Cardioprotective Effects of Alpha-Lipoic Acid on Myocardial Reperfusion Injury: Suppression of Reactive Oxygen Species Generation and Activation of Mitogen-Activated Protein Kinase

오석규,윤경호,유남진,김남호,김민선,박병림,정진원 대한심장학회 2009 Korean Circulation Journal Vol.39 No.9

Background and Objectives: Reactive oxygen species (ROS) and mitogen-activated protein (MAP) kinase play an important role in the development of myocardial reperfusion injury. In this study, we examined whether treatment with alpha-lipoic acid (ALA) before reperfusion could prevent myocardial reperfusion injury in vivo. Materials and Methods: Sprague-Dawley rats were subjected to a 45-minute left anterior descending coronary artery ligation followed by 45- or 10-minute reperfusion. ALA was administered 10 minutes prior to reperfusion. The infarct size ratio of the infarct area to the ischemic area at risk, was measured based on 10, 25, 50, and 100 mg/kg of ALA, with propidium iodide (PI) fluorescence. Apoptosis was evaluated by TdT-mediated dUDP nick end labeling (TUNEL) staining. The generation of intracellular ROS was evaluated using the fluorogenic probe, dichlorodihydrofluorescein diacetate (CM-H2DCFDA). Western blot analysis was performed for MAP kinase (pERK 1/2 and pJNK 1/2) activity. Results: The infarct size, according to ALA dose, was significantly suppressed 29.1% with ALA 25 mg/kg (p<0.0001), 41.5% with 50 mg/kg (p<0.05), and 41.4% with 100 mg/kg (p<0.05) compared to the controls (54.3%). However, the results were not significantly different with 47.2% of the ALA 10 mg/kg (p=0.192). A few apoptotic nucleoli were detected in the ALA 25 mg/kg group, but were frequently detected in the control group. The ROS generation was significantly suppressed (p<0.0001), the activity of pERK 1/2 was significantly increased (p<0.05) and the activity of pJNK 1/2 was significantly decreased (p<0.05) in the ALA 25 mg/kg group compared to the controls. Conclusion: The results of this study suggested that adequate doses of ALA before reperfusion was effective for the prevention of myocardial reperfusion injury in vivo. This cardioprotective activity of ALA might be associated with an anti-apoptotic effect of ALA via suppression of ROS generation, increase of pERK 1/2 and decrease of pJNK 1/2 activity. Background and Objectives: Reactive oxygen species (ROS) and mitogen-activated protein (MAP) kinase play an important role in the development of myocardial reperfusion injury. In this study, we examined whether treatment with alpha-lipoic acid (ALA) before reperfusion could prevent myocardial reperfusion injury in vivo. Materials and Methods: Sprague-Dawley rats were subjected to a 45-minute left anterior descending coronary artery ligation followed by 45- or 10-minute reperfusion. ALA was administered 10 minutes prior to reperfusion. The infarct size ratio of the infarct area to the ischemic area at risk, was measured based on 10, 25, 50, and 100 mg/kg of ALA, with propidium iodide (PI) fluorescence. Apoptosis was evaluated by TdT-mediated dUDP nick end labeling (TUNEL) staining. The generation of intracellular ROS was evaluated using the fluorogenic probe, dichlorodihydrofluorescein diacetate (CM-H2DCFDA). Western blot analysis was performed for MAP kinase (pERK 1/2 and pJNK 1/2) activity. Results: The infarct size, according to ALA dose, was significantly suppressed 29.1% with ALA 25 mg/kg (p<0.0001), 41.5% with 50 mg/kg (p<0.05), and 41.4% with 100 mg/kg (p<0.05) compared to the controls (54.3%). However, the results were not significantly different with 47.2% of the ALA 10 mg/kg (p=0.192). A few apoptotic nucleoli were detected in the ALA 25 mg/kg group, but were frequently detected in the control group. The ROS generation was significantly suppressed (p<0.0001), the activity of pERK 1/2 was significantly increased (p<0.05) and the activity of pJNK 1/2 was significantly decreased (p<0.05) in the ALA 25 mg/kg group compared to the controls. Conclusion: The results of this study suggested that adequate doses of ALA before reperfusion was effective for the prevention of myocardial reperfusion injury in vivo. This cardioprotective activity of ALA might be associated with an anti-apoptotic effect of ALA via suppression of ROS generation, increase of pERK 1/2 and decrease of pJNK 1/2 activity.

