骨髓间充质干细胞对闭塞性支气管炎的治疗作用

Effects of bone marrow mesenchymal stem cells on experimental bronchiolitis obliterans

目的通过原位气管移植建立闭塞性细支气管炎（OB）模型，探讨骨髓间充质干细胞（BMSCs）对OB的治疗效果。方法Brown Norway→Lewis（BN→Lew）大鼠气管原位移植建模，术后分别给予15 mg/（kg·d）环孢菌素A（CsA）灌胃至预杀期，BMSCs单细胞混悬液1 ml（1×106/ml），生理盐水（NS）1 ml尾静脉注射治疗。移植后第7、30和60天获取标本，组织切片，苏木素-伊红（HE）染色，行组织病理观察，测量管腔阻塞率和上皮细胞脱落率；流式细胞术检测外周血CD4＋、CD8＋T细胞比例；Western blot法检测移植物转化生长因子-β1（TGF-β1）的表达。结果NS、CsA和BMSCs组移植术后60 d气道阻塞率分别为（52.62±10.21）%、（28.52±8.81）%和（21.30±2.27）%，CsA和BMSCs显著减轻气道阻塞（P＝0.030，P＝0.004）；气道上皮脱落率分别为（96.10±0.86）%、（93.67±4.04）%和（25.26±1.10）%，BMSCs组较NS组和CsA组低（P＝0.001，P＝0.009）；60 d外周血CD8＋T细胞比例分别为（24.13±1.82）%、（49.50±3.03）%和（26.27±0.40）%，BMSCs组较NS组和CsA组低有效抑制外周血CD8＋T细胞增殖（P＝0.007）；60 d TGF-β1相对表达量分别为1.21、0.77和0.36，BMSCs组表达较NS组和CsA组低（P＝0.000）。结论在大鼠原位气管移植OB模型中，BMSCs可下调TGF-β1表达，减轻CD8＋T细胞浸润，保护上皮细胞，从而明显减轻气道阻塞。

Objective Through orthotopic tracheal transplantation model to analyze the therapeutic effect of bone marrow mesenchymal stem cells （BMSCs） on obliterative bronchiolitis （OB）.Methods Brown Norway-to-Lewis rats were subjected to orthotopic tracheal transplantation, and intragastically given 15 mg/（kg·d） cyclosporine （CsA） until the day when the animals were ready to be killed. BMSCs single cell suspension liquid [1 ml, （1×106/ml） and normal saline （NS） （1 ml） were injected via the tail vein, respectively. Tracheal grafts were harvested at 7th, 30th, and 60th days post-transplantation. The tracheal luminal obliteration rate and epithelial loss were assessed on sections stained with hematoxylin and eosin. CD4＋ and CD8＋ T lymphocytes in peripheral blood were aexamined using flow cytometry. The expression of transforming factor-beta1 （TGF-β1） was detected by Western blotting.Results The luminal obliteration in NS, CsA and BMSCs treated groups after 60 days post-transplant were （52.62±10.21）%, （28.52±8.81）% and （21.30±2.27）% respectively, CsA and BMSCs were significantly attenuated （P=0.030, P=0.004）; the epithelial loss were （96.10±0.86）%, （93.67±4.04）% and （25.26±1.10）% respectively, BMSCs were protective against the epithelial loss post-transplant compared with NS and CsA group （P=0.009）; the percentage of CD8＋ T lymphocyte in peripheral blood were （24.13±1.82）%, （49.50±3.03）% and （26.27±0.40）% respectively, which were significantly suppressed by BMSCs compared with NS and CsA group （P=0.007）. The relative expression quantity of TGF-β1 were 1.21, 0.77 and 0.36 respectively, which can decrease TGF-β1 expression induced by transplant （P=0.000）.Conclusion BMSCs could prevent development of airway occlusion through downregulating the expression of TGF-β1, reducing the CD8＋ T lymphocyte infiltration and enhancing epithelial preservation in a orthotopic tracheal transplantation mouse model of OB.