Effects of cigarette smoke and chronic hypoxia on ventilation in guinea pigs. Clinical significance.
Ventilatory effects of chronic cigarette smoke (CS) alone or associated to chronic hypoxia (CH), as frequently occurs in chronic obstructive pulmonary disease (COPD), remain unknown. We have addressed this problem using whole-body plethysmography in guinea-pigs, common models to study harmful effects of CS on the respiratory system. Breathing frequencies (Bf) in control (2-5 months old) guinea pigs is 90-100 breaths/min, their tidal volume (TV) increased with age but lagged behind body weight gain and, as consequence, their minute volume (MV)/Kg decreased with age. MV did not change by acutely breathing 10% O(2) but doubled while breathing 5% CO(2) in air. Exposure to chronic sustained hypoxia (15 days, 12% O(2), CH) did not elicit ventilatory acclimatization nor adaptation. These findings confirm the unresponsiveness of the guinea pig CB to hypoxia. Exposure to CS (3 months) increased Bf and MV but association with CH blunted CS effects. We conclude that CS and CH association accelerates CS-induced respiratory system damage leading to a hypoventilation that can worsen the ongoing COPD process.
Department of Biochemistry and Molecular Biology and Physiology, IBGM Universidad de Valladolid, Valladolid, Spain.
Elena
E
Olea
Elisabet
E
Ferrer
Jesus
J
Prieto-Lloret
Carmen
C
Gonzalez-Martin
Victoria
V
Vega-Agapito
Elvira
E
Gonzalez-Obeso
Teresa
T
Agapito
Victor
V
Peinado
Ana
A
Obeso
Joan Albert
JA
Barbera
Constancio
C
Gonzalez
D000818:Animals; D001835:Body Weight; D002908:Chronic Disease; D006168:Guinea Pigs; D006400:Hematocrit; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology; D012119:Respiration; D012907:Smoking / Q000503:physiopathology*