RESUMO
PURPOSE: To investigate the effect of intermittent vibration at different intervals on bone fracture healing and optimize the vibration interval. METHODS: Ninety sheep were randomized to receive no treatment (the control group), incision only (the sham control group), internal fixation with or without metatarsal fracture (the internal fixation group), and continuous vibration in addition to internal fixation of metatarsal fracture, or intermittent vibration at 1, 2, 3, 5, 7 and 17-day interval in addition to internal fixation of metatarsal fracture (the vibration group). Vibration was done at frequency F=35 Hz, acceleration a=0.25g, 15 min each time 2 weeks after bone fracture. Bone healing was evaluated by micro-CT scan, bone microstructure and mechanical compression of finite element simulation. RESULTS: Intermittent vibration at 7-day interval significantly improved bone fracture healing grade. However, no significant changes on microstructure parameters and mechanical properties were observed among sheep receiving vibration at different intervals. CONCLUSIONS: Clinical healing effects should be the top concern. Quantitative analyses of bone microstructure and of finite element mechanics on the process of fracture healing need to be further investigated.
Assuntos
Consolidação da Fratura , Fraturas Ósseas , Ossos do Metatarso , Vibração , Animais , Análise de Elementos Finitos , Fixação Interna de Fraturas/instrumentação , Fixação Interna de Fraturas/normas , Consolidação da Fratura/fisiologia , Fraturas Ósseas/diagnóstico por imagem , Fraturas Ósseas/cirurgia , Fraturas Ósseas/terapia , Ossos do Metatarso/diagnóstico por imagem , Ossos do Metatarso/lesões , Ossos do Metatarso/cirurgia , Distribuição Aleatória , Ovinos , Vibração/uso terapêutico , Microtomografia por Raio-XRESUMO
Purpose: To investigate the effect of intermittent vibration at different intervals on bone fracture healing and optimize the vibration interval. Methods: Ninety sheep were randomized to receive no treatment (the control group), incision only (the sham control group), internal fixation with or without metatarsal fracture (the internal fixation group), and continuous vibration in addition to internal fixation of metatarsal fracture, or intermittent vibration at 1, 2, 3, 5, 7 and 17-day interval in addition to internal fixation of metatarsal fracture (the vibration group). Vibration was done at frequency F=35 Hz, acceleration a=0.25g, 15 min each time 2 weeks after bone fracture. Bone healing was evaluated by micro-CT scan, bone microstructure and mechanical compression of finite element simulation. Results: Intermittent vibration at 7-day interval significantly improved bone fracture healing grade. However, no significant changes on microstructure parameters and mechanical properties were observed among sheep receiving vibration at different intervals. Conclusions: Clinical healing effects should be the top concern. Quantitative analyses of bone microstructure and of finite element mechanics on the process of fracture healing need to be further investigated.(AU)
Assuntos
Animais , Ovinos/lesões , Consolidação da Fratura , Osso e Ossos , Cicatrização , Vibração/uso terapêutico , Análise de Elementos Finitos , ChinaRESUMO
Abstract Purpose: To investigate the effect of intermittent vibration at different intervals on bone fracture healing and optimize the vibration interval. Methods: Ninety sheep were randomized to receive no treatment (the control group), incision only (the sham control group), internal fixation with or without metatarsal fracture (the internal fixation group), and continuous vibration in addition to internal fixation of metatarsal fracture, or intermittent vibration at 1, 2, 3, 5, 7 and 17-day interval in addition to internal fixation of metatarsal fracture (the vibration group). Vibration was done at frequency F=35 Hz, acceleration a=0.25g, 15 min each time 2 weeks after bone fracture. Bone healing was evaluated by micro-CT scan, bone microstructure and mechanical compression of finite element simulation. Results: Intermittent vibration at 7-day interval significantly improved bone fracture healing grade. However, no significant changes on microstructure parameters and mechanical properties were observed among sheep receiving vibration at different intervals. Conclusions: Clinical healing effects should be the top concern. Quantitative analyses of bone microstructure and of finite element mechanics on the process of fracture healing need to be further investigated.
