title: Exposure time and ventricular remodeling induced by tobacco smoke exposure in rats.
abstract: BACKGROUND
  We investigated the effects of length of exposure to tobacco smoke on the cardiac remodeling process induced by exposure to cigarette smoke in rats.
  
  
  METHODS
  Rats were separated into 4 groups: nonsmoking (NS)2 (n=25; control animals not exposed to tobacco smoke for 2 months), smoking (S)2 (n=22; rats exposed to smoke from 40 cigarettes/d for 2 months), NS6 (n=18; control animals not exposed to tobacco smoke for 6 months), and S6 (n=25; rats exposed to smoke from 40 cigarettes/d for 6 months). All animals underwent echocardiographic, isolated heart, and morphometric studies. Data were analyzed with a 2-way analysis of variance.
  
  
  RESULTS
  No interaction among the variables was found; this suggests that length of exposure to tobacco smoke did not influence the effects of exposure to smoke. Values for left ventricular diastolic diameter/body weight and left atrium/body weight were higher (p=0.023 and p=0.001, respectively) in smoking (S2 and S6) than in nonsmoking animals (NS2 and NS6). Left ventricular mass index was higher (p=0.048) in smoking than in nonsmoking animals. In the isovolumetrically beating ventricle, peak systolic pressure was higher (p=0.034) in smoking than in nonsmoking animals. Significantly higher values were found for left ventricular weight (p=0.017) and right ventricular weight (p=0.001) adjusted for body weight in smoking as opposed to nonsmoking animals. Systolic pressure was higher (p=0.001) in smoking (128+/-14 mm Hg) than in nonsmoking animals (112+/-11 mm Hg).
  
  
  CONCLUSIONS
  Length of exposure to cigarette smoke did not influence cardiac remodeling caused by exposure to smoke in rats.
authors.affiliation: Internal Medicine Department, Botucatu Medical School, UNESP - São Paulo State University, Botucatu, Brazil.
authors.forename: Edson
authors.initials: E
authors.lastname: Castardeli
authors.forename: Daniella R
authors.initials: DR
authors.lastname: Duarte
authors.forename: Marcos F
authors.initials: MF
authors.lastname: Minicucci
authors.forename: Paula S
authors.initials: PS
authors.lastname: Azevedo
authors.forename: Beatriz B
authors.initials: BB
authors.lastname: Matsubara
authors.forename: Luiz S
authors.initials: LS
authors.lastname: Matsubara
authors.forename: Alvaro O
authors.initials: AO
authors.lastname: Campana
authors.forename: Sergio A R
authors.initials: SA
authors.lastname: Paiva
authors.forename: Leonardo A M
authors.initials: LA
authors.lastname: Zornoff
mesh_terms: D000818:Animals; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012907:Smoking / Q000009:adverse effects*; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right; D020257:Ventricular Remodeling