Haobo Jia1,2, Aixian Tian3, Xiaoyu Zhang4, Xinlong Ma1, Jianxiong Ma3, Jie Wang1, Lei Sun3, Bin Lu3. 1. Orthopaedics Institute, Tianjin Hospital, Tianjin University Jiefang Nan Road 406, Hexi District, Tianjin 300211, P. R. China. 2. Tianjin Medical University Qixiangtai Road 22, Heping District, Tianjin 300070, P. R. China. 3. Orthopedic Research Institute, Tianjin Hospital Heping Branch, Tianjin University Munan Street 122, Heping District, Tianjin 300050, P. R. China. 4. Orthopaedics Institute, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine Chang Ling Road 88, Xiqing District, Tianjin 300381, P. R. China.
Abstract
Purpose: To investigate whether mechanical load regulates LRP6 expression and whether different intensities of treadmill exercise have different effects on LRP6 expression and the biomechanical properties of hindlimb bones in Sprague-Dawley (SD) rats. Methods: Fifty-six three-month-old virgin female SD rats were randomly divided into seven groups (n=8). Each group was subjected to tail suspension, free physiological activity or different intensities of treadmill exercise according to the experimental design for four or eight weeks. Rats were sacrificed after the intervention based on experimental design, and fresh femurs, tibias and fibulas were harvested for molecular biological analysis, biomechanical testing and micro-CT analysis. Results: LRP6 expression and the Wnt/β-catenin pathway activity decreased, and bone mass and biomechanical properties decreased after loss of mechanical stimulation. For disuse osteoporosis, even physiological activity could improve LRP6 expression, Wnt/β-catenin pathway activity, bone mass and biomechanical properties. Compared with physiological activity, treadmill exercise had better and faster effects on bone recovery. Compared with the Low intensity Exercise Group (LE group), the Medium intensity Exercise Group (ME group) and High intensity Exercise Group (HE group) had higher LRP6 expression, bone mass and biomechanical properties, while there were no significant difference between the ME group and HE group. Conclusions: Mechanical load appears to be a regulator of LRP6 expression, and it further affects the Wnt/β-catenin pathway activity and bone mass. The LRP6 expression, bone mass and biomechanical properties gradually improve as treadmill exercise intensity increases, while there is no significant difference between the ME group and HE group. AJTR
Purpose: To investigate whether mechanical load regulates LRP6 expression and whether different intensities of treadmill exercise have different effects on LRP6 expression and the biomechanical properties of hindlimb bones in Sprague-Dawley (SD) rats. Methods: Fifty-six three-month-old virgin female SD rats were randomly divided into seven groups (n=8). Each group was subjected to tail suspension, free physiological activity or different intensities of treadmill exercise according to the experimental design for four or eight weeks. Rats were sacrificed after the intervention based on experimental design, and fresh femurs, tibias and fibulas were harvested for molecular biological analysis, biomechanical testing and micro-CT analysis. Results:LRP6 expression and the Wnt/β-catenin pathway activity decreased, and bone mass and biomechanical properties decreased after loss of mechanical stimulation. For disuse osteoporosis, even physiological activity could improve LRP6 expression, Wnt/β-catenin pathway activity, bone mass and biomechanical properties. Compared with physiological activity, treadmill exercise had better and faster effects on bone recovery. Compared with the Low intensity Exercise Group (LE group), the Medium intensity Exercise Group (ME group) and High intensity Exercise Group (HE group) had higher LRP6 expression, bone mass and biomechanical properties, while there were no significant difference between the ME group and HE group. Conclusions: Mechanical load appears to be a regulator of LRP6 expression, and it further affects the Wnt/β-catenin pathway activity and bone mass. The LRP6 expression, bone mass and biomechanical properties gradually improve as treadmill exercise intensity increases, while there is no significant difference between the ME group and HE group. AJTR
Authors: Joseph W Starnes; Daria B Neidre; Jeffry S Nyman; Anuradha Roy; Matthew J Nelson; Gloria Gutierrez; Xiaodu Wang Journal: Exp Gerontol Date: 2013-04-26 Impact factor: 4.032
Authors: H Wang; Y Wan; K-F Tam; S Ling; Y Bai; Y Deng; Y Liu; H Zhang; W-H Cheung; L Qin; J C-Y Cheng; K-S Leung; Y Li Journal: Osteoporos Int Date: 2011-12-09 Impact factor: 4.507
Authors: H B Jia; J X Ma; X L Ma; J T Yu; R Feng; L Y Xu; J Wang; D Xing; S W Zhu; Y Wang Journal: Osteoporos Int Date: 2014-07-30 Impact factor: 4.507