Animal models of emphysema and their relevance to studies of particle-induced disease

Emphysema is a pulmonary disease that may be exacerbated by inhaled particl es. Over the years, many animal models of emphysema have been developed tha t may be useful in studying the effects of inhaled particles on humans with emphysema. Models have been described in many species, and many approacher have been described for inducing emphysema. Emphysema in humans is a paren chymal component of chronic obstructive pulmonary disease and frequently co exists in a complex with disease of the airways such as bronchitis. Animal models of emphysema usually recapitulate only one or a few aspects of this complex disease. Thus, the emphysema model must be selected carefully in or der to answer specific questions about the interactive effects of particles and emphysema.