恒定磁场对缺血再灌注脑组织的保护作用(英文)

Protective effect of constant magnetic field on ischemic-reperfusion brain

背景:磁疗历史悠久,可用于治疗多种疾病,研究恒磁场对缺血性脑血管病的保护作用能为非药物、无创伤治疗提供新的临床治疗依据,开辟物理因子治疗新途径。目的:观察恒磁场治疗对缺血再灌注损伤大鼠宏观水平的血液流变学、亚细胞水平的红细胞膜流动性、分子水平的抗氧化酶活性以及一氧化氮和一氧化氮合成酶活性的影响。设计:完全随机设计。单位:哈尔滨医科大学生物物理教研室。材料:实验于2002-05/11在哈尔滨医科大学生物物理实验室进行,取40只健康Wistar大鼠适应性喂养1周后随机分成3组,假手术组(n=10)、模型组(n=15只)、磁疗组(n=15只)。方法:①模型组、磁疗组线栓法制作大鼠大脑中动脉缺血再灌注模型,假手术组线栓不阻塞动脉血流。②磁疗组脑缺血后立即将其头颈部置于40mT的恒磁场中30min,1次/d,假手术组和模型组不作暴磁处理。3组大鼠手术7d后麻醉状态下眼球取血、断头取脑。主要观察指标:①观察三组大鼠血液流变学变化。②各组大鼠红细胞膜流动性指标变化。③各组大鼠血清谷胱甘肽过氧化物酶及铜蓝蛋白含量变化。④各组大鼠脑组织丙二醛、一氧化氮、一氧化氮合成酶活性等指标的变化。结果:30只大鼠进入结果分析。①血液流变学指标:模型组全血高切、低切黏度、纤维蛋白原和红细胞压积显著高于假手术组(P<0.01),磁疗组上述指标显著低于模型组(P<0.01)。②红细胞膜流动性指标:模型组荧光偏振度、平均微黏度、各向异性显著高于假手术组(P<0.01),磁疗组上述指标低于模型组(P<0.05)。③模型组大鼠血清谷胱甘肽过氧化物酶及铜蓝蛋白含量显著低于假手术组(P<0.05),磁疗组高于模型组(P<0.01),并略高于假手术组。④模型组大鼠脑组织铜锌超氧化物歧化酶、丙二醛、一氧化氮、一氧化氮合成酶活性均显著高于假手术组(P<0.05或0.01),抗氧化酶活性显著低于假手术组(P<0.01);经过磁场治疗后,磁疗组大鼠各指标均较模型组好转(P<0.05,0.01)。结论:恒定磁场能显著改善大鼠的血液流变学特性,提高红细胞膜流动性及机体的抗氧化酶活力,降低丙二醛、一氧化氮、一氧化氮合成酶含量,提高了机体的抗氧化能力,从而有效地阻止了自由基、一氧化氮对神经组织的损伤,阻断了脑缺血的病理生理过程,对脑缺血再灌注损伤起到一定的保护作用。

BACKGROUND： Magnetic therapy has a long history and is used in the treatment of various diseases. To study the protective function of constant magnetic field for ischemic cerebrovascular diseases may provide new clinical foundation for non-medicinal and non-traumatic treatment and develop a novel way for treatment with physical factor. OBJECTIVE： To observe the influence of constant magnetic field treatment on hemodynamics at macroscopic level, RBC membrane fluidity at subcellular level and antioxidase activity at molecular level, as well as NO and NO synthetase activity in rats with ischemic-reperfusion （IR） injury. DESIGN： A completely randomized design. SETTING： Biophysical Teaching and Research Department of Harbin Medical University. MATERIALS： This experiment was carried out at Biophysical Laboratory, Harbin Medical University, between May and November 2002. Forty healthy Wistar rats were adaptively raised for 1 week before randomized into 3 groups, namely, sham-operation group （n=10）, model group （n=15） and magnetic therapy group （n=15）. METHODS：① IR model of middle cerebral artery （MCA） was established in rats in model group and magnetic therapy group, but MCA was only tied up without occlusion in sham-operation group. ② In magnetic therapy group, rat necks were exposed to 40 mT constant magnetic field instantly after ischemic injury for 30 minutes, once a day, while rats in sham-operation group and model group were not exposed to magnetic field. Three groups of rats were anaesthetized at postoperative 7 days for obtaining blood from eyeball, and cut off head for obtaining brain. MAIN OUTCOME MEASURES： ① Hemodynamic changes in three groups of rats. ② Changes of RBC membrane fluidity-related parameters. ③Changes of serum glutathione peroxidase and ceruloplasmin content. ④Changes of brain malonedialdehyde （MDA）, NO, and NO synthetase activity indexes. RESULTS： Thirty rats were included and all entered the result analysis. ① Hemodynamic parameters： Blood high-shearing, blood low-shearing viscosity, fibrinogen and HCT were remarkably higher in model group than in sham- operation group （P 〈 0.01）, but obviously lower in magnetic therapy group than in model group （P 〈 0.01）. ② RBC membrane fluidity： The fluorescence polarization, average microviscosity and aeolotropy were remarkably higher in model group than in sham-operation group （P 〈 0.01）, and the above indexes were lower in magnetic therapy group than in model group （P 〈 0.05）. ③ Serum glutathione peroxidase and ceruloplasmin contents in model group were remarkably lower than those in sham-operation group （P〈 0.05）, but were higher in magnetic therapy group than in model group （P 〈 0.01）, and slightly higher than sham-operation group. ④The brain Cu/Zn-SOD, MDA, NO, NO synthetase activities in model group were remarkably higher than in sham-operation group （P 〈 0.05 or 0.01）, but antioxidase activity was remarkably lower than that in sham-operation group （P 〈 0.01）; all parameters were proved to get better in magnetic therapy group after magnetic field treatment, and better than those in model group （P 〈 0.05, 0.01）. CONCLUSION： Constant magnetic field exposure can remarkably improve rat hemodynamic property, increase RBC membrane fluidity and antioxidase activity, and reduce the content of MDA, NO, NO synthetase, thereby improving organic anti-oxidation capability and effectively prevent-ing free radicals and NO-induced neural damage. It possesses certain function of protecting brain IR injury through holding up the pathophysiological development of brain ischemia injury.