内皮素受体B介导早发型子痫前期胎盘血管功能障碍及其机制初探

Endothelin Receptor B Mediates Placental Vascular Dysfunction in Early-onset Pre-eclampsia and Its Mechanism

目的:探索内皮素受体A(ET_(A)R)、内皮素受体B(ET_(B)R)在子痫前期胎盘血管功能障碍中的作用及机制。方法:以早发型子痫前期孕妇(PE组)和同期分娩的正常孕妇(Norm组)为研究对象,收集胎盘组织并分离得到绒毛膜板动脉(CPAs),采用免疫组织化学、qRT-PCR、Western Blotting、酶活性检测方法检测两组CPAs中ET_(A)R和ET_(B)R的表达水平、NO合酶(NOS)的表达水平和活性,通过体外血管张力检测系统检测内皮素-1(ET-1)经ET_(A)R/ET_(B)R介导的血管收缩和舒张。结果:(1)ET_(A)R和ET_(B)R在两组CPAs的内皮和平滑肌中均有表达。PE-CPAs中内皮ET_(B)R的表达水平显著低于Norm-CPAs(P<0.01);(2)PE-CPAs中ET-1介导的血管收缩程度显著高于Norm-CPAs(P<0.05)。去除血管内皮后,ET-1介导的血管收缩程度在Norm-CPAs中增加(P<0.05),而在PE-CPAs中无明显改变(P>0.05);(3)加入ET_(B)R拮抗剂BQ788后,ET-1介导的血管收缩程度在Norm-CPAs中显著增加(P<0.05),而在PE-CPAs中无明显改变(P>0.05)。加入ET_(A)R拮抗剂BQ123后,与Norm-CPAs相比较,PE-CPAs中ET-1介导的血管舒张功能显著降低(P<0.05)。加入ET_(B)R激动剂IRL1620后,与Norm-CPAs相比较,PE-CPAs中ET-1介导的血管舒张功能显著降低(P<0.05);(4)PE-CPAs中内皮型NOS(eNOS)和诱导型NOS(iNOS)的蛋白表达水平均低于Norm-CPAs(P<0.05),且eNOS活性显著低于Norm-CPAs(P<0.01)。结论:ET-1/ET_(B)R介导的血管舒张功能降低可能是早发型子痫前期胎盘血管功能紊乱的重要机制,其下游作用途径可能与NOS表达及活性下调有关。

Objective:To explore the role and mechanism of endothelin receptor A(ET A R)and endothelin receptor B(ET B R)in placental vascular dysfunction in pre-eclampsia.Method:Pregnant women with early-onset pre-eclampsia(PE group)and normal pregnant women(Norm group)were selected as subjects.Placentas were collected and chorionic plate arteries(CPAs)were isolated.Immunohistochemistry,qRT-PCR,Western Blotting and enzyme activity detection methods were used to detect the expression level of ET A R and ET B R,and the expression level and activity of NO synthase(NOS)in CPAs of the two groups.The vasoconstriction and relaxation of endothelin-1(ET-1)mediated by ET A R/ET B R were detected by vascular tone detection system.Results:(1)ET A R and ET B R were expressed in both endothelial and smooth muscle of CPAs.In PE-CPAs,the expression level of endothelial ET B R was significantly lower than Norm-CPAs(P<0.01).(2)In PE-CPAs,ET-1 mediated vasoconstriction was significantly higher than Norm-CPAs(P<0.05).After endothelial removal,ET-1-mediated vasoconstriction increased in Norm-CPAs(P<0.05),but there was no significant change in PE-CPAs(P>0.05).(3)After the addition of ET B R antagonist(BQ788),ET-1-mediated vasoconstriction was significantly increased in Norm-CPAs(P<0.05).The addition of ET A R antagonist BQ123 significantly reduced ET-1-mediated vasodilation in PE-CPAs compared with Norm-CPAs(P<0.05).The addition of ET B R agonist(IRL1620)significantly reduced ET-1-mediated vasodilation in PE-CPAs compared with Norm-CPAs(P<0.05).(4)In PE-CPAs,the protein levels of eNOS and iNOS were lower than Norm-CPAs(P<0.05),and the activity of eNOS was significantly lower than Norm-CPAs(P<0.01).Conclusion:ET-1/ET B R-mediated vasodilation may be an important mechanism of placental vascular dysfunction in early-onset pre-eclampsia,and its downstream pathway may be related to the down-regulation of NOS expression and activity.