Remote Postconditioning may Attenuate Ischaemia–Reperfusion Injury in the Murine Hindlimb Through Adenosine Receptor Activation

ObjectiveThis study aimed to determine the effect and mechanisms of remote postconditioning (RPC) upon ischaemia–reperfusion injury (IRI) in the ischaemic mouse hindlimb.DesignRPC is the brief application of ischaemia to remote organs immediately before reperfusion of an ischaemic target organ, and it is a novel approach to IRI attenuation.Materials and methodsRight hindlimb ischaemia was induced in mice using a rubber tourniquet, the release of which initiated reperfusion. We established RPC by 5 min of ischaemia followed by 5 min of reperfusion in the left hindlimb immediately before right hindlimb reperfusion. The wet/dry ratio of skeletal muscle (degree of tissue oedema), myeloperoxidase (MPO) activity (accumulation of neutrophils), and nitroblue tetrazolium reduction (tissue necrosis) were evaluated. We also intra-peritoneally injected 8-sulphophenyltheophylline (SPT), an adenosine receptor inhibitor, in RPC mice.ResultsWet/dry ratio, MPO activity and tissue necrosis were significantly lower in the RPC group than in the control group, and injection of SPT impaired the protective effect of RPC.ConclusionsOur results show that RPC attenuated IRI in murine hindlimb ischaemia, possibly through endogenous adenosine receptor activation, and that RPC might serve as a promising therapeutic option for treating serious limb ischaemia.     

Statins inhibit neutrophil infiltration in skeletal muscle reperfusion injury

BACKGROUND: Neutrophil infiltration is a major determinant of ischemia-reperfusion injury (IRI). Statins improve endothelial function by elevating nitric oxide synthase activity and inhibiting adhesion molecule expression and may, therefore, inhibit IRI-induced neutrophil extravasation. Although statins are protective against myocardial IRI and stroke, a role for statins in ameliorating skeletal muscle IRI has not yet been confirmed. This study, therefore, addressed the hypothesis that simvastatin would attenuate the severity of tissue damage during skeletal muscle IRI. METHODS: Rats were administered simvastatin for 6 d before 4 h hind limb ischemia and 24 h reperfusion. Neutrophil infiltration was assessed using myeloperoxidase (MPO) assays and tissue damage by quantitative immunohistochemical analysis of collagen IV. The effect of reducing nitric oxide levels on the severity of IRI was assessed by administering the NOS inhibitor, N-Imino-L-ornithine (L-NIO), before ischemia. RESULTS: Simvastatin significantly inhibited IRI-induced MPO activity but not collagen degradation in postischemic skeletal muscle. Inhibition of nitric oxide synthase by L-NIO markedly inhibited neutrophil infiltration and protected against IRI-induced collagen degradation. When both simvastatin and L-NIO were administered before IRI, the IRI-induced elevation in MPO activity was completely inhibited. However, paradoxically, simvastatin counteracted the protective effect of L-NIO against IRI-induced collagen IV degradation. CONCLUSIONS: The inhibition by simvastatin of IRI-induced neutrophil infiltration in skeletal muscle suggests that statins may be a useful therapy to attenuate the severity of IRI but their precise mechanisms of action remains to be determined. Nitric oxide also plays a cytotoxic, rather than protective, role in mediating IRI in this model.     

