模型,用免疫组化染色法检测脑缺血再灌流后IGF-Ⅰ的表达.结果 IGF-Ⅰ表达主要位于缺血周边区,高血压大鼠脑缺血再灌流后IGF-Ⅰ在各灌注时间点均明显低于正常血压大鼠.结论 高血压大鼠脑缺血再灌注后IGF-Ⅰ表达降低可能是高血压加重脑缺血再灌注损伤的机制之一.     

缺血后处理对脑缺血再灌注损伤后ERK1/2和Akt磷酸化及神经细胞凋亡的影响

目的:观察缺血后处理对大鼠局灶性脑缺血再灌注损伤后ERK1/2和Akt及神经细胞凋亡的影响。方法:成年健康SD大鼠72只,随机分为假手术(sham)组、缺血再灌注(I/R)组、缺血后处理(Postcond)组各24只,应用线栓法建立大脑中动脉闭塞(MCAO)再灌注模型。分别于再灌注10min、30min、6h、24h后留取大脑皮质。Western blot检测再灌注10min、30min、6h后ERK1/2和Akt活性变化;原位末端标记(TUNEL)检测再灌注后24h神经细胞凋亡。结果:Postcond组再灌注10min、30min、6h后ERK1/2和Akt活性高于I/R组(P<0.05);脑缺血再灌注24h后,Postcond组与I/R组比较,TUNEL阳性细胞减少(P<0.05)。结论:缺血后处理可提高大鼠脑缺血再灌注后皮质内ERK1/2和Akt活性,减少神经细胞凋亡。     

Ultrasound-Enhanced Protective Effect of Tetramethylpyrazine via the ROS/HIF-1A Signaling Pathway in an in Vitro Cerebral Ischemia/Reperfusion Injury Model

Reactive oxygen species-induced oxidative stress is an important pathophysiological process during cerebral ischemia/reperfusion (I/R) injury. It has been reported that the protective effect of tetramethylpyrazine (TMP) against cerebral I/R injury can be significantly improved by its combination with ultrasound exposure. However, the molecular mechanisms and signaling pathways underlying the synergistic protective effect remain unclear. In the present work, the damage induced by I/R injury was modeled by glutamate-induced toxicity to pheochromocytoma (PC12) cells. The ultrasound-enhanced protective effect of TMP was systemically investigated by measuring variations in cell viability, cell migration and levels of intracellular reactive oxygen species, the oxidative stress-related protein glutathione, apoptosis-related proteins (caspase-8, -9 and -3), as well as expression of related genes (hypoxia-inducible factor-1a, p53, murine double minute2). The results suggest that the ultrasound-enhanced protective effect of TMP against cerebral I/R injury might act via the reactive oxygen species/hypoxia-inducible factor-1a signaling pathway, and an appropriate ultrasound intensity should be selected to achieve an optimal synergistic neuroprotective effect.     

高压氧对急性损伤期缺血再灌注大鼠脑内水通道蛋白-4表达的影响

【目的】研究水通道蛋白－4（AQP4）在缺血／再灌注脑损伤大鼠脑内的表达,及高压氧（hyperbaric oxygen,HBO）对其表达的影响。【方法】将135只SD大鼠分为假手术对照组（Sham组）、缺血再灌注组（I／R组）和高压氧处理组（HBO组）,以四动脉阻断法建立全脑缺血再灌注大鼠模型。I／R组和HBO组按再灌注的时间不同分为四个亚组,每组15只,即动物缺血20min后分别再灌注6h、24h、3d和5d,HBO各亚组在再灌注后分别行不同次数的高压氧处理。测定脑组织含水量及伊文斯蓝含量,并采用免疫组织化学技术检测AQP4的表达。同时观察HB0对脑水肿和AQP4表达的影响。【结果]Sham组AQP4表达较低,在缺血损伤后表达升高,脑组织含水量及伊文斯蓝含量增加,给予HB0后AQP4的表达和脑组织含水量降低。【结论】缺血／再灌注脑损伤后AQP4表达上升,脑水肿明显,给予HB0可抑制AQP4的表达,减轻脑水肿。