OBJECTIVETo evaluate the change in protein expression of peroxiredoxin I (Prx I) during pulmonary fibrosis among rats exposed to silica dust and to investigate the role of Prx I in pulmonary fibrosis.

METHODSNinety male Wistar rats were randomly divided into control group (n = 60) and experimental group (n = 30). The control group received intratracheal perfusion of saline (1 ml), while the experimental group received intratracheal perfusion of suspension of silica dust (50 mg/ml) to establish a rat model of silicosis. At 1, 2, 3, 4, 6, or 8 weeks after treatment, 10 rats in control group and 5 rats in experimental group were sacrificed. The lung tissues were collected for conventional pathological observation. The protein expression of Prx I at each time point was measured by immunohistochemistry and Western blot.

RESULTSAmong the rats exposed to silica dust, Prx I was seen in the form of brown particles that were mainly distributed in the alveolar septa and the cytoplasm of alveolar epithelial cells, macrophages, vascular endothelial cells, and smooth muscle cells around the blood vessels and tracheae. The control group showed weak protein expression of Prx I, and the experimental group had significantly higher protein expression of Prx I than the control group at all time points (P < 0.05). In the experimental group, the protein expression of Prx I was upregulated significantly at 1 and 2 weeks and decreased at 3∼8 weeks.

CONCLUSIONThe change in protein expression of Prx I may be one of the important causes of the onset and development of pulmonary fibrosis in rats exposed to free silica.

Animals ; Disease Models, Animal ; Lung ; enzymology ; pathology ; Male ; Peroxiredoxins ; metabolism ; Pulmonary Fibrosis ; enzymology ; pathology ; Rats ; Rats, Wistar ; Silicon Dioxide ; toxicity ; Silicosis ; enzymology ; pathology

To investigate the protective effects of oxymatrine (OMT) against H2O2-induced damage in L02 cells and research the mechanism,L02 cells were used as the research object. The oxidative stress model of L02 was established by hydrogen peroxide (H2O2). CCK-8 was used to detect the cell activation of L02 cells treated by different OMT. FCM (flow cytometry) assay was used to evaluate the cell proliferation of L02 cells treated by OMT. The apoptosis of L02 cells was detected using Annexin-V/7-AAD apoptosis detection kit. The level of ROS was detected by DCFH-DA fluorescence probe. The GSH-PX and SOD were detected by micro plate and colorimetric method. Results showed that when the concentration of OMT is between 6.25 and 100 mg•L⁻¹, it could promote the production of NADPH and strengthen the activity of GSH-PX and SOD to get rid of the ROS to protect the L02 cell from the apoptosis of L02 cell induced by H2O2.