Objective To investigate whether cigarette smoke promote endoplasmic reticulum associated apoptosis gene Caspase-12 expression. Methods Forty adult male Wistar rats were randomly divided into four groups, ie. group A ( control group) , group B ( exposed to cigarette smoke for two months) ,group C ( exposed to cigarette smoke for four months) , and group D ( exposed to cigarette smoke for four months, then quit smoking for one month) . The COPD rat model was established with passive smoking.Percentage of forced expiratory volume in first 0. 3 second to forced vital capacity ( FEV0. 3 /FVC) and peak expiratory flow ( PEF) were measured. Reverse transcriptase-polymerase chain reaction ( RT-PCR) was used to determine the mRNA expression of Caspase-12. Immunohistochemistry and Western blot were used todetermine the protein expression of Caspase-12. Caspase-12-fluorometric-assay-kit was used to determine Caspase-12 activity. Results The pulmonary function decreased ( P lt; 0. 05) and the lung structure was damaged in the group B compared with the group A. The lung function markedly decreased( P lt; 0. 05) andthe lung structure was obviously damaged in the group C compared with the group B. The pulmonary function had minor improvement( P gt; 0. 05) , and the lung structure injury was also significant in the group D in contrast with the group C. The expression and activity of Caspase-12 were remarkably increased in the group B compared with the group A( P lt; 0. 05) , elevated significantly in the group C compared with the group B ( P lt; 0. 05) , decreased slightly in the group D compared with the group C ( P gt; 0. 05 ) . Conclusion Cigarette smoke promotes the development of COPD by inducing the endoplasmic reticulum associated apoptosis gene Caspase-12 expression.
ObjectiveTo investigate the endoplasmic reticulum stress associated apoptosis gene Caspase-12 expression in paraquat-induced pulmonary fibrosis. Methods30 adult healthy Sprague-Dawley(SD) rats were randomly divided into a nomal control group,two pulmonary fibrosis model groups (intragastrically administered paraquat for 14 days and 28 days,respectively).The model of pulmonary fibrosis was established through intragastrically administering paraquat at the dose of 30 mg/kg.RT-PCR was used to determine the mRNA expression of Caspase-12.Immunohistochemistry was used to determine the protein expression of Caspase-12.HE staining and Masson staining were used to determine the degree of alveolitis and pulmonary fibrosis. ResultsHE staining and Masson staining of lung tissues proved that pulmonary fibrosis model was successfully constructed.The degree of alveolitis and pulmonary fibrosis in the model group was significantly more serious than that in the control group(P<0.01).RT-PCR and Immunohistochemistry results showed that the expression of Caspase-12 were remarkably increased in the pulmonary fibrosis model group(14 d group)(P<0.01),even more elevated in 28 d group compared with the 14 d group. ConclusionThe results demonstrate that the expression of Caspase-12 in paraquat poisoned rats is up-regulated,suggesting endoplasmic reticulum stress plays an important role in paraquat induced-pulmonary fibrosis.