骨骼肌缺血再灌注损伤的研究现状

骨骼肌缺血再灌注损伤是临床常见的病理过程。目前对骨骼肌缺血再灌损伤的病理机制尚不十分清楚,为此,不少学者就骨骼肌缺血再灌注损伤的发病机制及其防治方法进行了广泛深入的研究。本文就骨骼肌缺血再灌注损伤的研究现状综述如下。1　骨骼肌缺血再灌注损伤的病理机制骨骼肌代谢活跃,对缺血反应比较敏感。在缺血再灌注过程中,骨骼肌损伤不仅发生在缺血期间,而且还发生在再灌注时期。缺血再灌注损伤的程度与缺血时间有关。当骨骼肌缺血缺氧时,细胞代谢转化为无氧酵解。细胞能量大量消耗,代谢产物聚集,从而引起骨骼肌在代谢、结构和功能等方…     

硫化氢预处理对兔脊髓缺血再灌注神经损伤的保护作用及其机制研究

目的 观察硫化氢（H2S）预处理对兔脊髓缺血再灌注损伤的保护效应。方法 将雄性新西兰大白兔随机分为假手术组、缺血再灌注组和H2S预处理组,观察H2S对模型神经行为学的影响,以及对神经细胞凋亡和超氧化物歧化酶（SOD）、过氧化氢酶（CAT）的影响。结果 H2S预处理提高神经功能的评分,降低神经细胞的凋亡,增强SOD和CAT活性（P＜0.05）。结论 H2S对脊髓缺血再灌注损伤有较好的保护作用,其作用机制可能与抗自由基生成有关     

缺血后适应减轻急性下肢缺血再灌注损伤的实验研究

目的 观察缺血后适应(IPC)减轻急性下肢缺血(AU)再灌注损伤的疗效并探讨其机制.方法 将45只新西兰大白兔采用高脂饮食与动脉内膜球囊损伤结合的方式建立下肢动脉粥样硬化狭窄动物模型,随机分为对照组、缺血再灌注组(IR组)、缺血后适应组(IPC组),每组各15只.检测三组大白兔阻断股动脉前、持续再灌注2h后血液中肌酸激酶(CK)、丙二醛(MDA)、超氧化物岐化酶(SOD)水平,观察再灌注后下肢骨骼肌组织学改变,并采用原位末端标记法(TUNEL)分析三组大白兔下肢再灌注后骨骼肌细胞凋亡情况.结果 与IR组比较,IPC组兔血浆CK、MDA明显降低[(7.49±0.84) U/L与(8.19±1.06) U/L,P＜0.05],[(3.67±0.36) nmol/L与(4.06±0.55) nmol/L,P＜0.05],而SOD则显著升高[(420.40±30.94)μmol/L与(384.73±44.12) μmol/L,P＜0.05],骨骼肌细胞凋亡指数降低[(12.27±2.11)％与(16.62±1.44)％,P＜0.01],差异有统计学意义,并且组织形态学观察IPC组兔骨骼肌损伤、坏死程度较IR组减轻.结论 急性下肢缺血应用IPC能显著减轻下肢缺血再灌注损伤,其机制与减少自由基生成、增强抗氧化及减轻缺血再灌注诱导的骨骼肌细胞凋亡有关.     

山茛菪碱对大鼠骨骼肌缺血再灌注损伤的保护作用

目的观察山莨菪碱对大量骨骼肌缺血再灌注损伤的影响.方法24只健康SD大鼠,随机分为三组,A组(对照组)8只,仅麻醉及颈外静脉插管术;B组(缺血再灌注损伤组)8只,缺血4小时之后放开止血带,再灌注4小时;C组(山莨菪碱处理组)8只,再灌注即刻颈外静脉给山莨菪碱5mg/kg.观察山莨菪碱对大鼠再灌注损伤血浆乳酸脱氢酶(LDH)、肌酸肌酶(CK)、丙二醛(MDA)和骨骼肌组织髓过氧化物酶(MPO)、MDA和湿重/干重值(W/D)的影响,并观察骨骼肌超微结构的变化.结果山莨菪碱能明显降低大鼠骨骼肌缺血再灌注损伤所引起的血浆LDH、MDA、CK和骨骼肌组织MPO、MDA、W/D水平的升高,减轻其组织超微结构的损伤.结论山莨菪碱对骨骼肌缺血再灌注损伤具有保护作用.     

