• Applied Microscopy
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• v.20 no.1
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• pp.65-76
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• 1990

The effect of calcium-free reperfusion for 5, 10, and 15 minutes, respectively, followed by continuous reperfusion with normal Tyrode solution containing 1.0mM calcium chloride, after global ischemia in the isolated perfused guinea pig heart by Langendorff techniques was examined with transmission electron microscope. Compared to the nomal Tyrode solution-perfused control hearts, the 5 minute calcium-free-reperfused hearts showed loss or thickening of Z lines, focal sarcolemmal disruption, mitochondrial swelling, clumping of chroma-tin, intracellular fluid accumulation, and some separation of cell junctions, especially the fasciae adherentes. These changes became more severe in the hearts of 10 minute calcium-free reperfusion. Subsarcolemmal larger bleb and near complete separation of cell junctions were noticed. In the 15 minute calcium-free-reperfused hearts, irreversible ultrastructural changes including contraction bands, biazrre mitochondria, and sarcolemmal destruction were widely distributed. The severity of myocardial changes were in accordance with the duration of calcium-free reperfusion. These changes indicate that calcium-free reperfusion regardless of its duration could not salvage the post-ischemic myocardium probably due to development of calcium paradox.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.199-199
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• 1998

In this study, the effects of ursodeoxycholic acid (UDCA) on ischemia/reperfusion injury were investigated on retrograded aortic perfusion model. Hearts from Sprague-Dawley rats were perfused with oxygenated Krebs-Henseleit solution (pH 7.4, 37) on a Langendorff apparatus. After equilibration, hearts were treated with ursodeoxycholic acid 10, 20, 40 and 800 M or vehicle (0.04% DMSO) for 10 min before the onset of ischemia. Following 25 min of global ischemia, ischemic hearts were reperfused and allowed to recover for 30 min. The physiological (i.e. heart rate, left ventricular diastolic pressure, coronary flow and time to contracture formation) and biochemical (lactate dehydrogenase, LDH) endpoints were evaluated. In vehicle group, time to contracture formation (TTC) value was 19.5 min during ischemia, LVDP was 20.8 mmHg at the endpoint of reperfusion and LDH activity in reperfusate was 59.7 U/L. Cardioprotective effects of UDCA following ischemia/reperfusion consisted of a reduced TTC (EC$\_$25/ = 16.10 M), reduced LDH release and enhanced recovery of contractile function during reperfusion. Especially, the treatments of UDCA 80 M remarkably increased LVDP (68.1 mmHg) and reduced LDH release (33.2 U/L). Our findings suggest that UDCA ameliorates ischemia/reperfusion-induced myocardial damage, in agreement with physiological and biochemical parameters.

• YAKHAK HOEJI
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• v.56 no.4
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• pp.260-267
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• 2012

This study examined the effects of baicalin, a bioactive flavonoid isolated from Scutellaria baicalensis, on hepatic injury caused by ischemia/reperfusion (I/R) in alcoholic fatty liver. Rats were fed an ethanol liquid diet or a control isocaloric diet for 5 weeks, and then subjected to 60 min of hepatic ischemia and 5 h of reperfusion. Baicalin (200 mg/kg) was administered intraperitoneally 24 and 1 h before ischemia. After reperfusion, baicalin attenuated the increase in serum alanine aminotransferase activity. The levels of cytosolic cytochrome c protein expression, caspase-3 activity, the number of apoptotic cells increased after reperfusion, which were higher in ethanol-fed animals, were attenuated by baicalin. Following I/R, the hepatic lipid peroxidation was elevated, whereas hepatic glutathione content was decreased. These changes attenuated by baicalin. In ethanol-fed animals, baicalin augmented the increases in heme oxygenase-1 protein and mRNA expressions, and nuclear Nrf2 expression. In conclusion, our findings suggest that baicalin ameliorates I/R-induced hepatocellular damage by suppressing apoptosis and oxidative stress in alcoholic fatty liver.

