枸杞多糖通过Akt/eNOS通路减轻LPS致ARDS小鼠肺损伤

Lycium barbarum polysaccharide protects against LPS-induced ARDS via an Akt/eNOS signaling pathway

目的探讨枸杞多糖(Lycium barbarum polysaccharide,LBP)对LPS致小鼠急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)的作用及可能机制。方法 32只♂C57BL/6小鼠随机分为对照组、LPS组、LBP组和LY294002组(Akt抑制剂),每组8只。HE染色观察肺组织病理改变;肺湿干比(W/D)检测肺水肿情况;检测小鼠肺泡灌洗液(bronchoalveolar lavage fluid,BALF)中蛋白浓度及炎性因子水平;检测肺组织MDA、SOD水平及肺组织细胞凋亡情况;Western blot法检测肺组织cleaved caspase-3蛋白、Akt及eNOS磷酸化水平。结果与对照组相比,LPS组肺组织损伤明显,W/D值、BALF中蛋白含量和炎性因子水平、肺组织中MDA水平及cleaved caspase-3表达明显增高(P<0.05),而肺组织SOD活性、Akt及eNOS磷酸化水平明显下调(P<0.05);LBP能明显改善上述变化(P<0.05);而Akt抑制剂LY294002能阻断LBP的作用(P<0.05)。结论LBP可抑制肺部炎症反应、减轻氧化应激及减少细胞凋亡,从而缓解ARDS肺微血管内皮屏障损伤,其作用机制可能与Akt/eNOS信号通路激活有关。

To investigate the effects of Lycium barbarum polysaccharide(LBP)on LPS-induced ARDS in mice and the potential mechanisms.Methods Thirty-two C57BL/6 male mice were randomly divided into control group,LPS group,LBP group and LY294002(Akt inhibitor)group,with eight mice in each group.The pathological changes in lung tissues were evaluated by HE staining,pulmonary edema was measured by wet/dry ratio(W/D),and the concentrations of total protein and the levels of inflammatory cytokines in BALF were determined.MDA and SOD levels in lung tissues and the apoptosis of lung tissues were detected.The protein expression levels of cleaved caspase-3,p-Akt and p-eNOS were determined by Western blot.Results Compared with control group,severe pathological lung injury changes were observed in LPS group,and the W/D ratio,levels of total protein and inflammatory cytokines in BALF,levels of MDA in lung tissues and the expression of cleaved caspase-3 significantly increased(P<0.05),while the lung SOD activity,the p-Akt and p-eNOS expression decreased(P<0.05).LBP could significantly attenuate the indexes above(P<0.05).However,the protective effects of LBP on ARDS were inhibited by Akt inhibitor LY294002.Conclusions LBP protects against LPS-induced ARDS in mice by alleviating EC barrier dysfunction via the suppression of inflammation,oxidative stress and apoptosis,at least partially via activation of the Akt/eNOS singaling pathway.