黄芩苷对脓毒症急性肺损伤小鼠TLR4/NF-κB通路及Treg/Th17平衡的影响

Effects of Baicalin on TLR4/NF-κB pathway and Treg/Th17 balance in mice with sepsis-induced acute lung injury

目的:探究黄芩苷(BA)对脓毒症急性肺损伤小鼠TLR4/NF-κB通路及Treg/Th17平衡的影响。方法:腹腔注射脂多糖溶液建立脓毒症急性肺损伤小鼠模型,随机分为模型组、地塞米松(7.2 mg/kg)组、BA低剂量(75 mg/kg)组、BA中剂量(150 mg/kg)组、BA高剂量(300 mg/kg)组,每组12只,另取12只小鼠以等量0.9%氯化钠溶液腹腔注射,设定为对照组。分组处理后,测定小鼠肺组织湿干比(湿重/干重,W/D);检测小鼠动脉血气指标(PaCO、PaO、OI);HE染色检测小鼠肺组织病理变化情况;流式细胞术检测各组小鼠外周血中Th17、Treg比例,计算Th17/Treg;以试剂盒检测小鼠血清细胞因子TNF-α、IL-6、IL-17、TGF-β及肺组织SOD、MDA水平;免疫印迹法检测小鼠肺组织TLR4/NF-κB通路相关蛋白(TLR4、MyD88、核NF-κB p65)表达。结果:与对照组相比,模型组小鼠肺组织呈现明显的病理损伤,W/D、PaCO、Th17/Treg、血清TNF-α、IL-6及IL-17水平、肺组织MDA水平、TLR4及MyD88、核NF-κB p65蛋白表达水平明显升高(P<0.05),PaO、OI、血清TGF-β水平、肺组织SOD水平明显降低(P<0.05);与模型组相比,BA各剂量组及地塞米松组小鼠肺组织病理损伤减轻,W/D、PaCO、Th17/Treg、血清TNF-α、IL-6及IL-17水平、肺组织MDA水平、TLR4及MyD88、核NF-κB p65蛋白表达水平降低(P<0.05),PaO、OI、血清TGF-β水平、肺组织SOD水平升高(P<0.05),且BA不同剂量组之间呈剂量依赖性(P<0.05);BA高剂量组与地塞米松组相比,各指标间差异无统计学意义(P>0.05)。结论:BA可抑制TLR4/NF-κB通路激活,促使Treg/Th17平衡向Treg偏移,阻止炎症与氧化应激反应发生发展,减轻脓毒症小鼠肺组织急性损伤,修复肺功能。

Objective:To investigate the effects of Baicalin(BA)on TLR4/NF-κB pathway and Treg/Th17 balance in mice with sepsis-induced acute lung injury.Methods:Mouse model of sepsis-induced acute lung injury was established by intraperitoneal injection of lipopolysaccharide solution,and mice were randomly divided into model group,dexamethasone(7.2 mg/kg)group,BA low dose(75 mg/kg)group,BA medium dose(150 mg/kg)group,BA high dose(300 mg/kg)groups,with 12 mice in each group.Another 12 mice were intraperitoneally injected with the same amount of 0.9% sodium chloride solution as control group. After treatment,lung wet/dry ratio(W/D)of mice lung tissue was measured;arterial blood gas indexes(PaCO,PaO,OI)were detected;HE staining was used to detect the pathological changes of lung tissue;ratio of Th17 and Treg in peripheral blood of mice in each group was detected by flow cytometry,and Th17/Treg was calculated;the serum levels of TNF-α,IL-6,IL-17,TGF-β,SOD and MDA in lung tissue were detected by kit;and expressions of TLR4/NF-κB pathway related proteins(TLR4,MyD88,nuclear NF-κB p65)were detected by Western blot.Results:Compared with those in control group,the lung tissue showed obvious pathological damage in model group,W/D,PaCO,Th17/Treg,serum TNF-α,IL-6 and IL-17 levels,MDA level in lung tissue,TLR4,MyD88 and NF-κB p65 protein expressions in lung tissue were significantly higher(P<0.05),PaO,OI,serum TGF-β level and SOD level in lung tissue were significantly lower(P<0.05);compared with those in model group,the pathological damage of lung tissue in BA group and dexamethasone group were reduced,W/D,PaCO,Th17/Treg,serum TNF-α,IL-6 and IL-17 levels,MDA level in lung tissue,TLR4,MyD88and NF-κB p65 protein expressions in lung tissue were significantly lower(P<0.05),PaO,OI,serum TGF-β level and SOD level in lung tissue were significantly higher(P<0.05);there was a dose-dependent relationship between different dose of BA groups(P<0.05);there was no significant difference in each index between high dose BA group and dexamethasone group(P>0.05).Conclusion:BA can inhibit the activation of TLR4/NF-κB pathway,promote the shift of Treg/Th17 balance to Treg,prevent the development of inflammation and oxidative stress,alleviate acute lung injury and repair lung function in septic mice.