ERK1/2参与自发性高血压大鼠离体血管环对apelin-13舒张反应性降低作用

ERK1/2 Mediated The Vasodilatation of Apelin-13 on Vascular Rings of Spontanously Hypertensive Rat in vitro

研究自发性高血压大鼠(spontanously hypertensive rat,SHR)离体血管环对G蛋白偶联受体APJ的内源性配体apelin-13的血管收缩与舒张反应及其与一氧化氮(NO)和ERK1/2通路关系.采用离体血管环体外灌流方法用Power-Lab生物信息采集仪检测血管环的张力.实验分组如下:新福林(Phenylephrine,PE)组,乙酰胆碱(acetylcholine,Ach)组,apelin-13组,apelin-13+PE组,apelin-13+Ach组,PD98059(ERK1/2抑制剂)+PE组,PD98059+Ach组,LNNA(L-nitro-arginine,硝基左旋精氨酸,一氧化氮合酶抑制剂)+PE组,LNNA+Ach组,apelin-13(预孵育)+PD98059+PE组,apelin-13(预孵育)+PD98059+Ach组,apelin-13(预孵育)+LNNA+PE组和apelin-13(预孵育)+LNNA+Ach组,以WKY大鼠血管环为对照组.培养大鼠血管平滑肌细胞,Western blot检测ERK1/2蛋白表达.结果显示:a.apelin-13对于有内皮的血管表现出浓度依赖性舒张作用,血管舒张百分比SHR<WKY大鼠,而对于去除内皮血管,apelin-13则表现出收缩血管的作用,且收缩张力SHR>WKY大鼠,apelin-13预孵育,能减少SHR和WKY大鼠血管对新福林的缩血管反应性,增加对乙酰胆碱的舒张反应性;b.NOS抑制剂LNNA阻断NO形成后,血管环对apelin-13的舒张反应明显抑制,且SHR组较WKY组对apelin的舒张反应减少更明显,提示apelin-13的舒血管效应至少部分依赖NO通路,而SHR高血压大鼠NO通路障碍减弱了apelin对血管的舒张作用;c.ERK1/2抑制剂PD98059预孵育后血管环对apelin-13表现出浓度依赖性的收缩,与去除内皮后apelin-13的收缩血管效应趋势一致,血管收缩张力SHR>WKY大鼠,PD98059逆转了apelin-13引起的血管舒张效应;d.Apelin-13促大鼠VSMCsERK1/2磷酸化增加并呈剂量依赖性和时间依赖性,ERK1/2抑制剂PD98059可以减少apelin-13诱导ERK1/2的磷酸化.结果表明,自发性高血压大鼠离体血管环对apelin-13舒张反应性降低,NO通路和ERK1/2通路介导了apelin-13的舒张血管作用.

In order to study the effect of G protein-coupled receptor APJ endogenous ligand apelin-13 to the vasoconstriction and relaxation of spontaneously hypertensive rat＇s vascular rings in vitro and its NO and ERK1/2 pathway, perfusion method in vitro vascular ring and Power-Lab system was used to detect tension on rat＇s vascular rings. Experimental groups below： Phenylephrine group, Acetylcholine group, apelin-13 group, apelin-13＋ PE group, apelin-13＋Ach group, PD98059＋PE group, PD98059＋Ach group, LNNA＋PE group, LNNA＋Ach group, apelin-13 （preincubation） ＋PD98059 ＋PE group, apelin （preincubation）-13 ＋PD98059 ＋Ach group, apelin-13 （preincubation） ＋LNNA ＋PE group and apelin- 13 （preincubation） ＋LNNA ＋Ach group, compared with WKY rats. Rats＇ vascular smooth muscle cells were cultured and the expression of ERK1/2 protein was detected by Western blot. Apelin-13 for the blood vessel with endothelium has demonstrated concentration-dependent vasodilation and SHR 〈 WKY in percentage vasodilation, but for the blood vessel without endothelium, apelin-13 shows the role of vascular contraction and SHR 〉 WKY in contraction tension. Apelin-13 pre-incubation can reduce the SHR and WKY rats＇ the reactivity of vascular contraction tension on phenylephrine and increases the relaxation response to acetylcholine. After NOS inhibitors LNNA blocking the formation of NO, the relaxation response of the vascular rings to apelin-13 is significantly inhibited and apelin more pronounced reduces the diastolic response in the SHR group than in the WKY group. This suggests that the vasodilator effect of apelin-13 partly depends on NO-dependent pathway at least and SHR hypertensive rats with NO pathway obstacles reduces the vasodilation of blood vessels to apelin-13. After pre-incubation of ERK1/2 inhibitor PD98059, the response of vascular rings to apelin-13 shows concentration-dependent contraction, which is the same as the blood vessel without endothelium to apelin-13, SHR 〉 WKY in contraction tension. PD98059 reversals the apelin-13＇s vasodilation effect. Western blot analysis showed that apelin-13 promoted the concentration-dependent and time-dependentexpression of pERK1/2. The potent ERK inhibitor PD98059 decreased the expression of pERK1/2. The diastolic reactivity of apelin in ex-vivo vascular rings of SHR is reduced and the effect is mediated by NO pathway and the ERK1/2 pathway.