Exercise training attenuates blood pressure elevation and adverse remodeling in the aorta of spontaneously hypertensive rats.
OBJECTIVE
To observe the extracellular matrix modifications and quantify the structural alterations of the aortic wall in spontaneously hypertensive rats (SHR) submitted to an aerobic physical activity (PA) protocol.


METHODS
Three groups of five rats each were studied: sedentary normotensive Wistar rats (SED-Wistar) and SHR (divided in SHR that underwent a 1 h/day 5 days/week PA for 20 weeks (EX-SHR) and those that were restricted to cage-bound activity (SED-SHR).


RESULTS
BP was lower in EX-SHRs and SED-Wistar rats (-35%) than in SED-SHRs. This difference became significant from the 3rd week of PA. The wall thickness was smaller in the EX-SHR and SED-Wistar (-45%) than in the SED-SHR (p<0.0001). In EX-SHR group, oxytalan and elaunin fibers were more pronounced than in the other groups, while SED-SHR and SED-Wistar rats showed an equivalent appearance of aortic elaunin fibers. EX-SHR and SED-Wistar rats showed more than 65% greater smooth muscle nuclei numerical density per unit area than SED-SHRs while SED-SHRs showed more than 45% smaller surface density of lamellae than both EX-SHR and SED-Wistar rats. However, no quantitative differences were found in the aortic wall comparing EX-SHR and SED-Wistar rats.


CONCLUSIONS
PA might alter the aortic wall remodeling to adapt the artery to a hyperkinetic blood flow resulting in alterations of the extracellular matrix modulation and vascular resistance.
Horta
Pedro Paulo
PP
Laboratory of Morphometry and Cardiovascular Morphology, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Brazil.
de Carvalho
Jorge José
JJ
Mandarim-de-Lacerda
Carlos Alberto
CA
D000818:Animals; D001011:Aorta / Q000473:pathology / Q000503:physiopathology*; D001794:Blood Pressure; D006973:Hypertension / Q000473:pathology / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D010805:Physical Conditioning, Animal; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D013045:Species Specificity; D014655:Vascular Resistance