The use of an in vivo model to study the effects of hyperhomocysteinaemia on vascular function

Background/Aims. To use an in vivo rat model of hyperhomocysteinaemia (HHCy) to study its impact on vascular function. Methods. Twenty rats were fed either a control or HHCy-inducing diet for 10 wk. The response of aortic rings to contraction with phenylephrine, and relaxation to acetylcholine (endothelium-dependant relaxation) or sodium nitroprusside (endothelium-independent relaxation) was analyzed. The results were compared using an analysis of variance (ANOVA). Results. There was a significant elevation of HCy in the treated group (20.5 versus 1.6 mu mol/L, P = 0.004). There was no significant difference between the two groups in blood pressure measurements (ANOVA, P = 0.152). In a dose-dependant manner, phenylephrine elicited significantly greater contraction in aorta taken from HHCy rats than that taken from controls (ANOVA, P < 0.001), acetylcholine elicited significantly less percentage relaxation in aorta taken from HHCy rats than from controls (ANOVA, P = 0.003) and though sodium nitroprusside stimulated less percentage relaxation in aorta taken from HHCy rats than controls, this did not reach significance (ANOVA, P = 0.051). Conclusions. In diet induced hyperhomocysteinaemic rats, there is enhanced vascular contraction in response to phenylephrine and impaired endothelium-dependant relaxation in response to acetylcholine. (c) 2008 Elsevier Inc. All rights reserved.