백서 대퇴직근의 재관류 손상에 있어 Mn-Superoxide dismutase의 면역 활성 및 Allopurinol 전처치가 미치는 영향

황치원,최덕호,조근렬,백두진 大韓成形外科學會 1999 Archives of Plastic Surgery Vol.26 No.2

It has been well known that ischemia reperfusion injury to skeletal muscle following an acute arterial occlusion causes significant morbidity and mortality. There are many causes of reperfusion injury, but the oxygen free radicals have a significant role. During ischemia the ATP is catalyzed to hypoxanthine anaerobically and hypoxanthine dehydrogenase is converted to xanthine oxidase under the presence of O₂ resulting in the production of cytotoxic oxygen free radical, which are harmful to muscle. The reactivity of superoxide dismutase(SOD), one of the major antioxidant enzymes, is increased against the formation of the superoxide radical during reperfusion. SOD metabolyzes the superoxide radical to H₂O₂ and O₂.The severity of ischemic damage deports on the duration of muscle ischemia. The reversible changes in the muscle occur afar 2 hours of ischemia and recover within 24 hours after reperfusion. After 6 hours ischemia, irreversible damage occurs and causes necrosis of muscle. The authors performed the resent study to investigate the changes of Mn-SOD and the effects of allopurinol, the inhibitor of xanthine oxidase, by measuring the immunoreactivitiy of the ischemic reperfused rectus femoris muscle of rats after 2 hours and 6 hours ischemia and timely reperfusion. A total of 176 healthy spraque-Dawley rats weighing from 200 gm to 250 gm were used. Under urthane(3.0 gm/kg.,IP) anesthesia, a lower-abdominal incision was made and the left common iliac artery was ligated by using a vascular clamp for 2 hours and 6 hours. Rectus femoris muscle was obtained at 0 hour, 1 hour, 2 hours, 24 hours, and 48 hours after removal of the vascular clamp. The specimens were sectioned in 14㎛ thickness with a cryostat. The immunoreactivities of Mn-SOD were observed by using Mn-SOD antibodies. The result were as follows. 1. The immunoreactivies of Mn-SOD around sarcolemma were stronger than those on the sarcoplasm. 2. The immunoreactivities of Mn-S0D after 2 hours of ischemia increased to moderate or weak reactivities at 1 hour and 2 hours of reperfusion and returned to week or trace reactivities at 24 hours and 48 hours of reperfusion 3. The pretreatment of allopurinol decreased the immunoreactivies of Mn-SOD during reperfusion. The pattern of changes of SOD immunoreactivies were similar, but the range of changes significantly decreased. 4. The immunoreactivies of Mn-SOD after 6 hours of ischemia increased after 6 hours of ischemia increased after reperfusion and showed peak at 2 hours and 24 hours specimen. After 48 hours in the reperfused group, the reactivities slightly decreased. 5. After 6 hours in the ischemia-reperfused group, the pretreatment of allopurinol decreased the immunoreactivies of Mn-SOD during reperfusion, but the effects were weak. These results suggest that the immunoreactivities of the 6 hours ischemia reperfused group were higher than those of 2-hours ischemia reperfused group in the rectus femoris muscle of rats and that allopurinol pretreatment can be credited with decreasing ischemia reperfusion injury within a reversible period.

Gradual Reperfusion Lowers the Incidence of Reperfusion-Induced Ventricular Fibrillation in a Cat Model of Regional Ischemia

You-Ho Kim,Heung Sik Na,Hyun Jung Nam,Gyu-Young Hur,Seung-Whan Lee,Sung Sook Park,Seung Kil Hong 대한생리학회-대한약리학회 1999 The Korean Journal of Physiology & Pharmacology Vol.3 No.1

<P> Blood flow restoration to ischemic zone of the heart is essential to salvage of ischemic tissue. However, there is a large body of evidence documenting that the reperfusion can induce reperfusion injury like reperfusion-induced malignant arrhythmias. In the present study, employing a cat model of regional cardiac ischemia, we examined if reperfusion rendered in a gradual fashion could lower the incidence of reperfusion-induced ventricular fibrillation (VF), which usually precipitated within a few to several tens of seconds after abrupt reperfusion. The experiments were conducted with male mongrel cats (n=46, 2.5-5 kg). The animals in the control and 30 MIN groups were subjected to an episode of 20- and 30-min left anterior descending coronary artery occlusion, respectively, followed by abrupt reperfusion. The animals in 5 G and 10 G groups received gradual reperfusion over a 5- and 10-min period, respectively, following a 20-min occlusion. The proportion of animals that exhibited VF during the reperfusion phase was 11/15 in the control, 7/10 in the 30 MIN, 5/10 in the 5 G and 2/11 in the 10 G groups. The incidence of VF in the 10 G group was significantly lower than that in the control or 30 MIN group subjected to abrupt reperfusion. These results suggest that the gradual reperfusion is a useful procedure against reperfusion-induced VF.

