血管紧张素-(1-7)对自发性高血压大鼠颈动脉去外膜后蛋白激酶C-ζ和胞外信号调节激酶1/2蛋白表达的影响

Effect of angiotensin-(1-7) on protein kinase C-ζ and the expression of extracellular signal-regulated kinase1/2 protein in carotid artery after adventitia removal in SHR

目的探讨血管紧张素-(1-7)[Ang-(1-7)]对自发性高血压大鼠(SHR)一侧颈动脉外膜去除后蛋白激酶C-ζ(PKC-ζ)和胞外信号调节激酶1/2(ERK1/2)蛋白表达的影响。方法24只雄性SHR右侧颈动脉外膜去除后,随机分为3组(每组8只):对照组、Ang-1(1-7)组和Ang779[Ang-(1-7)拮抗剂]组。另选8只WKY大鼠作为WKY组。机械和化学方法去除大鼠右侧颈动脉外膜,左侧作假手术对照。采用微渗泵植入技术经颈静脉给药2周,鼠尾袖法测量尾动脉收缩压(SBP),放免法测定血浆及双侧颈动脉血管紧张素II(AngII)浓度。取双侧颈动脉制成光镜标本,病理图像分析系统测定颈动脉腔横截面积(LA)、内弹力层围绕面积(IELA)、外弹力层围绕面积(EELA),评价内膜和中膜增生状况。免疫组织化学方法测定双侧颈动脉PKC-ζ和ERK1/2蛋白表达。结果(1)各组SBP于给药前差异无统计学意义(P>0.05),给药2周后,Ang-(1-7)组SBP较Ang779组和对照组显著下降(均P<0.01);(2)对照组和Ang779组颈动脉内膜增生去外膜侧较未去外膜侧差异有统计学意义(均P<0.01),未去外膜侧和去外膜侧颈动脉内膜增生Ang-(1-7)组较对照组和Ang779组明显改善(P均<0.01);(3)与未去外膜侧比较,去外膜侧颈动脉AngII浓度显著增高(P<0.01);(4)颈动脉PKC-ζ和ERK1/2蛋白表达对照组和Ang779组去外膜侧较未去外膜侧显著增高(均P<0.01),未去外膜侧和去外膜侧颈动脉PKC-ζ和ERK1/2蛋白表达Ang-(1-7)组较对照组和Ang779组显著减少(均P<0.01)。结论Ang-(1-7)可通过减少PKC-ζ及ERK1/2蛋白表达而实现对SHR去外膜后颈动脉内膜增生的抑制作用。

Objective To investigate the effect of angiotensin-（1-7） on protein kinase C-ζ（PKC-ζ） and the expression of extracellular signal-regulated kinasel/2 （ERK1/2） protein in carotid artery after adventitia removal in spontaneously hypertensive rats （SHR）.Methods 24 SHR with right carotid artery adventita removed were randomly divided into 3 groups （ n = 8 each） ;Ang-（1-7）, Ang779 and SHR control group. 8 Wistar-Kyoto rats were selected as normal control group （WKY group）. Adventitia in right carotid after＇ was removed by mechanical and chemical ways. Adventitia in left carotid artery was sham-operated. Ang-C 1-7） in saline （25 μg·kg^-1·h^-1 ） was infused intravenously for 14 days.The systolic blood pressure （SBP） was taken by tail-cuff method. Plasma and carotid artery angioteusin Ⅱ （Ang Ⅱ） levels were measured by radioimmunoassay. Lumen crosssection area （LA）, intraelastic layer area （IELA） and extraetastic layer area （EELA） were measured by computed video processing, and the ratio of （IELA-LA）/（ EE- LA-IEIA） was calculated.The expression of local PKC-ζ and ERK1/2 protein in both arteries was determined by im- munothistochemistry. Results There was no significant difference in SBP among SHR groups （ P 〉0.05）. Two weeks later,SBP in Ang-（1-7） had no significantly effect on plasma and local Ang Ⅱ levels （ P 〉 0.05）.As compared with that of no adventitia removal, the inlimal hyperplasiain adventitia removal was exacerbated significantly （ P 〈 0.05）, and which was obviously inhibited in Ang-（1-7） group （ P 〈 0.01 ）. The expression of PKC-ζ and ERKI/ 2 protein in adventitia removal was significantly higher than that in no adventitia removal SHR and Ang799 group. As compared with that of Ang779 and SHR group, the expression of PKC-ζ and ERK1/2 protein in Ang-（1-7） group was significantly down-regulated （ P 〈 0.01 ）. Conclusion Ang-（1-7） can markedly improve intimal hyperplasia caused by advential removal in SHR by down-regulating local PKC-ζ and ERK1/2 protein.