脑源性微囊泡对脐静脉内皮细胞骨架的影响研究

Effect of brain-derived microvesicles on cytoskeleton of human umbilical vein endothelial cells

目的探讨脑源性微囊泡(BDMVs)对脐静脉内皮细胞骨架的影响。方法体外制备BDMVs,并予透射电镜观察及粒径检测。将PKH26荧光染料标记的BDMVs与脐静脉内皮细胞共培养0.5 h、1 h、2 h后,应用流式细胞术检测不同时间点的脐静脉内皮细胞吞噬BDMVs情况。将体外常规培养的脐静脉内皮细胞分为对照组、BDMVs组(加入终浓度1.5×10^7/mL的BDMVs处理细胞)及尼莫地平组[予2μg尼莫地平(0.2 mg/mL)预处理10 min后加入终浓度1.5×10^7/mL的BDMVs处理细胞],应用激光共聚焦显微镜观察罗丹明标记鬼笔环肽染色后各组脐静脉内皮细胞中纤维型肌动蛋白的荧光强度及应力纤维数目。结果透射电镜下可见体外制备的BDMVs具有完整的膜结构,粒径范围为100~1000 nm。流式细胞术检测显示,吞噬BDMVs的脐静脉内皮细胞比例随培养时间的延长呈时间依赖性升高(0.5 h:22.7%±1.2%;1 h:52.3%±1.3%;2 h:71.6%±1.9%),各时间点间两两比较差异均有统计学意义(P<0.05)。激光共聚焦显微镜观察显示,与对照组相比,BDMVs组中纤维型肌动蛋白的荧光强度明显升高且应力纤维数目明显增多增粗;而与BDMVs组相比,尼莫地平组中纤维型肌动蛋白的荧光强度明显降低且应力纤维数目明显减少变细。结论脐静脉内皮细胞吞噬BDMVs的作用随时间延长而增强,且吞噬BDMVs后可导致细胞骨架重构,而尼莫地平可部分阻断该作用。

Objective To observe the effect of brain-derived microvesicles(BDMVs)on cytoskeleton in human umbilical vein endothelial cells(HUVECs).Methods BDMVs were prepared in vitro and identified by transmission electron microscopy and particle size identification.HUVECs were co-cultured with PKH26-labeled BDMVs for 0.5,1,and 2 h;flow cytometry was used to detect the phagocytosis of HUVECs for BDMVs at different time points.HUVECs cultured in vitro were divided into control group,BDMVs treatment group and nimodipine treatment group;cells in the BDMVs treatment group were given 1.5×10^7/mL BDMVs;cells in the nimodipine treatment group were pretreated with 2μg nimodipine(0.2 mg/mL)for 10 min,and then,given 1.5×10^7/mL BDMVs.After being stained with rhodamine-labeled phalloidin,the fluorescence intensity and number of stress fibers of fibroactin in HUVECs were observed by laser confocal microscopy.Results BDMVs had complete membrane structure with a diameter of 100-1000 nm under transmission electron microscopy.The proportion of cells phagocytizing BDMVs increased significantly with prolonged incubation time,enjoying significant differences(0.5 h:22.7%±1.2%;1 h:52.3%±1.3%;2 h:71.6%±1.9%,P<0.05).Laser confocal microscopy showed that,as compared with the control group,the fluorescence intensity of cytoskeletal protein was obviously increased and the number of stress fibers increased was obviously larger in the BDMVs treatment group.As compared with those in the BDMVs treatment group,the fluorescence intensity of cytoskeletal protein was decreased and the number of stress fibers was obviously smaller in the nimodipine group.Conclusion The role of BDMVs in phagocytosis of HUVECs becomes stronger as time being prolonged,and BDMVs phagocytosis leads to cytoskeletal remodeling,which can be partially blocked by nimodipine.