17β-Estradiol의 심근 보호작용에 대한 연구 ; 재관류 부정맥을 유발한 동물실험

홍정석,김원,조규종,이미우,장성은,임경수 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Background: Although reperfusion certainly prevents tissue ischemia from possible cardiac death, several lines of evidence suggest that reperfusion may paradoxically aggravate the frequency of serious reperfusion-induced lethal arrhythmias. It has been reported that acute administration of estrogen at physiological concentrations reduced with myocardial ischemic injury in women with coronary heart disease. In studies with canines, acute administration by either the intra-muscular or the intra-coronary route similarly prevented ischemia and reperfusion dysrhythmias and also reduced the infarct size because the estrogen increased the distal coronary perfusion pressure, scavenged free radicals and had other effects during both ischemia and reperfusion. However, the canine heart is notoriously well collateralized. 17β-estradiol induces very little vasorelaxation in cat coronary rings, suggesting that increased ischemic myocardial blood flow dose not contribute to the protective effect. In the present study, employing a cat model of regional cardiac ischemia, we examined whether reperfusion rendered after acute administration of 17β-estradiol could lower the incidence of reperfusion-induced lethal arrhythmia and the death rate. Method: Adult mongrel male cats(n=31, 2.7∼4.5 kg) were anesthetized under positive-pressure artificial ventilation with room air. Electrocardiograms were recorded. The animals of the control group(n=15) were subjected to 20-minute left anterior descending coronary artery(LAD) occlusion followed by abrupt reperfusion. The animals in the experimental 17β-estradiol(2 or 20 ㎍/kg) group were subjected to ischemia/reperfusion insult following drug treatment: 17 β -estradiol was applied intravenously within the 60 seconds just before LAD ligation followed by abrupt reperfusion. The Fisher's exact test was used to compare the data from different animal groups(p<0.05). Results: The number of arrhythmias(ventricular premature beat, ventricular tachycardia and ventricular fibrillation) emerging during the reperfusion phase were not statistically different from that in the control group. The death rate in the 17β-estradiol 20㎍/kg group was lower from that in the control group(P value = 0.039). Conclusion: Acute administration of 17β -estradiol at a supraphysiological concentration might produce cardioprotective effects, not by modificating the coronary blood flow into the threatened myocardial region, but by other mechanisms that directly or indirectly increase the intrinsic myocardial ischemic tolerance in the cat during the reperfusion phase.