L-Arg与腹腔注射PPAF诱导的大鼠急性肺损伤的实验研究

目的建立腹腔注射穿孔性腹膜炎腹水(PPAF)诱导大鼠急性肺损伤(ALI)模型,探讨ALI的发生机理和L-精氨酸(L-Arg)的作用。方法 60只SD大鼠建立消化道穿孔性腹膜炎(PP)模型,收集PPAF;48只大鼠按随机数字表法分为NS组(n=16),PPAF组(n=16)和L-Arg组(n=16)。各组大鼠再按随机数字表法分为7 h和12 h 2个亚组。检测外周血WBC计数、血清NO及脂质过氧化物丙二醛(MDA)水平、肺组织病理损害评分、肺组织湿/干质量比、肺组织髓过氧化物酶(MPO)水平和肺细胞凋亡情况。结果 PPAF组各时间点血WBC计数、血清NO及MDA水平、肺组织MPO水平、肺组织病理损害评分、湿/干质量比和细胞凋亡率均高于NS组(P<0.01)。L-Arg组血清NO水平显著高于PPAF组(P<0.01),血清MDA水平、肺组织MPO水平、肺组织病理损害评分和湿/干质量比以及细胞凋亡率均显著低于PPAF组(P<0.05)。PPAF组和L-Arg组12 h血清NO水平、肺湿/干质量比和细胞凋亡率均显著高于7 h(P=0.000)。PPAF组和L-Arg组血清NO水平与血清MDA水平(r=-0.257,P=0.021)、肺组织MPO水平(r=-0.444,P=0.011)和肺细胞凋亡率(r=-0.351,P=0.010)呈负相关。各组血清MDA与肺细胞凋亡率呈正相关(r=0.969,P<0.001)。结论腹腔注射PPAF可诱导大鼠ALI,肺内氧化反应增强和细胞凋亡参与了ALI的发生,而L-Arg对ALI具有保护作用。     

Inosine attenuates tourniquet-induced skeletal muscle reperfusion injury

BACKGROUND: Adenosine attenuates skeletal muscle reperfusion injury, but its short half-life in vivo limits potential therapeutic benefits. The aim of this study was to ascertain whether inosine, a stable adenosine metabolite, modulates skeletal muscle reperfusion injury. MATERIALS AND METHODS: C57BL/6 mice were randomized (8-10 per group) to six groups: time controls; inosine (100 mg/kg) before anesthesia; 2 h of bilateral tourniquet hindlimb ischemia; I/R (2 h of bilateral tourniquet hindlimb ischemia, 3 h of reperfusion); inosine (100 mg/kg) before I/R; drug vehicle before I/R. Serum tumor necrosis factor (TNF)-alpha and macrophage inflammatory protein (MIP)-2 were measured before ischemia and at the end of reperfusion. Tissue edema was determined by wet/dry weight ratios. Tissue leucosequestration was assessed by the myeloperoxidase (MPO) content. RESULTS: At the end of reperfusion, inosine pretreatment resulted in lower MPO levels in muscle (P = 0.02) and lung (P = 0.0002) than saline pretreatment. Similarly, muscle (P = 0.04) and lung (P = 0.02) wet/dry ratios were significantly reduced with inosine but not with saline pretreatment. At the end of reperfusion, serum proinflammatory cytokine levels (TNF-alpha and MIP-2) were significantly reduced (P < 0.05) compared to preischemia levels following inosine pretreatment but not saline pretreatment. Ischemia alone did not alter any of the parameters assessed. CONCLUSIONS: These findings demonstrate that pretreatment with inosine attenuates the local and systemic proinflammatory responses associated with skeletal muscle reperfusion injury.     

Remote preconditioning improves hepatic oxygenation after ischaemia reperfusion injury

Hepatic ischaemia reperfusion injury (IRI) lowers hepatic oxygenation and induces tissue acidosis. Remote ischaemic preconditioning (RIPC) reduces hepatic IRI through increased hepatic blood flow but its effect on hepatic oxygenation and acidosis is not known. This study investigates these effects through near infrared spectroscopy (NIRS). Twenty-four NZ rabbits were grouped into four: sham, RIPC, IRI alone, RIPC + IRI. RIPC was induced through three cycles of 10 min ischaemia and reperfusion to the limb. Total hepatic ischaemia was produced by complete portal inflow occlusion for 25 min. Serum transaminases, bicarbonate and hepatic venous nitrite/nitrate (NO(x) ) levels were measured 2 h postreperfusion. Hepatic oxygenation was monitored with NIRS. At 2 h post reperfusion, IRI alone resulted in reduced mitochondrial oxygenation (CytOx CuA Redox), serum bicarbonate, hepatic venous NO(x) with an increase in serum transaminases and hepatic deoxyhaemoglobin levels. RIPC before IRI caused significant improvement in mitochondrial oxygenation (P = 0.01), increased serum bicarbonate (P = 0.02), hepatic venous NO(x) (P = 0.025) with a decrease in serum transaminases (P = 0.04) and hepatic deoxyhaemoglobin levels (P = 0.03). There was a positive correlation (P = 0.02) between hepatic venous NO(x) levels and mitochondrial oxygenation. RIPC before IRI improves hepatic mitochondrial oxygenation and reduces acidosis and currently undergoing clinical study.     

