- Email: [email protected]
Reoxygenation–Induced Pulmonary Vasoconstriction is Attenuated by a Cyclooxygenase Inhibitor in Rats
Inducible Cyclooxygenase Expression Mediating Hypoxia/Reoxygenation–Induced Pulmonary Vasoconstriction is Attenuated by a Cyclooxygenase Inhibitor in Rats C.L. Su, D.W. Yuan, L.L. Chiang, H.L. Lee, K.H. Chen, and D. Wang ABSTRACT Objective. Hypoxic pulmonary vasoconstriction (HPV) is a well known phenomenon to temporarily offset a ventilation-perfusion mismatch. Sustained HPV may lead to pulmonary hypertension. In this protocol, we studied the relationships between the HPV response and inducible cyclooxygenase II (COX II) activation after hypoxia-reoxygenation (H-R) challenge in an isolated perfused lung model. Methods. An in situ isolated perfused rat lung model underwent inaction of hypoxia by ventilation with 5% CO2–95% N2 for 10 minutes instead of 5% CO2–95% air; they were then reoxygenated with 5% CO2–95% air. We measured pulmonary arterial pressure (PAP) changes before, during, and after H-R challenge. We also estimated changes in blood concentrations of hydroxyl radicals, nitric oxide (NO) and thromboxane B2 (TxB2) before and after H-R as well as mRNA expressions of COX II in lung tissue thereafter. A COX II inhibitor, celecoxib (10 mg/kg), was administered between 2 consecutive challenges. Results. Hypoxia induced pulmonary vasoconstriction by increasing PAP (4.1 ⫾ 0.8 mm Hg). Consecutive hypoxic challenges did not show tachyphylaxis (P ⬎ .05). H-R of lung tissues induced significant increases in blood concentrations of hydroxyl radicals (48.5 ⫾ 7.6 vs 75.8 ⫾ 11.5 mmol/L; P ⬍ .01), NO (54.3 ⫾ 12.3 vs 77.7 ⫾ 15.7 pmol; P ⬍ .05), and TxB2 (42.3 ⫾ 6.9 vs 58.7 ⫾ 8.6 pg/mL; P ⬍ .05). Lung tissue H-R also significantly increased COX II mRNA expression compared with sham tissues (1 ⫾ 0 vs 4.0 ⫾ 2.8; P ⬍ .001). The COX II inhibitor celecoxib significantly attenuated HPV responses (P ⬍ .05) and attenuated the elevated blood concentrations of TxB2 (P ⬍ .05), hydroxyl radicals (P ⬍ .01), nitric oxide (P ⬍ .05), and COX II mRNA expression (P ⬍ .05) after H-R challenge. Conclusions. Lung tissue H-R induced significant increases blood concentrations of inflammatory mediators and tissue mRNA expression of COX related to elevation of HPV responses. COX II inhibitor celecoxib attenuated the HPV responses by reducing TxB2 release.
From the Department of Chemistry, Graduate Institute of Basic Medicine (C.L.S.), Fu Jen Catholic University, New Taipei City, Taiwan and School of Respiratory Therapy, Taipei Medical University Taipei City, Taiwan; School of Medicine (D.W.Y.), Fu-Jen Catholic University, New City Taipei, Taiwan; School of Respiratory Therapy (L.L.C.), Taipei Medical University, and Division of Pulmonary Medicine, Taipei Medical UniversityShuang Ho Hospital, New Taipei City, Taiwan; Department of Chemistry (H.L.L.), Fu Jen Catholic University; Jen-The Junior College of Medicine (K.H.C.), Nursing and Management, Maoli © 2012 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710 Transplantation Proceedings, 44, 929 –932 (2012)
County, Taiwan; and Department of Medicine (D.W.), College of Medicine Fu Jen Catholic University, New Taipei City, Taiwan. Supported by grants NSC 98-2320-B-038-010 from the National Science Council. Address reprint requests to David Wang, Professor, Department of Medicine, Fu Jen Catholic University, No. 510, Zhongzheng Rd., Xinzhuang Dist., New Taipei City, 24205, Taiwan. E-mail: [email protected]
0041-1345/–see front matter doi:10.1016/j.transproceed.2012.03.005 929
930
esearch in ischemia-reperfusion injury after organ transplantation surgery has attracted increased attention in a number of organ systems.1–3 Much of this work suggests that free oxygen radicals play critical roles to elevats pulmonary arterial pressure (PAP) during hypoxia challenge.4 – 6 Oxygen radicals can activate the COX pathway, looking to production of thromboxane (Tx).7,8 In the present study we analyzed the expression of inducible cyclooxygenase (COX II) in lung tissues after hypoxiareperfusion (H-R) challenge using real-time polymerase chain reactions (PCR). Furthermore, we analyzed blood concentrations of hydroxyl radical, nitric oxide, TxB2 as well as PAP changes during hypoxic challenge. The COX II inhibitor celecoxib was used to study the role of the COX cascade in the HPV response.