흰쥐 간장에서 허혈/재관류로 인한 분비 기능 및 약물대사 변동

조준필,정윤석 대한응급의학회 1997 대한응급의학회지 Vol.8 No.4

Ischemia causes tissue necrosis in a wide variety of pathologic conditions. Permanent deprivation of blood flow is lethal to any tissue and the prudent therapy for ischemia unquestionably is reperfusion. While reperfusion is necessary to reverse the progression towards ischemic death, reperfusion is also thought to be accompanied by its own component of injury. Oxygen free radicals, formed during ischemia/reperfusion, have been proposed as one of main causes of reperfusion injury. Free radical attacks on biological membrane, such as mitochondria and endoplasmic reticulum, and can lead to the oxidative destruction of the polyunsaturated fatty acids of the membranes through lipid peroxidation. However, direct association between microsomal lipid peroxidation in vivo after ischemia/reperfusion and changes in secretory function and drug metabolism on the liver have not been established. Therefore, present study was performed to evaluate the hepatic secretory function and the hepatic microsomal drug metabolizing enzyme activity after ischemia/reperfusion preparation in rat liver. Further, the effect of oxygen free radical scavengers was investigated. The animals were divided into sham operation group and ischemia/reperfusion group. The ischemia/reperfusion group was subdivided into non-treated control and treated(with superoxide dismutase, allopurinol, α- tocopherol, deferoxamine)groups. Hepatic ischemia was produced by clamping the left branches of portal vein and hepatic artery, resulting in complete ischemia to the median and left lobes while the right lobes remained perfused to prevent intestinal congestion. Reperfusion was permitted by declamping after 1 hour. After 1 or 5 hours of reperfusion, bile was collected, blood was obtained from abdominal aorta, and liver microsomes were isolated. The results are as follows. Serum aminotransferase was increased 15-20 times by ischemia/reperfusion. However, this increase was attenuated by free radical scavengers, especially 5 hours of reperfusion. The wet weight-to9 dry weight ratio of the liver was significantly increased by ischemia/reperfusion. α- tocopherol pretreatment minimized the increase of ratio. Malondialdehyde level in the liver microsomal fraction was significantly increased after ischemia/reperfusion, but this increase was attenuated by scavenger pretreatment, especially α- tocopherol. Bile flow and cholate output, but not the bilirubin output, were decreased after ischemia/reperfusion. The free radical scavenger pretreatment restored the secretion significantly. Cytochrome P-450 content was significantly decreased after ischemia/reperfusion and ameliorated by free radical scavenger pretreatment. NADPH cytochrome p-450 reductase activity and aminopyrine N-demethylase activity were also decreased and improved by free radical scavengers pretreatment. These results indicate that ischemia/reperfusion deteriorates the hepatic secretory function as well as hepatic microsomal drug metabolizing enzyme activity, and the oxygen free radical scavengers the functional changes of the liver induced by ischemia/reperfusion.

쥐의 국소 허혈 재관류 모델에서 허혈 전후에 투여한 Propofol의 심근 보호 효과

신일우,임병원,정영석,이효민,손주태,이헌근,정영균 대한마취통증의학회 2008 Korean Journal of Anesthesiology Vol.53 No.3

Background: It is known that propofol protects myocardium against a global ischemia-reperfusion injury in the isolated rat heart model. The aim of this study was to investigate whether propofol, at a clinically relevant concentration infused during the peri-ischemic period, also provides a protective effect against a regional myocardial ischemia-reperfusion injury in vivo. Methods: Rats were subjected to 25 minutes of coronary artery occlusion followed by 24 hours of reperfusion. Propofol or intralipid was administrated during 35 minutes starting 5 minutes before the onset of ischemia until 5 minutes after the onset of reperfusion. A micromanometer catheter was advanced into the left ventricle and the hemodynamic function was evaluated. The infarct size was determined by triphenyltetrazolium staining after 24 hours of reperfusion. Results: Propofol administration during the peri-ischemic period demonstrated protective effects on hemodynamic function and infarct size reduction. In the control group, the peak rate of the ventricular pressure increase (+dP/dtmax)(P = 0.0001) and the peak rate of the intraventricular pressure decline (−dP/dtmax)(P = 0.0001) were significantly decreased compared to the sham group. In the propofol group, the +dP/dtmax (P = 0.003) and −dP/dtmax (P = 0.002) were significantly improved compared to the control group. The infarct size was 47.6% of the area at risks in the control group, and was reduced markedly by administration of propofol during the peri-ischemic period to 26.2% in the propofol group (P = 0.004). Conclusions: Propofol, at a clinically relevant concentration infused during the peri-ischemic period, have protective effect after regional myocardial ischemia-reperfusion injury in an in vivo rat heart model Background: It is known that propofol protects myocardium against a global ischemia-reperfusion injury in the isolated rat heart model. The aim of this study was to investigate whether propofol, at a clinically relevant concentration infused during the peri-ischemic period, also provides a protective effect against a regional myocardial ischemia-reperfusion injury in vivo. Methods: Rats were subjected to 25 minutes of coronary artery occlusion followed by 24 hours of reperfusion. Propofol or intralipid was administrated during 35 minutes starting 5 minutes before the onset of ischemia until 5 minutes after the onset of reperfusion. A micromanometer catheter was advanced into the left ventricle and the hemodynamic function was evaluated. The infarct size was determined by triphenyltetrazolium staining after 24 hours of reperfusion. Results: Propofol administration during the peri-ischemic period demonstrated protective effects on hemodynamic function and infarct size reduction. In the control group, the peak rate of the ventricular pressure increase (+dP/dtmax)(P = 0.0001) and the peak rate of the intraventricular pressure decline (−dP/dtmax)(P = 0.0001) were significantly decreased compared to the sham group. In the propofol group, the +dP/dtmax (P = 0.003) and −dP/dtmax (P = 0.002) were significantly improved compared to the control group. The infarct size was 47.6% of the area at risks in the control group, and was reduced markedly by administration of propofol during the peri-ischemic period to 26.2% in the propofol group (P = 0.004). Conclusions: Propofol, at a clinically relevant concentration infused during the peri-ischemic period, have protective effect after regional myocardial ischemia-reperfusion injury in an in vivo rat heart model

