The Expression Of Nrf2、Bach1、γ-GCS In Lung Tissue Of The Patients With COPD

Background and ObjectiveChronic obstructive pulmonary disease (COPD) is a common and chronic disease of the respiratory system. Because of the high disease prevalence and mortality, the progressive development, this disease can seriously affect labor ability and the quality of life of patients at the end-stage. At present,the pathogenesis of COPD is unclear, but the studies have confirmed that oxidative stress is one of the important pathogenesis of COPD. Nuclear factor erythroid2-related factor2(Nrf2) is the nuclear transcription factor in oxidative stress reaction, which can positively regulate the expression of a variety of antioxidant genes,and plays an important role in the pathogenesis of COPD. BTB and CNC homologl Bachl (Bachl) is one of the heme binding proteins, which widely exists in the body.But it can inhibit the transcription of oxidation resistance genes,that is different from Nrf2.Reduced glutathione (GSH) is an important antioxidant,which plays an important role in the process of resisting the Oxidative damage of lung. y-Glutamylcysteine Synthetase (y-GCS) is an important enzymes,which can limit the speed of synthesis of GSH,also can decided the speed and quantity of the synthesis GSH.The expression of y-GCS is mainly regulated in the level of transcription, thus, we can increase the synthesis of GSH to enhance antioxidant capacity of lung through this way. The studies of COPD rats show that Nrf2can compete with Bachl to regulate the expression of the antioxidant gene of y-GCS in the process of the development of COPD.Some Overseas studies have found that Bachl can downgrade the expression of antioxidant gene through competing with Nrf2to bind the original oxidation reaction. This experiment aims to study the change of the expression level of Nrf2, Bachl, y-GCS in the lung tissue of COPD and the correlation between them, to explore their roles in the pathogenesis of COPD and how Nrf2and Bachl regulate the expression of γ-GCS.Subjects and methods40patients were selected from the thoracic surgery of the second affiliated hospital of zhengzhou university from March2011to May2012, who had done Lung resection surgery because of lung cancer. We asked the medical history of each person,done the regular check-up, chest X-ray or CT, lung function test and so on before the surgery.He would be included in the COPD group (20cases),who conformed to the diagnosis and treatment of COPD guideline set by the respiratory branch of Chinese Medical Association.If he didn’t conform to the guideline,would be in the control group (20cases). The patient was excluded suffering from heart, liver, kidney, skin, breast, kidney, digestive tract, ovary, blood diseases, ect. The patient was also eliminated suffering from bronchiectasis disease, tuberculosis and other diseases which could affect the function of pulmonary, and had not done preoperative chemoradiation therapy.All patients who met the inclusion criteria, were told that the purpose of this study and methods, signed informed consent form, and would be given appropriate economic compensation.the samples were taken from the tumor tissue more than4cm, and were the peripheral lung tissue not infiltrated by Lung cancer through macroscopic observation. The samples were fixed in4%paraformaldehyde (including1%oDiethypyrocarbonat), and sectioned them after conventional paraffin embedding. Then we done the HE staining;In situ hybridization and immunohistochemistry were used to detect the mRNA and protein expressions of Nrf2,Bachl and y-GCSmRNA in the lung tissues of two groups of patients. SPSS17.0statistical software was used for statistical analysis of experimental data.Results 1. Lung tissue pathological slices by HE staining under the optical microscope:In COPD group, alveolar walls become thinner, and appeared different degree of fracture, some parts of the fractured alveolar fused. The structure of alveolar was normal in the control group.2. In situ hybridization results:The expressions of Nrf2, Bachl and y-GCS mRNA were mainly in alveolar epithelial cells and inflammatory cells. In the lung tissue of patients in COPD group, Nrf2and Bachl mRNA were strong positively expressed, γ-GCSmRNA was positively expressed.Compared with the control group,the difference was statistically significant (P<0.05).3. Immunohistochemical results:The expressions of Nrf2, Bach1, γ-GCS proteins were mainly in alveolar epithelial cells and inflammatory cells.In the COPD group, Nrf2, Bach1, γ-GCS proteins were strong positively expressed.Compared with the control group, the difference was statistically significant (P<0.05).4. Correlation analysis in the COPD group:The expressions of Nrf2,y-GCS proteins and FEV1/FVC(%), FEV1(%) were positively correlated (P<0.01). The expression of Bachl protein and FEV1/FVC(%), FEV1(%) were negatively correlated (P<0.01). The expression of Nrf2protein and the expressions of y-GCS mRNA, γ-GCS protein were positively correlated (P<0.01), The expression of Bachl protein and the expressions of γ-GCS mRNA, γ-GCS protein were negatively correlated (P<0.01).Conclusions1.In the lung tissue of patients with COPD, the expressions of Nrf2, Bachl, y-GCS mRNA and its protein were enhanced.The result showed that all of them played an important role in the oxidation/antioxidation system of COPD.2. The correlation analysis results of Nrf2, Bachl, γ-GCS proteins and FEV1/FVC (%),FEV1(%),which were both the key indicators of diagnosis and evaluation of COPD, further confirmed that all of them may have a close relation to COPD.3.In the process of the development of COPD, Nrf2may positively regulate the expression of GCS gene, Bachl may negatively regulate the expression of GCS gene. The result provided a new theoretical basis of regulatory mechanism for γ-GCS.