Only 20% of smokers develop chronic obstructive pulmonary disease. An important determinant of susceptibility is genomic variation. We undertook this study to define strains of mice with different susceptibilities for the development of smoking-induced emphysema because they could help identify genetic factors of susceptibility. NZWLac/J, C57BL6/J, A/J, SJ/L, and AKR/J strains were exposed to cigarette smoke for 6 months. Elastance (Htis), the extent of emphysema (mean linear intercept [Lm]), and the inflammatory cell and cytokine response were measured. NZWLac/J had no change in Lm or Htis (resistant). C57BL6/J, A/J, and SJ/L increased Lm, but not Htis (mildly susceptible). AKR/J increased Lm and Htis (super-susceptible). Only AKR/J had significant inflammation comprising macrophages, neutrophils, and T cells. The AKR/J showed an upregulation of Th1 cytokines whereas in the C57BL/6/J and NZWlac/J, cytokines did not change or were downregulated. We conclude that Lm, elastance, and inflammation are features that are needed to phenotype emphysema in mice. The inflammatory cell and cytokine profile may be an important determinant of the phenotype in response to cigarette smoke exposure. The identification of resistant and susceptible strains for the development of emphysema could be useful for genomic studies of emphysema susceptibility in mice and eventually in humans.

Cigarette smoking in humans is associated with various patterns of emphysema and functional consequences. We tested the hypothesis that variations in alpha1-antitrypsin expression modulate the pattern of emphysema and functional consequences in cigarette smoke-exposed mice. We compared the effects of up to 6 months of cigarette smoke exposure in C57BL/6J (C57) mice and in low-alpha1-antitrypsin, C57BL/6J pa+/pa+ (pallid) mice. At the end of the experiment, we determined lung mechanical properties, the extent (mean linear intercept) and type of emphysema, and the cellular inflammatory response. After 4 months of cigarette smoking, pallid smoking mice, but not C57 smoking mice, had a significant increase in mean linear intercept. After 6 months of smoke exposure, C57 smoking mice and pallid smoking mice had similar degrees of emphysema. The pattern of emphysema in pallid smoking mice was more diffuse than in C57 smoking mice, affecting all airspaces. Pallid mice, but not C57 mice, developed a T cell inflammation in the alveolar wall after 6 months of smoking (p < 0.01). Although lung compliance was not changed in C57 smoking mice after smoke exposure, it increased significantly in pallid smoking mice over the 6 months of exposure (p < 0.0082). In summary, cigarette smoking induces emphysema in C57 and pallid mice, but the emphysema, inflammatory infiltrate, and resulting physiologic abnormalities were substantially different in the two strains, with the C57 and pallid mice exhibiting features similar to centrilobular and panlobular emphysema, respectively.