Simvastatin pretreatment reduces the severity of limb ischemia in an experimental diabetes model

OBJECTIVE: The purpose of this study was to examine the effects of simvastatin pretreatment in the setting of acute limb ischemia-reperfusion injury in an experimental diabetes model that is associated with a high risk for limb loss. METHODS: Adult male Sprague-Dawley rats were randomized into two groups. Diabetes was induced in the first group by intravenous streptozotocin injection. The second group served as the nondiabetic group. Eight weeks after the streptozotocin injection, half of the rats in the diabetic and the nondiabetic groups were further randomized to receive either intraperitoneal simvastatin (1 mg/kg per day) or saline treatment for 6 weeks. Bilateral hind-limb ischemia was induced for 4 hours by the tourniquet method. After 24 hours of reperfusion, tissue samples were collected from the gastrocnemius and anterior tibial muscles bilaterally for measurement of muscle edema, percentage of necrosis, and malondialdehyde (MDA), glutathione, and myeloperoxidase (MPO) levels. RESULTS: Ischemic injury was more prominent in diabetic animals. The diabetic animals with limb ischemia exhibited a 7% increase in tissue edema, a 47% increase in muscle necrosis and MPO level, and a 15% reduction in glutathione levels compared with the nondiabetic animals (P < .05). Simvastatin treatment with 1 mg/kg for 6 weeks reduced the ischemic injury. Simvastatin pretreatment led to a 71% reduction in muscle necrosis in diabetic animals (P < .001). The protective effects of simvastatin pretreatment also correlated with a 23% improvement in tissue edema, a 75% reduction in tissue myeloperoxidase content, and a 71% increase in glutathione levels in diabetic animals (P < .01). Furthermore, skeletal muscle injury, characterized by tissue edema and leucosequestration, was significantly less severe with simvastatin pretreatment compared with the nondiabetic animals (P < .01). CONCLUSION: Simvastatin pretreatment reduced limb ischemia-reperfusion injury in diabetic and nondiabetic animals. We conclude that simvastatin pretreatment may be a potential therapeutic intervention for skeletal muscle ischemia-reperfusion injury in the clinical setting.     

Skeletal Muscle Ischaemia-reperfusion Injury: Further Characterisation of a Rodent Model

BACKGROUND: Postischaemic damage in skeletal muscle may be reflected in changes to microvascular blood flow, vascular permeability, and subsequent tissue viability. Previous preclinical studies have not addressed all these parameters, and have not used periods of ischaemia and reperfusion relevant to the clinical setting. This study aimed to develop an animal model hindlimb ischaemia-reperfusion to simulate acute lower limb ischaemia. METHODS: A rodent model of hindlimb tourniquet-induced ischaemia-reperfusion was employed. Gastrocnemius muscle blood flow (GMBF; radio-labelled microspheres), oedema (GMO; using a wet:dry ratio method) and viability (GMV; histochemistry and computerised planimetry) were quantified. RESULTS: 6 h ischaemia per seresulted in neither muscle oedema nor loss of viability, but these changes were apparent following 4 h reperfusion. Early reperfusion at 10 min demonstrated low reflow, with GMBF improving at 120 min before declining sharply at 240 min. CONCLUSION: Prolonged hindlimb ischaemia followed by reperfusion in this rodent model caused significant reductions in gastrocnemius muscle blood flow, associated with muscle oedema and necrosis. These three parameters have not been previously reported together in the same model. This reproducible model could be used in the evaluation of potential therapeutic intervention strategies aimed at ameliorating skeletal muscle reperfusion injury.     

