甘草苷对感染后咳嗽(肺阴虚证)小鼠的止咳作用机制及抗氧化作用的研究

为探讨甘草苷对感染后咳嗽(肺阴虚证)小鼠的止咳疗效及抗氧化的作用机制.采用烟熏＋内毒素(LPS)滴鼻＋甲状腺素灌胃＋辣椒素雾化诱咳来构建感染后咳嗽(肺阴虚证)小鼠模型；造模成功后随机分为空白组(生理盐水)、模型组(生理盐水)、阳性组(孟鲁司特钠)和甘草苷低、中、高剂量组；观察造模前后各组小鼠的行为学及体质量变化，采用辣椒素雾化诱咳来测定各组小鼠的咳嗽敏感性及咳嗽次数，通过酶联免疫吸附法(ELISA)测定小鼠血清中炎症与肺组织中抗氧化损伤相关蛋白水平变化并经由苏木精-伊红(HE)染色法来观察各组小鼠的肺组织病变.结果表明，甘草苷止咳的作用机制可能为有效减少小鼠血清中TNF-α、IL-6、IL-13、TLR2、TGF-β1、IgE等细胞因子及炎性介质的释放，进而减轻气道感染性及变态性炎性反应环境来降低咳嗽高敏感性，减少对咳嗽中枢的刺激来达到止咳的目的；抗氧化的作用机制可能为有效提高小鼠肺组织中SOD的含量，减少小鼠肺组织中MDA的含量，来改善体内抗氧化平衡系统的紊乱，有效清除机体中的过量自由基，提高机体内抗氧化酶的含量，以减轻氧化损伤来达到抗氧化的目的.

Studies on the antitussive mechanism and antioxidative effect of glycyrrhizin on post-infection cough (pulmonary yin deficiency syndrome) mice

This paper aims at studying the antitussive effect and antioxidative effect of glycyrrhizin on post-infection cough (pulmonary yin deficiency syndrome) mice.The PIC (pulmonary yin deficiency syndrome) model mice were established by cigarette-smoking exposure， intranasaladministration with small dose of LPS， thyroid hormone and capsaicin atomization method.The mice were randomly divided into control group (physiological saline)， model group (physiological saline)， positive group (montelukast sodium) and glycyrrhizin low， medium， and high dose groups after successful modeling.The behavioral and body mass changes of mice were observed before and after modeling.The sensitivity and number of coughs in mice were determined by capsaicin aerosolized method.Enzyme-linked immunosorbent assay (ELISA) was used to determine levels of inflammation in mouse serum and changes of protein levels associated with antioxidant damage in lung tissue.Hematoxylin-eosin (HE) staining method was used to observe the pathological changes of lung tissue in each group of mice.The results showed that the mechanism of glycyrrhizin in relieving cough might due to its effectively reduction of the release of TNF-α， IL-6， IL-13， TLR2， TGF-β1 and IgE in serum of mice.The airway infection and allergic inflammatory response environment are reduced to attenuate the high sensitivity of cough， and the stimulation of cough center is weakened to relieve the cough.The mechanism of antioxidation might be its ablility on increasing the content of SOD and decreasing the content of MDA in the lung tissue of mice， which improving the disturbance of the antioxidant balance system in vivo，removing excessive free radicals and increasing the content of antioxidant enzymes in the body.