A rat model of bronchopulmonary dysplasia induced by cigarette smoke exposure

Abstract

Objective To establish a model of bronchopulmonary dysplasia (BPD) induced by cigarette smoke exposure. Methods After mated with male SD rats, female rats were randomly divided into two groups: control group and cigarette smoke exposure group.Exposure group were put in fumigation device for one hour twice daily until the pups were born which were exposed for one hour once daily.The total particle concentration was monitored during exposure for ten minutes each time, and the concentrations of O2, CO and CO2 in the smoke were continuously monitored.Control group was fed without any intervention.Weight and mortality rate of pups were recorded.At the 14th day, pups′ lungs were collected and cell count was made in the bronchoalveolar lavage fluid (BALF). Hematoxylin and eosin (HE) staining was performed to observe the morphological changes of the lungs.The expressions of vascular endothelial growth factor (VEGF) and nicotinic acetylcholine receptor alpha 7 (α7-nAChR) were analyzed by Western blot. Results The body weight of cigarette smoke exposure group was significantly lower than that of control group (P<0.05), and the mortality rate was higher than that of control group.Compared with control group, the number of neutrophil and macrophage in BALF increased (all P<0.01), HE staining showed alveolar fusion, alveolar septal thickening, radical alveolar count decreased and mean linear intercept increased (all P<0.05), Western blot showed VEGF expression decreased and α-7nAChR expression increased (all P<0.05) in cigarette smoke exposure group. Conclusions The pathological manifestations caused by cigarette smoke exposure during pregnancy and postnatal stage are consistent with BPD, which can be used as an animal model to study the mechanism of BPD in infants exposed to cigarette smoke. Key words: Bronchopulmonary dysplasia; Pregnancy; Cigarette smoking exposure; Model