High concentration of glucose inhibits endothelium-dependent vasorelaxation of rabbit aortic artery.
AIM
To determine whether high concentration of glucose inhibits endothelium-dependent vasorelaxation of rabbit aortic artery and possible mechanisms.


METHODS
The organ-bath of rings of rabbit aorta was used to determine changes of tension of vessel in response to different concentrations of acetylcholine (ACh) and sodium nitroprusside (SNP) after removal of endothelium, coincubated with nitric oxide synthase (NOS) inhibitor L-NMMA, different concentrations of glucose, vitamin C, and cell-permeable superoxide dismutase-mimetic and oxygen-derived free radical scavenger manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin (MnTMPyP).


RESULTS
ACh induced concentration- and endothelium-dependent aortic vasorelaxation. High concentration of glucose markedly inhibited this vasorelaxation, and vitamin C and MnTMPyP could not antaganize this inhibitory effect by high concentrations of glucose. SNP induced concentration-dependent and endothelium-independent vasorelaxation, and high concentration of glucose had no effect on the vasorelaxation by SNP.


CONCLUSION
High concentration of glucose inhibited endothelium-dependent vasorelaxation and this effect was unlikely mediated through activating oxygen-derived free radical production.