Remote ischaemic preconditioning of the hind limb reduces experimental liver warm ischaemia-reperfusion injury

BACKGROUND: Direct ischaemic preconditioning of the liver reduces ischaemia-reperfusion injury (IRI). Remote ischaemic preconditioning (RIPC) of a limb has been shown to reduce IRI to the heart. This study determined the effect of brief remote ischaemia to the limb in reducing early liver warm IRI. METHODS: Twenty-eight male rabbits were allocated to four groups: sham operated, RIPC alone, IRI alone, and RIPC plus IRI. RIPC was induced in the leg with a tourniquet, before liver IRI, by three alternate cycles of 10 min ischaemia followed by 10 min reperfusion. Liver IRI was produced by total inflow occlusion for 25 min. Markers of liver injury and systemic and hepatic haemodynamics were measured for 2 h after reperfusion. RESULTS: At 2 h, IRI alone was associated with increased serum levels of aminotransferases, and reduced mean arterial blood pressure, hepatic blood flow and peripheral oxygen saturation. There was significant improvement in these variables in animals that had RIPC before liver IRI, and hepatic venous nitrate/nitrite levels were also significantly higher. CONCLUSION: In this experimental model RIPC appeared to reduce liver IRI.     

Oral vitamin C attenuates acute ischaemia-reperfusion injury in skeletal muscle.

Ischaemia-reperfusion injury (IRI) is caused by endothelial and subendothelial damage by neutrophil-derived oxidants. Vitamin C is an antioxidant which attenuates endothelial injury after IRI. Our aim was to evaluate the effect of oral vitamin C in the prevention of IRI in skeletal muscle. We used a model of cross-clamping (3 hours) and reperfusion (1 hour) of the cremaster muscle in rats. Muscle function was assessed electrophysiologically by electrical field stimulation. Infiltration by neutrophils was determined by the activity of tissue myeloperoxidase (MPO) and tissue oedema by the wet-to-dry ratio. Neutrophil respiratory burst activity was measured in control animals and groups pretreated with vitamin C. IRI significantly decreased muscle function and increased muscle neutrophil MPO activity and muscle oedema. Pretreatment with vitamin C preserved muscle function and reduced tissue oedema and neutrophil infiltration. Neutrophil respiratory burst activity was reduced in the group treated with vitamin C compared with the control group. We conclude that pretreatment with oral vitamin C protects against acute muscle IRI, possibly by attenuating neutrophil respiratory burst activity.     

Antithrombin III pretreatment reduces neutrophil recruitment into the lung and skeletal muscle tissues in the rat model of bilateral lower limb ischemia and reperfusion: a pilot study

BACKGROUND: Anti-inflammatory action of Antithrombin III (AT III) is still not well understood in ischemia/reperfusion (I/R) injury. In the present study, we aimed to investigate the anti-inflammatory action of AT III on remote lung and local skeletal muscle tissue injury in a rat model of bilateral lower limb I/R model. METHODS: Bilateral lower limb ischemia and reperfusion were produced by means of tourniquets occlusions and releases, respectively. Three groups of rats were used in this controlled study: sham group (sham, n=3) underwent 5 h of anesthesia only; control group (I/R, n=7) underwent 3 h of bilateral lower limb ischemia followed by 2 h of reperfusion; and AT III pretreated group (I/R-AT III, n=6) underwent the same procedure as the control group, but also received i.v. 250 U kg-1 AT III 30 min before ischemia induction under midazolam and fentanyl anesthesia. MEASUREMENTS AND RESULTS: Lung and muscle tissue accumulation of polymorphonuclear leukocytes (PMN) were assessed by measuring tissue myeloperoxidase (MPO) activity. Histopathological changes in tissues were assessed by PMN counts in the lung, and muscle tissues and by histological lung injury score. Plasma 6-keto prostaglandin F(1alpha) and tumor necrosis factor alpha levels were measured by an enzyme immunoassay technique. Myeloperoxidase activity could not be detected in the muscle tissues of all groups. The lung and muscle tissue PMN counts in the I/R group were significantly higher compared with the I/R-AT III group (P<0.05). CONCLUSIONS: Data from the present study provides some evidence that AT III pretreatment attenuates remote lung and local skeletal muscle tissue injury caused by lower limb I/R.     

Pravastatin attenuates tourniquet-induced skeletal muscle ischemia reperfusion injury

Background Revascularization of a limb following prolonged ischemia results in substantial skeletal muscle injury. Statins play a well-understood role in the treatment of hypercholesterolemia but are also known to have anti-inflammatory properties. The purpose of this study was to examine the effects of pravastatin pre-treatment in the setting of skeletal muscle ischemia reperfusion injury (IRI).