蝮蛇抗栓酶对骨骼肌缺血再灌注损伤保护的实验研究

为探讨骨骼肌缺血再灌注损伤前后微循环变化及蝮蛇抗检酶 (Svate)的保护作用 ,将 2 4只兔随机分成两组 ,以气囊止血带造成兔左下肢缺血再灌注损伤模型。实验组分别在缺血前及再灌注前给予 Svate静注 ,对照组给予等量生理盐水 ,以微循环显微镜观察兔缺血前及再灌注后骨骼肌微循环的变化。结果显示 ,Svate通过疏通微循环对骨骼肌缺血再灌注损伤起保护作用     

山莨菪碱对大鼠骨骼肌缺血再灌注损伤的保护作用

目的：观察山莨菪碱对大量骨骼肌缺血再灌注损伤的影响。方法：24只健康SD大鼠，随机分为三组，A组（对照组）8只，仅麻醉及颈外静脉插管术，B组（缺血再灌注损伤组）8只，缺血4小时之后放开止血带，再灌注4小时；C组（山莨菪碱处理组）8只，再灌注即刻颈外静脉给山莨菪碱5mg/kg，观察山莨菪碱对大鼠再灌注损伤血浆乳酸脱氢酶（LDH），肌酸肌酶（CK）、丙二醛（MDA）和骨骼肌组织髓过氧化物酶（MPO）、MDA和湿重／干重值（W／D）的影响，并观察骨骼肌超微结构的变化。结果：山莨菪碱能明显降低大鼠骨骼肌缺血再灌注损伤所引起的血浆LDH，MDA，CK和骨骼肌组织MPO，MDA，W／D水平的升高，减轻其组织超微结构的损伤。结论：山莨菪碱对骨骼肌缺血再灌注损伤具有保护作用。     

山莨菪碱抗肺缺血再灌注损伤作用的实验研究

目的　探讨山莨菪碱 (6 5 4 - 2 )抗兔肺缺血再灌注损伤作用及其机制。方法　在建立兔单肺原位缺血再灌注损伤模型上 ,观察山莨菪碱对肺组织湿 /干比值 (W /D)、丙二醛 (MDA)、肺匀浆髓过氧化物酶(MPO)活性和肺毛细血管通透性 (LPI)作用和肺组织光镜、电镜形态学变化肺组织损伤 (LTD)程度。结果　缺血 90min、再灌注 12 0min后 ,肺组织的W /D、LPI、MDA、MPO活性、LTD程度减少 ,6 5 4— 2可使肺组织病理损伤明显减轻。结论　山莨菪碱具有抗肺缺血再灌注损伤作用 ,其作用机制可能与抑制中性粒细胞在肺内聚集 ,减轻氧自由基造成的肺损伤有关。     

乌司他丁对肝脏缺血再灌注损伤中线粒体的作用

目的探讨乌司他丁在肝脏缺血再灌注损伤中对线粒体的作用及其机制。方法采用健康杂交狗全肝缺血再灌注模型,检测肝功能、线粒体H+-ATP酶活性及电镜观察线粒体形态的变化。结果肝功能指标的测定:对照组、实验组较假手术组丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)均增高,差异有统计学意义(P<0.05),肝脏缺血再灌注损伤实验模型制作成功。实验组较对照组ALT、AST均降低,差异有统计学意义(P<0.05)。线粒体结构及功能检测:阻断组较假手术组H+-ATP酶活性均降低,差异有统计学意义(P<0.05)。实验组较对照组H+-ATP酶活性均增高,差异有统计学意义(P<0.05)。手术组线粒体分级为0级;对照组:缺血15min线粒体分级为2￣3级;再灌注损伤1h线粒体分级为4级;实验组:缺血15min,分级为1￣2级;再灌注损伤1h线粒体分级为2￣3级。结论乌司他丁对线粒体损伤有保护作用,其作用机制为稳定线粒体脂质双分子膜,增高线粒体H+-ATP酶活性,保护线粒体结构及其功能,从而保护肝细胞,减轻肝脏缺血再灌注损伤。     

不同高压氧预处理对大鼠肾缺血再灌注损伤的研究

目的 研究不同时间高压氧预处理对大鼠肾脏缺血再灌注损伤的影响并探讨其机制.方法 雌性SD大鼠50只随机分为5组:假手术组(S组,n=10)打开腹腔不夹闭肾蒂;缺血再灌注组(IR组,n=10)夹闭双侧肾蒂30 min后再灌注;高压氧预处理1组(H1,n=10); 高压氧预处理2组(H2,n=10);高压氧预处理3组(H...     

