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Low‐level accelerations applied in the absence of weight bearing can enhance trabecular bone formation
Author(s) -
Garman Russell,
Gaudette Glenn,
Donahue LeahRae,
Rubin Clinton,
Judex Stefan
Publication year - 2007
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.20354
Subject(s) - anabolism , apposition , tibia , chemistry , skeleton (computer programming) , epiphysis , anatomy , bone formation , cortical bone , weight bearing , long bone , endocrinology , biology , medicine , surgery , biochemistry
High‐frequency whole body vibrations can be osteogenic, but their efficacy appears limited to skeletal segments that are weight bearing and thus subject to the induced load. To determine the anabolic component of this signal, we investigated whether low‐level oscillatory displacements, in the absence of weight bearing, are anabolic to skeletal tissue. A loading apparatus, developed to shake specific segments of the murine skeleton without the direct application of deformations to the tissue, was used to subject the left tibia of eight anesthesized adult female C57BL/6J mice to small (0.3 g or 0.6 g ) 45 Hz sinusoidal accelerations for 10 min/day, while the right tibia served as an internal control. Video and strain analysis revealed that motions of the apparatus and tibia were well coupled, inducing dynamic cortical deformations of less than three microstrain. After 3 weeks, trabecular metaphyseal bone formation rates and the percentage of mineralizing surfaces (MS/BS) were 88% and 64% greater ( p < 0.05) in tibiae accelerated at 0.3 g than in their contralateral controls. At 0.6 g , bone formation rates and mineral apposition rates were 66% and 22% greater ( p < 0.05) in accelerated tibiae. Changes in bone morphology were evident only in the epiphysis, where stimulated tibiae displayed significantly greater cortical area (+8%) and thickness (+8%). These results suggest that tiny acceleratory motions — independent of direct loading of the matrix — can influence bone formation and bone morphology. If confirmed by clinical studies, the unique nature of the signal may ultimately facilitate the stimulation of skeletal regions that are prone to osteoporosis even in patients that are suffering from confinement to wheelchairs, bed rest, or space travel. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25: 732–740, 2007