| [Objective]Silicosis is one of the most serious occupational disease in our country. Atpresent, the pathogenetic mechanism of silicosis is unclear. The basic pathological change of silicosis is the lung interstitial fibrosis and the formation of silicotic nodule. Similar to the silicosis, idiopathic pulmonary fibrosis (IPF), which is another lung interstitial disease, is characterized by lung fibrosis. The same character of these two diseases is the persistent inflammation of alveolar and the formation of proinflammatic mediators and profibriotic mediators. So it shows the common origin of the lung fibrosis in these two lung diseases. But compared with IPF and other interstitial lung diseases, silicosis has the remarkable pathological alteration which is the formation of silicotic nodule.The protein compeonent of the BALF derives from the thin layer of epitheliallining fluid of the peripheral airways and alveolar, and may reflect parenchymal disease processes. Because of the complicated pathogenetic mechanisms of lung disease, the research is focused on the proteins and proteomes of BALF nowadays. The mechanism of silicosis is furthering to the molecular and cellular level on the basic research.To explore the various cytokines of lung fibrosis, the solution protein in BALF of normal control, IFF and silicosis were separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). The 2D maps of the three groups were compared and the differential display protein spots were screened. It lays the foundation for identification of the differential protein by mass spectrum (MS) in the next step. And also it can provide a new way to study the pathogenetic mechanisms of silicosis.[Method]Healthy and male SD rats (weight about 200g) were supplied by the center of laboratory animal in the medical school of zhejiang university. All rats were divided at random into three groups. The health, IFF and silocosis animal model were structured by injecting intratracheally with 1ml 0.9% N.S., 5mg/kg Bloemycin and 1ml suspension of quartz dust (SiO2) at a concentration of 50mg/ml respectively. The bronchoalveolar lavage fluid (BALF) of the three groups was obtained by bronchoalveolar lavage of these animals. The protein quantitation in BALF was measured. The protein were precipitated with TCA(10% final concentration) in an ice bath for 20 min, and subsequently centrifuged at 3500 rpm for 15 min and 4 . The pellet was suspended in ice-cold acetone using a sonicator and centrifuged as described above. The pellet was air-dried for a few minutes and, finally, re-suspended in the sample solution by sonication. A 180 g amount of proteins dissolved in total 300 l Rehydration Buffer (8mol/L urea, 2%CHAPS, 20mmol/L DTT, 0.5%IPG Buffer pH3-10L, Trace Bromophenol blue) were loaded on pH 3-10 linear IPG strips (170mm 3mm 0.5mm) for isoelectric focusing. Second-dimensional separation of the proteins was done on ExcelGel XL 12% SDS-PAGE and detected by silver staining. The BALF 2-DE maps were analyzed by the 2D software PDQuest 7.1. Thedifferential protein spots, which have relationship with lung fibrosis and silicotic nodule, were screened. The data were analyzed by the software SPSS for windows 11.0.[Result]1. Pathology of the rats lung tissueUnder light microscope, it was found that the lung structure of normal control rats was intact and distinct. In the IPF group, the lung structure was also intact but the hyperplasia of the collegen in the lung interstitial was found. And the lung structure was destroyed and the typical silicotic nodule was found in the silicosis group. The cell aggregation and cellular nodule were predominant in this group and the collegen increased in these silicotic nodules. Also the fibroplasia in the lung interstitial tissue was found in these rats.2. Comparing of the protein quantitation in the BALF of the differential groupsThe measured values of the protein quantitations in the BALF of normal, IPF and silicosis were 0.3196 mg/ml, 0.3075 mg/ml and 1.27...
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