Adaptation of an amphibian mucociliary clearance model to evaluate early effects of tobacco smoke exposure.
BACKGROUND
Inhaled side-stream tobacco smoke brings in all of its harmful components impairing mechanisms that protect the airways and lungs. Chronic respiratory health consequences are a complex multi-step silent process. By the time clinical manifestations require medical attention, several structural and functional changes have already occurred. The respiratory system has to undergo an iterative process of injury, healing and remodeling with every exposure.


METHODS
To have a better understanding of the initial changes that take place when first exposed to environmental tobacco smoke, we have developed an exposure model, using the frog palate that closely represents the features of obstructive airways where ciliary dysfunction and mucus hypersecretion occur.


RESULTS
Mucus transport was significantly reduced, even after exposure to the smoke of one cigarette (p < 0.05) and even further with 4-cigarettes exposure (p < 0.001). Morphometric and ultrastructural studies by SEM show extensive areas of tissue disruption. Gelatinase zymography shows activation of MMP9 in mucus from palates exposed to tobacco smoke.


CONCLUSIONS
The clearance of mucus on the frog palate is significantly reduced after exposure to environmental tobacco smoke. Cilia and the extracellular matrix are anatomically disrupted. Tobacco smoke triggers an increased activity of matrix metalloproteinases associated with a substantial defoliation of ciliated epithelium. These studies enhance the knowledge of the changes in the mucociliary apparatus that occur initially after exposure to environmental tobacco smoke, with the goal of understanding how these changes relate to the genesis of chronic airway pathologies in humans.
Zayas
J Gustavo
JG
Mucobiology Research Unit, Pulmonary Research Group, University of Alberta, Edmonton, Canada. g.zayas@ualberta.ca <g.zayas@ualberta.ca>
O'Brien
Darryl W
DW
Tai
Shusheng
S
Ding
Jie
J
Lim
Leonard
L
King
Malcolm
M
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000009:adverse effects*; D023421:Models, Animal; D009079:Mucociliary Clearance / Q000187:drug effects*; D010159:Palate / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology*; D011892:Rana catesbeiana / Q000033:anatomy & histology*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
D014028:Tobacco Smoke Pollution