骨髓间充质干细胞治疗矽肺小鼠肺纤维化效果

The effects of bone marrow mesenchymal stem cells on the treatment of pulmonary fibrosis in silicosis mice

目的观察骨髓间充质干细胞(BMSCs)改善矽肺小鼠肺纤维化的效果。方法取无特定病原体级健康雄性C57BL/6小鼠随机分为对照组、矽肺组和治疗组,每组10只。采用气管暴露法,对照组小鼠予一次性注射0.90%氯化钠溶液20.0μL,矽肺组和治疗组小鼠均一次性注射质量浓度为250 g/L的矽尘混悬液20.0μL;于造模第4周,治疗组小鼠经鼠尾静脉一次性输注细胞密度为2×10~9/L的BMSCs混悬液250.0μL,矽肺组小鼠输注0.90%氯化钠溶液250.0μL,每周1次,连续治疗4周;对照组小鼠不予任何处理。末次治疗后2周,处死小鼠。观察肺组织病理学改变,进行肺纤维化评分(Aschcroft评分);检测肺脏脏器系数、肺组织中羟脯氨酸(HYP)和血清中转化生长因子-β(TGF-β)水平,检测脾脏和肺门淋巴结(HLN)中辅助性T细胞17(Th17细胞)和调节性T细胞(Treg细胞)比率。结果肺组织病理学检查结果显示:BMSCs移植疗程结束后,矽肺组小鼠肺部严重纤维化,见大量胶原纤维,且出现大量矽结节;治疗组小鼠肺部见轻度纤维化,见少量胶原纤维,矽结节数量明显减少。矽肺组小鼠肺脏器系数、Aschcroft评分、肺组织中HYP水平、血清中TGF-β水平以及脾脏和HLN中Th17细胞比率均高于对照组(P<0.05),治疗组小鼠上述指标均低于矽肺组(P<0.01)。矽肺组小鼠脾脏和HLN中Treg细胞比率均低于对照组(P<0.05);治疗组小鼠上述指标均高于矽肺组(P<0.01)。结论 BMSCs可有效改善矽肺小鼠的肺纤维化,且可纠正矽肺小鼠体内Th17/Treg失衡。

Objective To observe the effects of bone marrow mesenchymal stem cells （BMSCs） on the treatment of pulmonary fibrosis in silicosis mice. Methods Specific pathogen free healthy male C57BL/6 mice were randomly divided into control group, silicosis group and treatment group with 10 mice in each group. The mice of the control group were given one intra-tracheal injection of 20. 0 μL 0. 90% sodium chloride solution. The silicosis group and treatment group received one 20. 0 μL （ mass concentration 250 g/L） of silica dust suspension. After 4 weeks, mice in treatment group were injected with 250. 0 μL of BMSCs suspension （ cell density 2 × 10^9/L） by tail vein and silicosis group injected with 250. 0 μL of 0. 90% sodium chloride solution instead, once a week with continuous treatment for 4 weeks. Control group was not given any treatment. Mice were euthanized two weeks after the last treatment. Pathological sections were observed, pulmonary fibrosis score （Ashcroft scores ） was marked. Lung coefficient was measured. Lung tissue hydroxyproline （HYP） level and serum transforming growth factor β1 （TGF-β1） level were measured. The level of pulmonary fibrosis was scored and the percentages of T helper cell 17 （Th17 cell） and regulatory T cell （Treg cell） of spleen and hilar lymph node （HLN） were measured by flow cytometry. Results The results of lung histopathological examination showed that the pulmonary fibrosis was severe in silicosis group. Massive collagen fiber accumulation and silicotic nodule were found. In treatment group, fibrosis was mild, little collagen fiber accumulation and silicotic nodule were found. The lung coefficient,Aschcroft scores, lung tissue HYP level, serum TGF-β level and the percentage of Th17 cell of spleen and HLN in silicosis group were higher than that of control group （ P 〈 0. 05 ）, while the above indexes of treatment group were lower than that of silicosis group （P 〈0.01 ）. The percentage of Treg cell of spleen and HLN in silicosis group were lower than that of control group （ P 〈 0. 05 ） , while those indexes of treatment group were higher than that of silicosis group （ P 〈 0. 01 ）. Conclusion BMSCs could effectively alleviate the pulmonary fibrosis in silicosis mice and correct the imbalance of Th17/Treg.