肾上腺髓质素与内皮细胞功能

Adrenomedullin and the endothelial cell functions in vitro

目的了解肾上腺髓质素(AM)对内皮细胞(EC)功能指标的影响及其可能的作用机制。方法以培养的人脐静脉内皮细胞(HUVECs)作为靶细胞,对AM进行了以下方面的研究:(1)对高糖诱导的血管EC功能紊乱的影响;(2)用激光共聚焦显微镜及Western印迹分别观察高糖诱导的蛋白激酶C(PKC)α、PKCδ的位置变化及蛋白表达量的影响;实验分组:(1)对照组;(2)高糖组(30mmol/L葡萄糖);(3)AM(10-9、10-8、10-7mol/L)+高糖组;各组均培养48h。结果(1)高糖可诱导EC功能紊乱:EC凋亡增加,一氧化氮(NO)浓度降低,可溶性细胞间黏附分子1(sICAM-1)水平增加,AM可抑制高糖诱导的上述变化;(2)AM可抑制高糖诱导的HUVECs的PKCα及PKCδ位置转移;(3)AM可抑制高糖诱导的HUVECs PKCδ表达增强的作用,高糖对HUVEC的PKCα表达影响不明显。结论AM可纠正高糖诱导的EC功能异常,其保护作用可能部分是通过抑制PKCα及PKCδ的激活来实现的。

Objective To explore the effects of adrenomedullin（AM） on human umbilical vein endothelial cells （HUVECs） and possible mechanisms involved. Methods The HUVECs were selected to be a model and the following aspects were studied： （ 1 ） Effects of high glucose （30 mmol/L） on the endothelial dysfunction induced. （ 2 ） The role of protein kinase C （ PKC ）α and PKCδ in the endothelial dysfunction induced by high glucose and the effects of AM. The translocation of PKCδ or PKCα in a single HUVEC was observed by laser-scanning confocal microscope and the expressions analysis was conducted quantificationally by Western blotting. HUVECs were cultured and divided into 3 groups： （ 1 ） Matched control group; （2） High glucose group （30 mmol/L glucose） ; （3） AM （10^-9, 10^-8, 10^-7 mol/L） ＋ high glucose group HUVECs were incubated with AM for 48 h. Results （1） High glucose could induce HUVECs dysfunction： increased apoptosis, decreased NO concentration and increased sICAM level of HUVECs. AM reversed the above changes of HUVECs induced by high glucose. （2） It was observed that AM inhibited the translocation of PKCα from plasma to nucleus in HUVECs induced by high glucose and the translocation of PKCδ from nucleus to plasma and membrane in HUVECs. （3） AM inhibited the increasing expressions of PKCδ in HUVECs induced by high glucose. The expressions of PKCα in high glucose group were not different from that of the control. Conclusion AM appears to correct the endothelial cell dysfunctions induced by high glucose. The inhibition of PKCα and PKCδ seems to play some roles during the process.