Protective effect of ischaemic preconditioning against ischaemia-induced reperfusion injury of skeletal muscle: how many preconditioning cycles are appropriate?

We investigated the efficacy of ischaemic preconditioning (IPC), consisting of repeated brief episodes of vascular occlusion followed by reperfusion, as protection against ischaemia-reperfusion injury of skeletal muscle, using a rat amputation-like model. Wistar rats underwent temporary amputation at the level of the femur, excluding the femoral vessels. The femoral artery and vein were clamped for 4h, using a micro-clamp, in the groups exposed to ischaemia. The rats were randomly divided into eight groups: a control (C) group (n = 7) with non-amputated and non-ischaemic hind limbs; a sham control (SC) group (n = 7) with amputated but non-ischaemic hind limbs; an ischaemia-reperfusion (IR) group (n = 7) with amputated and ischaemic hind limbs; and five IPC groups (n = 7 in each) with hind limbs that were subjected to 4h of ischaemia after one to five cycles of brief ischaemia and reperfusion for 10 min each, respectively. All rats were sacrificed 24h after reperfusion. The viability of the anterior tibial muscles was evaluated using nitroblue tetrazolium staining. The total viable area ratio (T-VAR) of the muscle tissue was calculated in each animal as follows: T-VAR\total viable area/total slice areae 100%. The T-VAR values of the eight groups were as follows: C group, 100% +/- 0%; SC group, 100% +/- 0%; IR group, 73.5% +/- 1.7%; IPC1 group, 79.4% +/- 6.5%; IPC2 group, 70.5% +/- 6.2%; IPC3 group, 90.6% +/- 2.8%; IPC4 group, 90.0% +/- 1.6%; and IPC5 group, 87.8% +/- 1.8%. The T-VARs in the IPC3, IPC4 and IPC5 groups were significantly higher (alpha < 0.01) than those in the IR group. In contrast, there were no significant differences between the T-VARs of the IPC1 and IPC2 groups and those of the IR group. In conclusion, three to five cycles of IPC could protect skeletal muscle against ischaemia. 2002 The British Association of Plastic Surgeons.     

缺血预处理减轻骨骼肌缺血再灌注损伤

目的 观察缺血预处理对骨骼肌缺血再灌注损伤的保护作用。方法 选择２４只健康兔,随机等分为实验组和对照组。实验组先进行缺血预处理,再持续阻断后肢血流４ｈ;对照组直接阻断后肢血流４ｈ,制作骨骼肌缺血再灌注损伤模型。测定再灌注期血清中肌酸磷酸激酶（ＣＰＫ）和天门冬氨酸氨基转移酶（ＡＳＴ）,镜下观察骨骼肌变化。结果 实验组血清中ＣＰＫ和ＡＳＴ的含量均明显低于对照组（Ｐ〈０．０５）。实验组骨骼肌线粒体空泡变     

姜黄素对骨骼肌缺血再灌注损伤的保护作用及其机制研究

目的:观察姜黄素对肢体骨骼肌缺血再灌注损伤中血浆肌酸磷酸激酶(CPK)、乳酸脱氢酶(LDH)、丙二醛(MDA)含量及骨骼肌99m锝亚甲基二磷酸钠(99mTcMDP)吸收量的影响,探讨姜黄素对肢体骨骼肌缺血再灌注损伤的保护作用及其机制。方法:制作大鼠后肢缺血再灌注损伤模型,30只大鼠随机分为假手术组、对照组、干预组。分别于再灌注1 h后测定血浆CPK、LDH、MDA含量和腓肠肌99mTcMDP吸收量变化,透射电镜观察腓肠肌超微结构变化。结果:缺血再灌注对照组和姜黄素干预组与假手术组相比,血浆CPK(7296.18±1086.53,5168.49±975.39,3014.26±963.78)、LDH(1203.66±282.53,726.56±203.65,463.85±75.32)、MDA(10.36±2.65,6.78±2.12,3.54±1.89)含量明显增高(P<0.01),99mTcMDP吸收量(16.69±3.14,11.45±2.35,9.12±1.96)明显升高(P<0.01);腓肠肌超微结构损伤明显加重;姜黄素组血浆和骨骼肌的各项指标与缺血再灌注对照组相比显著降低(P<0.01),腓肠肌超微结构损伤明显减轻。结论:姜黄素能有效降低血浆CPK、LDH、MDA含量,减少骨骼肌99mTcMDP吸收量,减轻缺血再灌注骨骼肌坏死程度和坏死范围,改善骨骼肌再灌注损伤的超微结构,说明姜黄素对骨骼肌缺血再灌注损伤具有明显的保护作用。     

