The effects of bone marrow mesenchymal stem cells on the treatment of pulmonary fibrosis in silicosis mice / 中国职业医学

ABSTRACT

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.