瑞芬太尼对大鼠肝脏缺血再灌注早期细胞凋亡的影响

目的:观察瑞芬太尼对大鼠肝脏缺血再灌注早期细胞凋亡的影响及其机制。方法:SD大鼠54只分为假手术组(S组),生理盐水对照组(C组),瑞芬太尼预处理组(R组)。缺血均为30 min,瑞芬太尼预处理组为缺血前输注瑞芬太尼30 min,生理盐水对照组以相同的速率及容积输注生理盐水。分别在再灌注1,3,5 h处死6只大鼠,取左肝组织检测细胞凋亡及Bc1-2和Bax表达水平。结果:与S组相比,C组细胞凋亡指数、Bax蛋白表达均增高,而瑞芬太尼预处理减弱了缺血再灌注上述指标的升高(P<0.05);C组Bc1-2蛋白表达减少,瑞芬太尼预处理可增强其在肝组织的表达(P<0.05)。光镜和电镜检查显示瑞芬太尼预处理减轻肝缺血再灌注损伤。结论:瑞芬太尼预处理可以抑制大鼠肝脏缺血再灌注损伤早期细胞凋亡,其机制与上调Bc1-2蛋白表达、下调Bax蛋白表达有关。     

Calcium dobesilate ameliorates lung injury following lower limb ischemia/reperfusion

We examined the effects of calcium dobesilate on ameliorating the lung damage following ischemia-reperfusion injury in skeletal muscle of rats. A well known antioxidant, dimethyl sulfoxide, was also tested for comparison. The study included three groups: normal saline, dimethyl sulfoxide and calcium dobesilate. Plasma bicarbonate, creatine kinase, lactate dehydrogenase, thiobarbituric acid reactive substances (TBARS), as well as muscle and lung tissue TBARS levels were measured. Lung tissue samples were taken for histological examination. The dimethyl sulfoxide group showed significant amelioration of plasma (p = 0.004), skeletal muscle (p = 0.006) and lung TBARS (p = 0.004) levels, compared with controls. Calcium dobesilate-treated rats showed significantly low level muscle (p = 0.025) and lung TBARS (p = 0.004), compared with the control group. The extent of lung injury according to the histological findings was less in the dimethyl sulfoxide (p = 0.004) and calcium dobesilate (p = 0.003) groups. These observations indicated that calcium dobesilate acted effectively in the prevention of lung damage following ischemia-reperfusion injury in the rat skeletal muscle.     

Efficacy and mechanism of hypoxic postconditioning in salvage of ex vivo human rectus abdominis muscle from hypoxia/reoxygenation injury

In reconstructive surgery, skeletal muscle may endure protracted ischemia before reperfusion, which can lead to significant ischemia/reperfusion injury. Ischemic postconditioning induced by brief cycles of reperfusion/reocclusion at the end of ischemia has been shown to salvage skeletal muscle from ischemia/reperfusion injury in several animal models. However, ischemic postconditioning has not been confirmed in human skeletal muscle. Using an established in vitro human skeletal muscle hypoxic conditioning model, we tested our hypothesis that hypoxic postconditioning salvages ex vivo human skeletal muscle from hypoxia/reoxygenation injury and the mechanism involves inhibition of opening of the mitochondrial permeability transition pore (mPTP) and preservation of ATP synthesis. Muscle strips (~0.5×0.5×15mm) from human rectus abdominis muscle biopsies were cultured in Krebs-Henseleit-HEPES buffer, bubbled with 95%N(2)/5%CO(2) (hypoxia) or 95%O(2)/5%CO(2) (reoxygenation). Samples were subjected to 3h hypoxia/2h reoxygenation. Hypoxic postconditioning was induced by one or two cycles of 5min reoxygenation/5min hypoxia after 3h hypoxia. Muscle injury, viability and ATP synthesis after 2h of reoxygenation were assessed by measuring lactate dehydrogenase (LDH) release, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) reduction and ATP content, respectively. Hypoxic postconditioning or treatment with the mPTP-opening inhibitors Cyclosporine A (CsA, 5×10(-6)M) or N-Methyl-4-isoleucine Cyclosporine (NIM811, 5×10(-6)M) 10min before reoxygenation decreased LDH release, increased MTT reduction and increased muscle ATP content (n=7 patients; P<0.05). Conversely, treatment with the mPTP opener Atractyloside (5×10(-6)M) 10min before hypoxic postconditioning abolished its protective effect (n=7 patients; P<0.05). We conclude that hypoxic postconditioning effectively salvages human skeletal muscle from hypoxia/reoxygenation injury by inhibition of mPTP opening and preservation of ATP synthesis during reoxygenation.     

