Observation and measurement of silicosis animal model by PET-CT / 中国职业医学

ABSTRACT

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.