Geraniol improves the impaired vascular reactivity in diabetes and metabolic syndrome through calcium channel blocking effect

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• 作者：Hany M. El-Bassossy^a ; ^b ; Ahmed A. Elberry^c ; ^d ; ^{berry_ahmed@yahoo.com" class="auth_mail" title="E-mail the corresponding author} ; Salah A. Ghareib^a
• 关键词：Geraniol ; Diabetes ; Vascular reactivity ; Nitric oxide ; Advanced glycation end products ; Calcium channels
• 刊名：Journal of Diabetes and its Complications
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：30
• 期：6
• 页码：1008-1016
• 全文大小：1990 K

文摘

The aim of the present study is to investigate the effect and possible mechanism of action of geraniol on the impaired vascular reactivity of aortic rings isolated from diabetes or metabolic syndrome (MS) -induced rats.

Methods

Male Wistar rats were divided into control, type 1 diabetes and metabolic syndrome (MS) groups. Diabetes was induced by a single intraperitoneal injection of streptozotocin (50 mg/kg) and left for 10 weeks to develop vascular complications. MS was induced by adding 10% fructose and 3% salt to water and diet for 12 weeks. The present study investigated the effect of in vitro incubation with geraniol (10–300 μM) on the vasoconstrictor response to phenylephrine (PE) and the vasodilator response to acetylcholine (ACh) as well as its effect on aortae incubated with methylglyoxal (MG) as an advanced glycation end product (AGE). To investigate the mechanism of action of geraniol, different blockers are used, including Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME, 100 μM), tetraethylammonium chloride (TEA, 10 mM), and indomethacin (INDO, 5 μM). Moreover, the effect of calcium chloride (CaCl₂) on aortic rings precontracted with PE or potassium chloride (KCl) was examined.

Results

Thirty minutes incubation with geraniol alleviated the exaggerated vasoconstriction in aortae isolated from diabetic or MS animals or in vitro exposed to MG in a concentration-dependent manner. In addition, geraniol improved the vasodilatation response of diabetic or MS aortae or aortae exposed to MG. In search for the mechanism; geraniol produced concentration-dependent relaxation of both PE and KCl-precontracted aorta. Geraniol relaxation was not affected by L-NAME, INDO or TEA. However, geraniol significantly inhibited voltage dependent and receptor mediated Ca^2 +-induced contraction activated by KCl or PE respectively.

Conclusion

In conclusion, geraniol ameliorates impaired vascular reactivity in experimentally induced diabetes and MS. The effect may be partially attributed to an endothelium-independent pathway involving blockage of both voltage dependent and receptor operated calcium channel.