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Inoue S1, Yakuwa T1, Suzuki R1, Aoki H2, Niikura T3, Oe K3, Fukui T3, Nomura M1,4, Wakimoto Y1, Mizuno E1, Li C1, Moriyama H5
1Kobe University Graduate School of Health Sciences, Department of Rehabilitation Science, Kobe, Japan, 2Nihon Medix Co., Ltd., Chiba, Japan, 3Kobe University Graduate School of Medicine, Department of Orthopaedic Surgery, Kobe, Japan, 4Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan, 5Kobe University, Life and Medical Sciences Area, Health Sciences Discipline, Kobe, Japan
Background: Osteoporosis is inevitable for postmenopausal women, and is characterized by low bone mass and deterioration of bone tissue, leading to increased risk of osteoporotic fractures. Pharmacological treatments for osteoporosis have been developed, but have the side effects. Therefore, novel therapeutic strategies were required to prevent and improve osteoporosis. On the other hand, some animal studies have demonstrated that the electrical muscle stimulation improves the bone atrophy with disuse. However, whether or not it prevents and improves osteoporosis remains unclear, and further its optimal stimulation intensity has not been clarified.
Purpose: The aim of this study was to investigate the effect of transcutaneous electrical stimulation on bone mass and strength in a well-established osteoporotic rat model, and to determine the optimal intensity by electrical stimulation leading to the best improvement of deterioration of bone tissue and strength.
Methods: A total of 11 female Wistar rats were used in this study. All rats received a bilateral ovariectomy to simulate postmenopausal osteoporosis. Rats randomly divided into control group and 2 experimental groups which received electrical stimulation with 2 intensities (8 mA or 16 mA), starting at 8 weeks after ovariectomy. The bilateral quadriceps were stimulated with paired surface electrodes for 10 min/day, daily, for 4 weeks. At the end of the experimental period, trabecular bone architecture in the distal femurs was assessed by bone volume fraction, bone mineral contents/tissue volume, structure model index, trabecular thickness, and number and separation with micro-computed tomography analysis. In addition, biomechanical properties were assessed by maximal load, stiffness, and energy absorption with compression test of distal femoral metaphysis.
Results: Bone volume fraction and bone mineral contents/tissue volume of the 16 mA group were significantly greater than that of the control group. Trabecular separation and structure model index of both the 8 and 16 mA groups were significantly lower than that of the control group. Furthermore, stiffness of the 8 mA group and energy absorption of the 16 mA was significantly greater than that of the control group.
Conclusion(s): Based on our results, the transcutaneous electrical stimulation may be effective therapeutic strategies for postmenopausal osteoporosis. Moreover, the muscle stimulation with 16 mA may be the optimal intensity to improve the trabecular bone architecture and bone strength.
Implications: Osteoporotic fractures have been recognized as one of the most common causes of disability. Furthermore, a number of them are rapidly increasing worldwide, and therefore innovative strategies for osteoporosis are required. The transcutaneous electrical stimulation is non-invasive and can be treated locally, so it has the potential to be able to treat osteoporosis and prevent osteoporotic fractures more efficiently.
Keywords: Osteoporosis, electrical stimulation, mechanical stress
Funding acknowledgements: This study was supported by Grant-in-Aid for Challenging Exploratory Research from JSPS (16K12933), and by Suzuken Memorial Foundation.
Purpose: The aim of this study was to investigate the effect of transcutaneous electrical stimulation on bone mass and strength in a well-established osteoporotic rat model, and to determine the optimal intensity by electrical stimulation leading to the best improvement of deterioration of bone tissue and strength.
Methods: A total of 11 female Wistar rats were used in this study. All rats received a bilateral ovariectomy to simulate postmenopausal osteoporosis. Rats randomly divided into control group and 2 experimental groups which received electrical stimulation with 2 intensities (8 mA or 16 mA), starting at 8 weeks after ovariectomy. The bilateral quadriceps were stimulated with paired surface electrodes for 10 min/day, daily, for 4 weeks. At the end of the experimental period, trabecular bone architecture in the distal femurs was assessed by bone volume fraction, bone mineral contents/tissue volume, structure model index, trabecular thickness, and number and separation with micro-computed tomography analysis. In addition, biomechanical properties were assessed by maximal load, stiffness, and energy absorption with compression test of distal femoral metaphysis.
Results: Bone volume fraction and bone mineral contents/tissue volume of the 16 mA group were significantly greater than that of the control group. Trabecular separation and structure model index of both the 8 and 16 mA groups were significantly lower than that of the control group. Furthermore, stiffness of the 8 mA group and energy absorption of the 16 mA was significantly greater than that of the control group.
Conclusion(s): Based on our results, the transcutaneous electrical stimulation may be effective therapeutic strategies for postmenopausal osteoporosis. Moreover, the muscle stimulation with 16 mA may be the optimal intensity to improve the trabecular bone architecture and bone strength.
Implications: Osteoporotic fractures have been recognized as one of the most common causes of disability. Furthermore, a number of them are rapidly increasing worldwide, and therefore innovative strategies for osteoporosis are required. The transcutaneous electrical stimulation is non-invasive and can be treated locally, so it has the potential to be able to treat osteoporosis and prevent osteoporotic fractures more efficiently.
Keywords: Osteoporosis, electrical stimulation, mechanical stress
Funding acknowledgements: This study was supported by Grant-in-Aid for Challenging Exploratory Research from JSPS (16K12933), and by Suzuken Memorial Foundation.
Topic: Electrophysical & isothermal agents; Musculoskeletal: lower limb; Disability & rehabilitation
Ethics approval required: Yes
Institution: Kobe University
Ethics committee: Institutional Animal Care and Use Committee
Ethics number: P160607
All authors, affiliations and abstracts have been published as submitted.
