Tobacco smoke-induced lung emphysema in guinea pigs is associated
with increased interstitial collagenase.
Selman, Mois[acute]es, Martha Monta[tilde]no, Carlos Ramos, Beatriz
Vanda, Carina Becerril, Javier Delgado, Raul Sansores, Roberto
Barrios, Annie Pardo.
Instituto Nacional de Enfermedades Respiratorias, Tlalpan 4502;
Mexico DF 14080, Department of Pathology, Baylor College of Medicine,
Houston TX. Facultad de Ciencias, UNAM, Mexico DF 04510.
APStracts 3:0088L, 1996.
We examined the expression of interstitial collagenase and its
enzymatic activity in lung damage induced by tobacco smoke. Guinea
pigs were exposed to the smoke of 20 cigarettes per day from 1 to 8
weeks. Age-matched guinea pigs were used as controls. At 6 and 8
weeks of smoke exposure, lungs exhibited interstitial and
peribronchiolar inflammation and moderate emphysematous changes. In
situ hybridization of injured lungs revealed patchy expression of
collagenase mRNA mainly in macrophages, but also in alveolar
epithelial and interstitial cells. Immunoreactive protein was
detected in alveolar macrophages and in the alveolar walls and
interstitium. Collagenolytic activity increased beginning in the
fourth week of exposure (0.7 + 0.43 [mu]g of collagen degraded per mg
of collagen incubated relative to 0.23 + 0.14 in controls; p <
0.05). At 6 and 8 weeks, values were 0.85 + 0.34, and 0.98 + 0.33
compared to 0.25 + 0.11 and 0.26 + 13 in controls (p < 0.005 and
0.001). Collagen concentration decreased from 50.7 + 8.5 mg/g dry
weight in control lungs to 40.2 + 5.0, and 42.9 + 6.0 at 6 and 8
weeks of exposure respectively (P < 0.05). These results
strongly suggest that increased interstitial collagen degradation
plays a role in the development of lung emphysema.
Received 1 December 1995; accepted in final form 29 May 1996.
APS Manuscript Number L351-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 17 June 96