R
METHODS Preparation of Isolated and Perfused Rat Lungs The procedure to prepare isolated-perfused lungs was similar to that previously described by Shen et al.9 Sprague-Dawley rats (300 –350 g) were deeply anesthetized with an injection of pentobarbital sodium. After performing a tracheostomy, artificially ventilated the lungs with 5% CO2–95% room air. Heparin (1 U/g) was administered intravenously after performing midsternal thoractomy to collect 10 mL blood from the right ventricle to be mixed with 10 mL Hanks balanced salt solution. A cannula (inflow) and large catheter (outflow) were inserted into the pulmonary artery and left atrium, respectively. The lungs were artificially ventilated and perfused via a roller pump at a constant flow rate (8 –10 mL/min). The venous outflow from the left atrium was collected into the reservoir. A water bath was used to prewarm the perfusate which was maintained at constant temperature (37 ⫾ 0.5°C). The PAP was measured with a pressure transducer connected to a side arm from the inflow cannula.
Induction of Lung Hypoxia Reoxygenation The lungs underwent 2 consecutive hypoxic challenges. The isolated lungs were ventilated for 10 minutes with 5% CO2–95% N2 instead of 5% CO2–95% air to decrease the oxygen content of the blood. Then they were reoxygenated with 5% CO2–95% air. A second hypoxic challenge was administered thereafter for 10 minutes and the system allowed to reoxygenate again. The amount of time separating the 2 challenges was determined by the speed of recovery after the first challenge.
SU, YUAN, CHIANG ET AL
RNA Isolation and Real-Time PCR mRNA isolated from lung tissues using an mRNA isolation kit (Qiagen RNeasy kits; Qiagen, Valencia, CA) was reverse transcribed to cDNA following the manufacturer’s recommendations. PCR primers and TaqMan-MGB probes were designed using Primer Express v.2.0 software (Applied Biosystems, Foster City, CA) based on the sequences from GenBank. TaqManMGB probes were labeled with 6-carboxy-fluorescein (FAM) as the reporter dye. PCR reactions were monitored in real time using the ABI Prism 7000 Sequence Detector (Applied Biosystems).
Experimental Design Animals were randomly divided into 3 groups: 1) H-R rats (n ⫽ 7) were prepared and exposed to H-R as described above; 2) COX II inhibitor rats (n ⫽ 7), received celecoxib (10 mg/kg) by oral administration between the 2 consecutive challenges; 3) Sham, rats were prepared as described above, without H-R challenge.
Data Analysis Data are expressed as mean ⫾ SD. Comparisons within each group for a given parameter were performed using paired and unpaired Student’s t tests. Values of P ⬍ .05 were considered to be statistically significant.
RESULTS
In this study we showed that H-R of the rat lung induced pulmonary vasoconstriction (Fig 1). PAP increased significantly (⌬PAP ⫽ 4.1 ⫾ 0.8 mm Hg); however, consecutive hypoxic challenges did not show tachyphylaxis. Administration of the COX II inhibitor significantly attenuated the HPV response (Fig 1). The hypoxic vasoconstriction could be related to the production of inflammatory mediators such as oxygen radicals, nitrosative stress, and COX cascade TxB2 product. Administration of the COX II inhibitor celecoxib attenuated the respiratory burst 75.8 ⫾ 11.5 vs 50.5 ⫾ 7.8 mmol/L; P ⬍ .01; (Fig 2), nitrosative stress (77.7 ⫾ 15.7 vs 52.0 ⫾ 8.1 pmol; P ⬍ .05), and prostanoid cascade TxB2 product
Spectrofluorimetric Measurement of Methyl Guanidine We measured the formation of methyl guanidine (MG) as an index of hydroxyl radical production in blood10 and are indicator of H-R injury.