• Journal of Korean Neurosurgical Society
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• v.29 no.2
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• pp.167-179
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• 2000

Objective : We studied to clarify the effective time zone of mild hypothermic neural protection during ischemia and/or reperfusion after middle cerebral artery occlusion. Methods : In a reversible cerebral infarct model which maintained reperfusion of blood flow after middle cerebral artery occlusion for two hours, the size of cerebral infarction, cerebral edema and the extent of neurological deficit were observed and analyzed for comparison between the control and the experimental groups under hypothermia($33.5^{\circ}C$). The temporalis muscle temperature was reduced to $33.5^{\circ}C$ by surface cooling for two hours during middle cerebral artery occlusion for study group I. The following groups applied hypothermia for two-hour periods after reperfusion : group II(0-2 hours), group III(2-4 hours), and group IV(4-6 hours). They were rewarmed to $36.5^{\circ}C$ until sacrified at 2, 4, 6, 12, and 24 hours after reperfusion. Control group was maintained at normothermia without hypothermia. Results : In the experimental groups with hypothermia, the average value of the size of cerebral infarction($mean{\pm}SD$) was $1.97{\pm}1.65%$, which was a remarkable reduction over that of the control, $4.93{\pm}3.79%$. In the control, a progressive increase was shown in the size of infarction from point of reperfusion to 6 hours after reperfusion without further changes in size afterward. Intra-ischemic hypothermia(group I) prevented ischemic injury but did not prevent reperfusion injury. Group II examplified the most neural protective effect in comparison to the control group and group IV(p<0.05). The cortex was more vulnerable to reperfusion injury than the subcortex. Mild hypothermia showed more neural protective effects on the cortex than subcortex. Conclusion : The most appropriate time zone for application of mild hypothermia was defined to be within four hours following reperfusion.

• Journal of Chest Surgery
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• v.33 no.3
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• pp.213-220
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• 2000

Background: Adhesion of leukocytes to myocardium or vascular endothelium has been known as an importation initial step in the ischemia-reperfusion injury which may affect the cardiac function. Therefore, leukocyte-depleted reperfusion may inhibit ischemia-reperfusion induced functional and ultrastructural deterioration. In this study, we quantified the time-dependent expression of the vascular cell adhesion molecule-1(VCMA-1) on piglet myocardium and demonstrated its relation to functional recovery using isolated piglet heart perfusion model. Material and Method: Neonatal(1 to 3 day old) piglet heart was harvested with 4$^{\circ}C$ University of Wisconsin solution (UWS) and presrved in the same solution for 12 hours. Ex vivo model of an isolated working neonatal piglet heart perfusion consisting of membrane oxygenator and roller-pump was used (Fig. 1). Hearts were grouped into leukocyte-non-depleted (group A, n=8) and leukocyte-depleted group(group B, n=8). In group B, hearts were reperfused with leukocyte-depleted blood using a leukocyte filter (Sepacell R, Asahi Medical, Japan). Segments of right atrium were taken before and after 1, 2, 3, and 4 hours of reperfusion for the evaluation of expression of VCAM-1. The intensity of immunohistochyemical satining of the VCAM-1 on the myocardium were graded semiquantitatively (0 to 4). For the evaluation of myocardial stroke work indices were calculated as well at the same time-points. Result: Mean expressins of VCAM-1 on the myocardium at 0, 1, 2, 3, adn 4 hours of reperfusion were 0.63, 1.44, 1.64, 2.65, and 3.34 in group A, while 0.56, 1.40, 1.50, 1.88 and 2.14 in group B (Fig. 3). Mean stroke work indices at 0.5, 1, 2, 3, and 4 hours after reperfusion were 1.35$\times$104, 1.32$\times$104, 1.14$\times$104, 0.81$\times$104, 0.68$\times$104 erg/gm in group A, while 1.40$\times$104, 1.43$\times$104, 1.43$\times$104, 1.28$\times$104, and 1.12$\times$104 erg/em in group B(Fig. 4). Conclusion : In this study, we demonstrated that leukocyte-depletion attenuated the expression of VCAM-1 during reperfusion and the time-dependent functional deterioration of the myocardium was well correlated with the degree of VCAM-1 expression.

