151. Toll-like receptor 4 plays a central role in cardiac dysfunction during trauma hemorrhage shock.
- Author
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Zhang X, Lu C, Gao M, Cao X, Ha T, Kalbfleisch JH, Williams DL, Li C, and Kao RL
- Subjects
- Animals, Dose-Response Relationship, Drug, Hemodynamics drug effects, Hemodynamics physiology, Lipid A analogs & derivatives, Lipid A pharmacology, Male, Mice, Knockout, NF-kappa B metabolism, Neutrophil Infiltration drug effects, Neutrophil Infiltration physiology, Phosphorylation drug effects, Phosphorylation physiology, Proto-Oncogene Proteins c-akt metabolism, Shock, Hemorrhagic etiology, Shock, Hemorrhagic metabolism, Soft Tissue Injuries complications, Toll-Like Receptor 4 antagonists & inhibitors, Toll-Like Receptor 4 deficiency, Tumor Necrosis Factor-alpha biosynthesis, Heart physiopathology, Shock, Hemorrhagic physiopathology, Toll-Like Receptor 4 physiology
- Abstract
Cardiac dysfunction is a major consequence that contributes to the high mortality of trauma-hemorrhage (TH) patients. Recent evidence suggests that innate immune and inflammatory responses mediated by Toll-like receptors (TLRs) play a critical role in the pathophysiologic mechanisms of acute organ dysfunction during TH. This study investigated the role of TLR4 in cardiac dysfunction following TH. Toll-like receptor 4-deficient (TLR4-/-, n = 7/group) and age-matched wild-type (WT, n = 8/group) mice were subjected to TH that was induced by soft tissue injury and blood withdrawal from the jugular vein to a mean arterial pressure of 35 ± 5 mmHg. Cardiac function and mean arterial pressure were measured with a Millar system before, during, and after blood withdrawal. Sham surgical-operated mice served as control (WT, n = 9/group; TLR4-/-, n = 10/group). Cardiac function in WT mice was significantly reduced following TH. However, cardiac function was well preserved in TLR4-/- mice. Administration of a TLR4 antagonist (3 mg/kg) to WT mice also significantly attenuated TH-induced cardiac dysfunction. Western blot showed that either TLR4-/- or TLR4 antagonist markedly attenuated TH-induced decreases in the levels of phosphorylated-Akt in myocardium. In addition, inhibition of TLR4 attenuated TH-induced myocardial nuclear factor κB-binding activity as well as lung myeloperoxidase activity and tumor necrosis factor α production. The data indicate that TLR4 plays a central role in TH-induced cardiac dysfunction. Toll-like receptor 4 deficiency or TLR4 inhibition attenuated cardiac dysfunction following TH, which may involve activation of the phosphoinositide 3-kinase/Akt signaling and decrease in nuclear factor κB-binding activity. Toll-like receptor 4 antagonism may be a new and novel approach for the treatment and management of cardiac dysfunction in TH patients.
- Published
- 2014
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