• Tuberculosis and Respiratory Diseases
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• v.54 no.5
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• pp.532-541
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• 2003

Background : Phospholipase $A_2$ ($PLA_2$) has been known to be involved in the pathogenesis of acute lung injury (ALI) including ARDS. Since doxycycline has the property of inhibiting secretory group II $PLA_2$, the therapeutic effect of doxycycline hyclate was investigated for gut ischemia/reperfusion (I/R)-induced ALI in Sprague-Dawley rats. Methods : ALI was induced in Sprague-Dawley rats by clamping of the superior mesenteric artery for 60 min, followed by 120 min of reperfusion. To confirm the pathogenetic mechanisms of this ALI associated with neutrophilic oxidative stress, we measured bronchoalveolar lavage (BAL) protein content and lung MPO, and performed cyto-chemical electron microscopy for detection of free radicals, assay of $PLA_2$ activity and cytochrome-c reduction assay. Results : In gut I/R-induced ALI rats, protein leakage, pulmonary neutrophil accumulation, free radical production and lung $PLA_2$ activity were all increased. These effects were reversed by doxycycline hyclate. Conclusion : Doxycycline appears to be effective in ameliorating the gut I/R-induced ALI by inhibiting $PLA_2$, thereby decreasing the production of free radicals from neutrophils.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.4
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• pp.281-296
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• 2021

The beneficial effects of hypoxic preconditioning are abolished in the diabetes. The present study was designed to investigate the protective effects and mechanisms of repeated episodes of whole body hypoxic preconditioning (WBHP) in db/db mice. The protective effects of preconditioning were explored on diabetes-induced vascular dysfunction, cognitive impairment and ischemia-reperfusion (IR)-induced increase in myocardial injury. Sixteen-week old db/db (diabetic) and C57BL/6 (non-diabetic) mice were employed. There was a significant impairment in cognitive function (Morris Water Maze test), endothelial function (acetylcholine-induced relaxation in aortic rings) and a significant increase in IR-induced heart injury (Langendorff apparatus) in db/db mice. WBHP stimulus was given by exposing mice to four alternate cycles of low (8%) and normal air O₂ for 10 min each. A single episode of WBHP failed to produce protection; however, two and three episodes of WBHP significantly produced beneficial effects on the heart, brain and blood vessels. There was a significant increase in the levels of brain-derived neurotrophic factor (BDNF) and nitric oxide (NO) in response to 3 episodes of WBHP. Moreover, pretreatment with the BDNF receptor, TrkB antagonist (ANA-12) and NO synthase inhibitor (L-NAME) attenuated the protective effects imparted by three episodes of WBHP. These pharmacological agents abolished WBHP-induced restoration of p-GSK-3β/GSK-3β ratio and Nrf2 levels in IR-subjected hearts. It is concluded that repeated episodes of WHBP attenuate cognitive impairment, vascular dysfunction and enhancement in IR-induced myocardial injury in diabetic mice be due to increase in NO and BDNF levels that may eventually activate GSK-3β and Nrf2 signaling pathway to confer protection.

• Biomolecules & Therapeutics
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• v.28 no.2
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• pp.152-162
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• 2020

Cerebral ischemia exhibits a multiplicity of pathophysiological mechanisms. During ischemic stroke, the reactive oxygen species (ROS) concentration rises to a peak during reperfusion, possibly underlying neuronal death. Recombinant human erythropoietin (EPO) supplementation is one method of treating neurodegenerative disease by reducing the generation of ROS. We investigated the therapeutic effect of PEGylated EPO (P-EPO) on ischemic stroke. Mice were administered P-EPO (5,000 U/kg) via intravenous injection, and middle cerebral artery occlusion (MCAO) followed by reperfusion was performed to induce in vivo ischemic stroke. P-EPO ameliorated MCAO-induced neurological deficit and reduced behavioral disorder and the infarct area. Moreover, lipid peroxidation, expression of inflammatory proteins (cyclooxygenase-2 and inducible nitric oxide synthase), and cytokine levels in blood were reduced by the P-EPO treatment. In addition, higher activation of nuclear factor kappa B (NF-κB) was found in the brain after MCAO, but NF-κB activation was reduced in the P-EPO-injected group. Treatment with the NF-κB inhibitor PS-1145 (5 mg/kg) abolished the P-EPO-induced reduction of infarct volume, neuronal death, neuroinflammation, and oxidative stress. Moreover, P-EPO was more effective than EPO (5,000 U/kg) and similar to a tissue plasminogen activator (10 mg/kg). An in vitro study revealed that P-EPO (25, 50, and 100 U/mL) treatment protected against rotenone (100 nM)-induced neuronal loss, neuroinflammation, oxidative stress, and NF-κB activity. These results indicate that the administration of P-EPO exerted neuroprotective effects on cerebral ischemia damage through anti-oxidant and anti-inflammatory properties by inhibiting NF-κB activation.

