Heart and blood pressure adaptations in Wistar rats fed with different high-fat diets for 18 months.
OBJECTIVE
We investigated the effect of long-term administration of four different high-fat diets on systolic blood pressure (SBP), body and heart biometry, and left ventricular myocyte nuclei number (N[lvm]).


METHODS
Twenty-four Wistar rats were assigned to one of four groups from weaning to age 18 mo. The rats were fed experimental diets containing soybean oil (S group), canola oil (CA group), lard and egg yolk (LE group), and canola oil plus lard and egg yolk (CA + LE group). N(lvm) was measured with the disector method in isotropic uniform random sections of the left ventricular myocardium.


RESULTS
There were no significant differences across experimental groups in morphometric indices. SBP was higher in the LE group at all ages and lower in the 18-mo CA group. The myocardium structure analysis separated the animals in three major categories: the CA and LE groups as the extreme and the S and CA + LE groups as the intermediary. In the LE group the myocardium presented more important structural changes: cardiac myocytes were enlarged and surrounded with thick collagen bundles, and some regions exhibited myocardial necrosis.


CONCLUSIONS
Long-term intake of the CA diet was more efficient in maintaining normal N(lvm) and SBP than the S and LE diets. The CA + LE diet resulted in balanced levels of SBP and N(lvm) in rats, suggesting that canola oil reduces cardiovascular injury caused by intake of lard and egg yolk.
Aguila
Marcia B
MB
Laboratory of Morphometry and Cardiovascular Morphology, State University of Rio de Janeiro, Rio de Janeiro, Brazil. mandarim@uerj.br
Mandarim-de-Lacerda
Carlos Alberto
CA
D000222:Adaptation, Physiological; D000375:Aging / Q000502:physiology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004041:Dietary Fats / Q000008:administration & dosage*; D004530:Egg Yolk; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage*; D006321:Heart / Q000033:anatomy & histology*; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000166:cytology*; D011897:Random Allocation; D000074262:Rapeseed Oil; D051381:Rats; D017208:Rats, Wistar; D013024:Soybean Oil / Q000008:administration & dosage*
D004041:Dietary Fats; D005229:Fatty Acids, Monounsaturated; D005231:Fatty Acids, Unsaturated; D000074262:Rapeseed Oil; D013024:Soybean Oil; C029310:lard