Methods Adult male Sprague Dawley rats (n = 27) were randomized into 3 groups: control group, I/R group, IR group pre-treated with pravastatin. Bilateral hind-limb ischemia was induced by rubber band application proximal to the level of the greater trochanters for 2.5 h. Treatment groups received normal saline in equal volumes prior to tourniquet release. Following 12 h reperfusion, the tibialis anterior muscle was dissected and muscle function assessed electrophysiologically by electrical field stimulation. The animals were then killed and skeletal muscle harvested for evaluation.

Results We found that pre-treatment with pravastatin reduces the tissue oxidative damage and edema associated with skeletal muscle reperfusion injury. Skeletal muscle injury, measured by edema, leucose-questration and electrical properties were significantly lower with pravastatin pre-treatment compared to the non-treated group.

Interpretation We feel that pravastatin pre-treatment may be a potential therapeutic intervention for skeletal muscle ischemia reperfusion injury in the clinical setting. ▪     

Low-molecular-weight heparin calcium attenuates the tourniquet-induced ischemia-reperfusion injury in rats

Ischemia-reperfusion injury (IRI) is a common postoperative complication of the tourniquet used surgery; low-molecular-weight heparin calcium (LMWH) is frequently used postoperatively to prevent the formation of deep venous thrombosis. However, subcutaneous hemorrhage can usually be seen in patients who underwent lower limb surgery, especially in total knee arthroplasty, the influence of LMWH on IRI remains controversial. In this experiment, we designed an animal model to observe the influence of LMWH on the skeletal muscle injury induced by tourniquets. Sprague-Dawley (SD) rats underwent either 2 h of unilateral hindlimb ischemia or anesthesia alone, at different time points of reperfusion interval, animals received either 4mg/kg LMWH or normal saline subcutaneously twice a day. The levels of inflammatory markers in serum, the expression of apoptosis proteins, as well as histological examination of skeletal muscles, were detected at 48-h reperfusion. We found that the injury of skeletal muscle and the systemic inflammatory response was less severe in LMWH-treated animals, indicating that LMWH could attenuate the tourniquet-induced IRI. In conclusion, LMWH given postoperatively after limb surgery may be clinically beneficial.     

Ischemic preconditioning attenuates the lipid peroxidation and remote lung injury in the rat model of unilateral lower limb ischemia reperfusion

BACKGROUND: Ischemia and reperfusion of the skeletal muscle tissue may cause remote lung injury. We aimed to evaluate the protective effect of ischemic preconditioning (IP) on the lung during unilateral lower limb ischemia reperfusion (IR). METHODS: Four groups of rats were used in this study: (i) the sham group (sham, n = 6) served as time controls, they remained anesthetized for the whole duration of the study; (ii) the ischemia and reperfusion group (IR, n = 10) underwent 4 h of left lower limb ischemia followed by 2 h of reperfusion; (iii) the ischemic preconditioning group (IP, n = 10), the left lower limbs of rats were exposed to three cycles of IP (10 min of ischemia followed by 10 min of reperfusion); and (iv) the ischemic preconditioning plus ischemia reperfusion group (IP/IR, n = 10) underwent IP followed by IR as in the IP and IR groups. Plasma and tissue samples were taken at the end of the study period for determination of lung tissue myeloperoxidase activity (MPO) and polymorphonuclear leukocyte count (PMNL), histological lung injury score and plasma thiobarbituric acid reactive substances (TBARS) level. RESULTS: PMNL count and MPO activity in the lung tissue, and plasma TBARS level were higher in the IR group compared with other groups while there were no differences between the sham and the IP and between the sham and the IP/IR groups. Histological lung injury score was higher in the IR group than in the IP/IR and sham groups. The plasma TBARS level in the IP group was significantly lower than in the IP/IR group. CONCLUSION: IP pretreatment reduces lipid peroxidation and lung injury caused by lower limb IR.     

