杜仲黄酮对脂多糖诱导小鼠急性肺损伤的保护作用及机制

Protective effect and mechanism of flavonoids from Eucommia umoides on lipopolysaccharide-induced acute lung injury in mice

目的探讨杜仲黄酮调节TGF-β/Smad信号通路对脂多糖(Lipopolysaccharide,LPS)诱导小鼠急性肺损伤(acute lung injury,ALI)的影响。方法采用RAW 264.7细胞进行细胞实验,不同浓度杜仲黄酮预防性给药,LPS(80 ng/mL)诱导细胞24 h,CCK-8法检测细胞存活率和细胞培养液中TNF-α和IL-1β的浓度。选取60只SPF级BALB/c小鼠,随机分为假手术组、模型组、地塞米松(DEX)组,杜仲黄酮低、中、高剂量组,每组10只。通过气管内滴注脂多糖(LPS)的方法建立小鼠ALI模型。各组预防给药7 d,其中DEX组灌胃给药2 mg/(kg·d),杜仲黄酮给药组分别灌胃给药50 mg(kg·d)、100 mg/(kg·d)、200 mg/(kg·d)。24 h后检测各组小鼠肺灌洗液蛋白浓度和白细胞数量、血清丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性,观察右肺上叶湿/干比(W/D)和右肺组织病理形态,检测小鼠肺组织中TGF-β1和Smad2表达水平。结果与模型组比较,在细胞实验中,杜仲黄酮给药组显著降低TNF-α和IL-1β含量。动物实验中,杜仲黄酮给药组明显降低肺灌洗液蛋白浓度、白细胞数量、血清MDA含量和肺组织TGF-β1、Smad2表达量(P<0.05),升高血清SOD活性(P<0.05),改善肺组织病理学变化,且呈剂量依赖性。结论杜仲黄酮对小鼠ALI具有较好的保护作用,其作用机制可能与其调节TGF-β/Smad信号通路有关。

Objective To explore the effect of flavonoids from Eucommia umoides on LPS-induced acute lung injury(ALI)in mice.Methods RAW264.7 cells were used for cell experiments,and different concentrations of flavonoids from Eucommia umoides were administrated prophylactically.LPS stimulated cells for 24 h,and cell survival rate and TNF-αand IL-1βconcentrations in culture medium were measured by CCK-8 and ELISA.Sixty SPF BALB/c mice were randomly divided into six groups,including the sham-operated group,the model group,dexamethasone group(DEX),and low,middle and high doses of Eucommia ulmoides flavonoids groups.ALI mice model was built by intratracheal injection of LPS.The prophylactic doses of DEX group,DZ-L group,DZ-M group and DZ-H were 2 mg/(kg·d),50 mg/(kg·d),100 mg/(kg·d)and 200 mg/(kg·d),respectively,which given by lavage administration for 7 days.After LPS stimulation for 24 h,the changes of protein concentration and total white cell count in bronchoalveolar lavage fluid(BALF),wet-to-dry weight ratio and pathomorphology of right lung were measured.The activity of superoxide dismutase(SOD)and the content of malondialdehyde(MDA)in serum were assayed.Results Flavones from Eucommia ulmoides significantly reduced the levels of TNF-αand IL-1βin cell experiments.Compared with the model group,flavones decreased the total white cell count and protein concentration in BALF,serum MDA and lung TGF-βand smad2 expression,but increased the activity of serum SOD.Flavones also improved the histopathological changes of lung in a dose-dependent manner.Conclusion Flavonoids from Eucommia ulmoides have a protective effect on acute lung injury in mice,which may be related to regulation of TGF-β/Smad signal pathway.