缺血后处理和预处理对大鼠骨骼肌缺血-再灌注损伤的作用

目的 探讨缺血后处理( IPost)和缺血预处理(IPC)对大鼠骨骼肌缺血再灌注(IR)损伤的影响.方法 将40只大鼠随机分成缺血再灌注组(A组)、缺血后处理组(B组)、缺血预处理组(C组)、缺血预处理加缺血后处理组(D组)以及对照组(E组),采用切断患肢全部皮肤、肌肉和神经,保留患肢股动、静脉的动物模型,通过夹闭和开放股动、静脉造成骨骼肌缺血再灌注损伤,通过测定骨骼肌缺血4h、再灌注1h后血清丙二醛(MDA)和骨骼肌髓过氧化物酶(MPO),以及再灌注6h后骨骼肌的坏死程度来观察缺血后处理.缺血预处理及缺血预处理加缺血后处理对大鼠骨骼肌缺血再灌注损伤的影响.结果 B组、C组和D组再灌注1 h MDA和MPO水平以及再灌注6h骨骼肌坏死程度均低于A组(P＜ 0.05),但是高于E组(P＜0.05);B组和D组再灌注1 h MDA和MPO水平以及再灌注6h骨骼肌坏死程度基本相同(P＞0.05);B组和D组再灌注1 h MDA和MPO水平低于C组(P＜0.05),但再灌注6h骨骼肌坏死程度基本相同(P＞0.05).结论 应用缺血后处理和缺血预处理对大鼠骨骼肌缺血再灌注损伤有一定的保护效果,联合应用缺血后处理和缺血预处理,对骨骼肌缺血再灌注损伤的保护作用并没有明显增强.     

Protective effect of low-grade hypothermia in experimental skeletal muscle ischemia.

In the present study, a rat hindlimb tourniquet model was used to investigate the effect of moderate hypothermia on ischemic muscle necrosis. Complete circulatory arrest was maintained for 4.5 h. During the ischemic period the animals were kept in an infant incubator at different temperatures. After 72 h survival the percentage of necrosis in the anterior tibial muscle was measured morphometrically on histological slides. At an ambient temperature of 24 degrees C there was 80% necrosis in the anterior tibial muscle. At 22 degrees C the necrosis was reduced to 29%. This reduction corresponds to more than 30 min shortening of the ischemia time. Differences in tissue temperature may explain some of the discrepancies reported in tolerance limits for muscle ischemia. To achieve consistent results in experimental muscle ischemia, it is necessary to control the ambient temperature.     

重组人促红细胞生成素对骨骼肌缺血再灌注损伤的保护作用

[目的]观察重组人促红细胞生成素（rHuEPO）对肢体骨骼肌缺血再灌注（IZR）损伤的保护作用。[方法]建立大鼠后肢缺血再灌注模型。40只大鼠随机均分为：假手术组（I组），I/R组（Ⅱ组），I/R＋生理盐水组（Ⅲ组），I/R＋rHuEPO组（Ⅳ组）。取血浆测定丙二醛（MDA）、肌酸磷酸激酶（CPK）和乳酸脱氢酶（LDH）含量。取骨骼肌标本测定髓过氧化酶（MP0）活性、湿重／干重比（Wet／dry）。[结果]Ⅱ组与I组比较，血浆和骨骼肌的各项生化指标显著增高（P〈0．01）；IV组血浆及骨骼肌各项测定指标较Ⅱ组相比明显降低（P〈0．01）。Ⅲ组和Ⅱ组之间比较，差异无显著意义。[结论]rHuEPO对肢体骨骼肌缺血再灌注损伤有保护作用。     

