Expression of apelin-APJ in chronic obstructive pulmonary disease and its significance

WANG Jia; ZHANG Ping; LI Zhu; SUN Jia-wei; ZHANG Bin; SUN Wu-zhuang

doi:10.3969/j.issn.1006-5725.2014.12.007

Abstract：Objective To detect the expression of apelin and angiotensin I receptor related protein (APJ) in rats with chronic obstructive pulmonary disease (COPD), and to explore the role of apelin-APJ system in the occurrence and development of COPD. Methods A rat model of COPD was established using the method of smoke exposure. SD rats were randomly divided into a control group and a COPD group. The rats in COPD group were exposed to secondhand cigarette smoke in a fume box twice a day for 4 months. Expressions of apelin mRNA and APJ mRNA in rat lung tissues were detected by real-time quantitative polymerase chain reaction (qRT-PCR). Expressions of apelin protein and APJ protein were determined by immunohistochemistry. Results The expressions of apelin mRNA and APJ mRNA in COPD group were decreased by 44% and 13% as compared with those in the control group. The mRNA expressions of apelin and APJ in rat lung tissues were negatively correlated with RV/(LV + S) (r = -0.454 and -0.448, P < 0.05), and positively related with FEV0.3/FVC (r = 0.529 and 0.475;P < 0.05). Apelin and APJ were mainly expressed in the epithelial cells of the bronch and lung, alveolar macrophages, vascular endothelial cells, and the membrane and cytoplasm of some alveolar wall cells. The expression of apelin and APJ protein was lower in COPD group than in the control group (P < 0.05). Conclusions The mRNA and protein expressions of apelin and APJ are decreased in the lung tissues in rats with COPD , which may be an important factor leading to the development of COPD. Apelin-APJ system might be a new target for prevention and treatment of pulmonary hypertension and right ventricular hypertrophy induced by COPD.