低频电磁场对大鼠主动脉平滑肌细胞基质金属蛋白酶的影响

目的 观察不同磁场强度及作用时间的低频电磁场（LFEMF）对培养的大鼠主动脉血管平滑肌细胞（VSMC）表达基质金属蛋白酶-2（MMP-2）的影响。方法 用含10％小牛血清的DMEM培养液体外培养大鼠主动脉VSMC，随机分为对照组、LFEMF不同磁场强度（20，40，60mT）及时间（10，20，30min）干预组，运用MMP-2活性酶图分析法结合光密度扫描分析，观察LFEMF对VSMC的MMP-2表达的影响。结果 不同磁场强度组均明显抑制MMP-2的活性，且具有剂量依赖性，但抑制作用不随时间延长而变化，不具有时间依赖性。结论 适当强度和作用时间的LFEMF抑制VSMC的MMP-2活性的表达，磁场对经皮腔内冠状动脉成形术（PTCA）及支架植入术后的再狭窄（RS）可能具有防治作用。

Effect of low frequency electromagnetic field on matrix metalloproteinase-2 expression of rat vascular smooth muscle cell

Objective To investigate the effect of low frequency electromagnetic field (LFEMF) of different intensities and action times on matrix metalloproteinase-2(MMP-2) expression of rat vascular smooth muscle cell (VSMC). Methods Rat VSMCs were cultured in vitro with DMEM and 10% calf plasma, and then divided into a control group and various exposure groups. The VSMCs in the exposure groups were exposed to different intensities of LFEMF for different durations. The expression of MMP-2 was monitored by enzyme image analysis technique, SDS-PAGE contained gelatin was used to observe activity of MMP-2. Results Different intensities of LFEMF could significantly inhibit activity of MMP-2, exhibiting dose-dependent effect. Different durations of exposure to LFEMF could also inhibit activity of MMP-2, exhibiting no time-dependence effect. Conclusion The expression of MMP-2 was significantly inhibited by LFEMF of appropriate intensity and time. The results suggested the possibility of using magnetic field to prevent and cure the coronary restenosis after percutaneous transluminal coronary angioplasty(PTCA) and in-stent.