BACKGROUND Hypoxia reportedly increases free radical generation in the body, causing oxidative stress and inhibiting β2-AR signaling. The present study correlates the prophylactic potential of quercetin and salbutamol in ameliorating fluid clearing capacity of lungs by re-sensitizing β2-AR signaling under hypoxia. METHODS Male SD rats supplemented orally with quercetin (50 mg/Kg BW), and salbutamol (2 mg/Kg BW) were exposed to hypobaric hypoxia at 7620 m for 6 h. Western blotting and ELISA quantitated NFĸB and related genes and GPCR pathway proteins. The binding affinities of drugs with receptor were determined by SPR spectroscopy and further confirmed insilico. RESULTS Quercetin and salbutamol pre-treatment significantly up-regulated the expressions of β2-AR, GPR-1, GPR-10, GCSα, cAMP content, and down-regulated GRK-2, β-arrestin, ROS, NFκB (p < 0.001), thus, enhancing alveolar fluid clearance (AFC). SPR and insilico findings revealed a higher binding affinity of β2-AR with quercetin over salbutamol. CONCLUSION Results indicated quercetin to be a better prophylactic that augmented AFC in rats exposed to hypoxia by attenuating inflammation and stimulating β2-AR.

中文翻译：

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槲皮素作为有效的β2-AR增敏剂对抗缺氧大鼠肺部液体清除损伤的功效。

背景技术据报道，低氧增加了体内自由基的产生，引起氧化应激并抑制了β2-AR信号传导。本研究通过降低缺氧条件下的β2-AR信号转导，将槲皮素和沙丁胺醇的预防潜力与改善肺部液体清除能力相关联。方法雄性SD大鼠口服槲皮素（50 mg / Kg BW）和沙丁胺醇（2 mg / Kg BW）于7620 m下进行低压缺氧6 h。Western印迹和ELISA定量了NFĸB及其相关基因和GPCR通路蛋白。药物与受体的结合亲和力通过SPR光谱法确定，并进一步证实为硅胶。结果槲皮素和沙丁胺醇预处理可显着上调β2-AR，GPR-1，GPR-10，GCSα，cAMP含量的表达，并下调GRK-2，β-arrestin，ROS的表达。NFκB（p <0.001），从而增强了肺泡液清除率（AFC）。SPR和insilico结果表明，β2-AR与槲皮素的结合亲和力高于沙丁胺醇。结论结果表明，槲皮素通过减弱炎症反应和刺激β2-AR可以更好地预防缺氧大鼠AFC。