title: Protection by 20-5,14-HEDGE against surgically induced ischemia reperfusion lung injury in rats.
abstract: BACKGROUND
  We previously reported that the cytochrome P450 product 20-hydroxyeicosatetraenoic acid has prosurvival effects in pulmonary artery endothelial cells and ex vivo pulmonary arteries. We tested the potential of a 20-hydroxyeicosatetraenoic acid analog N-[20-hydroxyeicosa-5(Z),14(Z)-dienoyl]glycine (20-5,14-HEDGE) to protect against lung ischemic reperfusion injury in rats. Furthermore, we examined activation of innate immune system components, high mobility group box 1 (HMGB1) and toll-like receptor 4 (TLR4), in this model as well as the effect of 20-5,14-HEDGE on this signaling pathway.
  
  
  METHODS
  Sprague-Dawley rats treated with 20-5,14-HEDGE or vehicle were subjected to surgically induced, unilateral lung ischemia for 60 minutes followed by reperfusion for 2 hours in vivo. Injury was assessed histologically by hematoxylin and eosin, and with identification of myeloperoxidase immunohistochemically. The HMGB1 and TLR4 proteins were identified by Western blot. Caspase 3 activity or 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole, incorporation were used to measure apoptosis and cell survival.
  
  
  RESULTS
  The ischemia reperfusion injury evoked atelectasis and hemorrhage, an influx of polymorphonuclear cells, and increased TLR4 and HMGB1 expression. Caspase 3 activity was increased, and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide incorporation was decreased. The 20-5,14-HEDGE protected against each of these endpoints, including infiltration of polymorphonuclear cells, with no changes in caspase 3 activity in other organs.
  
  
  CONCLUSIONS
  Lung ischemia reperfusion produces apoptosis and activation of the innate immune system including HMGB1 and TLR4 within 2 hours of reperfusion. Treatment with 20-5,14-HEDGE decreases activation of this response system, and salvages lung tissue.
authors: Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors: Irshad
authors: I
authors: Ali
authors: Stephanie
authors: S
authors: Gruenloh
authors: Ying
authors: Y
authors: Gao
authors: Anne
authors: A
authors: Clough
authors: John R
authors: JR
authors: Falck
authors: Meetha
authors: M
authors: Medhora
authors: Elizabeth R
authors: ER
authors: Jacobs
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000037:antagonists & inhibitors; D055371:Acute Lung Injury / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D000818:Animals; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D004195:Disease Models, Animal; D024243:HMGB1 Protein / Q000096:biosynthesis; D055666:Lipopeptides / Q000494:pharmacology*; D008168:Lung / Q000601:surgery; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000150:complications / Q000378:metabolism / Q000517:prevention & control*; D015398:Signal Transduction / Q000187:drug effects; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis
chemical_list: D024243:HMGB1 Protein; C104200:Hbp1 protein, rat; D055666:Lipopeptides; C533498:N-(20-hydroxyeicosa-5,14-dienoyl)glycine; C495347:Tlr4 protein, rat; D051197:Toll-Like Receptor 4; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D053148:Caspase 3