Effect of Preconditioning Ischemia on Endothelial Dysfunction Produced by Ischemia-Reperfusion in Rabbit Coronary Artery

Suh. Suk-Hyo,Park. Yee-Tae,Kim. Woong-Heum,Kim. Ki-Whan 대한생리학회 1995 대한생리학회지 Vol.29 No.1

This study was designed to test whether or not 1) ischemia-reperfusion attenuates endothelium-dependent relaxation of coronary arteries and 2) preconditioning protects the arterial endothelium from ischemia-reperfusion injury. In anesthetized open chest rabbits, branches of the left circumflex artery were exposed to different combinations of the experimental conditions; ischemia (15 minutes), ischemia (15 minutes)-reperfusion (10 minutes), preconditioning ischemia, and pre-conditioning fellowed by ischemia-reperfusion. Preconditioning consisted of 3 occlusions of 2-min duration, each followed by n 5-min reperfusion. Rings of the artery exposed to the experimental condition and of normal left anterior descending coronary artery were prepared and suspended for isometric force measurement in organ chambers containing Krebs Ringer bicarbonate solution. The rings were contracted with 29.6 mM KCI. Ischemia alone did not attenuate endothelium-dependent relaxation by acetylcholine. However, ischemia-reperfusion significantly impaired endothelium-dependent relaxation. Endothelium-independent relaxation by sodium nitroprusside was not impaired by ischemia-reperfusion and the constrictive response to acetylcholine was not altered in reperfused rings without endothelium, compared with control rings. Arterial rings exposed to preconditioning followed by ischemia-reperfusion exhibited impaired endothelium-dependent relaxation by acetyl-choline. However, although preconditioning not fellowed by ischemia-reperfusion, attenuated endothelium-dependent relaxation at low concentrations of acetylcholine, the magnitude of the impairment by preconditioning followed by ischemia-reperfusion was significantly less than that of the impairment by ischemia-reperfusion alone. These data demonstrate that ischemia-reperfusion significantly attenuates endothelium-dependent relaxation by producing endothelial dysfunction and preconditioning Protects the endothelium of coronary arteries from ischemia-reperfusion injury.

생체내 심근허혈-재관류 모델에서 멜라토닌의 재관류 부정맥에 대한 심근보호작용에 관한 연구

조규종,김원,홍정석,이미우,장성은,오세현,임경수 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Background: Recently, a few studies demonstrated that melatonin reduced the severity of myocardial reperfusion injuries, such as reperfusion arrhythmias. However, it is uncertain whether the melatonin reduces reperfusion arrhythmias in thus anesthetized animals because results were obtained using isolated hearts. Thus, to see whether melatonin reduces reperfusion arrhythmias in anesthetized animals, we examined the effect of melatonin on the incidence of reperfusion arrhythmias in an anesthetized-cat model of regional ischemia. Method: Adult mongrel male cats(n=30, 2.9∼4.2 kg) were anesthetized under positive-pressure artificial ventilation with room air. The animals of the control group(n=15) were subjected to 20-minute left anterior descending coronary artery(LAD) occlusion followed by abrupt reperfusion. The animals in experimental group(n=15) were divided into two. Group I(n=6) was pretreated with melatonin, 1 mg/kg, before occluding the LAD. Group II(n=9) was pretreated with melatonin, 10 mg/kg. The animals in experimental group were subjected to ischemia/reperfusion insult following drug treatment: melatonin was applied intra-peritoneally for 3 minutes just before LAD coronary artery ligation. The Fisher's exact test was used to compare the data from different animal groups. p<0.05 was considered significant. Results: The incidence of ventricular fibrillation(VF) during the reperfusion phase in group II(pretreated with melatonin, 10 mg) was significantly smaller than that in the control group(p-value = 0.0029). However, no statistically significant difference of VF incidence was found between group I(pretreated with melatonin, 1 mg) and the control group. Conclusion: Employing an anesthetized-cat model of regional cardiac ischemia, we investigated the dose-dependant effects of melatonin on reperfusion-induced arrhythmia. The cats pretreated with 10 mg/kg of melatonin before ischemia had a significantly reduced incidence of lethal reperfusion-induced arrhythmia, but there was no difference between the cats pretreated with 1 mg/kg of melatonin before ischemia and the control group.

