title: Toll-like receptor 4 regulates heme oxygenase-1 expression after hemorrhagic shock induced acute lung injury in mice: requirement of p38 mitogen-activated protein kinase activation.
abstract: Acute lung injury (ALI) leading to respiratory distress is a common sequela of shock or trauma. The toll-like receptors (TLRs) stand at the interface of innate immune activation in the settings of both infection and sterile injury by responding to a variety of microbial and endogenous ligands alike. This work explored the effects of TLR-4 on hemorrhage-induced ALI and characterizes the signaling pathways and the mechanisms involved in noninfectious ALI. Mice underwent hemorrhagic shock and resuscitation (HSR). Arterial blood gases; expressions of TLR-4, heme oxygenase 1 (HO-1), and p38 mitogen-activated protein kinase (p38MAPK); myeloperoxidase activity; lung wet/dry ratios; and IL-10 levels in lung tissues were obtained at 6, 24, and 48 h after HSR. Hemorrhagic shock and resuscitation induced significant expressions of TLR-4, HO-1, and p38MAPK in C3H/HeN mice. IL-10 and myeloperoxidase were markedly increased at 24 h after HSR, and C3H/HeN mice had ALI with PaO2/fraction of inspired oxygen less than 300 mmHg. The induced amount of each cytokine level and the expressions of TLR-4, HO-1, and p38MAPK of C3H/HeN mice were significantly higher compared with C3H/HeJ mice. This study demonstrated that lung p38MAPK is activated after HSR, and p38MAPK inhibitor FR167653 suppresses HO-1 induction after ALI. We concluded that TLR-4 might induce HO-1 messenger RNA expression, which is probably involved in p38MAPK activation in the development of the lung dysfunction after HSR.
authors.affiliation: Department of Anesthesiology, Zhongnan Hospital, Medical College of Wuhan University, Wuhan, Hubei, People's Republic of China.
authors.forename: Chang
authors.initials: C
authors.lastname: Chen
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Wang
authors.forename: Zongze
authors.initials: Z
authors.lastname: Zhang
authors.forename: Chengyao
authors.initials: C
authors.lastname: Wang
authors.forename: Mian
authors.initials: M
authors.lastname: Peng
mesh_terms: D055371:Acute Lung Injury / Q000209:etiology* / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D000818:Animals; D015153:Blotting, Western; D004195:Disease Models, Animal; D005786:Gene Expression Regulation; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D007150:Immunohistochemistry; D016753:Interleukin-10 / Q000378:metabolism; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008853:Microscopy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012771:Shock, Hemorrhagic / Q000503:physiopathology*; D013997:Time Factors; D051197:Toll-Like Receptor 4 / Q000378:metabolism / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D051197:Toll-Like Receptor 4; D016753:Interleukin-10; D051547:Heme Oxygenase-1; D048051:p38 Mitogen-Activated Protein Kinases