Assuntos
Animais , Vibração/uso terapêutico , Ossos do Metatarso/lesões , Consolidação da Fratura/fisiologia , Fraturas Ósseas/diagnóstico por imagem , Ovinos , Ossos do Metatarso/cirurgia , Ossos do Metatarso/diagnóstico por imagem , Distribuição Aleatória , Análise de Elementos Finitos , Fraturas Ósseas/cirurgia , Fraturas Ósseas/terapia , Microtomografia por Raio-X , Fixação Interna de Fraturas/instrumentação , Fixação Interna de Fraturas/normasRESUMO
BACKGROUND: Mechanical strain plays a great role in growth and differentiation of osteoblast. A previous study indicated that integrin-ß (ß1, ß5) mediated osteoblast proliferation promoted by mechanical tensile strain. However, the involvement of integrin-ß in osteoblastic differentiation and extracellular matrix (ECM) formation induced by mechanical tensile strain, remains unclear. RESULTS: After transfection with integrin-ß1 siRNA or integrin-ß5 siRNA, mouse MC3T3-E1 preosteoblasts were cultured in cell culture dishes and stimulated with mechanical tensile strain of 2500 microstrain (µÎµ) at 0.5 Hz applied once a day for 1 h over 3 or 5 consecutive days. The cyclic tensile strain promoted osteoblastic differentiation of MC3T3-E1 cells. Transfection with integrin-ß1 siRNA attenuated the osteoblastic diffenentiation induced by the tensile strain. By contrast, transfection with integrin-ß5 siRNA had little effect on the osteoblastic differentiation induced by the strain. At the same time, the result of ECM formation promoted by the strain, was similar to the osteoblastic differentiation. CONCLUSION: Integrin-ß1 mediates osteoblast differentiation and osteoblastic ECM formation promoted by cyclic tensile strain, and integrin-ß5 is not involved in the osteoblasts response to the tensile strain.
Assuntos
Diferenciação Celular/fisiologia , Matriz Extracelular/fisiologia , Cadeias beta de Integrinas/fisiologia , Integrina beta1/fisiologia , Osteoblastos/fisiologia , Resistência à Tração/fisiologia , Animais , Western Blotting , Linhagem Celular , Proliferação de Células/fisiologia , Camundongos , RNA Interferente Pequeno , Reação em Cadeia da Polimerase em Tempo Real , Estresse Mecânico , TransfecçãoRESUMO
BACKGROUND: Mechanical strain plays a great role in growth and differentiation of osteoblast. A previous study indicated that integrin-ß (ß1, ß5) mediated osteoblast proliferation promoted by mechanical tensile strain. However, the involvement of integrin-ß; in osteoblastic differentiation and extracellular matrix (ECM) formation induced by mechanical tensile strain, remains unclear. RESULTS: After transfection with integrin-ß1 siRNA or integrin-ß5 siRNA, mouse MC3T3-E1 preosteoblasts were cultured in cell culture dishes and stimulated with mechanical tensile strain of 2500 microstrain (µÎµ) at 0.5 Hz applied once a day for 1 h over 3 or 5 consecutive days. The cyclic tensile strain promoted osteoblastic differentiation of MC3T3-E1 cells. Transfection with integrin-ß1 siRNA attenuated the osteoblastic diffenentiation induced by the tensile strain. By contrast, transfection with integrin-ß5 siRNA had little effect on the osteoblastic differentiation induced by thestrain. At thesametime, theresultofECM formation promoted by the strain, was similar to the osteoblastic differentiation. CONCLUSION: Integrin-ß1 mediates osteoblast differentiation and osteoblastic ECM formation promoted by cyclic tensile strain, and integrin-ß5 is not involved in the osteoblasts response to the tensile strain.