缺血预处理对肺缺血-再灌注损伤的保护作用及机制

目的　探讨缺血预处理 (IP)对肺缺血 -再灌注 (IR)损伤的保护作用和可能的机制。　方法　建立兔在体IR损伤模型 ,将 36只兔随机分为 IP组、IR组和对照组 ,每组 12只 ,观察各组肺湿 /干重比 ,检测各组肺组织超氧化物歧化酶 (SOD)活性、丙二醛 (MDA)含量及髓过氧化物酶 (MPO)活性 ,对支气管肺泡灌洗液 (BAL F)中白细胞进行分类计数 ,并检测各组肺通透性指数。　结果　 IP组与 IR组比较 ,肺湿 /干重比明显降低 (P<0 .0 1) ;肺组织中 SOD活性显著增高 ,MDA含量和 MPO活性明显降低 (P<0 .0 1) ;BAL F中中性粒细胞分类计数、肺通透性指数明显降低(P<0 .0 1)。IP组与对照组比较 ,上述指标差别无显著性意义 (P>0 .0 5 )。　结论　 IP可通过减轻 IR时肺组织中性粒细胞的浸润与激活 ,提高机体抗氧化自由基的能力 ,而减轻 IR引起的肺损伤。     

罗格列酮对大鼠急性胰腺炎肺损伤黏附分子表达的作用

目的 探讨过氧化物酶体增殖物激活受体-γ(PPAR-γ)激动剂罗格列酮(ROSI)对大鼠急性胰腺炎肺损伤(APALI)黏附分子的作用及其机制.方法 雄性Wistar大鼠54只,随机分为假手术组(SO组)、急性胰腺炎组(SAP组)和罗格列酮预处理组(ROSI组).胆胰管逆行注射5%牛磺胆酸钠制备急性胰腺炎模型.ROSI组造模前30 min经股静脉注射10%二甲基亚砜(DMSO)溶解的罗格列酮(6 mg/kg);SO组、SAP组则注射等量10%DMSO.术后3 h、6 h、12 h分批剖杀大鼠,每个时间点6只.检测血清淀粉酶(AMY)、肺组织髓过氧化物酶(MPO)、肺湿干比(W/D),取肺组织行病理学检查;逆转录聚合酶链反应(RT-PCR)检测肺组织细胞间黏附分子-1(ICAM-1)、P-选择素和E_选择素mRNA表达水平.结果 SAP组各时间点AMY、MPO、W/D和肺组织病理评分均较S0组升高(P<0.05);ROSI组上述指标较SAP组下降,AMY、MPO、W/D和病理评分在6 h、12 h差异有统计学意义(P<0.05).SAP组ICAM-1、P-选择素和E-选择素mRNA表达在12 h达高峰,均较SO组12 h升高(P<0.05),ROSI组上述指标mRNA表达在12 h点均较SAP组下降(P<0.05).结论 罗格列酮通过抑制肺组织IcAM-1、P-选择素和E-选择素的表达,减轻急性胰腺炎肺损伤程度.     

罗格列酮对大鼠急性胰腺炎肺损伤黏附分子表达的作用

目的 探讨过氧化物酶体增殖物激活受体-γ(PPAR-γ)激动剂罗格列酮(ROSI)对大鼠急性胰腺炎肺损伤(APALI)黏附分子的作用及其机制.方法 雄性Wistar大鼠54只,随机分为假手术组(SO组)、急性胰腺炎组(SAP组)和罗格列酮预处理组(ROSI组).胆胰管逆行注射5%牛磺胆酸钠制备急性胰腺炎模型.ROSI组造模前30 min经股静脉注射10%二甲基亚砜(DMSO)溶解的罗格列酮(6 mg/kg);SO组、SAP组则注射等量10%DMSO.术后3 h、6 h、12 h分批剖杀大鼠,每个时间点6只.检测血清淀粉酶(AMY)、肺组织髓过氧化物酶(MPO)、肺湿干比(W/D),取肺组织行病理学检查;逆转录聚合酶链反应(RT-PCR)检测肺组织细胞间黏附分子-1(ICAM-1)、P-选择素和E_选择素mRNA表达水平.结果 SAP组各时间点AMY、MPO、W/D和肺组织病理评分均较S0组升高(P<0.05);ROSI组上述指标较SAP组下降,AMY、MPO、W/D和病理评分在6 h、12 h差异有统计学意义(P<0.05).SAP组ICAM-1、P-选择素和E-选择素mRNA表达在12 h达高峰,均较SO组12 h升高(P<0.05),ROSI组上述指标mRNA表达在12 h点均较SAP组下降(P<0.05).结论 罗格列酮通过抑制肺组织IcAM-1、P-选择素和E-选择素的表达,减轻急性胰腺炎肺损伤程度.     

