人参皂苷Rb1介导TLR3/TRIF信号通路对哮喘大鼠的抗炎作用机制

目的探讨人参皂苷Rb1介导Toll样受体(TLR)3/β干扰素TIR结构域衔接蛋白(TRIF)信号通路对哮喘大鼠模型抗炎作用的影响。方法80只SD大鼠随机分成5组:对照组、模型组、地塞米松组(1 mg/kg)、人参皂苷Rb1低剂量组(100 mg/kg)、人参皂苷Rb1高剂量组(200 mg/kg),每组16只。模型组、地塞米松组、人参皂苷Rb1低、高剂量组建立哮喘大鼠模型,建模成功后地塞米松组、人参皂苷Rb1低、高剂量组给予相应药物灌胃,对照组及模型组给予等量的生理盐水灌胃,每天1次,连续给药14 d。末次给药后24 h,测定大鼠血液淋巴细胞、嗜酸性粒细胞、中性粒细胞、动脉血氧分压(PaO₂)水平,计算大鼠肺/体比值,苏木素-伊红(HE)染色观察肺组织病理学变化,实时荧光定量PCR及蛋白免疫印迹法测定大鼠肺组织中TLR3、TRIF mRNA和蛋白表达水平。结果与对照组比较,模型组大鼠肺/体比值、淋巴细胞、嗜酸性粒细胞、中性粒细胞水平、TLR3、TRIF mRNA和蛋白表达水平明显升高,PaO₂水平明显降低(P<0.05);与模型组比较,地塞米松组、人参皂苷Rb1低、高剂量组大鼠肺/体比值、淋巴细胞、嗜酸性粒细胞、中性粒细胞水平、TLR3、TRIF mRNA和蛋白表达水平降低,PaO₂水平升高(P<0.05);且人参皂苷Rb1高剂量组大鼠肺/体比值、淋巴细胞、嗜酸性粒细胞、中性粒细胞水平、TLR3、TRIF mRNA和蛋白表达水平低于人参皂苷Rb1低剂量组,PaO₂水平高于人参皂苷Rb1低剂量组(P<0.05);与地塞米松组比较,人参皂苷Rb1低剂量组大鼠肺/体比值、淋巴细胞、嗜酸性粒细胞、中性粒细胞水平、TLR3、TRIF mRNA和蛋白表达升高,PaO₂水平降低(P<0.05);人参皂苷Rb1高剂量组与地塞米松组上述指标差异无统计学意义(P>0.05)。结论人参皂苷Rb1能够减轻哮喘模型大鼠肺部炎症反应,其机制可能与人参皂苷Rb1抑制哮喘大鼠肺部TLR3、TRIF mRNA和蛋白表达水平进而抑制TLR3/TRIF信号通路的激活有关。

The anti-inflammatory effect of Ginsenoside Rb1 in rats with asthma mediated by TLR3/TRIF signaling pathway

Objective To explore the anti-inflammatory effect of Ginsenoside Rb1 in rats with asthma mediated by Toll-like receptor(TLR)3/TIR-domain-containing adaptor inducing interferon-β(TRIF)signaling pathway.Methods 80 SD rats were randomly divided into 5 groups:control group,model group,dexamethasone group(1 mg/kg),Ginsenoside Rb1 low dose group(100 mg/kg),Ginsenoside Rb1 high dose group(200 mg/kg),16 in each group.The rats in the model group,dexamethasone group and Ginsenoside Rb1 low and high dose group were used to establish asthma model.After modeling,the rats in the dexamethasone group,Ginsenoside Rb1 low and high dose group were given corresponding drugs by gavage,the rats in the control group and model group were given corresponding volumes of normal saline,once a day for 14 consecutive days.24 h after the last administration,lymphocyte,eosinophils,neutrophils and arterial partial pressure of oxygen(PaO₂)were measured,the lung/body ratio was calculated,hematoxylin eosin(HE)staining was used to observe the pathological changes of lung tissue,the mRNA and protein expressions of TLR3 and TRIF in rat lung tissue were measured by real-time fluorescence quantitative PCR and Western blot.Results Compared with the control group,the lung/body ratio,lymphocyte,eosinophil,neutrophil level,TLR3,TRIF mRNA and protein expression level in the model group were significantly increased,while the PaO₂ level significantly decreased(P<0.05).Compared with the model group,the lung/body ratio,lymphocyte,eosinophil,neutrophil level,TLR3,TRIF mRNA and protein expression level in dexamethasone group,Ginsenoside Rb1 low and high dose group were decreased,while the PaO₂ level increased(P<0.05).And the lung/body ratio,lymphocyte,eosinophil,neutrophil level,TLR3,TRIF mRNA and protein expression level in the Ginsenoside Rb1 high dose group were lower than those in the Ginsenoside Rb1 low dose group,and the PaO₂ level was higher than that in the Ginsenoside Rb1 low dose group(P<0.05).Compared with dexamethasone group,the lung/body ratio,lymphocyte,eosinophil,neutrophil level,TLR3,TRIF mRNA and protein expression level in the Ginsenoside Rb1 low dose group were increased,while PaO₂ level decreased(P<0.05).There was no significant difference between Ginsenoside Rb1 high dose group and dexamethasone group(P>0.05).Conclusions Ginsenoside Rb1 could reduce the pulmonary inflammatory response in asthmatic rats.The mechanism may be related to Ginsenoside Rb1 inhibiting the expression of TLR3,TRIF mRNA and protein in the lung of asthmatic rats and then inhibiting the activation of TLR3/TRIF signaling pathway.