The effect of ischemia reperfusion injury on skeletal muscle

Ischemia reperfusion (IR) injury occurs when tissue is reperfused following a period of ischemia, and results from acute inflammation involving various mechanisms. IR injury can occur following a range of circumstances, ranging from a seemingly minor condition to major trauma. The intense inflammatory response has local as well as systemic effects because of the physiological, biochemical and immunological changes that occur during the ischemic and reperfusion periods. The sequellae of the cellular injury of IR may lead to the loss of organ or limb function, or even death. There are many factors which influence the outcome of these injuries, and it is important for clinicians to understand IR injury in order to minimize patient morbidity and mortality. In this paper, we review the pathophysiology, the effects of IR injury in skeletal muscle, and the associated clinical conditions; compartment syndrome, crush syndrome, and vascular injuries.     

银杏叶提取液对缺血再灌注骨骼肌线粒体的保护作用

目的：观察银杏叶提取液对肢体缺血再灌注损伤的影响，方法：制作兔肢体缺血再灌注损伤动物模型，实验分对照组，再灌注组和治疗组，检测骨骼肌三磷酸腺苷（ATP）水平并观察线粒体超微结构的变化，测定线粒体丙二醛（MDA），还原型谷胱甘肽（GSH）和线粒体Ca含量。结果：再灌注组和对照组比较，以上各项指标差异显著（P＜0．01，P＜0．05），银杏叶提取液促进骨骼肌能量代谢，维持线粒体结构完整性，降低线粒体MDA含量，提高线粒体GSH水平并抑制线粒体Ca超载，治疗组各项测定指标较再灌注组比较明显改善（P＜0．05，P＜0．01），结论：银杏叶提取液对缺血再灌注骨骼肌线粒体有保护作用。     

腺苷预处理对人未成熟心肌缺血再灌注损伤的保护作用

目的探讨腺苷预处理对人未成熟心肌缺血再灌注损伤的保护作用及其可能机制。方法将42例5岁以下行室间隔缺损修补术的患儿随机分成腺苷组和对照组,每组21例。腺苷组在术前用腺苷预处理,对照组经相同路径滴入相同体积的生理盐水后开始转流。观察心肌肌钙蛋白-I(cTnI)、肌酸激酶同工酶(CK-MB)、心肌超微结构改变,记录和计算两组自动复跳率、T波倒置发生率、室性心律失常发生率、术后平均住院日(d)。结果腺苷预处理明显减少了cTnI、CK-MB的漏出,在心肌超微结构和心电活动方面具有良好的保护作用。结论腺苷预处理对人未成熟心肌缺血再灌注损伤具有保护作用。     

腺苷与异丙酚预处理对犬心肌缺血再灌注损伤的保护作用

目的探讨腺苷与异丙酚预处理对犬心肌缺血再灌注损伤的保护作用。方法 21只杂种犬,雌雄不拘,随机分为3组(n=7):缺血再灌注组(A组)、异丙酚预处理组(B组)、异丙酚与腺苷联合预处理组(C组)。A组冠状动脉的左前降支结扎60min后松开结扎,再灌注:120min;B组缺血前30min经静脉以5．6mg·kg-1·h-1速率持续泵注异丙酚30min;C组缺血前10min经主动脉根部一次性注入腺苷(10mmol·L-1,10ml),其余处理同B组。记录心脏血液动力学指标,并行节段性室壁运动评分(RWMS)。结果缺血即刻出现了缺血性心电图的变化。与基础值比较,A组缺血期及再灌注期 LVEDP升高,CO、SV、LVEF、CPP、RPP降低,再灌注期MAP降低,HR减慢,B、C组上述缺血再灌注诱导的血液动力学变化减弱,A组缺血期及再灌注期RWMS增加,但B、C组缺血期RWMS低于A组(P< 0．05或0．01)。结论异丙酚预处理对犬心肌缺血再灌注损伤有一定的保护作用,腺苷预处理并未增强其保护作用。     

