外加电场对血管平滑肌细胞生物学行为的影响

目的探讨电场作用下血管平滑肌细胞(VSMCs)膜表面细胞生长因子受体表达的变化及其对细胞增殖迁移的影响。方法通过外加电场干预装置,对体外培养的大鼠主动脉VSMC直流电场干预,间断显微细胞图像记录和分析,研究不同强度电场(EFs)、不同作用时间下VSMCs迁移和细胞形态的变化;采用免疫细胞化学或免疫荧光染色方法检测EFs干预后,与VSMCs迁移密切相关的血小板衍化生长因子受体(PDGFR)、血管紧张素Ⅱ1型受体(AT1R)和2型受体(AT2R)等的表达,研究EFs影响VSMCs增殖及迁移的机制。结果(1)改进的EFs干预装置作用下,VSMCs膜PDGFR表达增加,部分细胞内PDGFR表达上调,呈不对称分布,在EFs阴极面较集中;细胞中AT1R表达亦增加,但无明显不对称分布现象;AT2R表达未见明显改变。(2)150mV/mmEFs长时间作用下,培养的VSMCs有明显的电场趋化性,细胞向阴极迁移的距离明显高于无EFs作用对照组;细胞PCNA表达与对照培养细胞未见明显差异。结论外加直流EFs干预下,大鼠VSMCs发生形状改变和定向迁移。细胞膜向阴极方向伸展,定向迁移依赖于EFs强度,生理强度的直流EFs对VSMCs增殖没有明显影响。EFs作用下,部分细胞生长因子的表达上调和重分布,可能与细胞定向迁移的启动和维持有关。

The change of cellular growth factor receptor and its effect on the proliferation and migration of vascular smooth muscle cells under electrical fields

Objective To study the change of the expression of cellular growth factor receptor and its effect on the proliferation and migration of vascular smooth muscle cells (VSMCs) under electrical field. Methods 1) A electrophoresis apparatus was designed for applying the direct current electric fields to the cultured VSMCs, which were separated from the aorta of rats. Interval photographs were used to analyse the direction and distance of VSMCs migration. Cellular growth factors such as platelet derived growth factor receptor (PDGFR), angiotensin II type 1 receptor (AT1R) and its type 2 receptor(AT2R) were studied by immunohistochemistry or immunofluorescence to show the mechanism relation to the migration of VSMCs. Results Under the direct current electric field, the expression of PDGFR was increased obviously and distributed asymmetricly on the membrane of VSMCs. The receptor mainly focused on the cathode side of cellular membrane in electric field. The AT1R were also enhanced in the cells after exposure to the electric field, but the expression of AT2R was uncharged. The longer exposure time to the 150 mV/mm electric field, the more electrotaxis the cells showed. The distance of cellular migration increased obviously with the time to exposure the electric field comparing with the control group. There was no significant difference in the expression of proliferating cell nuclear antigen (PCNA) between two groups. Conclusion External electric fields applying to the rat VSMCs can change the growth characteristic and enhance directional migration of VSMCs. These effects maybe related to the up-regulated expression and re-distribution of some cellular growth factors such as PDGFR, AT1R and AT2R.