miR-132调控SIRT1表达对慢性阻塞性肺疾病大鼠肺损伤的影响

Effects of miR-132 regulating SIRT1 expression on lung injury in COPD rats

目的探讨miR-132在慢性阻塞性肺疾病(COPD)大鼠肺组织中的表达及其对大鼠肺功能及肺损伤的影响。方法根据随机数表法将30只SD大鼠分为3组,即对照组(Sham组)、COPD组和COPD+miR-132组,每组10只。COPD组和COPD+miR-132组大鼠气道内滴注脂多糖联合烟熏28d构建COPD模型,Sham组大鼠滴加等剂量的生理盐水,COPD+miR-132组大鼠额外滴加miR-132转染复合物,每周一次,持续4周。COPD疾病造模成功后,检测大鼠肺组织中miR-132的表达、大鼠肺功能、肺组织形态结构、肺组织中促炎症细胞因子、氧化应激及凋亡水平。检测各组大鼠肺组织中沉默调节蛋白1(SIRT1)及乙酰化的叉头转录因子-1(Ac-FOXO-1)的蛋白表达水平。结果与Sham组相比,COPD组大鼠肺组织中miR-132表达水平明显降低(P<0.05)、0.3s用力呼气量占用力肺活量比值(FEV0.3/FVC)和呼气峰流速(PEF)升高(P<0.05)、肺泡平均截距增宽(P<0.05)、促炎症细胞因子IL-1β,TNF-α及MCP-1的mRNA表达水平增高(P<0.05)、细胞凋亡和氧化应激水平升高(P<0.05)、SIRT1及Ac-FOXO-1的蛋白表达水平明显降低(P<0.05);与COPD组相比较,COPD+miR-132组大鼠肺组织的miR-132的表达水平明显升高(P<0.05)、FEV0.3/FVC和PEF升高(P<0.05);苏木精-伊红(HE)染色结果显示,miR-132明显降低了COPD大鼠肺泡平均截距(P<0.05);RT-PCR结果显示,miR-132表达增加可明显抑制大鼠肺组织中促炎症细胞因子IL-1β,TNF-α及MCP-1的mRNA表达水平(P<0.05);TUNEL染色结果表明,COPD+miR-132组大鼠肺组织中细胞凋亡水平明显低于COPD组(P<0.05);同时,miR-132预处理可明显抑制COPD大鼠肺组织的氧化应激水平(P<0.05);机制上,miR-132过表达可上调COPD大鼠肺组织中SIRT1及Ac-FOXO-1的蛋白表达水平(P<0.05)。结论在COPD大鼠模型中,miR-132的表达水平明显降低,过表达miR-132可以降低肺泡腔扩大,抑制大鼠肺组织炎症、凋亡及氧化应激水平,其保护作用可能与SIRT1信号通路的激活有关。

Objective To investigate the expression of miR-132 in the lung tissue of chronic obstructive pulmonary injury(COPD)rats and its effect on lung function and lung injury in rats.Methods Intra-airway infusion of lipopolysaccharide combined with smoking for 28 days was used to construct a COPD rat model.The rats were divided into 3 groups,namely the control group(Sham),COPD group and COPD+miR-132 group.After successful modeling,the lung function,morphological structure of lung tissue,proinflammatory cytokines,oxidative stress and apoptosis levels in lung tissue were detected.Finally,the Silent Information Regulator 1(SIRT1)and Acetylated-fork head transcription factor-1(Ac-FOXO-1)in the lung tissue of each group were detected separately Protein expression level.Results Compared with the Sham group,the expression level of miR-132 in the lung tissue of the COPD group was significantly reduced(P<0.05);compared with the COPD group,the 0.3-second forced expiratory volume occupancy of the COPD+miR-132 group rats Vital capacity ratio(FEV0.3/FVC)and peak expiratory flow rate(PEF)increased(P<0.05);H&E staining results showed that miR-132 significantly reduced the average alveolar intercept of COPD rats(P<0.05);RT-PCR results show that increased expression of miR-132 can significantly inhibit the mRNA expression levels of pro-inflammatory cytokines IL-1β,TNF-αand MCP-1 in rat lung tissue(P<0.05);TUNEL staining results show that COPD+The level of apoptosis in lung tissue of miR-132 group was significantly lower than that in COPD group(P<0.05);meanwhile,we found that miR-132 pretreatment could significantly inhibit the level of oxidative stress in lung tissue of COPD rats(P<0.05);mechanistically,miR-132 overexpression can reduce the protein expression levels of SIRT1 and Ac-FOXO-1 in the lung tissue of COPD rats(P<0.05).Conclusion In the COPD rat model,the expression level of miR-132 Significantly reduced,overexpression of miR-132 can reduce alveolar cavity expansion,inhibit inflammation,apoptosis and oxidation of rat lung tissue The protection level of stress may be related to the activation of SIRT1 signaling pathway.