低频脉冲电磁场对大鼠骨髓源性内皮祖细胞增殖活性和NO分泌的影响

Effects of low frequency pulsing electromagnetic field on proliferation and NO secretion of rat bone marrow-derived endothelial progenitor cells

目的:观察不同作用时间下低频脉冲电磁场对大鼠骨髓源性内皮祖细胞(EPCs)增殖活性和NO分泌的影响.方法:密度梯度离心法获取大鼠骨髓单个核细胞,培养4 d后收集贴壁细胞,每日给予低频脉冲电磁场干预,磁场强度0.6mT,频率15 Hz.按作用时间的不同分为对照组(0 h)和磁场作用时间组(0.5,2,4,8 h组),各组细胞培养及磁场干预3 d后,分别采用MTT比色法测定EPCs的增殖活性,流式细胞仪检测细胞周期,G riess法检测培养上清中NO水平.结果:对照组A490 nm为(0.37±0.07),0.5 h组(0.37±0.06),2 h组(0.40±0.09)与对照组(0.37±0.07)相比差异无统计学意义(P>0.05);4 h组A490 nm值开始增加[(0.45±0.03)vs(0.37±0.07);P<0.05],8 h组较对照组增加最为明显[(0.49±0.08)vs(0.37±0.07);P<0.01].0.5 h组,2 h组细胞增殖指数PI(S+G2M)%与对照组相比差异无统计学意义(P>0.05),4 h组,8 h组细胞增殖指数与对照组相比差异均有统计学意义(P<0.05).NO分泌随磁场作用时间的延长,其分泌增加.结论:低频脉冲电磁场可影响EPCs的增殖及NO分泌,随着作用时间的延长,细胞增殖及NO分泌增加.

AIM： To investigate the effects of low frequency pulsing electromagnetic field on proliferation and nitric oxide （NO） secretion of rat bone marrow-derived endothelial progenitor cells （ EPCs ）. METHODS： Total mononuclear cells （ MNCs ） were isolated from rat bone marrow by density gradient centrifugation, and then plated on fibronectin-coated culture dishes. After 4 d, the adherent cells were collected and exposed to low frequency pulsing electromagnetic field （0. 6 mT, 15 Hz） every day. The coUected cells were divided into control group and different time point groups （0.5, 2, 4 and 8 h）. After 3 d exposure, proliferation capacity was measured by MTT assay, cell cycle was detected by flow cytometry （FCM） , and NO secretion of EPCs was measured by the Griess assay. RESULTS： Compared with control group（0,37±0.07）, 0.5 h（0.37 ±0.06） and2 h（0. 40± 0.09） exposure groups showed no statistical difference （P 〉 0.05）, while 4 h and 8 h exposure groups showed higher EPC proliferation capacity [ A490 nm ： 4 h, （0.45 ± 0.03 ） vs （ O. 37 ± 0.07）, P〈0.05; 8 h, （0.49 ±0.08） vs （0.37 ±0.07）, P〈 0.01 ]. Except 0. 5 and 2 h exposure groups, 4 and 8 h groups showed statistically significant difference in proliferation index as compared with control group （ P 〈 0.05 ）. NO was produced more and more with the exposure time going on. CONCLUSION： Low frequency pulsing electromagnetic field can increase the proliferation and NO secretion of EPGs over time.