Measurement of Nitric Oxide by High-Performance Liquid Chromatography (HPLC) HPLC was used to measure blood levels of nitrite and nitrate anions derived from nitric oxide.
Measurement of TxB2 by Enzyme-Linked Immunosorbent Assay Analysis of TxB2 in the perfusate was performed using a commercially available immunoassay kit (Cayman).
Fig 1. PAP changes in 2 consecutive hypoxic challenges and intervention with cyclooxygenase inhibitor celecoxib. The sham group, was not exposed to hypoxia. ⫹P ⬍ .05 (significant difference between 1st and 2nd hypoxic challenges.
CELECOXIB AND PULMONARY VASOCONSTRICTION
931
ture, was dependent on the activation of p38 (MAPK).14 Malek et al observed that the COX II inhibitor celecoxib attenuated the lung injury induced by hindlimb ischemia and reperfusion.15 In addition, COX expression mediates pulmonary vasoconstriction in septic lungs,16 canine pulmonary reperfusion injury,17 rat lung reperfusion,18 and oleic acid–induced lung injury.19 In the present study, we demonstrated that the COX II inhibitor celecoxib attenuated the HPV response, which may be related to decreased Tx production after H-R challenge. In summary, we demonstrated that reoxygenation of hypoxic lung tissues induced pulmonary vasoconstriction and a PAP increase with oxidative and nitrosative stresses, COX II expression and prostanoid cascade. The COX II inhibitor celecoxib attenuated the HPV responses by reducing COX II expression and TxB2 release. REFERENCES Fig 2. H-R of the lung tissues induced significant increases of blood concentration of thromboxane (TXB2; *P ⬍ .05), hydroxyl radical (**P ⬍ .01), and nitric oxide (NO; *P ⬍ .05) and lung tissue COX II mRNA expression (***P ⬍ .01). COX II inhibitor significantly attenuated the increases (⫹P ⬍ .05; ⫹⫹P ⬍ .01; significant differences after celecoxib intervention).
(58.7 ⫾ 8.6 vs 45.6 ⫾ 8.1 pg/mL; P ⬍ .05). H-R induced an increase in mRNA expression of COX II which was also decreased by COX II inhibitor administration (P ⬍ .05). The attenuating effect of the COX II inhibitor on the H-R–induced pulmonary vasoconstriction may be related to the reduced TxB2 production (P ⬍ .05). DISCUSSION
Substantial evidence has accumulated that reactive oxygen radicals are involved in ischemia-reperfusion– or H-R–induced tissue injury in many organs.2– 4 The involved oxygen radicals include hydrogen peroxide, superoxide anion, and hydroxyl, as well as xanthine oxidase activation. During hypoxic challenge, PAP increased steadily. Hydroxyl radical and nitric oxide concentrations also increased significantly after the HPV response (Fig 1). Possible upstream mediators known to be elevated by oxidant stress include the COX II cascade and TxA2, which bind to and activate the TxA2/prostaglandin H2 receptor.7,11,12 The key enzymes to synthesize prostaglandin and Thromboxane are COX I, which is constitutive, and COX II, which is inducible. Prostanoids, major regulators of smooth muscle function are generated by interactions between COX and oxygen radicals. We hypothesized that various mediators of oxidative stress and nitrosative stress or cytokines alter COX expression and prostanoid generation in pulmonary artery smooth muscle cells. Bradykinin, transforming growth factor, and interleukin-1 increase COX II expression and prostaglandin release.13 Yang et al demonstrated that hypoxic induction of COX II expression in pulmonary vascula-