Protective effect of anisodamine on reperfusion injury of skeletal muscles in rabbit

Anisodamine is an alkaloid isolated from a Chinese plant, which was subsequently synthesized. Its chemical structure is similar to atropine. It inhibits cholinergic nerve function, improves microcirculation, and was reported to have a protective effect on reperfusion injury in various organs. We used anisodamine in a rabbit model with ischemia and reperfusion injury of hind limb muscles. We evaluated its effect on skeletal muscle cells, using transmission electron microscopy, and analyzed lipid peroxidation by measuring malondialdehyde and lactate dehydrogenase blood concentrations. We found that malondialdehyde and lactate dehydrogenase concentrations after 1 hour of reperfusion were lower in animals treated with anisodamine than in controls. Damage to membrane structures and myofilaments in muscle cells was less severe after anisodamine treatment. Our findings indicate that anisodamine protects skeletal muscles with ischemia and reperfusion injury.     

Free radical injury in skeletal muscle ischemia and reperfusion.

This study was made in a canine isolated gracilis muscle model to measure directly the free radicals, to predict the severity of ischemia and reperfusion injury of the skeletal muscle by measuring its surface pH (mspH), and to determine the effect of Coenzyme Q10 (CoQ10) in reducing the extent of muscle injury. Animals were divided into three groups: group A (control, n = 10), group B (untreated, n = 10), and group C (CoQ10 treated, n = 10). In both groups B and C, 5 hr ischemia followed by 40 min of reperfusion was made. Free radicals were measured directly by electron spin resonance spectrometer (ESR) and mspH was measured using a pH microprobe. Serum creatine phosphokinase (CPK) was estimated before ischemia, 5 and 30 min after reperfusion. The extent of muscle injury was evaluated morphologically by Evan's blue dye exclusion test. ESR intensity in group B was 0.55 +/- 0.19 and decreased to 0.30 +/- 0.04 in group C (P less than 0.01). Rate of recovery of mspH was higher in group C (7.16 +/- 0.06) compared to group B (6.88 +/- 0.11, P less than 0.01) and CPK in group C was less (847 +/- 381 IU/liter) than in group B (1356 +/- 519 IU/liter, P less than 0.05) after 30 min of reperfusion. In group C the morphological muscle injury was less (37.8 +/- 5%) compared to group B (56.7 +/- 3.6%, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

L-selectin and leukocyte function in skeletal muscle reperfusion injury.

HYPOTHESIS: Treatment with anti-L-selectin monoclonal antibody will reduce venular neutrophil-endothelial rolling (flux and velocity) and adhesion associated with ischemia reperfusion injury in rat skeletal muscle. DESIGN: Prospective, randomized experimental trials. SETTING: Basic science research laboratory. MATERIALS: Male Wistar rats weighing 109 +/- 5 g (mean +/- SEM). INTERVENTIONS: Gracilis pedicle muscle flaps were elevated and microcirculation was observed by intravital microscopy. Two groups were evaluated: (1) the control group, which received 4 hours of global ischemia, and (2) the experimental group, which received 4 hours of global ischemia, plus treatment with anti-L-selectin monoclonal antibody 30 minutes before reperfusion. MAIN OUTCOME MEASURES: The number of rolling and adherent leukocytes in postcapillary venules were counted in the 2 groups at baseline and at 1 through 5, 10, 15, 20, 30, 45, and 60 minutes of reperfusion. RESULTS: Treatment with the monoclonal antibody to L-selectin significantly reduced the number of rolling leukocytes (flux) at 2 through 5, 20, 30, 45, and 60 minutes of reperfusion compared with controls (P<.05). Use of the monoclonal antibody significantly reduced the number of adherent neutrophils at 5, 10, 15, 20, 30, 45, and 60 minutes of reperfusion (P<.05). There was no significant difference in leukocyte velocity. CONCLUSION: L-Selectin plays a significant role in leukocyte rolling and adherence to venular endothelium in rat skeletal muscle ischemia reperfusion injury.     

