The aims of this study were to identify the effect of
clofibrate administration in the development of
high blood pressure secondary to
aortic coarctation (AoCo) and to assess its effect on vascular reactivity. Three experimental groups of rats were used:
sham-operated, aortic coarctated vehicle-treated (AoCo-V), and aortic coarctated
clofibrate-treated (AoCo-C100). The rats were treated for seven days. Blood pressure was measured, and the vascular response to
angiotensin II (AngII),
norepinephrine (NE), and
acetylcholine (ACh) were evaluated in aortic rings. The activity and expression of
endothelial nitric oxide synthase (eNOS) was also evaluated. The major findings of this study include the following: AoCo induced a rise in blood pressure, and this effect was attenuated by
clofibrate. The vascular response to AngII was higher in aortic rings from the AoCo-V group compared to the
Sham-V or AoCo-C100 groups. ACh-elicited vasorelaxation was lower in the arteries of AoCo-V rats than
Sham-V or AoCo-C100, while it was comparable between the
Sham-V and AoCo-C100 groups. In every case, vasorelaxation was dependent on NO. However, the ACh-induced release of NO as well as NOS activity and expression were reduced in the arteries of AoCo-V rats.
Clofibrate maintained normal NOS activity and increased eNOS expression. In conclusion,
clofibrate administration attenuated the AoCo-induced rise in blood pressure by a mechanism that involves the participation of the NO system at both the NO synthesis and the eNOS
protein expression levels. These events improved endothelial function, preserved normal vascular responses to both
vasorelaxants and
vasoconstrictors, and led to better blood pressure control.