• Archives of Pharmacal Research
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• v.24 no.3
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• pp.229-233
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• 2001

This Paper deals with the development of a technology for making a hydrophilic gel of Polyethylene oxide reception in which radiating ability is employed to cause cross-linking of Polymers in a water solution. The gel of polyethylene oxide was shown to be nontoxic contain 5-50% of polymer and be useful in composite medicinal forms along with biologically active substances including Bac. subtilis proteases. Proteases immobilized in the gel possess high thermal stability and proteolytic activity and are readily applied in medicine. The effect of immobilized proteolytic and glucolytic enzymes of Bac. subtillis (Immozimase) on the warm ischemia-reperfusion (I/R) which can cause hepatic and jejunum injury was also studied. These enzymes were immobilized on water-soluble polymer polyethylene glycol by means of an electron beam. The number of degraanulated mast cells as well as serum ALT after I/R in the group with Immozimase was decreased to almost half as compared with the control group. Pretreatment with Immozimase resulted in significant reduction of hepatic and gut neutrophil accumulation as compared with control animals. It was concluded that Immozimase has a protective effect for hepatic and gut ischemia/reperfusion, and this effect seems to be associated with prevention of leukocyte accumulation .

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.92-92
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• 1995

It has been suggested that oxygen-derived free radicals have an important role in the pathophysiology of acute gastric ulceration induced by NSAIDs and ischemia-reperfusion. Taurine is hypothetized to exert its protective effect on NSAIDS-induced gastric injury by its antioxidant properties, Protect ive effect of taurine on indomethacin-induced gastric mucosal lesion and its protective mechanism were investigated. Intragastric administration of 25 mg/kg of indomethacin induced hemorrhagic lesions on the glandular stomach in rats, Pretreatment with 0.25 g/kg of taurine for 3 days significantly reduced the gastric lesion formation and Inhibited the elevation of lipid peroxide level In gastric mucosa. Both resting and FMLP-induced luminol-dependent chemiluminescence of rat peritoneal neutrophils increased immediately after treatment of indomethacin. 5-20mM of taurine inhibited chemiluminescence of neutrophils activated by indomethacin and/or FMLP. Human neutrophils (polymorphonuclear leukocytes) significantly adhered to confluent monolayer of human umbilical vein endothelial cells(HUVEC) after coincubation with aspirin or indomethacin. Also taurine prevented neutrophil adhesion induced by these drugs to HUVEC in dose-dependent manner. These results indicate that the protective effect of taurine against NSAIDS-induced gastric mucosal Injury is due to its antioxidant effect, which inhibits lipid peroxidation and neutrophil activation.

• Journal of Yeungnam Medical Science
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• v.38 no.1
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• pp.27-33
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• 2021

The gut is a complex organ that has played an important role in digestion, absorption, endocrine functions, and immunity. The gut mucosal barriers consist of the immunologic barrier and nonimmunologic barrier. During critical illnesses, the gut is susceptible to injury due to the induction of intestinal hyperpermeability. Gut hyperpermeability and barrier dysfunction may lead to systemic inflammatory response syndrome. Additionally, gut microbiota are altered during critical illnesses. The etiology of such microbiome alterations in critical illnesses is multifactorial. The interaction or systemic host defense modulation between distant organs and the gut microbiome is increasingly studied in disease research. No treatment modality exists to significantly enhance the gut epithelial integrity, permeability, or mucus layer in critically ill patients. However, multiple helpful approaches including clinical and preclinical strategies exist. Enteral nutrition is associated with an increased mucosal barrier in animal and human studies. The trophic effects of enteral nutrition might help to maintain the intestinal physiology, prevent atrophy of gut villi, reduce intestinal permeability, and protect against ischemia-reperfusion injury. The microbiome approach such as the use of probiotics, fecal microbial transplantation, and selective decontamination of the digestive tract has been suggested. However, its evidence does not have a high quality. To promote rapid hypertrophy of the small bowel, various factors have been reported, including the epidermal growth factor, membrane permeant inhibitor of myosin light chain kinase, mucus surrogate, pharmacologic vagus nerve agonist, immune-enhancing diet, and glucagon-like peptide-2 as preclinical strategies. However, the evidence remains unclear.

• Journal of Oriental Physiology
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• v.14 no.2 s.20
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• pp.179-187
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• 1999

To investigate how Jagamchotang provent cellular injury by a certain starting point on reperfusion injury after ischemia in myocardial cell, conducted MTT assay, LM stydy and measured LDH secretion, heart rate and nitric oxide(NO), and got the following results. 1. Jagamchotang did not injure cells even in $20{\mu}g/ml$. 2. Jaganchotang repressed the toxicity of mitochondria and cell membrane in reperfusing after ischemia and repressed the contraction of promontory of myocardial cell and reduction of the number of cells. Also maintained regular heart rate and reduced the number of heart rate. 3. Synthesis of NO by Jagamchotang in ischemia increased 1.9 times than a control. 4. When reperfusing with sodium nitropruside (SNO), NO donor in ischemia repressed the toxicity of mitochondria as the case of reperfusing with Jagamchotang in ischemia. Therefore, putting these findings together, it. can be said the effect of Jagamchotang in ischemia will be closely related with generation of NO.

