磁场暴露对兔血液流变特性及血脂水平的影响

背景目前许多关于磁场生物效应的研究指出,低强度脉冲电磁场(low-intensity pulsed electromagnetic fields,LPEF)能改善血液流变学的指标、对心血管病能起到预防作用,但对其机制的阐述尚不明确.目的探讨低强度脉冲电磁场暴露对兔血液流变特性及血脂水平的影响,研究LPEF预防心血管疾病的机制.设计随机对照的实验研究.地点、材料和干预本实验的全过程在解放军第四军医大学实验动物中心完成.实验动物采用24只雌性5月龄新西兰大耳白兔(解放军第四军医大学实验动物中心提供).动物被随机分为正常组、模型组、磁场组,正常组用正常饲料,模型组、磁场组用高胆固醇饲料饲养.其中磁场组饲养于磁场环境中,暴磁时间为10h/d,所采用激励磁场的强度为4×10-4T,频率为15Hz.饲养8周后测定其血液流变特性和血脂水平等指标.主要观察指标LPEF对兔血液流变学各项指标(血细胞比容、血浆黏度、全血高切黏度、全血低切黏度、高切还原黏度、低切还原黏度、红细胞聚集指数)以及血脂水平(胆固醇、三酰甘油、高密度脂蛋白等指标)的影响.结果模型组与正常组比较,血液流变学各项指标及血脂水平差异具有显著性意义(t=2.147～2.859,P＜0.05);磁场组与模型组比较,血清中胆固醇模型组(14.71±0.22)mmol/L,磁场组(8.75±1.32)mmol/L]、三酰甘油模型组(2.69±0.03)mmol/L,磁场组(0.70±0.16)mmol/L]以及血液流变中的血细胞比容、血浆黏度、全血低切黏度等指标降低显著(t=3.478～14.253,P＜0.01),而高密度脂蛋白升高显著(t=11.345,P＜0.01).结论低强度脉冲电磁场能够显著降低血脂、血液流变学等指标,提高血液流动性,对心血管疾病有良好的预防作用.

Effects of exposing rabbits to low-intensity pulsed electromagnetic fields on levels of blood lipid and properties of hemorheology

BACKGROUND: A large amount of studies indicate that low-intensity pulsed electronagnetic fields(LPEF) is effective in improving hemorheology,and can help prevent cardiovascular diseases. However, its mechanism has not been demonstrated in detail.OBJECTIVE: To study the effects of exposing rabbits to LPEF on levels of blood lipid and properties of bemorheology.DESIGN: Examiner-blinded randomized and controlled experiment was conducted between March and July in 2001.SETTING and PARTICIPANTS: Twenty-four female white big-ear rabbits, aged 5 months old, were purchased from the Experimental Animal Center of the Fourth Military Medical University of Chinese PLA, and acclimatized for one week prior to the experiments. The whole process was completed in the Experimental Animal Center.INTERVENTIONS: Twenty-four female white big-ear rabbits were randomly divided into three groups. Normal group was fed with normal diet and the other two groups were fed with hypercholesterolemic diet. Magnetic group were fed in 15 Hz pulsed electromagnetic fields (4 × 10 -4 T), 10 hours a day. After 8 weeks, indexes of blood lipid and hemorheology were examined.MAIN OUTCOME MEASURES: Effect of LPEF on hemorheological indexeshematocrit(Hct), plasma viscosity(ηp), whole blood viscosity of high shear rates(ηb1), whole blood viscosity of law shear rates(ηb2), whole blood reduction viscosity of high shear rates (ηb ) , whole blood reduction viscosity of high shear rates(ηb2 ), aggregation indexes of RBC(AI) serum total cholesterol(TC), triglyceride(TG) high density lipoprotein(HDL), etc. ].RESULTS: There were significant differences in the hemorheological indexes and blood lipid levels between the model and normal group(t =2.147-2.859, P ＜0.05) . Compared with the model group, serum TCmodel group: (14.71 +0. 22)mmol/L, magnetic group: (8.75 + 1.32)mmol/L], TG model group: 2.69 +0.03]mmol/L, magnetic group: (0.70 +0. 16)mmol/L]Hct, ηp, ηb2 in the magnetic group were significantly decreased( t = 2. 147 -2. 859, P ＜0.05), while HDL was increased significantly( t = 11.345, P ＜0.01).CONCLUSION: LPEF can improve blood circulation and is helpful to the prevention of cardiovascular diseases.