Effects of endogenous carbon monoxide on collagen synthesis in pulmonary artery in rats under hypoxia.
ABSTRACT To study the role of endogenous carbon monoxide (CO) in collagen metabolism during hypoxic pulmonary vascular remodeling, a total of 18 Wistar rats were used in the study and they were randomly divided into three groups: hypoxia group (n = 6), hypoxia with zinc protoporphyrin-IX (ZnPP-IX) group (n = 6) and control group (n = 6). The measurement of mean pulmonary artery pressure (mPAP) and carboxyhemoglobin (HbCO) formation in lung tissue homogenates was measured. A morphometric analysis of pulmonary vessels was performed, in which the percentage of muscularized arteries (MA); partially muscularized arteries (PMA) and nonmuscularized arteries (NMV) in small and median pulmonary vessels, relative medial thickness (RMT) and relative medial area (RMA) of pulmonary arteries were analyzed. Collagen type I and III and transforming growth factor-beta3 (TGF-beta3) expressions were detected by immunohistochemical assay. The expressions of procollagen type I and III and TGF-beta3 mRNA were detected by in situ hybridization. The results showed that ZnPP-IX significantly increased mPAP and markedly decreased HbCO formation in lung tissue homogenates in rats under hypoxia (P < 0.01). In the hypoxia rats treated with ZnPP-IX, the percentage of muscularized arteries of small and median pulmonary vessels was obviously increased, and RMT and RMA of intra-acinar muscularized pulmonary arteries were markedly increased compared with hypoxic rats. Ultrastructural changes, such as hyperplasia and hypertrophy of endothelial cells (ECs) and smooth muscle cells (SMCs) and the increased number of SMCs in synthetic phenotype were found in intra-acinar pulmonary muscularized arteries of hypoxic rats treated with ZnPP-IX. Meanwhile, ZnPP-IX promoted the expression of collagen type I and III and TGF-beta3 protein in pulmonary arteries of rats under hypoxia (P < 0.01). Furthermore, ZnPP-IX elevated obviously the expressions of procollagen type I and III mRNA, and TGF-beta3 mRNA in pulmonary arteries of rats under hypoxia (P < 0.01). The results of this study suggested that ZnPP-IX played an important role in promoting collagen synthesis in pulmonary arteries of rats with hypoxic pulmonary structural remodeling by increasing the expression of TGF-beta3. The above findings also suggested a possible role of endogenous CO in the pathogenesis of chronic hypoxic pulmonary hypertension.
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ABSTRACT: Transforming growth factor-β (TGF-β) is a multifunctional regulatory cytokine that is implicated in a variety of kidney diseases, including diabetic nephropathy and chronic transplant rejection, where it promotes stimulation of the extracellular matrix deposition, cell proliferation, and migration. TGF-β exerts its biological functions largely via its downstream complex signaling molecules, Smad proteins. Paradoxically, TGF-β also is essential for normal homeostasis and suppression of inflammation through mechanisms that are yet to be fully elucidated. One feasible mechanism by which TGF-β may exert its beneficial properties is through induction of heme oxygenase-1 (HO-1). Induction of this redox-sensitive enzyme is known to be cytoprotective through its potent antioxidant, anti-inflammatory, and anti-apoptotic properties in different conditions including several kidney diseases. In this overview, recent advances in our understanding of the role of TGF-β in kidney disease, its molecular regulation of HO-1 expression, and the potential role of HO-1 induction as a therapeutic modality in TGF-β-mediated kidney diseases are highlighted.Seminars in Nephrology 05/2012; 32(3):277-86. DOI:10.1016/j.semnephrol.2012.04.007 · 2.94 Impact Factor
