| Objective： To investigate the IRE1pathway and JNK pathway inendoplasmic reticulum stress of CS-induced chronic obstructive pulmonary disease.Methods：This experiment included two parts，animal part and clinic part.1. Animal part:Forty adult male SD rats were randomly divided into Control group, groupexposed to CS for2months，group rats exposed to CS for4months and quitsmoking group(exposed to CS for4months and then quit smoking for1monthrespectively). With passive exposing to CS to establish the COPD model. Collectingall the lung tissues, Immunohistochemistry and Western blot were used to detect theprotein expression of IRE1α, P-IRE1, JNK and P-JNK in all groups.2. Clinical part:Lung tissue specimens of the control group, non-COPD group, COPD groupwere collected from patients accepted lobectomy because of lung cancer for10specimens in each group (the smoking index of non-COPD group had no significantdifference with COPD group). Immunohistochemistry and Western blot were used todetect the protein expression of IRE1α, P-IRE1, JNK and P-JNK in all groups.Results：1. Animal part:1.1Lung morphological observation：compared with the control group, ratsexposed to CS for2months had slight disorders of lung structure, some alveolideveloped into bulla; in group rats exposed to CS for4months,lung structure weredisorder, alveolar ruptured, alveolar space appeared to expand and developed into bulla;those quit smoking group had a similar situation with the rats exposed to CS for4months.1.2The pulmonary function (FEV0.3and PEF) greatly decreased in rats exposedto CS for2months in comparison with control group（FEV0.375.48±2.57(%) VS83.47±4.98(%)，PEF33.42±3.21VS40.11±3.66（ml/s） P <0.05）,markedlydecreased in rats exposed to CS for4months compared with rats exposed to CS for2months (FEV0.366.18±4.12(%) VS75.48±2.57(%)，PEF25.89±2.22（ml/s）VS33.42±3.21（ml/s），P <0.05）,and improved a little in quit smoking group,butwithout no significant difference(P>0.05).1.3IHC results showed that IRE1α mainly expressed in the cytoplasm of lungstructure cells, no significant difference between the control rats and smoking rats;P-IRE1mainly located in cytoplasmin of alveolar epithelial cells, endothelial cells,and bronchial epithelial cells. Control rats expressed the lowest, compared with thecontrol group rats exposed to CS for2months showed significantly higher expression(P <0.05), the group exposed to CS for4months and ex-smoking group showed ahigher expression than the group rats exposed to CS for2months (P <0.05) andexpression between quit smoking group and group exposed to CS for4months had nosignificant difference (P>0.05). JNK mainly located in cytoplasm of alveolarepithelial cells, endothelial cells, bronchial epithelial cells, and a small amount ofexpression in the nucleus. JNK expression in all the groups had no significantdifference; p-JNK mainly localized in nucleus of alveolar epithelial cells, endothelialcells, bronchial epithelial cells. The control group had the lowest expression, thegroup exposed to CS for2months expressed higher than the control group (P <0.05),the group exposed to CS for4months and ex-smoking group showed a higherexpression than the group exposed to CS for2months (P <0.05) and expressionsbetween quit smoking group and the group exposed to CS for4months had nosignificant difference (P>0.05). Western blot results were consistent with IHC results.1.4Correlation analysis results showed P-IRE1protein and P-JNK proteinexpression were positively correlated with apoptosis rate and negatively correlatedwith lung function.P-JNK protein was positively correlated with P-IRE1protein expression.2Clinical part:2.1Lung tissue morphological observation: compared with control group COPDgroup showed thickened bronchial epithelium and smooth muscle, with the influx ofinflammatory cells in the airway and shedding epithelial cells, expanded alveolarducts, alveolar capsule and alveolar appeared to merge into bulla.2.2The results of western blot: IRE1α showed no significant differences in allgroups. P-IRE1expression was lower in control group, non-COPD group had ascendexpression than the control group (P <0.05), COPD group showed higher expressionthan non-COPD group (P <0.05). The control group, non-COPD group and COPDgroup gave no significant difference in JNK protein expression. Compared with thecontrol group, P-JNK expression in non-COPD group was significantly higher (P<0.05), and COPD group showed higher level than non-COPD group (P <0.05).2.3The correlation analysis showed that P-IRE1protein and P-JNK proteinexpression were positively correlated with apoptosis rate and negatively correlatedwith lung function. P-JNK protein was positively correlated with P-IRE1proteinexpression.Conclusions：1. IRE1and JNK involved in the endoplasmic reticulum stress mechanism ofcigarette smoke-induced COPD.2. IRE1and JNK play roles in UPR and apoptosis of lung structure cellsduring endoplasmic reticulum stress of cigarette smoke-induced COPD. |
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