Pravastatin attenuates tourniquet-induced skeletal muscle ischemia reperfusion injury

Background?Revascularization of a limb following prolonged ischemia results in substantial skeletal muscle injury. Statins play a well-understood role in the treatment of hypercholesterolemia but are also known to have anti-inflammatory properties. The purpose of this study was to examine the effects of pravastatin pre-treatment in the setting of skeletal muscle ischemia reperfusion injury (IRI).

Methods?Adult male Sprague Dawley rats (n = 27) were randomized into 3 groups: control group, I/R group, IR group pre-treated with pravastatin. Bilateral hind-limb ischemia was induced by rubber band application proximal to the level of the greater trochanters for 2.5 h. Treatment groups received normal saline in equal volumes prior to tourniquet release. Following 12 h reperfusion, the tibialis anterior muscle was dissected and muscle function assessed electrophysiologically by electrical field stimulation. The animals were then killed and skeletal muscle harvested for evaluation.

Results?We found that pre-treatment with pravastatin reduces the tissue oxidative damage and edema associated with skeletal muscle reperfusion injury. Skeletal muscle injury, measured by edema, leucose-questration and electrical properties were significantly lower with pravastatin pre-treatment compared to the non-treated group.

Interpretation?We feel that pravastatin pre-treatment may be a potential therapeutic intervention for skeletal muscle ischemia reperfusion injury in the clinical setting.??     

前列地尔对兔肾缺血再灌注时细胞凋亡的保护作用

目的 观察前列地尔对兔肾缺血再灌注损伤时肾小管上皮细胞凋亡的保护作用.方法 建立兔肾缺血再灌注损伤动物模型,将实验兔随机分为3组:即对照组、缺血再灌注组和前列地尔组,每组10只.检测兔血清肌苷(Cr)、尿素氮(BUN)浓度及肾组织中丙二醛(MDA)、超氧化物歧化酶(SOD)和髓过氧化物酶(MPO)含量及肾组织中凋亡细胞.结果 与对照组比较,缺血再灌注组和前列地尔组在再灌注后Cr、BUN水平均大幅度上升(P＜0.05);但前列地尔组动物在再灌注60min后Cr水平(231.32±17.57)μmol/L明显低于缺血再灌注组(390.61±20.42)μmol/L(P＜0.05);肾小管上皮细胞bcl-2、bax、Caspase-3表达与对照组比较,缺血再灌注组明显增强(P＜0.05);前列地尔组与缺血再灌注组比较表达减弱,但仍强于对照组(P＜0.05).前列地尔组、缺血再灌注组与对照组比较凋亡细胞数增多,前列地尔组与缺血再灌注组比较凋亡细胞数减少.MDA、SOD与MPO的活性与对照组比较,缺血再灌注组与前列地尔组明显增强(P＜0.05);前列地尔组与缺血再灌注组比较,该两者活性明显减弱(P＜0.05).结论 前列地尔在肾脏缺血再灌注损伤时能有效的保护肾功能其作用机制可能是通过减少细胞脂质过氧化,从而降低bcl-2、bax、Caspase-3等凋亡基因的表达.