Ischemia/reperfusion injury in skeletal muscle

Ischemia reperfusion injury to skeletal muscle may be explained by a cascade of cellular and systemic events initiated by an ischemic period followed by reperfusion. During the period of ischemia there is a gradual reduction of intracellular energy stores. Adenosine triphosphate is gradually depleted despite the buffering effect of creatine phosphate which is present in large stores in muscles. As well, glycogen stores are depleted with resultant production of small amounts of energy and large accumulations of lactate. Upon reperfusion there is a reactive hyperemia, resulting in an overall increase in muscle blood flow, despite the fact that areas may continue to be underperfused. Results of this blood flow are mixed with the beneficial effects of removing metabolic by-products and supplying exogenous substrates and oxygen. However, this blood flow also causes harmful effects by washing out necessary precursors for adenine nucleotide resynthesis. Production of oxygen free radicals occurs with resultant membrane lipid peroxidation, and calcium influx occurs upon reoxygenation with resultant disruption of oxidative rephosphorylation in the mitochondria. The sequestration of white blood cells in the muscle due to up regulation of both neutrophil receptors and endothelial leukocyte adhesion molecules results in a prolongation of the reperfusion injury. This subsequently results in damage to remote organs, including lung, heart, and kidneys. The future for therapeutic interventions aimed at reducing this injury lie mostly in the ability to modulate the reperfusion effect.     

缺血后处理对减轻骨骼肌缺血再灌注损伤作用的实验研究

目的：研究缺血后处理对鼠骨骼肌缺血再灌注损伤的保护影响,组织中凋亡和胀亡的存在情况。方法将54只SD大鼠随机分为空白对照组、缺血再灌注组、缺血后处理组,持续缺血4 h,再灌注6 h,24 h,48 h。检测血浆乳酸脱氢酶（LDH）、肌酸磷酸激酶（CPK）活性、肌肉内丙二醛（MDA）含量及总超氧化物歧化酶（SOD）活性,进行组织学、免疫组化、超微结构分析。结果相比缺血再灌注组,后处理组在再灌注6 h时,只SOD活性明显升高,而再灌注24 h,48 h时,在MDA含量下降、SOD活性升高、W/D值下降、组织学改变范围及免疫组化阳性范围方面,均较缺血再灌注组有明显差异。结论再灌注开始时应用后处理对于缺血再灌注损伤有明显的保护作用,主要体现在再灌注的稍后期阶段（再灌注24 h,48 h）。缺血再灌注过程中,凋亡和胀亡是并存的。     

Ischaemic preconditioning of skeletal muscle. 1. Protection against the structural changes induced by ischaemia/reperfusion injury

Ischaemic preconditioning is a process by which exposure of a tissue to a short period of non-damaging ischaemic stress leads to resistance to the deleterious effects of a subsequent prolonged ischaemic stress. It has been extensively described in the heart, but few studies have examined the possibility that it can occur in skeletal muscle. We have used a rat model of ischaemia of one limb to examine this possibility. Exposure of the hind limb to a period of ischaemia of five minutes and reperfusion for five minutes significantly protected the tibialis anterior muscle against the structural damage induced by a subsequent period of limb ischaemia for four hours and reperfusion for one hour. This protection was evident on examination of the muscle by both light and electron microscopy. Longer or shorter times of prior ischaemia had no effect.     