Antiproliferative mechanisms of raxofelast (IRFI-016) in H2O2-stimulated rat aortic smooth muscle cells

Reactive oxygen species-mediated cellular injury is involved in the pathogenesis of many diseases, including those affecting the cardiovascular system, such as myocardial ischemia-reperfusion injury, inflammation, and atheroscleosis. Raxofelast (IRFI-016; (+/-)-5-acetoxy-2, 3-dihydro-4, 6, 7-trimethyl-2-benzofuran-acetic acid) was designed with the aim of maximizing the antioxidant potency of phenols chemically related to vitamin E. The antioxidant activity of raxofelast has been convincingly demonstrated in several in vitro studies and in various models of ischemia-reperfusion injury. In this study, the antiproliferative effects of raxofelast were investigated to determine whether transduction signals and protooncogenes are affected in H(2)O(2)-stimulated rat aortic smooth muscle cells. In a tetrazolium-based colorimetric assay, the proliferation of rat aortic smooth muscle cells was increased by 3-fold in 0.1% fetal bovine serum/Dulbecco's modified Eagle's medium (DMEM) containing 500 microM H(2)O(2), indicating that exogenous 500 microM H(2)O(2) was a growth stimulator of rat aortic smooth muscle cells. Exogenous H(2)O(2) significantly activated extracellular signal-regulated kinases (ERKs) activity within 30 min and raxofelast inhibited the ERKs activation dose dependently in 500 microM H(2)O(2)-stimulated rat aortic smooth muscle cells (IC(50): 200 microM). Raxofelast reduced the intracellular reactive oxygen species generated by exogenous H(2)O(2) in a dose-dependent manner. In 500 microM H(2)O(2)-stimulated rat aortic smooth muscle cells, raxofelast dramatically attenuated the activation of mitogen-activating protein kinase (MAPK)/ERK kinase 1, 2 (MEK1,2) and protein kinase C (PKC) without affecting Ras expression. Induction of c-myc mRNA was significantly reduced dose dependently up to 100 microM by raxofelast in concentrations. These data indicate that the antiproliferative effects of raxofelast in H(2)O(2)-stimulated rat aortic smooth muscle cells may involve the suppression of intracellular reactive oxygen species formation and the inhibition of ERKs by inactivation through PKC and MEK1,2 and down-regulation of c-myc expression, regardless of Ras activation.     

Inactivation of the beta-adrenergic receptor in skeletal muscle by dithiols

The effect of sulfhydryl compounds on binding of the beta-adrenergic antagonist (-)-[3H]dihydroalprenolol [(-)-[3H]DHA] to a microsomal fraction from rabbit skeletal muscle was examined. Inhibition of binding by a variety of adrenergic agonists and antagonists and the effects of these agents on adenylate cyclase were consistent with the beta-adrenergic receptor in this tissue being of the beta 2-subtype. Binding of (-)-[3H]DHA was reduced by incubating the membranes with dithiols such as dithiothreitol (DTT), 1,3-dimercapto-2-propanol and 1,4-dimercaptobutane; monothiols were much less potent. DTT-induced decline in (-)-[3H]DHA binding resulted primarily from a decrease in receptor number. Inactivation was partially reversed by the oxidant H2O2. Binding sites could be locked in the inactivated state by incubating DTT-treated membranes with the alkylating agent iodoacetamide. Both beta-adrenergic agonists and antagonists protected against inactivation. Adenylate cyclase activity in the membranes was increased by DTT. The enzyme was rapidly inactivated by H2O2, and this could be partially reversed by DTT. It is concluded that the beta-adrenergic receptor of skeletal muscle contains an essential disulfide moiety which can be inactivated by reducing dithiols. Adenylate cyclase, on the other hand, contains at least one essential sulfhydryl which is preserved by dithiols.     

Emerging drugs for treating skeletal muscle injury and promoting muscle repair

INTRODUCTION: Musculoskeletal injuries represent a major global public health problem and muscle injury contributes significantly to the burden of disability and suffering. Drugs that can attenuate muscle trauma and/or hasten muscle repair to restore function can help reduce the economic burden and alleviate personal suffering and financial hardship. AREAS COVERED: This review provides an update on some emerging drugs with therapeutic potential for muscle injury including those that could attenuate damage or improve regeneration. Although there are few (if any) drugs in development specifically for muscle injury, there are numerous drugs in development for cardiovascular complications, such as ischemia-reperfusion, that might also have efficacy for promoting regeneration after similar events in skeletal muscle. EXPERT OPINION: Drugs in development for muscle wasting or inflammatory diseases should also be considered within the context of modulating the events associated with muscle degeneration and regeneration. More rigorous pre-clinical evaluations, especially of a drug's efficacy for improving function, would help minimize false leads and hasten development of effective approaches for treating muscle damage and promoting repair after injury.     

