Effect Of Leonurine On The Structure And Function Of Rat Mesenteric Artery

Background: Leonurine is an effective monomer extracted from Herba Leonuri,which has attracted much attention of researchers in recent years.Modern pharmacological research shows that it has a wide range of biological activities,and it can cure many diseases and has broad application prospects.Objective: To investigate the effectand mechanismof Leonurine on the structure and mechanicsofrat mesenteric artery.Methods: 50 healthy male Sprague-Dawley rats were randomly divided into the control group(Group A),the low(Group B),middle(Group C)and high(Group D)dose groups,10 rats in each group,and the other 10 remained in vitro experiments(Group E).Drug intervention after 3 days of adaptive feeding,Group A,B and C were given leonurine saline suspension(10 mg·kg-1·d-1,20 mg·kg-1·d-1,40 mg·kg-1·d-1),the Group A was given normal saline.Four weeks later,enzyme linked immunosorbent assaythe content of nitric oxide in the serum and endothelin-1 in the plasma,Isolate the 3rd mesenteric artery stained by Hematoxylin-eosin,the diameter and structure of mesenteric artery were observed under microscope.And use Multi Wire Myograph System(DMT-620M),to observe and draw the diameter-tension curve of rat 3rd mesenteric artery rings of group A,group B,group C and group D by increase the inner diameter of 10%,20%,30% and 40%,each step for 2 to 3 mins.To observe the relaxation effect of Leonurine on group E endothelium-intact and endothelium-denuded third rats mesenteric artery rings,and the relaxation effect with inhibitor of nitric oxide synthase(L-NAME),soluble guanylate cyclase(sGC)inhibitor(NS-2028)and calcium channel antagonist nifedipine incubated.Results: Compared with the control group,the content of nitric oxide(NO)in serum and the content of endothelin-1(ET-1)in plasma of Leonurine group decreased As the dose of leonurine increases(P<0.05).Hematoxylin-eosin staining showed the blood vessel wall of the Leonurine group was thinner than that of the saline control group(P<0.05),and the effectis dose-dependent.The tension of rat 3rd mesenteric artery rings increased with the increase of microvessel diameter,and the Leonurine group tension increased slower compared with the control group,and the tension was concentrationdependent.Leonurine can directly relax the endothelium-intact isolated mesenteric artery rings.The relaxation effect of Leonurine on the endotheliumdenuded isolated mesenteric artery rings is obviously weaker compared with endothelium-intacted rings[(30.62±5.86)% ?(88.24±6.25)%,P < 0.01],with inhibitor of nitric oxide synthase(L-NAME),soluble guanylate cyclase(sGC)inhibitor(NS-2028)and calcium channel antagonist nifedipineincubated incubated the relaxation effect of Leonurine is significantly reduced compared with endothelium-intacted rings(P<0.01).Conclusion:Leonurine intragastric administration can Improvement of vascular compliance,has a protective effect on rat mesenteric artery.Leonurine has a concentration-dependent and endothelium-dependent relaxation effect on isolated rat mesenteric artery rings.The relaxation effect of Leonurine is related to NO-sGC-cGMP signaling pathway and L-type calcium channel.