非创伤性双下肢缺血预处理对兔肺缺血/再灌注损伤的保护作用

目的探讨非创伤性双下肢缺血预处理（N-WIP）对兔肺缺血／再灌注（I／R）损伤的保护作用。方法采用N—WIP及经典缺血预处理（C-IP）的动物模型，比较两种预处理方法对肺I／R损伤的保护效应。将40只兔随机分4组：对照组（C）、I／R组、C—IP组和N-WIP组，每组10只。对比观察各组血氧分压、肺湿／干重比、血清及肺组织中超氧化物歧化酶（SOD）和髓过氧化物酶（MPO）活性，丙二醛（MDA）含量。结果再灌注后I／R组血氧分压呈进行性下降，尤以再灌注30min内明显；N—WIP组和CIP组血氧分压、SOD活性均优于I／R组（P〈0．01），肺湿／干重比和MDA含量均低于I／R组（P〈0．05,P〈0．01），MPO活性较I／R组明显降低（P〈0、05）；N—WIP组和C-IP组与C组之间差异均无统计学意义（P〉0．05）。结论N-WIP与C-IP可通过减轻肺毛细血管的通透性，抑制缺血再灌注时中性粒细胞的浸润、激活，提高机体抗氧自由基的能力，同等强度的减轻I／R损伤，起到保护肺脏的作用。     

缺血预处理对肝硬化大鼠肝缺血再灌注损伤的保护作用

目的探讨缺血预处理(IP)对硬化肝脏缺血再灌注(I/R)损伤的保护作用.方法将采用四氯化碳复制的SD肝硬化大鼠随机按I/R前是否行IP分为预处理(IP组)和非预处理组(NIP组).比较两组大鼠肝I/R后肝功能、肝组织的抗氧化能力、能量代谢、NO含量与组织学变化及大鼠术后1周的存活率.结果与NIP组大鼠比较,IP组血清谷丙转氨酶,谷草转氨酶及乳酸脱氢酶活性显著降低(分别为P＜0.05,P＜0.001和P＜0.001);肝组织的超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)活力明显提高(分别为P＜0.05和P＜0.01);脂质过氧化产物丙二醛(MDA)含量降低(P＜0.05);ATP含量与能荷值(EC)增高(分别为P＜0.01和P＜0.05);NO合成显著增加(P＜0.01);光镜和电镜检查显示肝损伤的组织形态学表现明显减轻.大鼠术后1周存活率虽有提高,但两组差别无统计学意义(P=0.069).结论 IP对肝硬化大鼠的肝I/R损伤具有明显的保护作用.     

Ischemic preconditioning of skeletal muscle improves tissue oxygenation during reperfusion

Ischemic preconditioning (IPC) renders tissue resistant to the deleterious effects of prolonged ischemia and reperfusion by prior exposure to brief, repeated periods of vascular occlusion. Although the mechanism by which IPC exerts its effect is unclear, it likely mediates an attenuation in capillary no-reflow. Tissue oximetry provides a potential technique to assess microvascular flow during ischemia/reperfusion and to measure the effect of IPC on muscle tissue oxygenation. The authors aimed to (a) establish that tissue oximetry is a sensitive method to assess the "no-reflow" phenomenon in skeletal muscle; and (b) to test the hypothesis that IPC would increase tissue oxygenation during reperfusion. In Group 1 (n = 5), the rabbit rectus femoris muscle was subjected to 2-hr ischemia. In Group 2 (n = 5), the muscle was subjected to 3.5-hr ischemia. In Group 3 (n = 6) the muscle was subjected to 3.5-hr ischemia preceded by three cycles of 10 min of pedicle occlusion and 10 min of reperfusion. Muscle oxygen tension was continuously monitored during the ischemic interval and for 6 hr of reperfusion. It was found that muscle oxygen tension in the flap at 5, 10, 30, 60, and 360 min after reperfusion was significantly decreased after 3.5-hr ischemia, compared with 2-hr ischemia (p < 0.05). Muscle oxygen tension at 30 and 60 min after reperfusion was significantly improved in the preconditioned group (p < 0.05). The results suggest that tissue oximetry is a sensitive method to assess tissue perfusion in reperfused skeletal muscle. Ischemic preconditioning improves tissue oxygenation during reperfusion following prolonged ischemia, which likely reflects an attenuation in capillary no-reflow.