Intervening effect of bone marrow-derived mesenchymal stem cells for silica-induced pulmonary fibrosis in rats / 中国职业医学

ABSTRACT

OBJECTIVE: To explore the intervening effects of bone marrow-derived mesenchymal stem cells(BMMSCs) for pulmonary fibrosis of rats exposed to silica dust at different stages. METHODS: Specific pathogen free SD rats were randomly divided into model group,2-week group,4-week group and control group with 6 rats in each group(half males and half females). Rats of the first three groups were one-time endotracheally injected with 0. 5 mL aseptic silica suspension at 30 g/L mass concentration. Rats of control group were injected with 0. 5 mL 0. 90% sodium chloride solution. Rats of 2-week group and 4-week group were injected with 0. 5 mL BMMSCs suspension with cell density was 5 × 10~9/L at 2 weeks and 4 weeks respectively after silica dust exposure,while model group and control group were injected with aseptic 0. 90% sodium chloride solution in the same volume. After that all rats were examined by lung computed tomography(CT) scan,pathological sections were observed,lung coefficient were measured,lung tissue hydroxyproline(HYP) content and serum transforming growth factor β1(TGF-β1) concentration were investigated at the 12 th week after silica dust exposure. RESULTS: Lung CT image showed clean lung field and clear pulmonary parenchyma in control group.Multiple and diffused high density granular shadows of different size and streak/reticular fiber shadows in model group;diffused distribution of very small granular shadows in 2-week group; granular shadows and local reticular fiber shadows in 4-week group,and either the size or the area of granular shadows was smaller than model group. The lung CT value,lung coefficient,lung tissue HYP content and serum TGF-β1 concentration of model group,2-week group and 4-week group were higher than those of control group(P < 0. 05). The lung CT value,lung tissue HYP content and serum TGF-β1 concentration of control group,2-week group,4-week group and model group were elevated in turn(P < 0. 05),while the lung coefficient of model group and 4-week group was higher than that of 2-week group respectively(P < 0. 05).CONCLUSION: BMMSCs could delay pulmonary fibrosis caused by silica dust,and the protective effect is better at early stage than later stage of fibrosis.