1. Feltes CM, Hassoun HT, Lie ML, et al: Pulmonary endothelial cell activation during experimental acute kidney injury. Shock 36:170, 2011 2. Xu B, Gao X, Xu J, et al: Ischemic postconditioning attenuates lung reperfusion injury and reduces systemic proinflammatory cytokine release via heme oxygenase 1. J Surg Res 166:e157, 2011 3. Peng CK, Huang KL, Wu CP, et al: Glutamine protects ischemia-reperfusion induced acute lung injury in isolated rat lungs. Pulm Pharmacol Ther 24:153, 2011 4. Frazziano G, Moreno L, Moral-Sanz J, et al: Neutral sphingomyelinase, NADPH oxidase and reactive oxygen species. Role in acute hypoxic pulmonary vasoconstriction. J Cell Physiol 226:2633, 2011 5. Knock GA, Snetkov VA, Shaifta Y, et al: Superoxide constricts rat pulmonary arteries via Rho-kinase-mediated Ca(2⫹) sensitization. Free Radic Biol Med 46:633, 2009 6. Shen CY, Lee JF, Su CL, Wang D, Chen CF: Hypoxia and reoxygenation of the lung tissues induced mRNA expressions of superoxide dismutase and catalase and interventions from different antioxidants. Transplant Proc 40:2182, 2008 7. Wong MS, Vanhoutte PM: COX-mediated endotheliumdependent contractions: from the past to recent discoveries. Acta Pharmacol Sin 31:1095, 2010 8. Tate RM, Morris HG, Schroeder WR, et al: Oxygen metabolites stimulate thromboxane production and vasoconstriction in isolated saline-perfused rabbit lungs. J Clin Invest 74:608, 1984 9. Shen CY, Wang D, Chang ML, et al: Protective effect of mepacrine on hypoxia-reoxygenation-induced acute lung injury in rats. J Appl Physiol 78:225, 1995 10. Lin HI, Chou SJ, Wang D, et al: Reperfusion liver injury induces down-regulation of eNOS and up-regulation of iNOS in lung tissues. Transplant Proc 38:2203, 2006 11. Zamora CA, Baron DA, Heffner JE: Thromboxane contributes to pulmonary hypertension in ischemia-reperfusion lung injury. J Appl Physiol 74:224, 1993 12. Roberts LJ, Morrow JD. The generation and actions of isoprostanes. Biochim Biophys Acta 1345:121, 1997 13. Bradbury DA, Newton R, Y-M Zhu, et al: Effect of bradykinin, TGF1, IL-1, and hypoxia on COX-2 expression in pulmonary artery smooth muscle cells Am J Physiol Lung Cell Mol Physiol 283:L717, 2002 14. Yang X, Sheares KK, Davie N, et al: Hypoxic induction of COX-2 regulates proliferation of human pulmonary artery smooth muscle cells. Am J Respir Cell Mol Biol 27:688, 2002 15. Malek HA, Saleh DM: Cyclooxygenase-2 inhibitor celecoxib in a rat model of hindlimb ischemia reperfusion. Can J Physiol Pharmacol 87:353, 2009
932 16. Fischer LG, Hollmann MW, Horstman DJ, Rich GF: Cyclooxygenase inhibitors attenuate bradykinin-induced vasoconstriction in septic isolated rat lungs. Anesth Analg 90: 625, 2000 17. Sunose Y, Takeyoshi I, Tsutsumi H, et al: Effects of FK3311 on pulmonary ischemia-reperfusion injury in a canine model. J Surg Res 95:167, 2001
SU, YUAN, CHIANG ET AL 18. Otani Y, Takeyoshi I, Yoshinari D, et al: Effects of the COX-2 inhibitor on ischemia-reperfusion injury in the rat lung. J Invest Surg 20:175, 2007 19. Leeman M, de Beyl VZ, Biarent D, et al: Inhibition of cyclooxygenase andn nitric oxide synthase in hypoxic vasoconstriction and oleic acid-induced lung injury. Am J Respir Crit Care Med 159:1383, 1999
From the Department of Chemistry, Graduate Institute of Basic Medicine (C.L.S.), Fu Jen Catholic University, New Taipei City, Taiwan and School of Respiratory Therapy, Taipei Medical University Taipei City, Taiwan; School of Medicine (D.W.Y.), Fu-Jen Catholic University, New City Taipei, Taiwan; School of Respiratory Therapy (L.L.C.), Taipei Medical University, and Division of Pulmonary Medicine, Taipei Medical UniversityShuang Ho Hospital, New Taipei City, Taiwan; Department of Chemistry (H.L.L.), Fu Jen Catholic University; Jen-The Junior College of Medicine (K.H.C.), Nursing and Management, Maoli © 2012 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710 Transplantation Proceedings, 44, 929 –932 (2012)
County, Taiwan; and Department of Medicine (D.W.), College of Medicine Fu Jen Catholic University, New Taipei City, Taiwan. Supported by grants NSC 98-2320-B-038-010 from the National Science Council. Address reprint requests to David Wang, Professor, Department of Medicine, Fu Jen Catholic University, No. 510, Zhongzheng Rd., Xinzhuang Dist., New Taipei City, 24205, Taiwan. E-mail: [email protected]
