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不同训练强度影响骨腱结合部损伤的机理研究

Mechanism Research of Osteotendinous Junction Injury Induced by Different Exercise Intensity

【作者】 樊丽霞

【导师】 王琳;

【作者基本信息】 北京体育大学 , 运动人体科学, 2012, 博士

【摘要】 研究目的:骨腱结合部损伤是一种困扰运动训练和人们日常生活的常见损伤,过度负荷是主要原因,其病理变化过程还不十分清楚。基质是肌腱载荷的主要承担者,在损伤的修复中有重要的作用。本文以不同强度的循环载荷作为预手段,对骨腱结合部损伤的机理进行研究探讨。揭示骨腱结合部损伤发生发展过程中的病理变化,以及不同载荷量引起的各种指标相应的变化规律,确定干引起损伤的载荷量。研究方法:48只新西兰大白兔随机分为6组,每组8只。其中一组为对照组,其余5组为实验组。采用循环载荷的刺激方式,强直收缩力的30%为100%的刺激负荷强度组,其它各组负荷强度依次采取此刺激强度的20%、40%、60%、80%,进行循环载荷刺激2小时/天,3天/周。4周后宰杀取材进行相应的¨E染色和免疫组织化学染色。研究结果:1.各负荷组骨腱结合部组织形态发生了改变。高运动负荷组,肌腱细胞密度发生显著性增加。纤维软骨带厚度无显著性差异。2.Ⅲ型胶原纤维发生显著性增加,从60%载荷强度开始与CON组、L20、L40载荷组出现显著性差异。Aggrecan免疫组化结果显示无显著差异。Tenascin-C表达出现显著性改变,60%载荷刺激强度时表达下降,L80、L100组比CON组、L20、L60载荷组显著性升高。TGF随负荷刺激强度的增加而增加,L20、L40载荷刺激强度与CON组比较出现显著性差异,L60、L80、L100载荷刺激强度组与CON组出现非常显著性差异。3.各指标相关结果显示,细胞密度与Ⅲ型胶原纤维、TGF具有非常显著性相关。TGF与型胶原纤维和TN有显著性相关。研究结论:1不同载荷强度作用于骨腱结合部4周,L60组、L80组、L100组出现损伤病理变化,说明这种低强度循环载荷叮以引起骨腱结合部损伤的发生2运动强度的不同导致骨腱结合部组织发生了相应的结构和成分改变。说明了骨腱结合部损伤程度与运动强度有关。3在损伤的病理变化中,Ⅲ型胶原纤维、Tenasin-C发生了显著性增加,说明骨腱结合部损伤的发生中,细胞外基质具有重要作用。4不同载荷强度作用于骨腱结合部4周,TGF表达发生了显著性增加,并且与细胞密度、Ⅲ型胶原纤维、TNC有显著性相关,说明TGF在骨腱结合部损伤修复过程中是重要的调节因素。

【Abstract】 Purpose:Osteolendinous junction injures are common clinical problems for both athletes’training and recreational individuals common life. Overuse is a main cause of osteotendinous junction injuries. But the pathogenesis is poorly understood. The extracellular matrix has played an important role in resisting mechanical forces and restoration following injury. The purposes of this study are to elucidate the carly structural, cellular, and molecular changes in the osteotendinous junction following exposure to cyclic loading. It reveals the injury mechanisms and evaluates the dose of load required to induce an injury with the cyclic loading in vivo.Method:Forty-eight New Zealand rabbits were divided into6groups with eight rabbits per group. One group was the control; the others were electrically simulated to contract repetitively for2hours per day,3days a week.30%of peak titanic force was the100%cyclic loading group, other groups were simulated at20%,40%,60%,80%of this force respectively and defined as L20, L40, L60, L80. After4weeks, samples were used for haematoxyl i ne and eosion and immunohistochenii stry of major proteoglyeans and collagens and growth factor.Results:There were considerable differences in morphology between control group and cyclic loading groups. An increase in tendon cell density was observed in high loading groups after4-week cycl ic loading. The thickness of fibrocartilage and the expression of aggrecan were unaffected by four-week cyclic loading. The expression of collagen type III increased in the60%to100%cyclic loading groups compared to the control,20%, and40%cyclic loading groups. Tenascin-C decreased at60%cyclic loading, and increased at80%and100%cyclic loading comparing to the control,20%,40%cyclic loading groups respectively. The expression of TGF increased from20%to100%cyclic loading. The correlation coefficient analysis showed the cell density has strong correlation to the collagen type III and TGF respectively (R=0.46,0.71). There are moderate correlations in TGF and collagen type III and Tenascin-C (R=0.43,0.36)Conclusion:1. The considerable pathological changes in L60, L80, L100groups after4-week cyclic loading indicating this low-intensity cyclic loading can induce the injury of osteotendinous junction.2. The changes of morphological structure and composition with increasing exercise intensity elucidates the degree of osteotendinous junction injury is directly related to the intensity of exercise.3. The collagen type III and Tenasin-C have increased significantly and demonstrates that the extracellular matrix plays an important role during the osteotendinous junction injury process.4. TGF has increased significantly and is correlated to the collagen type III and Tenascin-C. This indicates TGF is an important regulating factor during the osteotendinous junction injures process.

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