| Objective:To establish the model of radiation pulmonary fibrosis in rats,and to observe the pathological signs and the dynamic change of cell factor in the model caused by the examination with pathology and molecular biology methods.Then to explore the function of Tet in radiation pulmonary fibrosis,and study it' s mechanism.To provide theoretical basis for prevention and treatment of radiation pulmonary fibrosis in clinical.Method:The 140 adult male SD rats will be divided into 4 groups.The blank control group(N group:20);Model group(R group:40).Irradiation+Dexamethasone(logogram:DEX)group(R+D group:40);Irradiation+Tet group(R+T group:40).Either sham irradiation(N group)or single fraction of 15 Gy to whole thorax(groups R,R+D and R+T)were given to the rats by a linear accelerator of Varian.R+D group were gavage using DEX suspension at a dose of lmg/kg per day,R+T group were given Tet suspension at a dose of 30mg/kg per day by gavage,N group and R group were given isovolumetric 0.5%CMC-Na by gavage.The four groups were dosed 7 days before irradiation,until the end of 4 weeks after irradiation.To observe the general condition of rats,such as spirit?activity?diet and weight.6 rats were killed randomly in each group on the 4th,8th,and 12th week;and weight,number of death and lung coefficient score were record in different group.Removing left lung tissue in rats,then to observe the inflammation and fibrosis of lung stained with HE and Masson,and measure TGF betal and Alpha SMA expression level using Image Pro Plus 4.5 software after immunohistochemical stain.Results:1.The weight change:The rats weight have no obvious difference in N group,R group and R+T group by preventived drug in 1 week before irradiation(P>0.05),but the rats weight of R+D group decreased obviously in comparison with N group,R group and R+T group(P<0.05).The rats weight of four groups were increasing as time goes on after irradiation;the weight of rats was no statistically significan between N group and R+T group(P>0.05);the weight of rats were decreased of R group and R+D group in comparison with N group(P<0.05).2.The lung coefficient score:The lung coefficient score was increasing of R group,R+D group and R+T group in comparison with N group(P<0.05).And it was decreased of R+D group and R+T group in comparison with R group(P<0.05).It was decreased of R+D group and R+T group in comparison with R group.It was lower of R+T group in comparison with R+D group in 8,12 weeks after irradiation(P<0.05).3.The histological change:The surface was smooth and pink of the lung tissue in N group,and its'alveolar wall was thin and structure was normal.The surface was swelling and bleeding of the lung tissue in R group,and its' alveolar wall was moderately thickened and its' alveolar space grew down.There were infiltrated of vast inflammatory cell in the early,and a large of fibroblasts in the middle.It was decreased of R+D group and R+T group in comparison with R group.4.Immunohistochemical change:The expression of TGF-betal,Alpha-SMA of lung tissue were negative or weakly positive in N group,and it was most in R group(P<0.05).The expression was falling of R+D group and R+T group in comparison with R group(P<0.05).It was lower of R+T group in comparison with R+D group in 8,12 weeks after irradiation(P<0.05).Conclusion:1.Tet has control effect for RPF,and the curative effect of later period may be superior to glucocorticoids,to provide the basis for clinical treatment of RPF;2.Tet can inhibit the expression of TGF-betal and Fb,and it may be one of the molecular mechanism of RPF prevented;3.It is still a step forward in clinical research to use of the Tet as a preventive medication for RPF. |
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