Analysis of airway secretions in a model of sulfur dioxide induced chronic obstructive pulmonary disease (COPD)

In summary, SO2-exposure can lead to characteristic airway remodeling and changes in mucus secretion in rats. As only long-term exposure to 20 ppm leads to a combination of hypersecretion and airway inflammation, only this mode of exposure should be used to mimic human COPD. Concentrations less or higher than 20 ppm or short term exposure do not induce the respiratory symptom of hypersecretion. The present model may be used to characterize the effects of new compounds on mucus secretion in the background of experimental COPD.Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease that is characterized by hypersecretion, cough and inflammatory cell influx [1,2]. COPD is currently estimated to become the 3rd most common cause of death in 2020 [3]. The clinical and morphological features of the disease are mediated by humoral [4] and/or neuronal mediators [5,6] and display protective first-line responses against inhaled irritants. However, within chronic exposure to noxious substances such as tobacco smoke, urban dust, or occupational factors [7-9], the originally protective mechanisms lead to a state of chronic phlegm production [10], airway inflammation, and cough, significantly limiting the quality of life [11]. Under these conditions therapeutic options such as the efficacy of topically administered drugs become negatively influenced and respiratory pharmacotransporters may be negatively influenced [12-15].Next to tobacco smoke exposure, either active or passive, a number of other environmental factors can be associated to the development of COPD [16]. Sulfur dioxide belongs to these factors and its associations to airway diseases have been investigated since the London smogs [17], which are known to be one of the first characterized dramatic urban environmental exposures to air pollutants [18].The WHO definition of COPD is only based on clinical criteria. Moreover, there are some morphological methods such as the Reid index to define