电场对人视网膜色素上皮细胞移行的影响

Effects of electric fields on the migration of retinal pigment epithelial cells

目的观察外源性直流电场对人视网膜色素上皮(hRPE)细胞移行行为的影响,揭示电场在RPE细胞损伤修复中的生理作用及临床意义。方法培养的hRPE细胞依培养液成分不同分为改良Eagle培养液(DMEM)组、DMEM+10%新生小牛血清(FBS)组,两组中未暴露于电场的细胞设为对照。将细胞分别暴露于强度为0、4、6、8V/cm的电场中,显微摄像系统连续记录2h中每隔15min细胞移行的变化图像,测量细胞移行距离及细胞移行方向与场线间夹角。图像分析系统处理结果。结果DMEM组中细胞对电场的反应较弱,电压加至6V/cm时可观察到细胞向阴极方向的移动趋势(不同电场强度中2h里所有单个细胞总体的位移方向指标之间,即平均cosineФ相比,P<0.05)。DMEM+10%FBS组中电场对细胞的作用加强,4V/cm时细胞出现长轴垂直于场线的排列方式,并向电场阴极运动,该现象随电场强度的增加而更为明显(不同电场强度之间及不同培养液之间平均cosineФ相比,P<0.05)。当电极方向转换后,细胞的定向移行方向随阴极方向而改变。结论外加电场可诱导hRPE细胞的电场阴极方向的定向移行,此作用受血清影响并与电场强度成正相关。在视网膜损伤后的早期修复过程中,内源性的电场可能是诱导hRPE细胞移行的始动因素之一。

Objective To investigate the effects of applied electric fields on the migration of human retinal pigment epithelial （hRPE） cells, and probe the physiological effects and clinic significance of electric fields on the RPE cells during the wound-healing process. Methods hRPE cells were clutured with Dubbecco＇s modified Eagle medium （DMEM） （DMEM group） or DMEM＋10% fetal bovine serum （FBS） （DMEM＋ 10% FBS group）, and the cells unexposed to the electric fields were used as the control. After hRPE cells were exposed to direct current electric fields with the tension of 0,4, 6 and 8 V/cm, serial images were taken at 15 minuets intervals within 2 hours by photomicroscope to observe the migration of the cells, and then the migrating distances and angle between the cellular translocation direction and the field vector were measured. The results were analyzed by an image analyzer. Resutls The response of the hRPE cells cultured in DMEM group to the electric fields was not as obvious as that in DMEM＋10% FBS group. The cells showed a tendency of cathodal migration when the field tension was added to 6 V/cm （the average cosine φ was compared with the normal control, P〈0. 05）. The effect of electric fields on cells clutured in DMEM ＋ 10%FBS group was stronger than those in DMEM group. The long axes of the cells were perpendicular to the field line with the tension of 4 V/cm, and the cells continued migrating to the cathode, which was more obvious when the field tension increased （the average cosine φ was comparedwith the normal control, P〈0.05）. After the polarity of the electric field reversed, the cells migrated to the opposite direction in accord with the direction of the cathode. Conclusion Applied electric fields can induce the cathode-directed migration of hRPE cells, which is positively correlated with the field tension and can be influenced by the serum. Physiological electric fields may be one of the inducing factors of cell migration at the early phase of healing process of wounded retina.