阿魏酸钠对NALP3炎性复合体的调节及在肺纤维化中的作用

The Effect of Sodium Ferulate in Experimental Pulmonary Fibrosis via NALP3 Inflammasome

目的探讨NALP3炎性复合体在肺纤维化过程中的活化情况,并观察阿魏酸钠(sodium ferulate,SF)在肺纤维化过程中对炎性复合体的影响。方法体内实验以博莱霉素(BLM)气管滴注构建小鼠肺纤维化模型(BLM组),治疗组在用BLM建模后第2天以SF(100mg/kg)每日1次腹腔注射(SF组),对照组(不建模)和BLM组注射等量磷酸盐缓充液,建模后第21天取肺组织行Masson染色,观察肺组织胶原沉积(Ashcroft评分)情况;以碱水解法测定肺组织羟脯氨酸(HYP)含量;体外实验以H_2O_2刺激小鼠胚胎成纤维细胞NIH-3T3以构建成纤维细胞氧化应激模型,干预组以SF 400μg/mL预处理2h,再用H_2O_2培养细胞,采用Real time-PCR检测小鼠肺组织及体外实验分组处理细胞相关炎性细胞因子NALP3、caspase-1、凋亡相关斑点样蛋白(ASC)、collagen-1、α平滑肌肌动蛋白(α-SMA)mRNA,Western blot检测小鼠肺组织NALP3蛋白,分组处理细胞NALP3、collagen-1、α-SMA蛋白的表达;ELISA测定肺组织上清及细胞上清中IL-1β质量浓度。结果体内实验SF处理后,肺纤维化模型小鼠Ashcroft评分及HYP含量较BLM组有所减少(P<0.05);肺组织NALP3炎性复合体NALP3、ASC、caspase-1mRNA,NALP3蛋白的表达和IL-1β的合成较BLM组均有减少(P<0.05)。体外实验显示H_2O_2能有效刺激NALP3炎性复合体NALP3、ASC、caspase-1mRNA的表达(P<0.05)与IL-1β的分泌(P<0.05),并且能有效促进成纤维细胞NALP3蛋白、collagen-1和α-SMA的表达(P<0.05);SF预处理能在基因水平抑制NALP3、ASC、caspase-1、collagen-1和α-SMA的表达(P<0.05),且在蛋白水平减少NALP3、collagen-1、α-SMA的表达(P<0.05),降低IL-1β水平(P<0.05)。结论阿魏酸钠可能通过抑制氧化应激诱导的NALP3炎症复合体活化,从而抑制成纤维细胞活化,展现其抗纤维化作用。

Objective To investigate the activation of NALP3 inflammasome in the process of experimental pulmonary fibrosis （PF）, and evaluate the effect of sodium ferulate （SF） in the relationship of NALP3 and PF. Methods Establishing PF experimental model via bleomycin （BLM） intratracheal injection （BLM group, SF group）, treated with SF daily （SF group） or PBS [BLM group, control （CON） group] and mice were executed on day 21. Ashcroft score was used to assess lung fibrosis in mice PF model. The content of hydroxyproline （HYP） in lung tissue was determined by alkaline hydrolysis. Fibroblast NIH-3T3 was treated with H202 to trigger cell oxidative stress in vitro experiments （H202 group）. Cell was pre-administrated with SF 2 h before H202 stimulation in HzO2 q-SF group. Blank group without any treatments, was set as control. Real time-PCR was used to investigate the expressions of three elements of inflammasome [NALP3, caspase-1, apoptosis-associated speck- like protein （ASC）], collagen-1 and a smooth muscle actin （a-SMA） mRNA in both lung tissue and fibroblast. Western blot was used to detect protein level of NALP3 in mice lung tissue and collagen-l, a-SMA in fibroblast as well. Meanwhile, IL-113 content in lung tissue and cell supernatant was measured by ELISA. Results In vivo experiment, SF treated mice showed lower Ashcroft score and HYP content and decreased NALP3, ASC, caspase- 1 mRNA expressions and IL-113 production, NALP3 protein level compared with BLM group （P〈0.05）. In vitro experiment, H202 increased NALP3 （P〈0.05）, ASC （P〈O. 01）, caspase-1 （P〈0.05） expressions and IL-113 releasing （P〈0.05） and promoted the expressions of collagen-1 and a-SMA in both gene and protein levels （P〈0. 05） in NIH 3T3. NALP3 activation was partly inhibited in HeO2 t bP group t 〈 u. ua . expression levels of collagen 1 and a-SMA were reduced in H2 02 q-SF group （P〈0.05） and the protein expressions of u-SMA and coliagea-1 were decreased （P〈0, 05） compared with those of HeOa group. Conclusion Sodium ferulate may suppress oxidative stress mediated NALP3 activation to inhibit fibroblast activation in the anti-fibrosis effect.