[An inhalation chamber model for controlled studies of tobacco smoke toxicity in rodents].
BACKGROUND
Smoking is a serious worldwide public health problem. Animal models act as a bridge between laboratory and human studies. The models applied are difficult to reproduce because of the use of different types of inhalation chambers and mainly because of the lack of continuous monitoring of smoke concentration.


OBJECTIVE
To develop an inhalation chamber for rats (with only the nose exposed) in which the amount of carbon monoxide (CO) can be maintained and monitored constantly.


METHODS
Male Wistar rats weighing 250g were exposed to 50ppm CO produced by the smoke from a filter-free cigarette. The animals were submitted to a single 2-h exposure and then sacrificed at 0, 4, 24 and 48h. The control group was left restrained inside the small perpendicular chambers, receiving only 5L/min of compressed air.


RESULTS
The model was able to increase HbCO levels immediately after the end of exposure (p<0.001), with a decrease being observed from 2h onwards when compared to the levels of the control group. Plasma cotinine increased immediately after exposure, and showed still detectable levels at 2 and 4h (p<0.05).


CONCLUSIONS
We conclude that the presented inhalation chamber system is able to maintain a controlled CO concentration in a model in which small animals are exposed to the inhalation of cigarette smoke, permitting well-controlled studies, as well as investigations involving other toxic gases and air pollutants.
Jardim
José Roberto
JR
Pulmonary Rehabilitation Center, Universidade Federal de São Paulo, Brasil. joserjardim@yahoo.com.br
Bizeto
Luciana
L
Fleig Mayer
Anamaria
A
Camelier
Aquiles
A
Rosa
Fernanda Warken
FW
Oliveira
Daniele
D
Azevedo
Daiane
D
Saldiva
Paulo Hilário
PH
Martins
Milton de Arruda
Mde A
Bonassa
Jorge
J
Nascimento
Oliver A
OA
D000818:Animals; D001273:Atmosphere Exposure Chambers; D004195:Disease Models, Animal; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
D014028:Tobacco Smoke Pollution