• Archives of Reconstructive Microsurgery
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• v.21 no.1
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• pp.61-67
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• 2012

Purpose: The purpose of this study was to investigate the role of mast cells and their product, histamine and leukotriene in ischemia-reperfusion injury. Methods: Forty Sprague-Dawley rats were divided into four groups. (Group I: Control group without ischemia, Group II: Normal saline with ischemia, Group III: Cimetidine with ischemia, Group IV: Zafirlukast with ischemia) Skin flap was elevated and ischemic insult was given by clamping the artery for 12 hours. Before reperfusion, the rats were treated with saline, cimetidine and zafirlukast. Flap survival was evaluated at 7 days. Neutrophil counts, mast cell counts were evaluated 24 hours after reperfusion. Results: Flap survival rate in the control group was 92.33%, whereas normal saline group had 37.34% survivals. Cimetidine and zafirlukast treated group showed significantly higher survival rates than normal saline group. The neutrophil and mast cell counts in cimetidine and zafirlukast treated group were significantly decreased than normal saline group. Cimetidine treated group showed higher survival rate and lower cell counts than zafirlukast treated group. Conclusion: The administration of cimetidine and zafirlukast can decrease neutrophils and mast cells caused by ischemia-reperfusion and increase flap survivals. It is suggests that antihistamine and leukotriene receptor antagonist have protective effect against ischemia-reperfusion injury to skin flap in rat.

• Journal of Chest Surgery
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• v.33 no.5
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• pp.377-384
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• 2000

Background: Numerous studies of safe, long term preservation for lung transplantation have been performed using ex vivo models or in vivo single lung transplantation models. However, a safe preservation time which is applicable for clinical use is difficult to determine. We prepared LPDG solution for lung preservation study. In this study we examined the efficacy of LPDG(low potassium dextran glucose) solution in 24-hour lung preservation by using a sequential bilateral canine lung allotransplant model. Material and Method: Seven bilateral lung transplant procedures were performed using weight-matched pairs(24 to 25kg) of adult mongrel dogs. The donor lungs were flushed with LPDG solution and maintained hyperinflated with 100% oxygen at 1$0^{\circ}C$ for a planned ischemic time of 24 hours for the lung implanted first. After sequential bilateral lung transplantation, dogs were maintained on ventilators for 3 hours: arterial resistance were determined if the recipients hourly after bilateral reperfusion and compared with pretransplant-recipient values, which were used as controls. After 2hours of reperfusion, the chest X-ray, computed tomogram and lung perfusion scan were performed for assessmint of early graft lung function. Pathological examinations for ultrastructural findings of alveolar structure and endothelial structure of pulmonary artery were performed. Result: Five of seven experiments successfully finished the whole assessments after bilateral reperfusion for three hours. Arterial oxygen tension in the recipients was markedly decrased in immediate reperfusion period but gradually recovered after reperfusion for three hours. The pulmonary artery and pulmonary vascular resistance showed singificant elevation(p<0.05 versus control values) but also recovered after reperfusion for three hours(p<0.05 versus immediate period value). The ultrastructural findings of alveolar structure and endothelial structure of pulmonary artery showed reversible mild injury in 24 hours of lung perservation and reperfusion. Conclusion : This study suggests that LPDG solution provides excellent preservation in a canine model in which the dog is completely dependent on the function of the transplanted lung.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.340-340
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• 1994

Since total hepatic ischemia(IS) occurs with transplantation, there has been interest in evaluating hepatic function after ischemia and subsequent reflow of blood. Four groups of animals were studied: group 1 (sham), group 2 (30mins IS), group 3 (60mins IS), and g.cup 4 (90mins IS). Serum transaminase(STA), wet weight-to-dry weight ratio(W/D), lipid peroxides(LPO), glucose-6-phosphatase(G-6-Pase) activity, Na$\^$+//K$\^$+/-ATPase(ATPase) activity were measured at 1, 5 and 24hrs after hepatic ischemia. Significant changes occurred between 1 and 5hrs of reperfusion. STA was 3579${\pm}$401, 4593${\pm}$675 and 6348${\pm}$808 U/L in group 2, 3 and 4 respectively. These changes were ischemic time-dependent manner. W/D in group 3 and 4 were significantly increased than that in sham group at all time points measured. In sham group, the level of LPO in the liver microsome remained constant at approximately 0. 5nmole MDA formed/mg protein througllout the experiment, In all ischemic groups on the other hand, the level of LPO started to increase at ischemia and markedly increased at all reperfusion period. Similar to STA, these changes were also dependent on duration of ischemia. Although G-6-Pase activity remained unchanged in both group 2 and group 3 until 5hrs of reperfusion, marked decrease in G-6-Pase activity was observed at grcup 4. ATPase activity was significantly decreased at 1, 5 and 24 hrs of reperfusion in group 3, whereas it was not changed in group 2. Furthermore, ATPase activity in group 4 started to decrease at ischemia and markedly decreased for entire reperfusion period. These data suggest that severity of hepatocellular injury is associated with period of ischemia as well as period of reperfusion.

