Beta-carotene supplementation attenuates cardiac remodeling induced by one-month tobacco-smoke exposure in rats.
OBJECTIVE
The objectives were to analyze the cardiac effects of exposure to tobacco smoke (ETS), for a period of 30 days, alone and in combination with beta-carotene supplementation (BC).


METHODS
Rats were allocated into: Air (control, n = 13); Air + BC (n = 11); ETS (n = 11); and BC + ETS (n = 9). In Air + BC and BC + ETS, 500 mg of BC were added to the diet. After three months of randomization, cardiac structure and function were assessed by echocardiogram. After that, animals were euthanized and morphological data were analyzed post-mortem. One-way and two-way ANOVA were used to assess the effects of ETS, BC and the interaction between ETS and BC on the variables.


RESULTS
ETS presented smaller cardiac output (0.087 +/- 0.001 vs. 0.105 +/- 0.004 l/min; p = 0.007), higher left ventricular diastolic diameter (19.6 +/- 0.5 vs. 18.0 +/- 0.5 mm/kg; p = 0.024), higher left ventricular (2.02 +/- 0.05 vs. 1.70 +/- 0.03 g/kg; p < 0.001) and atrium (0.24 +/- 0.01 vs. 0.19 +/- 0.01 g/kg; p = 0.003) weight, adjusted to body weight of animals, and higher values of hepatic lipid hydroperoxide (5.32 +/- 0.1 vs. 4.84 +/- 0.1 nmol/g tissue; p = 0.031) than Air. However, considering those variables, there were no differences between Air and BC + ETS (0.099 +/- 0.004 l/min; 19.0 +/- 0.5 mm/kg; 1.83 +/- 0.04 g/kg; 0.19 +/- 0.01 g/kg; 4.88 +/- 0.1 nmol/g tissue, respectively; p > 0.05). Ultrastructural alterations were found in ETS: disorganization or loss of myofilaments, plasmatic membrane infolding, sarcoplasm reticulum dilatation, polymorphic mitochondria with swelling and decreased cristae. In BC + ETS, most fibers showed normal morphological aspects.


CONCLUSIONS
One-month tobacco-smoke exposure induces functional and morphological cardiac alterations and BC supplementation attenuates this ventricular remodeling process.
Zornoff
Leonardo A M
LA
Departamento de Clínica Médica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (UNESP), Botucatu, Brazil. lzornoff@fmb.unesp.br
Matsubara
Luiz S
LS
Matsubara
Beatriz B
BB
Okoshi
Marina P
MP
Okoshi
Katashi
K
Dal Pai-Silva
Maeli
M
Carvalho
Robson F
RF
Cicogna
Antonio C
AC
Padovani
Carlos R
CR
Novelli
Ethel L
EL
Novo
Rosangela
R
Campana
Alvaro O
AO
Paiva
Sergio A R
SA
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D006332:Cardiomegaly / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D004032:Diet; D004452:Echocardiography; D006352:Heart Ventricles / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D019570:Inhalation Exposure; D008054:Lipid Peroxides / Q000097:blood; D008297:Male; D009206:Myocardium / Q000648:ultrastructure; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012906:Smoke; D020257:Ventricular Remodeling / Q000187:drug effects*; D019207:beta Carotene / Q000008:administration & dosage*
D000975:Antioxidants; D008054:Lipid Peroxides; D012906:Smoke; D019207:beta Carotene