Characteristic plethysmographic findings in a guinea pig model of COPD.
Long-term exposure to cigarette smoke generates chronic obstructive pulmonary disease (COPD) in guinea pigs, but a comprehensive evaluation of changes in lung function, as assessed by barometric whole body plethysmography (WBP), is lacking.



Female guinea pigs were exposed to the smoke of 20 cigarettes/day, 5 days/week, during 10 weeks (COPD group, n = 8), and were compared with unexposed female guinea pigs of the same age (control group, n = 8). WBP was performed in both groups, followed by lung histology.



At the end of the exposure period, guinea pigs in the COPD group had higher respiratory frequency, while duty cycle (Ti/Ttot) was unaffected. There was a trend toward minute ventilation (MV) and expiratory flow at the mid-tidal volume (EF50) to be higher in the COPD group. Enhanced pause (Penh) was lower, while time of braking (TB) and time to PEF relative to Te (Rpef) were higher in the COPD group. All guinea pigs exposed to tobacco smoke developed emphysematous lesions in their lungs and gained less body weight than controls.



In this COPD model, exposure to cigarette smoke produced changes in WBP characterized by a shallow breathing pattern with decreased Penh and a trend toward increasing EF50 (probably due to decreased elastic recoil), increased TB (suggesting dynamic laryngeal narrowing), and a trend of increasing MV (probably due to a higher metabolic rate). Many of these functional changes resemble those observed in patients with COPD and corroborate the suitability of this guinea pig model for the study of COPD.
a Departamento de Investigación en Hiperreactividad Bronquial , Instituto Nacional de Enfermedades Respiratorias , Ciudad de México , México.|b Facultad de Medicina , Universidad Autónoma de Coahuila , Torreón , Coahuila , México.
Edgar
E
Ramírez-Ramírez
a Departamento de Investigación en Hiperreactividad Bronquial , Instituto Nacional de Enfermedades Respiratorias , Ciudad de México , México.|b Facultad de Medicina , Universidad Autónoma de Coahuila , Torreón , Coahuila , México.
Armando
A
Torres-Ramírez
a Departamento de Investigación en Hiperreactividad Bronquial , Instituto Nacional de Enfermedades Respiratorias , Ciudad de México , México.
Jesús
J
Alquicira-Mireles
c Departamento de Patología , Hospital General de México , Ciudad de México , México.
Abraham
A
Cañavera-Constantino
a Departamento de Investigación en Hiperreactividad Bronquial , Instituto Nacional de Enfermedades Respiratorias , Ciudad de México , México.
Patricia
P
Segura-Medina
d Departamento de Investigación en Fibrosis Pulmonar , Instituto Nacional de Enfermedades Respiratorias , Ciudad de México , México.
Martha
M
Montaño-Ramírez
d Departamento de Investigación en Fibrosis Pulmonar , Instituto Nacional de Enfermedades Respiratorias , Ciudad de México , México.
Carlos
C
Ramos-Abraham
a Departamento de Investigación en Hiperreactividad Bronquial , Instituto Nacional de Enfermedades Respiratorias , Ciudad de México , México.
Mario H
MH
Vargas
a Departamento de Investigación en Hiperreactividad Bronquial , Instituto Nacional de Enfermedades Respiratorias , Ciudad de México , México.
José Luis
JL
Arreola-Ramírez
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006168:Guinea Pigs; D010991:Plethysmography / Q000379:methods*; D029424:Pulmonary Disease, Chronic Obstructive / Q000209:etiology* / Q000503:physiopathology; D012123:Pulmonary Ventilation; D012119:Respiration; D012129:Respiratory Function Tests; D012906:Smoke / Q000009:adverse effects*; D013990:Tidal Volume; D062789:Tobacco Products
D012906:Smoke
barometric plethysmography; chronic obstructive pulmonary disease; emphysema; lung function; tobacco smoke