• Archives of Plastic Surgery
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• v.33 no.5
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• pp.621-626
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• 2006

Purpose: Erythropoietin is traditionally known to regulate erythropoiesis, but recently its protective effect against ischemia-reperfusion injury has been studied mainly in cardiovascular and neuronal systems. This study was planned to investigate the effects of recombinant human erythropoietin on ischemia-reperfusion injury in rat TRAM flap model. Methods: Superiorly based TRAM flap was elevated and ischemic insult was given for four hours. Thirty minutes before reperfusion, single dose recombinant human Erythropoietin(5000IU/kg) was injected via intraperitoneal route in the treatment group. At 24 hours postoperatively, systemic neutrophil count, tissue myeloperoxidase activity, malonyldialdehyde amount, nitric oxide content, tissue water content and histologic finding of inflammation was evaluated. On 10 days postoperatively, flap survival rate, angiogenesis and change in hematocrit level was evaluated. Results: Tissue nitric oxide level was significantly higher and myeloperoxidase activity was significantly lower in the treatment group 24 hours after reperfusion. Tissue water content was significantly lower in the treatment group. Perivascular neutrophil infiltration and intravascular adhesion was marked in the control group. Mean flap survival after ten days was 69% in the treatment group, and 47% in the control group, demonstrating a significant difference. Neovascularization in the treatment group also outnumbered the control group. No significant hematocrit rise was noted ten days after erythropoietin administration. Conclusion: Recombinant human Erythropoietin improved flap survival in ischemia-reperfusion injured rat TRAM flaps, at least partially owing to suppressed inflammation, increased nitric oxide, and enhanced angiogenesis.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.481-487
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• 2014

Ischemic postconditioning (IPost) could decrease ischemia-reperfusion (IR) injury. It has not yet reported whether IPost is useful when ischemic heart disease is accompanied with co-morbidities like hyperthyroidism. The aim of this study was to examine the effect of IPost on myocardial IR injury in hyperthyroid male rats. Hyperthyroidism was induced with administration of thyroxine in drinking water (12 mg/L) over a period of 21 days. After thoracotomy, the hearts of control and hyperthyroid rats were perfused in the Langendorff apparatus and subjected to 30 minutes global ischemia, followed by 120 minutes reperfusion; IPost, intermittent early reperfusion, was induced instantly following ischemia. In control rats, IPost significantly improved the left ventricular developed pressure (LVDP) and ${\pm}dp/dt$ during reperfusion (p<0.05); however it had no effect in hyperthyroid rats. In addition, hyperthyroidism significantly increased basal $NO_x$ (nitrate+nitrite) content in serum ($125.5{\pm}5.4{\mu}mol/L$ vs. $102.8{\pm}3.7{\mu}mol/L$; p<0.05) and heart ($34.9{\pm}4.1{\mu}mol/L$ vs. $19.9{\pm}1.94{\mu}mol/L$; p<0.05). In hyperthyroid groups, heart $NO_x$ concentration significantly increased after IR and IPost, whereas in the control groups, heart $NO_x$ were significantly higher after IR and lower after IPost (p<0.05). IPost reduced infarct size (p<0.05) only in control groups. In hyperthyroid group subjected to IPost, aminoguanidine, an inducible nitric oxide (NO) inhibitor, significantly reduced both the infarct size and heart $NO_x$ concentrations. In conclusion, unlike normal rats, IPost cycles following reperfusion does not provide cardioprotection against IR injury in hyperthyroid rats; an effect that may be due to NO overproduction because it is restored by iNOS inhibition.