恒定磁场对股骨头坏死致病因子的抑制作用

Inhibitory effect of permanent-magnetic field on virulence factors of femoral head necrosis

目的:探索恒定磁场对股骨头坏死相关重要致病因素的抑制作用,从而阐明其治疗股骨头坏死的机制。方法:实验于2003-12/2004-08于深圳大学生命科学学院微生物基因工程重点实验室进行。①选用60只健康成年新西兰兔,随机取8只兔为正常对照组,不进行任何处理,其余全部肌肉注射醋酸泼尼松龙(12.25mg/kg,2次/周,共8周)建立股骨头坏死动物模型。②随机选取造模成功的32只兔分为4组(n=8),磁疗1个月组和磁疗后1个月组进行磁场处理(采用HMF-6000低频旋转强恒定磁场,强度>0.4T,2h/d,连续1个月),造模后1,2个月组不进行磁疗。分别于治疗1个月后立即或再1个月后使用组织切片和显微CT观察股骨头内部小梁结构变化,并检测血液黏稠度、胆固醇,三酰甘油,髋关节腔压力等指标,以探明恒定磁场的影响。③分离、培养新生新西兰兔原代骨髓基质细胞,培养的同时分别进行0.38,0.48T恒定磁场处理,观察恒定磁场对骨髓基质细胞成骨分化(其指标为碱性磷酸酶活性)和成脂过程的影响,并与无磁场组进行对比。结果:40只兔进入结果分析。①磁疗1个月组和磁疗后1个月组兔股骨头组织切片和显微CT显示其骨小梁结构显著改善。②髋关节腔压力:磁疗1个月组显著低于造模后1个月组[(0.081±0.037),(0.235±0.042)kPa,P<0.01],磁疗后1个月组与正常对照组无差异[(0.072±0.029),(0.074±0.034)kPa,P>0.05]。③血浆黏稠度:磁疗1个月组显著低于造模后1个月组(P<0.01),磁疗后1个月组与正常对照组无差异(P>0.05)。④三酰甘油和总胆固醇:磁疗1个月组和磁疗后1个月组均显著低于造模后1,2个月组,与正常对照组相似。⑤经0.48T磁场处理的骨髓基质细胞碱性磷酸酶活性高于无磁场组,而0.38,0.48T磁场处理后细胞的成脂诱导后A值均低于无磁场组(P<0.01)。结论:①磁场可降低血脂含量,改善血液黏稠度,而且还可以抑制股骨头内骨髓细胞的脂肪化,从而改善股骨头内的微循环,降低髋关节腔内压力,同时促进成骨细胞的生长和功能,故可以有效抑制股骨头坏死病情的发展。②0.48T磁场的促进骨髓基质细胞成骨分化及抑制其脂肪化的作用强于0.38T磁场。

AIM： To investigate the inhibitory effect of permanent-magnetic field on the important inducement of femoral head necrosis, and clarify the therapeutic mechanism. METHODS： The experiment was carried out in the Shenzhen Key Laboratory of Microbial Genetic Engineering, Shenzhen University between December 2003 and August 2004. ①Sixty healthy adult New Zealand rabbits were used, 8 of them were not given any treatment （normal control group）, and all the others were treated with intramuscular injection of prednisolone acetate （12.25 mg/kg, twice every week for 8 weeks） to induce models of femoral head necrosis. ②The 32 successfully induced rabbit models were randomly divided into 4 groups with 8 rabbits in each group, the rabbits in the magnetic therapy 1 month group and 1 month after magnetic therapy group were given magnetic therapy （HMF-6000 permanent-magnetic field of low frequency and high rotation was used, intensity 〉 0.4 T, 2 hours a day for 1 month continuous）, and no magnetic therapy was performed in the 1 and 2 months after model establishment groups. The interior trabecular structure of femoral head was observed by using histological section and micro-CT at once or one month after treatment, and the indexes of blood viscosity, serum cholesterol, triglyceride and pressure in coxa articular cavity were detected to investigate the effect of permanent-magnetic field. ③The primary bone marrow stromal cells of newborn New Zealand rabbits were isolated and cultured, at the same time treated with permanent-magnetic field of 0.38 and 0.48 T, and the effect of permanent-magnetic field on the osteogeneic ability and lipoblast ability, and compared with those in the without magnetic field group. RESULTS： Finally 40 rabbits were involved in the analysis of results. ①The histological section and micro-CT observation of femoral head showed that the trabecular structure was significantly improved in the magnetic therapy 1 month group and 1 month after magnetic therapy group. ② Pressure in coxa articular cavity： It was significantly lower in the magnetic therapy 1 month group than in the 1 month after model establishment group [（0.081±0.037）, （0.235±0.042） kPa, P 〈 0.01], and it had no difference between the 1 month after magnetic therapy group and the normal control group [（0.072±0.029）, （0.074±0.034） kPa, P 〉 0.05].③ Blood viscosity, it was significantly lower in the magnetic therapy 1 month group than in the I month after model establishment group （P 〈 0.01）, and it had no difference between the 1 month after magnetic therapy group and the normal control group （P 〉 0.05）. ④Triglyceride and total cholesterol： Those in the magnetic therapy 1 month group and 1 month after magnetic therapy group than in those in the 1 and 2 months after model establishment group, but similar to those in the normal control group. ⑤The activity of alkaline phosphatase in the bone marrow stromal cells treated with 0.48 T magnetic field was significantly higher than that in the without magnetic field group, and the A values of lipoblast after 0.38 and 0.48 T magnetic field were lower than that in the without magnetic field group （P 〈 0.01）. CONCLUSION： ①Magnetic field can reduce the contents of blood lipids, ameliorate blood viscosity, and restrain the steatosis of bone marrow stromal cells in femoral head, so as to improve the microeireulation in femoral head, reduce the pressure in coxa articular cavity, and also accelerate the growth and function of osteoporosis, so it can effectively restrain the development of femoral head necrosis. ②The accelerating osteogeneic ability and inhibiting lipoblast ability of 0.48 T magnetic field are stronger than those of the 0.38 T one.