骨髓间充质干细胞对大鼠急性肺损伤时TGF-β1/Smad信号通路的影响

Effect of bone marrow-derived mesenchymal stem cells on TGF-β1/Smad signaling pathway during acute lung injury in rats

目的评价骨髓间充质干细胞(BMSCs)对大鼠急性肺损伤(ALI)时转化生长因子β1/ Smad(TGF-β1/Smad)信号通路的影响。方法清洁级健康雄性SD大鼠,4~5周龄,体重100~120 g,体外培养BMSCs。选取健康清洁级成年雄性SD大鼠84只,4周龄,体重170~190 g,采用随机数字表法分为4组(n=21):对照组(C组)、ALI组、ALI+BMSCs组和ALI+PBS组。腹腔注射5 mg/kg LPS 0.5 ml制备ALI模型。ALI+BMSCs组腹腔注射LPS后尾静脉注射1×10^4个/ml BMSCs 0.5 ml(用PBS溶解);ALI+PBS组腹腔注射LPS后尾静脉注射PBS 0.5 ml。分别于注射BMSCs后6、24和48 h时,采集动脉血样测定血气分析,测定肺组织湿重/干重(W/D)比值,采用HE染色观察肺组织病理学结果,采用Western blot法测定肺组织TGF-β1、Smad2和Smad3的表达。结果与C组比较,ALI组、ALI+BMSCs组和ALI+PBS组各时点PaO2降低,PaCO2和肺组织W/D比值升高,肺组织TGF-β1、Smad2和Smad3表达上调(P<0.05),肺组织病理学损伤加重。与ALI组比较,ALI+BMSCs组各时点PaO2升高,PaCO2和肺组织W/D比值降低,肺组织TGF-β1、Smad2和Smad3表达下调(P<0.05),肺组织病理学损伤减轻。结论BMSCs减轻大鼠ALI的机制可能与抑制TGF-β1/Smad信号通路有关。

Objective To evaluate the effect of bone marrow-derived mesenchymal stem cells(BMSCs)on transforming growth factor-β1(TGF-β1)/Smad signaling pathway during acute lung injury(ALI)in rats. Methods Healthy clean-grade adult male Sprague-Dawley rats, aged 4-5 weeks, weighing 100-120 g, were selected, and BMSCs were prepared and cultured in vitro.Eighty-four healthy clean-grade adult male Sprague-Dawley rats, aged 4 weeks, weighing 170-190 g, were selected and divided into 4 groups(n=21 each)using a random number table method: control group(group C), group ALI, ALI plus BMSCs group(group ALI+ BMSCs), and ALI plus phosphate buffer solution(PBS)group(group ALI+ PBS). ALI was induced by intraperitoneally injecting 5 mg/kg lipopolysaccharide 0.5 ml in anesthetized rats.In group ALI+ BMSCs, 1×10^4 cells/ml BMSCs 0.5 ml(in PBS)was injected via the tail vein after intraperitoneal injection of lipopolysaccharide.PBS 0.5 ml was injected via the tail vein after intraperitoneal injection of lipopolysaccharide in group ALI+ PBS.Arterial blood samples were collected at 6, 24 and 48 h after injecting BMSCs for blood gas analysis and for determination of wet to dry weight ratio(W/D ratio), pathological changes(using haematoxylin and eosin staining), and expression of TGF-β1, Smad2 and Smad3 in lung tissues(by Western blot). Results Compared with group C, PaO2 was significantly decreased, PaCO2 and W/D ratio were increased, the expression of TGF-β1, Smad2 and Smad3 in lung tissues was up-regulated(P<0.05), and the pathological changes of lung tissues were accentuated in ALI, ALI+ BMSCs and ALI+ PBS groups.Compared with group ALI, PaO2 was significantly increased, PaCO2 and W/D ratio were decreased, the expression of TGF-β1, Smad2 and Smad3 in lung tissues was down-regulated(P<0.05), and the pathological changes of lung tissues were significantly reduced in group ALI+ BMSCs. Conclusion The mechanism by which BMSCs mitigates ALI may be associated with inhibiting TGF-β1/Smad signaling pathway in rats.