Experimental Research Article : Propofol has delayed myocardial protective effects after a regional ischemia/reperfusion injury in an in vivo rat heart model

( Il Woo Shin ),( In Seok Jang ),( Seung Hwa Lee ),( Ji Seok Baik ),( Kyeong Eon Park ),( Ju Tae Sohn ),( Heon Keun Lee ),( Young Kyun Chung ) 대한마취과학회 2010 Korean Journal of Anesthesiology Vol.58 No.4

Background: It is well known that propofol protects myocardium against myocardial ischemia/reperfusion injury in the rat heart model. The aim of this study was to investigate whether propofol provides a protective effect against a regional myocardial ischemia/reperfusion injury in an in vivo rat heart model after 48 h of reperfusion. Methods: Rats were subjected to 25 min of left coronary artery occlusion followed by 48 h of reperfusion. The sham group received profopol without ischemic injury. The control group received normal saline with ischemia/ reperfusion injury. The propofol group received profopol with ischemia/reperfusion injury. The intralipid group received intralipid with ischemia/reperfusion injury. A microcatheter was advanced into the left ventricle and the hemodynamic function was evaluated. The infarct size was determined by triphenyltetrazolium staining. The serum level of cardiac troponin-I (cTn-I) was determined by ELISA (enzyme-linked immunosorbent assay). Results: Propofol demonstrated protective effects on hemodynamic function and infarct size reduction. In the propofol group, the +dP/dt(max) (P=0.002) was significantly improved compared to the control group. The infarct size was 49.8% of the area at risk in the control group, and was reduced markedly by administration of propofol to 32.6% in the propofol group (P=0.014). The ischemia/reperfusion-induced serum level of cTn-I was reduced by propofol infusion during the peri-ischemic period (P=0.0001). Conclusions: Propofol, which infused at clinically relevant concentration during the peri-ischemic period, has delayed myocardial protective effect after regional myocardial ischemia/reperfusion injury in an in vivo rat heart model after 48 h of reperfusion. (Korean J Anesthesiol 2010; 58: 378-382)

The Effect of Indomethacin on the Production of Eicosanoids and Edema during Ischemia-Reperfusion Injury in Skeletal Muscle

Yoon Jae Chung,Byung Kyu Sohn,Kwang Soon Hyun,Sang Hee Yoo,Hyong Kyun Ryu,Hyung Gun Kim 대한생리학회-대한약리학회 2000 The Korean Journal of Physiology & Pharmacology Vol.4 No.6

<P> During reperfusion of skeletal muscle after ischemia, lipid mediators, mainly eicosanoids, are released and may have a role in the pathogenesis of reperfusion injury. To validate the role of eicosanoids in the ischemia-reperfusion induced functional deficits in skeletal muscle, we compared muscle edema and the changes of eicosanoid concentration in the rat hind limb after ischemia-reperfusion injury by application of tourniquet. After 4 hours of ischemia, reperfusion was established for 4 hours by releasing tourniquet. To assess tissue damage, edema, and wet/dry weight ratios were determined and the eicosanoid concnentrations were measured by the HPLC. The muscle edema and the release of cyclooxygenase metabolites were not induced by the ischemia itself rather they were significantly increased by reperfusion. Indomethacin treatment ameliorated limb edema and decreased the release of 6-keto-PGF<SUB>1α</SUB>, thromboxane B<SUB>2</SUB>, and PGE<SUB>2 </SUB>induced<SUB> </SUB>by reperfusion. But the inhibitory effect of indomethacin on edema (35%) was relatively low than the inhibitory effect on release of cyclooxygenase metabolites (up to 69%) by reperfusion. These results support the view that cyclooxygenase products may play a significant role in the formation of muscle injury by ischemia-reperfusion and suggest that nonsteroidal antiinflammatory agents might be partially beneficial to the management of acute limb ischemia-reperfusion injury.