Abstract：

Objective To study the alprostadil effects of alprostadil on apoptosis by renal ischemia-reperfusion injury (IR[) in rabbits. Methods The rabbit IRI models were made, and randourly divided into three groups: control group, IR[group and prostavasin intervention group. The creatinine (Ct) and blood urea nitrogen (BUN) were determined. Malondialdehyde ( MDA), superoxide dismutase (SOD),myeloperoxidase ( MPO), bcl-2, bax, Caspase-3 and apoptosis were assayed at 60 min after reperfusion.Results The Cr and BUN levels in plasma in IRI group and Prostavasin intervention group were increased obviously after reperfusion. The Cr levels at 60 min after repeffusion in alprostadil intervention group (231.32 + 17. 57 ) μmol/L were significantly lower than in IRI group ( 390. 61 ± 20. 42 ) μ mol/L, ( P ＜0. 05 ). The levels of bcl-2, bax, Caspase-3 in the renal tissue in IRI group were significantly higher than in control group ( P ＜ 0. 05 ), and those in alprostadil intervention group were lower than in IRI group, but markedly higher than in control group (P ＜ 0. 05 ). The number of apoptotic cells in alprostadil intervention group and IRI group was increased as compared with control group, and that in alprostadil intervention group was reduced as compared with IRI group. The contents of MDA, SOD and MPO in renal tissue of IRI group and Prostavasin intervention group were significantly higher than in control group ( P ＜ 0. 05 ), and those in IRI group were significantly lower than in alprostadil intervention group (P ＜0. 05 ). Conclusion Alprostadil could be used to protect renal ischemia-reperfusion injury probably by decreasing oxygen free radicals generation, inhibiting neutrophils aggregating and activating in the renal tissues, thereby inhibiting the expression of bcl-2, bax, Caspase-3.     

缺血预适应对肢体缺血再灌注大鼠肝脏的保护效应

目的 观察缺血预适应(IPC)对大鼠肢体缺血再灌注后肝脏损伤的影响,以进一步探讨IPC对肢体缺血再灌注后肝脏功能的保护作用。方法 实验用雄性Wistar大鼠18只,随机分为对照(Control)组,缺血再灌注(IR)组和缺血预处理(IPC IR)组．每组6只。分别测定血浆谷草转氧酶(ALT)、谷丙转氨酶(AST)、乳酸脱氢酶(LDH)．血浆和肝组织超氧化物歧化酶(SOD)、黄嘌呤氧化酶(XOD)、丙二醛(MDA)的含量变化及肝组织的湿/干重比值(W／D)、髓过氧化物酶含量(MPO)及DNA双链百分率(Ratio of DNA Chain％)。结果 发现IPC减轻了肢体IR后引起的ALT、AST、LDH、XOD、MDA、MPO、W／D含量的升高．并且增加了SOD以及肝组织中DNA双链百分率。结论 IPC对肢体IR继发的肝脏功能损伤具有保护作用。     

罗格列酮对大鼠急性胰腺炎肺损伤黏附分子表达的作用

目的 探讨过氧化物酶体增殖物激活受体-γ(PPAR-γ)激动剂罗格列酮(ROSI)对大鼠急性胰腺炎肺损伤(APALI)黏附分子的作用及其机制.方法 雄性Wistar大鼠54只,随机分为假手术组(SO组)、急性胰腺炎组(SAP组)和罗格列酮预处理组(ROSI组).胆胰管逆行注射5%牛磺胆酸钠制备急性胰腺炎模型.ROSI组造模前30 min经股静脉注射10%二甲基亚砜(DMSO)溶解的罗格列酮(6 mg/kg);SO组、SAP组则注射等量10%DMSO.术后3 h、6 h、12 h分批剖杀大鼠,每个时间点6只.检测血清淀粉酶(AMY)、肺组织髓过氧化物酶(MPO)、肺湿干比(W/D),取肺组织行病理学检查;逆转录聚合酶链反应(RT-PCR)检测肺组织细胞间黏附分子-1(ICAM-1)、P-选择素和E_选择素mRNA表达水平.结果 SAP组各时间点AMY、MPO、W/D和肺组织病理评分均较S0组升高(P<0.05);ROSI组上述指标较SAP组下降,AMY、MPO、W/D和病理评分在6 h、12 h差异有统计学意义(P<0.05).SAP组ICAM-1、P-选择素和E-选择素mRNA表达在12 h达高峰,均较SO组12 h升高(P<0.05),ROSI组上述指标mRNA表达在12 h点均较SAP组下降(P<0.05).结论 罗格列酮通过抑制肺组织IcAM-1、P-选择素和E-选择素的表达,减轻急性胰腺炎肺损伤程度.