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背景:由于人体实验骨组织取材困难,骨组织形态体视学观察测定受到一定的限制。动物实验研究克服了人体实验此方面的局限性,可通过骨组织形态体视学观察测量直接评价骨质量。目的:对大鼠进行运动与负荷实验,以探讨运动对青少年长骨发育影响的机制。设计:以实验动物为研究对象,随机对照的实验研究。单位:第四军医大学西京医院全军骨科重点实验。对象:实验于2002-01/04北京体育大学运动实验室及第四军医大学西京医院全军骨科重点实验室完成。雄性4周龄SD大鼠120只,根据体质量随机搭配分成12组,每组10只。方法:使大鼠进行不同强度的跑台运动,同时结合悬吊和负重模型,宰杀大鼠后做右侧胫骨不脱钙切片的四环素、钙黄绿素双荧光标记观察。采用体视学全视野无偏采样方法对不同强度运动和不同形式机械负荷的生长期大鼠骨量、骨结构、骨代谢等形态参数进行测试分析。主要观察指标:①不同强度运动组间大鼠胫骨骨组织形态参数变化。②不同形式机械负荷组间骨小梁静态和动态参数的比较。结果:低负荷运动组的骨的重量、骨量、骨结构和骨代谢等多项指标参数随增龄而增长或降低的变化较高负荷运动组和对照组规律。悬吊组骨矿沉积率显著减少,骨小梁相对体积显著减小、厚度明显增大、数量减少以及间距(或分离度)显著增大,其骨代谢生化标志物和生物力学性能低于低负荷运动组,而与对照组差异无显著性意义。负重组所有参数均与低负荷运动组相接近。其特点为骨形成和骨吸收活跃,但以骨形成为主;骨抵抗破坏的能力和抵抗变形的能力皆明显增强。结论:不同强度的运动对生长期大鼠长骨发育可产生不同的影响,低负荷运动对骨代谢、骨量、骨组织形态以及骨生物力学等方面的综合作用好于高负荷运动。提示儿童少年在运动过程中,适当增加重力负荷,将有助于提高骨代谢和骨的力学性能,进而可提高发育过程中骨的质量。
BACKGROUND: Due to the difficulty of obtaining the bone tissue of human body experiment, the stereological observation of the bone tissue morphology is limited. Animal experiments to overcome the limitations of human experiments in this area, can be directly observed by bone histomorphometry observed bone mass measurement. OBJECTIVE: To study the effects of exercise on long bone development in adolescents. Design: Experimental animals as the research object, a randomized controlled experimental study. Unit: Key Laboratory of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University. PARTICIPANTS: The experiment was performed at the Key Laboratory of Orthopedic Surgery, Beijing Sport University, Beijing, China from January to April 04 and from the Xijing Hospital of the Fourth Military Medical University. 120 male 4-week-old SD rats were randomly divided into 12 groups according to body weight, with 10 rats in each group. Methods: The rats were subjected to treadmill exercise with different intensities. Simultaneously with the model of suspension and weight bearing, tetracycline and calcein double fluorescent labeling of right tibial non-decalcified sections were performed after slaughtered rats. The stereoscopic omnipotence sampling method was used to test the morphological parameters such as bone mass, bone structure, bone metabolism and other morphological parameters in growing rats with different strength exercises and different mechanical loads. MAIN OUTCOME MEASURES: ① The changes of morphological parameters of tibial bone in rats of different intensity exercise groups. ② Comparison of static and dynamic parameters of trabecular between different mechanical loading groups. Results: The changes of weight, bone mass, bone structure, bone metabolism and other parameters of low-load exercise group increased or decreased with increasing age compared with those of high-load exercise group and control group. The deposition rate of bone in the suspension group was significantly reduced, the relative volume of trabecular bone was significantly reduced, the thickness was significantly increased, the number decreased and the spacing (or separation) significantly increased, the biochemical markers of bone metabolism and biomechanical properties were lower than low Load exercise group, but no significant difference with the control group. All parameters of the load-bearing group were similar to those of the low-load exercise group. It is characterized by active bone formation and bone resorption but predominantly bone formation; its ability to resist vandalism and its resistance to deformation are significantly enhanced. CONCLUSION: Exercise with different intensities may have different effects on the development of long bones in developing rats. The combined effects of low-load exercise on bone metabolism, bone mass, bone morphology and biomechanics are better than those under high-load exercise. Prompted children and adolescents in the exercise process, the appropriate increase in gravity load, will help improve bone metabolism and bone mechanical properties, which can improve bone quality during development.