RÉSUMÉ
Aim To research into the effect of quercetin on coronary artery(CA) damage in diabetic rats and its relationship with Kv1.5.Methods Thirty male rats were randomly divided into blank control group, diabetes group and diabetes group + quercetin group.The effects of quercetin on heart coronary flow (CF) in diabetes rat were observed by CF measurement;the effects of quercetin on CA tension in diabetes rat were detected by CA tension measurement.To investigate the mechanism of quercetin improving CA lesions caused by diabetes, Kv currents of CA VSMC in rats were recorded using whole cell patch clamp, and Kv1.5 mRNA of CA VSMC was determined.Results Compared with normal group, CF of diabetic rats dropped significantly, and CF could increase with the supplement of quercetin in rat diet;the maximum contraction amplitude of CA in response to the contraction of KCl could be reduced with supplement of quercetin in diabetic rat dietary;compared with diabetes group, the contraction of CA from diabetes + quercetin to 4-AP significantly decreased;compared with blank control group, CA VSMC Kv currents of diabetes group had a significant decrease(P<0.05), and dietary supplement of quercetin could improve the above changes;RT-PCR results indicated that the expression of Kv1.5 mRNA on rat CA was the highest in control group, then in diabetes group and the lowest in diabetes+quercetin group.Conclusion Quercetin has protective effect on coronary muscle damage caused by diabetes, which maybe related to Kv1.5 channel.