Objective: To observe the effect of human umbilical cord mesenchymal stem cells (hUC-MSCs) on airway remodeling in asthma model of rat and its possible mechanism. Methods: hUC-MSCs were isolated and cultured, and surface markers of hUC-MSCs were identified by flow cytometry. Forty Wistar male rats were divided into 4 groups: Control, Model, MSCs, Budesonide. The rats of Control group were sensitized and challenged by normal saline. The rats of Model, MSCs and Budesonide group were sensitized and challenged by ovalbumin (OVA) for 8 weeks. The MSCs group rats were given a tail vein injection of MSCs 0.2 ml (1×10(6) /ml) on days 35, 45, and 55 half an hour befor each OVA exposure. The Budesonide group rats were given aerosol inhalation of budesonide 2 mg two hours before each OVA exposure. Specimens were collected within 24 hours after the last OVA challenge. The parameters of airway morphological changes and the degree of airway remodeling were analyzed using Image-pro plus computer graphics. The levels of transformation growth factor (TGF) -β(1) in bronchoalveolar lavage fluid (BALF) and serum were detected by enzyme linked immunosorbent assay (ELISA). The expressions of E-cadherin, α-smooth muscle actin (α-SMA) and fibronectin (Fn) were measured by immunohistochemistry. Results: The thickness of airway wall and smooth muscle of Model, MSCs and Budesonide group rats were significantly thicker than Control group. The levels of TGF-β(1) in both BALF and serum of Model, MSCs and Budesonide group rats were significantly higher than Control group. The expression of E-cadherin of Model, MSCs and Budesonide group rats was significantly lower than Control group, while the expression of α-SMA and Fn were significantly higher. The thickness of airway wall and smooth muscle of MSCs and Budesonide group rats were significantly lower than Model group[(38.40±2.50, 45.34±0.33) vs (80.18±1.75) μm and (15.71±0.89, 18.57±0.67) vs (40.97±0.90) μm]. The levels of TGF-β(1) in both BALF and serum of MSCs and Budesonide group were significantly lower than Model group[(3.53±0.43, 3.11±0.05) vs (20.88±0.37) μg/L and (31.07±0.89, 31.12±0.50) vs (70.58±0.39)μg/L](all P<0.01). The expressions of α-SMA, Fn of MSCs and Budesonide group rats were significantly lower than Model group[(0.438±0.057, 0.445±0.027) vs (0.521±0.030) and (0.459±0.041, 0.458±0.029) vs (0.527±0.022)], While the expression of E-cadherin was significantly higher[(0.308±0.023, 0.296±0.010) vs (0.256±0.087)](all P<0.01). Conclusion: MSCs could alleviate asthmatic airway remodeling, the mechanism of which may be associated with the inhibition of TGF-β(1) induced epithelial-mesenchymal transition.
目的： 探讨人脐带间充质干细胞(MSCs)对支气管哮喘(简称哮喘)大鼠气道重塑的治疗作用及可能机制。 方法： 分离、培养人脐带MSCs，采用流式细胞术鉴定人脐带MSCs表面标志物；按随机数字表法将40只Wistar雄性大鼠分为对照组、哮喘组、MSCs组、布地奈德组各10只。对照组以生理盐水致敏和激发，哮喘组以卵白蛋白致敏和激发建立哮喘气道重塑模型，共8周，MSCs组于第35、45及55天激发前30 min尾静脉注射脐带MSCs 0.2 ml(1×10(6)个/ml)，布地奈德组于激发前2 h雾化吸入布地奈德2 mg。末次激发后24 h内留取肺组织及支气管肺泡灌洗液，计算机图像系统分析气道重塑程度，酶联免疫吸附试验检测支气管肺泡灌洗液(BALF)及血清中转化生长因子β(1)(TGF－β(1))含量，免疫组化法检测肺组织上皮钙黏素、α－平滑肌肌动蛋白(α－SMA)、纤维连接蛋白(Fn)的表达。 结果： 哮喘组、MSCs组、布地奈德组支气管壁及平滑肌厚度均显著厚于对照组；BALF及血清中TGF－β(1)含量均显著高于对照组；上皮钙黏素表达均显著低于对照组，α－SMA及Fn表达均显著高于对照组。MSCs组、布地奈德组支气管壁及平滑肌厚度均显著低于哮喘组[(38.40±2.50、45.34±0.33)比(80.18±1.75)μm及(15.71±0.89、18.57±0.67)比(40.97±0.90)μm]；BALF及血清中TGF－β(1)含量均显著低于哮喘组[(3.53±0.43、3.11±0.05)比(20.88±0.37)μg/L及(31.07±0.89、31.12±0.50)比70.58±0.39)μg/L]；上皮钙黏素表达均显著高于哮喘组[(0.308±0.023、0.296±0.010)比(0.256±0.087)]；α－SMA及Fn相对表达量均显著低于哮喘组[(0.438±0.057、0.445±0.027)比(0.521±0.030)及(0.459±0.041、0.458±0.029)比(0.527±0.022)](均P<0.01)。 结论： 人脐带MSCs可减轻支气管哮喘气道重塑，其机制可能与抑制TGF－β(1)诱导的上皮细胞－间质转化有关。.
Keywords: Airway remodeling; Asthma; Epithelial-mesenchymal transition; Mesenchymal stem cells.