ABSTRACT
AIMS: Inflammation and Toll-like receptor (TLR) signalling have been linked to the development of cardiac hypertrophy following transverse aortic constriction (TAC). In the present study, we investigated whether pre-treatment with the synthetic TLR9 ligands 1668-thioate or 1612-thioate modulates the progression of TAC-induced cardiac inflammation and hypertrophy. METHODS AND RESULTS: C57BL/6N-mice were pre-treated with 1668-thioate, 1612-thioate (0.25 nmol/g, i.p.), or phosphate-buffered saline 16 h prior to TAC or sham surgery. Heart-weight/body-weight ratio (HW/BW), cardiomyocyte cell size, cellular macrophage accumulation, myofibroblast differentiation, and collagen deposition were investigated for up to 28 days. Cardiac function was monitored using a pressure-volume catheter and M-mode echocardiography. Inflammatory gene expression in the heart was analysed via gene array, while the time course of mRNA expression of key inflammatory mediators was assessed via RT-qPCR. TAC increased the HW/BW ratio and cardiomyocyte cell size and induced macrophage accumulation, myofibroblast differentiation, and collagen deposition. These changes were accompanied by cardiac inflammation and a significant loss of left ventricular function. Pre-treatment with cytosine-phosphate-guanine (CpG)-containing 1668-thioate attenuated the inflammatory response, the progression of cardiac hypertrophy, and cardiac remodelling, which resulted in a prolonged preservation of left ventricular function. These changes were induced to a smaller extent by the use of the non-CG-containing oligodeoxynucleotide 1612-thioate. CONCLUSION: Pre-treatment with 1668-thioate attenuated cardiac hypertrophy following pressure overload, possibly by modifying the hypertrophy-induced inflammatory response, thereby reducing cardiac growth and fibrosis as well as delaying loss of cardiac function.
Subject(s)
Cardiomegaly/prevention & control , Cardiotonic Agents/pharmacology , Myocarditis/prevention & control , Myocardium/immunology , Oligodeoxyribonucleotides/pharmacology , Toll-Like Receptor 9/agonists , Animals , Cardiac Catheterization , Cardiomegaly/diagnostic imaging , Cardiomegaly/genetics , Cardiomegaly/immunology , Cardiomegaly/metabolism , Cardiotonic Agents/chemical synthesis , Chemokine CCL2/metabolism , Chemokine CCL4/metabolism , Collagen/metabolism , Disease Models, Animal , Fibrosis , Gene Expression Profiling/methods , Gene Expression Regulation , Heart Failure/immunology , Heart Failure/physiopathology , Heart Failure/prevention & control , Inflammation Mediators/metabolism , Ligands , Macrophage Activation/drug effects , Male , Mice , Mice, Inbred C57BL , Myocarditis/diagnostic imaging , Myocarditis/genetics , Myocarditis/immunology , Myocarditis/metabolism , Myocardium/metabolism , Myocardium/pathology , Oligodeoxyribonucleotides/chemical synthesis , Oligonucleotide Array Sequence Analysis , RNA, Messenger/metabolism , Real-Time Polymerase Chain Reaction , Time Factors , Toll-Like Receptor 9/metabolism , Ultrasonography , Ventricular Function, Left/drug effects , Ventricular Pressure/drug effectsABSTRACT
BACKGROUND: Acute lung injury is a common complication in critically ill patients. Several studies suggest that volatile anesthetics have immunomodulating effects. The aim of the current study was to assess possible postconditioning with sevoflurane in an in vivo model of endotoxin-induced lung injury. METHODS: Rats were anesthetized, tracheotomized, and mechanically ventilated. Lipopolysaccharide (saline as control) was administered intratracheally. Upon injury after 2 h of propofol anesthesia, general anesthesia was continued with either sevoflurane or propofol for 4 h. Arterial blood gases were measured every 2 h. After 6 h of injury, bronchoalveolar lavage was performed and lungs were collected. Total cell count, albumin content, concentrations of the cytokines cytokine-induced neutrophil chemoattractant-1 and monocyte chemoattractant protein-1, and phospholipids were analyzed in bronchoalveolar lavage fluid. Expression of messenger RNA for the two cytokines and for surfactant protein B was determined in lung tissue. Histopathologic examination of the lung was performed. RESULTS: Significant improvement of the ratio of oxygen tension to inspired oxygen fraction was shown with sevoflurane (mean + or - SD: 243 + or - 94 mmHg [32.4 kPa]) compared with propofol (88 + or - 19 mmHg [11.7 kPa]). Total cell count representing effector cell recruitment as well as albumin content as a measure of lung permeability were significantly decreased in the sevoflurane-lipopolysaccharide group compared with the propofol-lipopolysaccharide group in bronchoalveolar lavage fluid. Expression of the cytokines protein in bronchoalveolar lavage fluid as well as messenger RNA in lung tissue was significantly lower in the sevoflurane-lipopolysaccharide group compared with the propofol-lipopolysaccharide group. CONCLUSIONS: Postconditioning with sevoflurane attenuates lung damage and preserves lung function in an in vivo model of acute lung injury.