Hydrogen peroxide production by monoamine oxidase during ischemia/reperfusion

Reactive oxygen species have been postulated to play a crucial role in the pathogenesis of renal ischemia-reperfusion injury. However, the intracellular sources of reactive oxygen species during ischemia-reperfusion are still unclear. In the present study, we examined whether catecholamine-degrading enzymes monoamine oxidases contribute to hydrogen peroxide (H(2)O(2)) generation during ischemia-reperfusion using an in vivo rat model of unilateral renal ischemia. The monoamine oxidases were characterized in homogenates of renal cortex by enzyme assay and by Western blot analysis. The monoamine oxidase-dependent H(2)O(2) production was measured by luminol-amplified chemiluminescence assay. Renal monoamine oxidase activity and H(2)O(2) generation by monoamine oxidases were suppressed during ischemia. The monoamine oxidase-dependent H(2)O(2) production was observed during the first 15 min of reperfusion. In addition, enzyme assays showed that monoamine oxidase is also activated in this period. Rat pre-treatment with the irreversible inhibitor of monoamine oxidase, pargyline, prevented H(2)O(2) production. These data suggest that monoamine oxidases are a potential source of H(2)O(2) generation in the early reperfusion following ischemia, which could be involved in renal ischemia-reperfusion injury.     

Sulforaphane protects kidneys against ischemia-reperfusion injury through induction of the Nrf2-dependent phase 2 enzyme

Reactive oxygen species are important mediators that exert a toxic effect during ischemia-reperfusion injury of various organs. Sulforaphane, which is a naturally occurring isothiocyanate that is present in cruciferous vegetables such as broccoli, is known to be an indirect antioxidant that acts by inducing Nrf2-dependent phase 2 enzymes. Phase 2 enzymes such as heme oxygenase-1, NAD(P)H: quinone oxidoreductase 1, glutathione reductase, and glutathione peroxidase participate in adaptive and protective responses to oxidative stress and various inflammatory stimuli. Therefore, we evaluated the preactivation of Nrf2 by sulforaphane to determine if it could inhibit ischemia-reperfusion-induced kidney damage. Treatment of HK2 renal tubular epithelial cells with sulforaphane effectively protected cells against cytotoxicity induced by hypoxia-reoxygenation, and sulforaphane dramatically induced phase 2 enzymes by decreasing the Keap1 protein levels and increasing Nrf2 nuclear translocation. Additionally, a second set of experiments using a renal ischemia-reperfusion model produced results that were essentially the same as those observed when HK2 cells were used; namely, that sulforaphane induced Nrf2-dependent phase 2 enzymes and thereby improved ischemia-reperfusion-induced changes in the lipid hydroperoxides, glutathione, creatinine clearance, kidney weight, and histologic abnormalities. Collectively, these results suggest that sulforaphane can be used as an effective adjunct for the prevention of renal oxidative insults during ischemia-reperfusion injury.     

局部亚低温对大鼠全脑缺血再灌注后血清S100B蛋白的影响

目的探讨局部亚低温对大鼠全脑缺血再灌注后血清S100B蛋白的影响。方法 24只SD雄性大鼠随机分为3组：假手术组（S组）、缺血再灌注组（IR组）、亚低温组（H组）,每组8只。采用双侧颈总动脉夹闭＋基底动脉丝线提拉法制备全脑缺血再灌注损伤模型,全脑缺血10min再灌注6h。实验过程中监测大鼠脑血流图并测定动脉血气。H组再灌注前即刻经股静脉缓慢注射10℃0.9%氯化钠溶液3.5ml,冰块包绕头部,60W白炽灯照射身体。控制鼓膜温度在32～34℃,直肠温度同时降低,20min左右升至并维持在37.5～38.3℃。低温维持3h,3h后60W白炽灯照射身体缓慢复温。实验结束后测定大鼠血清S100B蛋白浓度;用干（110℃24h烘干）、湿重法计算左侧大脑半球脑水含量。结果与S组比较,IR组S100B蛋白浓度、脑含水量升高（P〈0.05）;与IR组比较,H组S100B蛋白浓度、脑含水量降低（P〈0.05）。结论局部亚低温降低大鼠全脑缺血再灌注后血清S100B蛋白的表达量,对全脑缺血再灌注损伤大鼠有保护作用。