• Journal of Chest Surgery
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• v.35 no.1
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• pp.11-19
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• 2002

Background: Ischemia-reperfusion myocardial injury is an important factor to determine the early and the late mortality of transplanted patients. Recently, modulation of the cytosolic NADH/NAD+ ratio by Pyruvate and aspartate was tested to Protect the heart from ischemia-reperfusion injury. Material and Method: We added pyruvate and aspartate to the University of Wisconsin solution, and evaluated their effect on myocardial protection. We used 16 piglet(age 1 to 3 days) hearts. Eight hearts were arrested with and stored in the University of Wisconsin solution(UW solution) for 24 hours(control group), and the other eight hearts were arrested with and stored in the modified UW solution added pyruvate(3mmol/L) and aspartate(2 mmol/L)(test group). All hearts underwent modified reperfusion with blood cardioplegic solution followed by conversion to a left-sided working model with perfusion from a support pig. And then, we measured stroke work index(SWI), high-energy phosphate stores, and myocardial water content of the hearts. SWI was calculated at left ventricular end-diastolic pressures of 3, 6, 9, and 12 mmHg after 60 and 120 minutes reperfusion, respectively, Result: At 60 minutes and 120 minutes after reperfusion, SWI was higher in the test group than in the control group significantly. The levels of AMP, ADP, ATP of the test group were also higher. But, the creatine phosphate level and myocardial water content were similar in the two groups. Conclusion: From these results, we could Prove that pyruvate and aspartate enhance cardiac contractility and high-energy phosphate stores after ischemia.

• Journal of Veterinary Clinics
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• v.26 no.1
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• pp.29-35
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• 2009

This study was to determine the effects of ascorbic acid and alpha-tocopherol on the attenuation of an ischemia-reperfusion injury (IRI) after renal auto-transplantation in a pig model. In the treatment group, three pigs were subjected to a renal auto-transplantation followed by the administration of ascorbic acid and alpha-tocopherol and the flushing of ascorbic acid plus hepa-saline solution. Otherwise, the control group used only flushing of hepa-saline solution. Blood samples were collected from these pigs for measurement of serum blood urea nitrogen (BUN) and creatinine values on the day before surgery and day 1, 3, 5 and 7 after surgery. The kidneys were taken for histopathological evaluation following euthanasia on day 14 after surgery. Serum creatinine and BUN values showed a significantly difference between control and treatment group on day 1, 3 and 5 (P<0.05). In histopathologic findings, treatment group showed less damage than that of the control group on the basis of renal tubular damage. As a result, this study suggests that the exogenous ascorbic acid and alpha-tocopherol pretreatment therapy with ascorbic acid irrigation-aspiration has a role of attenuation of renal I/R injury and recovery of renal function in a pig transplantation model.

• Archives of Plastic Surgery
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• v.46 no.2
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• pp.108-113
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• 2019

Background The aim of this study was to assess the safety of one-per-mil tumescent injections into viable skin flaps that had survived an ischemic insult, in order to assess the potential suitability of one-per-mil tumescent injections in future secondary reconstructive procedures such as flap revision and refinements after replantation. Methods Forty groin flaps harvested from 20 healthy Wistar rats weighing 220 to 270 g were subjected to acute ischemia by clamping the pedicle for 15 minutes. All flaps showing total survival on the 7th postoperative day were randomly divided into group A (one-per-mil tumescent infiltration; n=14), group B (normal saline infiltration; n=13), and group C (control, with no infiltration; n=13) before being re-elevated. Transcutaneous oxygen tension ($TcPO_2$) was measured before and after infiltration, and changes in $TcPO_2$ were statistically analyzed using analysis of variance, the paired t-test, and the independent t-test. The viability of flaps was also assessed using the Analyzing Digital Images software at 7 days after the second elevation. Results Thirty-nine flaps survived to the final assessment, with the sole exception of a flap from group A that did not survive the first elevation. $TcPO_2$ readings showed significant decreases (P<0.05) following both one-per-mil tumescent ($99.9{\pm}5.7mmHg$ vs. $37.2{\pm}6.3mmHg$) and normal saline ($103{\pm}8.5mmHg$ vs. $48.7{\pm}5.9mmHg$) infiltration. Moreover, all groin flaps survived with no signs of tissue necrosis. Conclusions One-per-mil tumescent infiltration into groin flap tissue that had survived ischemia did not result in tissue necrosis, although the flaps experienced a significant decrease of cutaneous oxygenation.