The Study On Pulmonary Fibrosis Induced By Beryllium Oxide In Rats

Objective To study the pulmonary pathological changes and test the expression of thy-1 and TGF?1-smad2 / 3 signaling pathway related proteins on the pulmonary fibrosis models of rat that induced by beryllium oxide(BeO),exploring its role in pulmonary fibrosis and providing a evidence for follow-up study.Methods 64 SPF SD male rats were randomly divided into negative control group,beryllium oxide exposure group(BeO exposure group).Using disposable non-exposed type endotracheal perfusion infected method,beryllium oxide exposure group was injected with 10 g /L BeO(0.5 mL);the negative control group was injected with 0.9% saline(0.5 mL).Two groups of rats were put to execution respectively at the 20 d,40 d,60 d and 80 d in the whole experiment,there are eight rats in every time point.Experiments:(1)Prepared lung tissue pathology slice and observed the pathological changes through optical microscope and transmission electron microscopy(TEM).(2)RT-PCR was used to test the genic expression of collagen ?(COL-I),collagen III(COL-III)and ?-smooth muscle actin(a-SMA).(3)The protein levels of COL-I,CLOL-III and a-SMA in lung tissue were tested by western-blotting.(4)The proteins of TGF?1,smad2/3,p-smad2/3 and Thy-1 were tested by ELISA and Immunohistochemistry(IHC).Results(1)The morphological features of lung tissue were shown as follows: the lung was pink,smooth and soft in the negative control group.After BeO exposure,the lung damages aggravated gradually with the prolongation of exposure time,congestion,enlargement,local white miliary nodules,appeared gradually.Finally,the nodules and atrophies in the whole lung appeared.The results of HE staining showed that the lung tissue pathological changes of BeO exposure group are according with the cha racteristics of pulmonary fibrosis.The results of masson staining showed that blue collagen fibers were increased in lung tissue after BeO exposure.The TEM results were shown as follows.After 20 d and 40 d of BeO exposure the cytoplasmic lamellar bodies in alveolar type II epithelial cells were partially depleted;after 60 d and 80 d of BeO exposure the cytoplasmic lamellar bodies in alveolar type II epithelial cells were dense,pulmonary interstitial fiber bundles can be seen.(2)Compared with the negative control group,the COL-I mRNA and protein expression in BeO exposure group were higher(P<0.05);the a-SMA protein and mRNA in BeO exposure group were higher(P<0.05);the expression of Thy-1 in BeO exposure group was lower(P <0.05);the expression of TGF?1 in BeO exposure group increased(P <0.05);the expression of smad2 and smad3 protein in BeO exposure group was higher(P <0.05);the expression of p-smad2 and p-smad3 in BeO exposure group was higher(P <0.05).In the BeO group,COL-I mRNA and protein,COL-I mRN A and protein and a-SMA mRN A increased with time(P <0.05);the protein of TGF?1,smad3 and p-smad2/3 increased with time;the protein of Thy-1 decreased with time.Conclusion(1)The SD rat lung pulmonary rat model could be successfully prepared by the one-time non-exposed endotracheal instillation method(BeO solution,10 g/L,0.5 mL).(2)BeO can cause the deposition of extracellular matrix components and fibroblasts transdifferentiation into myofibroblasts in lung tissue.(3)The TGF?1-Smad2/3 signaling pathway was activated in the process of pulmonary fibrosis induced by BeO and TGF?1-smad2/3 signaling pathway was involved in the formation and development of pulmonary fibrosis.(4)The expression of Thy-1 was reduced during the pulmonary fibrosis induced by BeO,leading to the activation of TGF?1.