Effects of flaxseed intake on vascular contractile function in diabetic rats

Abstract

In diabetes, one of the most important causes of morbidity and mortality is vasculopathy. Though flaxseed (FXS) is known for improving cardiovascular health, only limited studies are available on FXS concerning diabetic vascular reactivity. Hence, in this study, we studied vascular reactivity changes after FXS treatment on streptozotocin (STZ)-induced diabetic rat aortae. Female Wistar rats were divided into following four groups: control (C), FXS treated (CT), diabetic (D), and FXS treated diabetic (DT) groups. FXS (0,714 g/kg/day; orally) was started after one week of STZ injection and was given for 12 weeks, phenylephrine (Phe)-induced contractions were obtained on isolated aortic rings in the presence of indomethacin, L-NAME and superoxide dismutase (SOD), individually. Phe-responses were increased significantly in D group and completely improved after FXS intake, whereas FXS increased vascular reactivity to Phe in C group. Indomethacin incubation significantly attenuated Phe-induced contractions in all groups of aorta, particularly in D group. L-NAME incubation significantly increased Phe responses in all groups except D group. SOD incubation decreased the contractions efficiently in D group. The decreament was much lower in DT compared to D group, but reverse effects were observed in CT group. Our findings suggest FXS may provide beneficial effects on diabetes-induced vascular reactivity changes through NO and prostaglandin dependent pathways, but in healty condition FXS may have adverse effect probably via pro-oxidant activity.