0041-1345/–see front matter doi:10.1016/j.transproceed.2012.03.005 929
930
esearch in ischemia-reperfusion injury after organ transplantation surgery has attracted increased attention in a number of organ systems.1–3 Much of this work suggests that free oxygen radicals play critical roles to elevats pulmonary arterial pressure (PAP) during hypoxia challenge.4 – 6 Oxygen radicals can activate the COX pathway, looking to production of thromboxane (Tx).7,8 In the present study we analyzed the expression of inducible cyclooxygenase (COX II) in lung tissues after hypoxiareperfusion (H-R) challenge using real-time polymerase chain reactions (PCR). Furthermore, we analyzed blood concentrations of hydroxyl radical, nitric oxide, TxB2 as well as PAP changes during hypoxic challenge. The COX II inhibitor celecoxib was used to study the role of the COX cascade in the HPV response.
R
METHODS Preparation of Isolated and Perfused Rat Lungs The procedure to prepare isolated-perfused lungs was similar to that previously described by Shen et al.9 Sprague-Dawley rats (300 –350 g) were deeply anesthetized with an injection of pentobarbital sodium. After performing a tracheostomy, artificially ventilated the lungs with 5% CO2–95% room air. Heparin (1 U/g) was administered intravenously after performing midsternal thoractomy to collect 10 mL blood from the right ventricle to be mixed with 10 mL Hanks balanced salt solution. A cannula (inflow) and large catheter (outflow) were inserted into the pulmonary artery and left atrium, respectively. The lungs were artificially ventilated and perfused via a roller pump at a constant flow rate (8 –10 mL/min). The venous outflow from the left atrium was collected into the reservoir. A water bath was used to prewarm the perfusate which was maintained at constant temperature (37 ⫾ 0.5°C). The PAP was measured with a pressure transducer connected to a side arm from the inflow cannula.
Induction of Lung Hypoxia Reoxygenation The lungs underwent 2 consecutive hypoxic challenges. The isolated lungs were ventilated for 10 minutes with 5% CO2–95% N2 instead of 5% CO2–95% air to decrease the oxygen content of the blood. Then they were reoxygenated with 5% CO2–95% air. A second hypoxic challenge was administered thereafter for 10 minutes and the system allowed to reoxygenate again. The amount of time separating the 2 challenges was determined by the speed of recovery after the first challenge.
SU, YUAN, CHIANG ET AL
RNA Isolation and Real-Time PCR mRNA isolated from lung tissues using an mRNA isolation kit (Qiagen RNeasy kits; Qiagen, Valencia, CA) was reverse transcribed to cDNA following the manufacturer’s recommendations. PCR primers and TaqMan-MGB probes were designed using Primer Express v.2.0 software (Applied Biosystems, Foster City, CA) based on the sequences from GenBank. TaqManMGB probes were labeled with 6-carboxy-fluorescein (FAM) as the reporter dye. PCR reactions were monitored in real time using the ABI Prism 7000 Sequence Detector (Applied Biosystems).
Experimental Design Animals were randomly divided into 3 groups: 1) H-R rats (n ⫽ 7) were prepared and exposed to H-R as described above; 2) COX II inhibitor rats (n ⫽ 7), received celecoxib (10 mg/kg) by oral administration between the 2 consecutive challenges; 3) Sham, rats were prepared as described above, without H-R challenge.
Data Analysis Data are expressed as mean ⫾ SD. Comparisons within each group for a given parameter were performed using paired and unpaired Student’s t tests. Values of P ⬍ .05 were considered to be statistically significant.