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ABSTRACT: Fluorofenidone (AKF-PD) is a novel pyridone derivate that targets transforming growth factor-β1 (TGF-β1) signaling. Previous studies have proven that AKF-PD functions as an antifibrotic agent in pulmonary fibrosis and renal fibrosis models. Activated TGF-β1 signaling is thought to be a major feature of pulmonary hypertension (PH). TGF-β1 exerts powerful pro-proliferation effects on pulmonary arterial smooth muscle cells (PASMCs), and hence, prompts vascular remodeling. This study is designed to investigate the effect of AKF-PD on vascular remodeling in a rat model of hypoxia-induced PH. PH was induced in rats by 4 weeks of hypoxia. The expression of TGF-β1, collagen I, and collagen III was analyzed by ELISA, immunohistochemistry, real-time PCR, or Western blot. Proliferation of cultured PASMCs was determined by the BrdU incorporation method and flow cytometry. The results showed that AKF-PD treatment (0.5 or 1.0 g·(kg body mass)·d(-1)) for 4 weeks attenuated pulmonary vascular remodeling and improved homodynamic parameters. TGF-β1 level was significantly down-regulated by AKF-PD both in vivo and in vitro. Furthermore, hypoxia- and TGF-β1-induced PASMC proliferation and collagen expression were both significantly suppressed by AKF-PD. These results suggest that AKF-PD ameliorates the progression of PH induced by hypoxia in rats through its regulation of TGF-β1 expression, PASMC proliferation, and the extracellular matrix.Canadian Journal of Physiology and Pharmacology 01/2014; 92(1):58-69. DOI:10.1139/cjpp-2013-0056 · 1.55 Impact Factor
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ABSTRACT: Chrysin (5,7-dihydroxyflavone) inhibits platelet-derived growth factor-induced vascular smooth muscle cell proliferation and arterial intima hyperplasia. This study aims to investigate the effects of chrysin on rat pulmonary vascular remodeling in hypoxia-induced pulmonary hypertension (PH). Sprague-Dawley rats were continuously exposed to 10% O2 for 4 weeks to induce PH. The effect of chrysin (50 or 100 mg/kg/d, subcutaneous) on vascular remodeling was investigated in hypoxia-induced PH model. At the end of the experiments, the indexes for pulmonary vascular remodeling and right ventricle hypertrophy were measured by vascular medial wall thickness and the ratio of right ventricle to (left ventricle plus septum). The expressions of NOX4, collagen I, and collagen III were analyzed by immunohistochemistry, real-time PCR, or western blotting. The proliferation of cultured pulmonary artery smooth muscle cells (PASMCs) was determined by BrdU incorporation and flow cytometry. The levels of malondialdehyde (MDA) and reactive oxygen species (ROS) were also determined by thiobarbituric acid reactive substances assay and 2'7'-dichlorofluorescein diacetate method. Chrysin treatment for 4 weeks significantly attenuated pulmonary vascular remodeling and improved collagen accumulation and down-regulated collagen I and collagen III expressions, accompanied by downregulation of NOX4 expression in the pulmonary artery (P = 0.012 for 50 mg/kg/d, P < 0.001 for 100 mg/kg/d) and lung tissue (P = 0.026, P < 0.001). In vitro, chrysin (1, 10, and 100 μM) remarkably attenuated PASMC proliferation (P = 0.021 for 1 μM, P < 0.001 for 10 μM, and P < 0.001 for 100 μM), collagen I expression (P = 0.035, P < 0.001, and P < 0.001), and collagen III expression (P = 0.027, P < 0.001, and P < 0.001) induced by hypoxia, and these inhibitory effects of chrysin were accompanied by inhibition of NOX4 expression (P = 0.019, P < 0.001, and P < 0.001), ROS production (P = 0.038, P < 0.001, and P < 0.001), and MDA generation (P = 0.024, P < 0.001, and P < 0.001). This study demonstrated that chrysin treatment in hypoxia-induced PH in rats reversed the hypoxia-induced (1) elevations of NOX4 expression, (2) productions of ROS and MDA, (3) proliferation of PASMC, and (4) accumulation of collagen.Chinese Medicine 12/2015; 10(1):4. DOI:10.1186/s13020-015-0032-2 · 2.34 Impact Factor