The Study On The Hypotensive Effect And Mechanism Of Rubiadin-1-methyl Ether

BackgroundThe pathogenesis of hypertension is mainly related to the imbalance of nitric oxide?NO?and endothelin.Some studies indicated that vascular endothelial dysfunction plays an important role in the pathogenesis of hypertension,so improving vascular endothelial function can help to reduce blood pressure.Rubiadin-1-methyl ether?R1ME?is extracted from morinda officinalis,we found that R1ME have abilities of anti-inflammatory and anti-oxidation.Related studies have shown that morinda officinalis has the effect of protecting vascular endothelium.R1ME is an effective component extracted from morinda officinalis,we speculate that R1ME could improve vascular endothelial dysfunction and reduce blood pressure.ObjectiveTo study the antihypertensive effect of R1ME and its mechanism,it is elucidated that vascular endothelial growth factor receptor 2?VEGFR2?might be a target of R1ME in the regulation of blood pressure.MethodsAged 4 weeks,male,30 Wistar-kyoto rats?WKY?rats and 30 Spontaneously hypertensive rats?SHR?were used.They were divided into 6 groups,WKY+R1ME group,WKY+ZD6472 group;SHR group;SHR+R1ME group;and SHR+ZD6472+R1ME group with 10 rats in each group.Vandetanib?ZD6472?is a specific inhibitor of VEGFR2.The100 mg/kg/day R1ME drug and 0.1 mg/kg/day ZD6472 reagent were was given orally for8 weeks.The following indicators were tested after 8 weeks,?1?caudal arterial blood pressure in rats;?2?plasma was taken to detect hydrogen sulfide?H₂S?content and NO content;the content of inositol 1,4,5-triphosphate?IP3?in artery of rats;the function of endothelium-dependent relaxation?EDR?in rats,?3?the changes of vascular morphology were observed with a microscope in artery of rats;?4?hematoxylin-eosin staining was performed to observe the changes of vascular morphology in artery of rats;?5?the expression of VEGFR2,endothelial nitric oxide synthase?eNOS?protein in vascular tissues was detected by immunofluorescence.Human umbilical vein endothelial cells?HUVEC?the 3-8 generation endothelial cells with good growth were selected for experiments.They were divided into 6 groups,HUVEC,HUVEC+R1ME,HUVEC+ZD6472,HUVEC+R1ME+ZD6472.R1ME incubation time was 12 hours,and ZD6472 incubation time was 4 hours.?6?the effect of R1ME on endothelial cells was observed by hematoxylin-eosin staining;?7?the contents of NO,H₂S and IP3 in the supernatant of endothelial cells were detected;?8?the expression of VEGFR2 protein in endothelial cells was detected by immunofluorescence;?9?the positive expression of eNOS in endothelial cells was detected by immunofluorescence technique.Results?1?Compared with the WKY group,the blood pressure was significantly increased,NO contents of the plasma and IP3 contents of the vascular tissue were decreased,and EDR was significantly decreased in the WKY+ZD6472 group,there were significant differences?P<0.05?;the blood pressure of rats was significantly higher,H₂S,NO contents of the plasma and IP3 contents of the vascular tissues were reduced,and EDR was significantly reduced in the SHR group,there were significant differences?P<0.05?;Compared with the SHR group,the blood pressure was significantly reduced,H₂S,NO contents of the plasma and IP3 contents of vascular tissue were significantly increased,and EDR was significantly improved in the SHR+R1ME group,there were significant differences?P<0.05?;compared with the SHR+R1ME group,the blood pressure was significantly increased,the NO contents of the plasma and IP3 contents of vascular tissue were significantly decreased,and the EDR was significantly decreased in the SHR+R1ME+ZD6472 group,there were significant differences?P<0.05?.?2?Compared with the WKY group,the vascular endothelium of rats were damaged in the SHR group;after R1ME treatment,compared with the SHR group,the vascular endothelium of rats were significantly improved in the SHR+R1ME group;when ZD6472and R1ME were administered to SHR,compared with the SHR+R1ME group,the effect of R1ME on vascular injury was decreased in the SHR+R1ME+ZD6472 group.?3?Compared with the WKY group,the positive expressions of VEGFR2 and eNOS were decreased in the SHR group,after R1ME treatment,compared with the SHR group,the positive expressions of VEGFR2 and eNOS showed high positive expression in the SHR+R1ME group,when ZD6472 was co-treated with R1ME,compared with that in SHR+R1ME group,the expression of VEGFR2 and eNOS was weakly positive in SHR+R1ME+ZD6472 group.?4?Compared with the HUVEC group,the effect of R1ME on endothelial remodeling was observed by hematoxylin-eosin staining;compared with HUVEC+R1ME group,when the endothelial cells were treated with R1ME and ZD6472,the effect of R1ME on endothelial remodeling was reduced in HUVEC+R1ME+ZD6472 group.?5?Compared with the HUVEC group,the contents of H₂S,NO and IP3 were increased in the HUVEC+R1ME group,there were significant differences?P<0.05?;the contents of H₂S,NO and IP3 were significantly decreased in the HUVEC+ZD6472 group,there were significant differences?P<0.05?;when HUVEC were treated with R1ME and ZD6472,compared with HUVEC+R1ME group,the contents of NO and IP3 were reduced in HUVEC+R1ME+ZD6472 group,there were significant differences?P<0.05?.?6?Compared with the HUVEC group,the positive expressions of VEGFR2 and eNOS were decreased in HUVEC+ZD6472 group;after R1ME treatment,the positive expression of VEGFR2 and eNOS factors were increased in HUVEC+R1ME group;when the HUVEC were treated with R1ME and ZD6472,compared with HUVEC+R1ME group,the positive expression of VEGFR2 and eNOS were decreased in HUVEC+R1ME+ZD6472 group.ConclusionR1ME reduce the blood pressure and the mechanism is due in part to activate VEGFR2 factor,repair eNOS-NO pathway,and improve vascular endothelial injury,so as to relieve hypertension.