■本研究旨在研究血流限制训练对肌肉力量的影响,骨组织结构材料,和生物力学特性在大鼠中应用各种运动干预措施,并通过识别骨转换标志物来分析过程,为BFRT在临床康复中的应用提供了理论依据。
■将24只3月龄雄性SD(SpragueDawley)大鼠随机分为加压对照组(CON,n=6),低强度训练组(LIRT,n=6),高强度训练组(HIRT,n=6),和血流限制训练组(LIBFR,n=6),用于8周的爬梯练习。压力对照组仅给予缺血治疗,不承担任何负担。允许低强度训练组以最大自愿承载能力(MVCC)的30%爬梯子。高强度训练组大鼠以70%MVCC爬梯。血流限制训练组在施加血流限制的同时,以30%的MVCC爬上梯子。取样前,最终的MVCC是使用逐渐增加的重量负荷的阶梯爬升方案测量的.血清,肌肉,并取出骨头进行取样。骨转换标志物PINP的浓度,BGP,用ELISA法测定血清中CTX。使用Micro-CT测量股骨的骨密度和微结构。通过万能试验机进行三点弯曲和扭转试验,测量股骨的材料力学和结构力学指标。
■最大强度测试结果表明,在LIRT中的MVCC,HIRT,LIBFR组明显大于CON组,HIRT组的MVCC明显高于LIRT组(P<0.05)。根据骨转换标记物测试的结果,CON组的骨形成指标PINP(I型前胶原的氨基末端延伸肽)和BGP(骨gla蛋白)的浓度明显低于HIRT组(P<0.01),LIRT组明显高于HIRT组(P<0.01)。在骨吸收指数方面,仅HIRT组和其他组之间存在显著差异(P<0.05)。Micro-CT检查显示HIRT组的骨密度指标值明显大于CON和LIRT组(P<0.05)。万能材料试验机三点弯曲扭转试验结果显示,HIRT组的弹性模量和最大载荷指数明显小于LIBFR组(P<0.05)。HIRT组的骨折负荷指数明显小于LIBFR组(P<0.05)。
■1.LIRT,HIRT,LIBFR,和CON都有显著差异,这种训练有助于提高最大的力量,HIRT是最有效的。2.血流限制训练可以提高骨转换标志物的表达,如PINP和BGP,促进骨组织形成。3.血流限制训练可以提高肌肉力量,增加骨转换标志物的正向发展,从而提高骨的生物力学特性,如骨的弹性模量和最大负荷。
The present study aimed to investigate the effects of blood flow restriction training on muscle strength, bone tissue structure material, and biomechanical properties in rats applying various exercise interventions and to analyze the process by identifying the bone turnover markers, it provides a theoretical basis for the application of BFRT in clinical rehabilitation.
A total of 24, 3-month-old male SD (Sprague Dawley) rats were randomly divided into pressurized control group (CON, n=6), low-intensity training group (LIRT, n=6), high-intensity training group (HIRT, n=6), and blood flow restriction training group (LIBFR, n=6) for 8-week ladder-climbing exercises. The pressured control group were given only ischemia treatments and did not undertake any burden. The low-intensity training group was allowed to climb the ladder with 30% of the maximum voluntary carrying capacity (MVCC). The rats in the high-intensity training group were allowed to climb the ladder with 70% MVCC. The blood flow restriction training group climbed the ladder with 30% MVCC while imposing blood flow restriction. Before sampling, the final MVCC was measured using a ladder-climbing protocol with progressively increasing weight loading. The serum, muscle, and bone were removed for sampling. The concentrations of the bone turnover markers PINP, BGP, and CTX in the serum were measured using ELISA. The bone mineral density and microstructure of femur bones were measured using micro-CT. Three-point bending and torsion tests were performed by a universal testing machine to measure the material mechanics and structural mechanics indexes of the femur bone.
The results of maximum strength test showed that the MVCC in LIRT, HIRT, and LIBFR groups was significantly greater than in the CON group, while the MVCC in the HIRT group was significantly higher than that in the LIRT group (P<0.05). According to the results of the bone turnover marker test, the concentrations of bone formation indexes PINP (amino-terminal extension peptide of type I procollagen) and BGP (bone gla protein) were significantly lower in the CON group than in the HIRT group (P<0.01), while those were significantly higher in the LIRT group compared to the HIRT group (P<0.01). In terms of bone resorption indexes, significant differences were identified only between the HIRT and other groups (P<0.05). The micro-CT examination revealed that the HIRT group had significantly greater bone density index values than the CON and LIRT groups (P<0.05). The results of three-point bending and torsion test by the universal material testing machine showed that the elastic modulus and maximum load indexes of the HIRT group were significantly smaller than those of the LIBFR group (P<0.05). The fracture load indexes in the HIRT group were significantly smaller than in the LIBFR group (P<0.05).
1. LIRT, HIRT, LIBFR, and CON all have significant differences, and this training helps to improve maximum strength, with HIRT being the most effective. 2. Blood flow restriction training can improve the expression of bone turnover markers, such as PINP and BGP, which promote bone tissue formation. 3. Blood flow restriction training can improve muscle strength and increase the positive development of bone turnover markers, thereby improving bone biomechanical properties such as bone elastic modulus and maximum load.