RESULTS
In this study we showed that H-R of the rat lung induced pulmonary vasoconstriction (Fig 1). PAP increased significantly (⌬PAP ⫽ 4.1 ⫾ 0.8 mm Hg); however, consecutive hypoxic challenges did not show tachyphylaxis. Administration of the COX II inhibitor significantly attenuated the HPV response (Fig 1). The hypoxic vasoconstriction could be related to the production of inflammatory mediators such as oxygen radicals, nitrosative stress, and COX cascade TxB2 product. Administration of the COX II inhibitor celecoxib attenuated the respiratory burst 75.8 ⫾ 11.5 vs 50.5 ⫾ 7.8 mmol/L; P ⬍ .01; (Fig 2), nitrosative stress (77.7 ⫾ 15.7 vs 52.0 ⫾ 8.1 pmol; P ⬍ .05), and prostanoid cascade TxB2 product
Spectrofluorimetric Measurement of Methyl Guanidine We measured the formation of methyl guanidine (MG) as an index of hydroxyl radical production in blood10 and are indicator of H-R injury.
Measurement of Nitric Oxide by High-Performance Liquid Chromatography (HPLC) HPLC was used to measure blood levels of nitrite and nitrate anions derived from nitric oxide.
Measurement of TxB2 by Enzyme-Linked Immunosorbent Assay Analysis of TxB2 in the perfusate was performed using a commercially available immunoassay kit (Cayman).
Fig 1. PAP changes in 2 consecutive hypoxic challenges and intervention with cyclooxygenase inhibitor celecoxib. The sham group, was not exposed to hypoxia. ⫹P ⬍ .05 (significant difference between 1st and 2nd hypoxic challenges.
CELECOXIB AND PULMONARY VASOCONSTRICTION
931
ture, was dependent on the activation of p38 (MAPK).14 Malek et al observed that the COX II inhibitor celecoxib attenuated the lung injury induced by hindlimb ischemia and reperfusion.15 In addition, COX expression mediates pulmonary vasoconstriction in septic lungs,16 canine pulmonary reperfusion injury,17 rat lung reperfusion,18 and oleic acid–induced lung injury.19 In the present study, we demonstrated that the COX II inhibitor celecoxib attenuated the HPV response, which may be related to decreased Tx production after H-R challenge. In summary, we demonstrated that reoxygenation of hypoxic lung tissues induced pulmonary vasoconstriction and a PAP increase with oxidative and nitrosative stresses, COX II expression and prostanoid cascade. The COX II inhibitor celecoxib attenuated the HPV responses by reducing COX II expression and TxB2 release. REFERENCES Fig 2. H-R of the lung tissues induced significant increases of blood concentration of thromboxane (TXB2; *P ⬍ .05), hydroxyl radical (**P ⬍ .01), and nitric oxide (NO; *P ⬍ .05) and lung tissue COX II mRNA expression (***P ⬍ .01). COX II inhibitor significantly attenuated the increases (⫹P ⬍ .05; ⫹⫹P ⬍ .01; significant differences after celecoxib intervention).
(58.7 ⫾ 8.6 vs 45.6 ⫾ 8.1 pg/mL; P ⬍ .05). H-R induced an increase in mRNA expression of COX II which was also decreased by COX II inhibitor administration (P ⬍ .05). The attenuating effect of the COX II inhibitor on the H-R–induced pulmonary vasoconstriction may be related to the reduced TxB2 production (P ⬍ .05). DISCUSSION
Substantial evidence has accumulated that reactive oxygen radicals are involved in ischemia-reperfusion– or H-R–induced tissue injury in many organs.2– 4 The involved oxygen radicals include hydrogen peroxide, superoxide anion, and hydroxyl, as well as xanthine oxidase activation. During hypoxic challenge, PAP increased steadily. Hydroxyl radical and nitric oxide concentrations also increased significantly after the HPV response (Fig 1). Possible upstream mediators known to be elevated by oxidant stress include the COX II cascade and TxA2, which bind to and activate the TxA2/prostaglandin H2 receptor.7,11,12 The key enzymes to synthesize prostaglandin and Thromboxane are COX I, which is constitutive, and COX II, which is inducible. Prostanoids, major regulators of smooth muscle function are generated by interactions between COX and oxygen radicals. We hypothesized that various mediators of oxidative stress and nitrosative stress or cytokines alter COX expression and prostanoid generation in pulmonary artery smooth muscle cells. Bradykinin, transforming growth factor, and interleukin-1 increase COX II expression and prostaglandin release.13 Yang et al demonstrated that hypoxic induction of COX II expression in pulmonary vascula-
