부산대학교 도서관

Introduction: The abnormal proliferation of pulmonary arterial smooth muscle cells (PASMCs) is one of pathological characteristics of pulmonary arterial hypertension (PAH). Inflammation is thought to play an important role for PASMCs proliferation in PAH. Dexmedetomidine (DEX) is a selective α2-adrenergic receptor agonist that is used as a sedative in clinical settings. It has been reported that DEX regulates certain inflammatory responses.Hypothesis: DEX ameliorates Monocrotaline (MCT)-induced PAH in rats through its anti-inflammatory effect.Methods: In vivo, 6-week-old male Sprague-Dawley rats were injected 60 mg/kg of MCT subcutaneously. At day 14 after MCT injection, continuous infusions of DEX (2μg/kg/hour) by osmotic pumps were started in one group (MCT + DEX group), and not in another group (MCT group). We performed cardiac catheterization to measure right ventricular systolic pressure (RVSP) and prepared rats paraffin embedded lung tissues for Immunohistochemistry at day 23. In vitro, we analyzed the effect of DEX on human PASMCs (hPASMCs) proliferation stimulated with fibroblast growth factor 2 (FGF2). In addition, we examined mRNA levels of proinflammatory cytokines in hPASMCs by FGF2 stimuation with/without DEX.Results: Both RVSP and survival rate markedly improved in MCT + DEX group compared with those in MCT group (RVSP; 34mmHg ± 4mmHg vs. 70mmHg ± 10mmHg, survival rate 42% vs. 0% at day 29). In histological analysis, medial hypertrophy of pulmonary arterioles and phosphorylated-p65 positive PASMCs significantly reduced in MCT + DEX group. DEX also inhibited hPASMCs proliferation dose dependently. Furthermore, IL-6 mRNA expression was suppressed by DEX in hPASMCs stimulated with FGF2.Conclusions: DEX improved MCT-induced PAH in rats by suppressing PASMCs proliferation through the anti-inflammatory effect, which may result from inhibition of NF-κB activation induced by IL-6. DEX can be a new therapeutic tool for PAH.