RESUMO
OBJECTIVE: To explore the feasibility of dynamic observation and measurement of living silicosis rat model by using small animal positron emission tomography( PET)-computed tomography( CT). METHODS: Specific pathogens free SD rats were divided into model group and control group. The silicosis rat model was established by one-time endotracheal injection of 30 g/L silica suspension,while the control group rats were injected of isopyknic 0. 9% sodium chloride solution. Six rats from each group were randomly selected for CT scan from 1st,2nd,3rd,4th,6th,8th and 12 th week after silica injection using the small animal PET-CT. CT value and standardized uptake value( SUV) of18F-fluorodeoxyglucose were measured. Lung tissue was collected for pathological sections. The levels of hydroxyproline( HYP) of lung tissue and serum transforming growth factor β1( TGF-β1) and interleukin-1( IL-1) were measured.RESULTS: Pathological sections of rats of model group showed inflammatory exudation,inflammation reduced and fibrosis increased with extended time. The results are identical with findings in PET-CT. Lung SUV of rats in model group in the1st-3rd weeks were higher than that in control group in the same time point( P < 0. 05) and decreased by the increasing time during the 1st-4 th weeks of dust injection( P < 0. 05). Lung CT values of model group in the 1st-12 th weeks were higher than that of control group in the same 7 time points( P < 0. 05) and decreased in the 1st-6th weeks and then increased in the 6th-12th weeks by the increasing time of dust injection( P < 0. 05). Lung coefficients and HYP levels of model group in the 7 time points were higher than that of control group in the same 7 time points( P < 0. 05). Lung coefficients decreased in 1st-4th weeks and lung HYP levels increased in 6th-12th weeks with the increasing time of dust injection( P < 0. 05). Excepted of the 3rd and 4th weeks,serum TGF-β1 levels of model group in other 5 time-points were higher than that of control group in the same 5 time points( P < 0. 05) and decreased in the 1st-4th weeks( P < 0. 05)then increased in the 4th-8th weeks( P < 0. 05) by the increasing time of dust injection. Serum IL-1 levels of model group in the 1st-4th weeks were higher than that of control group in the same 4 time points( P < 0. 05) and decreased by the increasing time of dust injection( P < 0. 05) and decreased by the increasing time of dust injection( P < 0. 05).CONCLUSION: Early inflammation and terminal fibrosis of living silicosis rat model could be observed effectively by small animal PET-CT,which can be used as a new approach for dynamic tracing silicosis in rat models.
RESUMO
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.
RESUMO
Objective:To investigate the expression of NKG2D receptor on natural killer(NK)cells and the expression of its ligand MHC classⅠ-related chain A and B(MICA/B)whereby to analyze the mechanism for escaping killing were deteced by NK cells of leukemic cells.Methods:Detection of NKG2D receptor and MICA/B ligand were aleteced by flow cytometry analysis.Results:The expression of NKG2D receptor were significantly lower in both pretherapy and complete remission group,compared with that in health group(P0.05).Conclusion:NK cell function mediated by NKG2D-MICA/B was inhibited,with possibly leads to the escape of leukemic cell from NK cell cytotoxicity;And after therapy the function of NK cells mediated by MICA/B in complete remission patients may be not ameliorated indicated by farther decrease of NKG2D-cells in the patients.