Pulmonary emphysema induced by cigarette smoke solution and lipopolysaccharide in guinea pigs

Exposure of animals to cigarette smoke for longer than 3 months leads to the development of chronic obstructive pulmonary disease (COPD) showing pulmonary emphysema. We attempted to create a COPD model with emphysema that could be established in a shorter period of time. Guinea pigs were intratracheally treated once a day on days 0-3, 5-8, 10-13 and 15-18 with a cigarette smoke solution (CSS), which was prepared by bubbling a stream of smoke into saline. Additionally, lipopolysaccharide (LPS) was administered intratracheally as an exacerbation factor on days 4, 9 and 14. By day 19, there was a gradual elevation of specific airway resistance (sRaw). In addition, both residual volume and functional residual capacity were found to be significantly higher on day 19. In the lungs, there was a marked increase in leukocytes, especially neutrophils. Histologically, we observed epithelial hyperplasia and emphysema. On the other hand, daily oral administration of theophylline during the administration of CSS and LPS suppressed the sRaw increase and the epithelial hyperplasia, but not other functional structural changes. In conclusion, we established an experimental COPD model in guinea pigs by using intratracheal instillations of CSS and LPS over a considerably shorter term than has been reported for other models.