丹参多酚酸盐通过Nrf2/HO-1信号通路对脂多糖诱导的小鼠急性肺损伤的保护作用

Salvianolate protects against lipopolysaccharide-induced acute lung injury in mice through Nrf2/HO-1 signaling pathway

目的本研究旨在探讨丹参多酚酸盐(SAL)对脂多糖(LPS)诱导的小鼠急性肺损伤(ALI)的影响及可能机制。方法鼻内滴注LPS诱导小鼠产生ALI,SAL干预组在造模前1 h接受不同剂量药物腹腔注射(15 mg/kg,30 mg/kg,60 mg/kg)。造模24 h后,HE染色检测肺组织病理变化、测量肺湿重/干重比和髓过氧化物酶(MPO)的活性;比色法检测肺泡灌洗液(BALF)中超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活性,并检测丙二醛(MDA)的含量;酶联免疫吸附法检测BALF中肿瘤坏死因子-α(TNF-α)、白介素1β(IL-1β)的含量;Western法检测肺组织中核因子E2相关因子(Nrf2)和血红素氧化酶1(HO-1)的表达水平。结果与空白对照组相比,ALI组小鼠肺组织出现结构破坏,且肺湿重/干重比值明显增加,肺部MPO活性增强(P<0.01)。与ALI组相比,30 mg/kg和60 mg/kg剂量的SAL预先处理可以显著改善小鼠肺组织的病理结构改变,且小鼠肺湿重/干重比和MPO活性显著下降(P<0.01)。与空白对照组相比,ALI组小鼠BALF中氧自由基代谢的关键酶SOD和CAT活性降低(P<0.01),脂质过氧化产物MDA含量增加(P<0.01),同时与炎症反应相关的细胞因子TNF-α和IL-1β含量上升(P<0.01)。与ALI组小鼠相比,中、高剂量SAL组小鼠BALF中SOD和CAT的活性显著上升(P<0.01),MDA的含量显著下降(P<0.01),同时TNF-α和IL-1β的含量显著下调(P<0.01)。SAL的保护作用与Nrf2/HO-1信号通路相关,与空白对照组相比,ALI组小鼠肺组织中Nrf2和HO-1表达水平显著降低(P<0.01),中、高剂量SAL组小鼠肺组织中Nrf2和HO-1的表达水平则比ALI组显著上调(P<0.01)。低剂量的SAL预处理对改善肺组织病理状况、氧化应激损伤和炎症反应的效果并不明显。结论SAL能够通过激活Nrf2/HO-1信号通路减少肺部组织氧化应激损伤,抑制局部炎症反应,从而减轻由LPS导致的小鼠ALI症状。

ObjectiveTo investigate the effect of salvianolate(SAL)on lipopolysaccharide(LPS)-induced acute lung injury(ALI)in mice and the possible mechanism involved.MethodsALI was induced in mice by intranasal drip of LPS.SAL intervention was performed by intraperitoneal injection of different doses of drugs(15 mg/kg,30 mg/kg,and 60 mg/kg)1 h before modeling.Twenty-four hours after modeling,HE staining was used to detect the pathological changes of lung tissue.The wet/dry weight ratio and myeloperoxidase(MPO)activity were measured in lung tissue.The activities of superoxide dismutase(SOD)and catalase(CAT),and the content of malondialdehyde(MDA)were detected by colorimetry in bronchoalveolar lavage fluid(BALF).Levels of tumor necrosis factorα(TNF-α)and interleukin 1β(IL-1β)in BALF were measured by enzyme-linked immunosorbent assay.The expression levels of nuclear factor E2 related factor(Nrf2)and hemo-oxygenase-1(HO-1)in lung tissue were detected by Western blot.ResultsCompared with the blank control group,the lung tissue structure of the ALI group was damaged,and the lung wet/dry weight ratio significantly increased.The MPO activity was also strengthened in the ALI group(P<0.01).Compared with the ALI group,SAL pretreatment at a doses of 30 mg/kg and 60 mg/kg significantly improved the pathological changes of lung tissue in mice,and the wet/dry weight ratio and the MPO activity were decreased in those two SAL groups(P<0.01).Compared with the blank control group,the activities of SOD and CAT in BALF significantly decreased in the ALI group(P<0.01).Meanwhile,the contents of MDA and inflammatory factors,including TNF-αand IL-1β,were significantly increased in the ALI group(P<0.01).Compared with the ALI group,the activities of SOD and CAT in BALF of mice in the medium-and high-dose SAL groups were significantly increased(P<0.01),while the content of MDA was significantly decreased(P<0.01),and the contents of TNF-αand IL-1βwere significantly down-regulated(P<0.01).The protective effect of SAL was related to the Nrf2/HO-1 signaling pathway.The expression levels of Nrf2 and HO-1 in lung tissue in the ALI group were significantly lower than those in the blank control group(P<0.01),while the expression levels of Nrf2 and HO-1 in lung tissue in the medium-and high-dose SAL groups were higher than those in the ALI group(P<0.01).Low-dose SAL pretreatment had no significant effect in improving the pathological condition of lung tissue,oxidative stress injury,or inflammatory response.ConclusionSAL can reduce oxidative stress injury in lung tissue and inhibit the local inflammatory response by activating the Nrf2/HO-1 signal pathway,thus alleviating LPS-induced ALI symptoms in mice.