1. Feltes CM, Hassoun HT, Lie ML, et al: Pulmonary endothelial cell activation during experimental acute kidney injury. Shock 36:170, 2011 2. Xu B, Gao X, Xu J, et al: Ischemic postconditioning attenuates lung reperfusion injury and reduces systemic proinflammatory cytokine release via heme oxygenase 1. J Surg Res 166:e157, 2011 3. Peng CK, Huang KL, Wu CP, et al: Glutamine protects ischemia-reperfusion induced acute lung injury in isolated rat lungs. Pulm Pharmacol Ther 24:153, 2011 4. Frazziano G, Moreno L, Moral-Sanz J, et al: Neutral sphingomyelinase, NADPH oxidase and reactive oxygen species. Role in acute hypoxic pulmonary vasoconstriction. J Cell Physiol 226:2633, 2011 5. Knock GA, Snetkov VA, Shaifta Y, et al: Superoxide constricts rat pulmonary arteries via Rho-kinase-mediated Ca(2⫹) sensitization. Free Radic Biol Med 46:633, 2009 6. Shen CY, Lee JF, Su CL, Wang D, Chen CF: Hypoxia and reoxygenation of the lung tissues induced mRNA expressions of superoxide dismutase and catalase and interventions from different antioxidants. Transplant Proc 40:2182, 2008 7. Wong MS, Vanhoutte PM: COX-mediated endotheliumdependent contractions: from the past to recent discoveries. Acta Pharmacol Sin 31:1095, 2010 8. Tate RM, Morris HG, Schroeder WR, et al: Oxygen metabolites stimulate thromboxane production and vasoconstriction in isolated saline-perfused rabbit lungs. J Clin Invest 74:608, 1984 9. Shen CY, Wang D, Chang ML, et al: Protective effect of mepacrine on hypoxia-reoxygenation-induced acute lung injury in rats. J Appl Physiol 78:225, 1995 10. Lin HI, Chou SJ, Wang D, et al: Reperfusion liver injury induces down-regulation of eNOS and up-regulation of iNOS in lung tissues. Transplant Proc 38:2203, 2006 11. Zamora CA, Baron DA, Heffner JE: Thromboxane contributes to pulmonary hypertension in ischemia-reperfusion lung injury. J Appl Physiol 74:224, 1993 12. Roberts LJ, Morrow JD. The generation and actions of isoprostanes. Biochim Biophys Acta 1345:121, 1997 13. Bradbury DA, Newton R, Y-M Zhu, et al: Effect of bradykinin, TGF1, IL-1, and hypoxia on COX-2 expression in pulmonary artery smooth muscle cells Am J Physiol Lung Cell Mol Physiol 283:L717, 2002 14. Yang X, Sheares KK, Davie N, et al: Hypoxic induction of COX-2 regulates proliferation of human pulmonary artery smooth muscle cells. Am J Respir Cell Mol Biol 27:688, 2002 15. Malek HA, Saleh DM: Cyclooxygenase-2 inhibitor celecoxib in a rat model of hindlimb ischemia reperfusion. Can J Physiol Pharmacol 87:353, 2009
932 16. Fischer LG, Hollmann MW, Horstman DJ, Rich GF: Cyclooxygenase inhibitors attenuate bradykinin-induced vasoconstriction in septic isolated rat lungs. Anesth Analg 90: 625, 2000 17. Sunose Y, Takeyoshi I, Tsutsumi H, et al: Effects of FK3311 on pulmonary ischemia-reperfusion injury in a canine model. J Surg Res 95:167, 2001
SU, YUAN, CHIANG ET AL 18. Otani Y, Takeyoshi I, Yoshinari D, et al: Effects of the COX-2 inhibitor on ischemia-reperfusion injury in the rat lung. J Invest Surg 20:175, 2007 19. Leeman M, de Beyl VZ, Biarent D, et al: Inhibition of cyclooxygenase andn nitric oxide synthase in hypoxic vasoconstriction and oleic acid-induced lung injury. Am J Respir Crit Care Med 159:1383, 1999