The Effects of Dynamic Axial Loading on the Rat Growth Plate

Ohashi, Naoko; Robling, Alexander G.; Burr, David B.; Turner, Charles H.

doi:10.1359/jbmr.2002.17.2.284

Cited by 105 publications

(101 citation statements)

References 38 publications

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“…A much smaller effect on growth occurs with cyclic loading. 8,15,16 Recent evidence 22 suggests that endochondral growth varies acutely and correlates inversely with activity level, but that over time the growth is relatively insensitive to cyclic loading. This differs from the The age is that of the animals at the time of growth measurement after administration of the second fluorochrome, that is 7 days after installation of the loading apparatus.…”

Section: Discussionmentioning

confidence: 99%

“…Growth plates appear to be affected less by cyclic stress than by sustained stress. 8,15,16 The primary aim of this study was to document the alteration of growth at two different anatomical growth plate locations, for three differing levels of sustained stress, in three different species, and for animals of differing ages. The secondary aim was to identify differences between the growth response to stress between species, anatomical location, and underlying growth rate that might help determine the likely growth-stress relationship in human growth plates.…”

Section: Introductionmentioning

confidence: 99%

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Endochondral growth in growth plates of three species at two anatomical locations modulated by mechanical compression and tension

Stokes

Aronsson

Dimock

et al. 2006

Journal Orthopaedic Research

137

158

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Sustained mechanical loading alters longitudinal growth of bones, and this growth sensitivity to load has been implicated in progression of skeletal deformities during growth. The objective of this study was to quantify the relationship between altered growth and different magnitudes of sustained altered stress in a diverse set of nonhuman growth plates. The sensitivity of endochondral growth to differing magnitudes of sustained compression or distraction stress was measured in growth plates of three species of immature animals (rats, rabbits, calves) at two anatomical locations (caudal vertebra and proximal tibia) with two different ages of rats and rabbits. An external loading apparatus was applied for 8 days, and growth was measured as the distance between fluorescent markers administered 24 and 48 h prior to euthanasia. An apparently linear relationship between stress and percentage growth modulation (percent difference between loaded and control growth plates) was found, with distraction accelerating growth and compression slowing growth. The growth-rate sensitivity to stress was between 9.2 and 23.9% per 0.1 MPa for different growth plates and averaged 17.1% per 0.1 MPa. The growth-rate sensitivity to stress differed between vertebrae and the proximal tibia (15 and 18.6% per 0.1 MPa, respectively). The range of control growth rates of different growth plates was large (30 microns/day for rat vertebrae to 366 microns/day for rabbit proximal tibia). The relatively small differences in growth-rate sensitivity to stress for a diverse set of growth plates suggest that these results might be generalized to other growth plates, including human. These data may be applicable to planning the management of progressive deformities in patients having residual growth. ß

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Endochondral growth in growth plates of three species at two anatomical locations modulated by mechanical compression and tension

Stokes

Aronsson

Dimock

et al. 2006

Journal Orthopaedic Research

137

158

View full text Add to dashboard Cite

show abstract

“…13 Experimental data have shown that cyclic forces applied to growth plates in the growing skeleton induce cellular proliferation, differentiation, matrix biosynthesis, as well as growth arrest under extreme loading. [15][16][17][18][19] However, whether chondral development is regulated by mechanical stresses in fetal or postnatal development is not well understood.…”

Section: Introductionmentioning

confidence: 99%

Modulation of endochondral development of the distal femoral condyle by mechanical loading

Sundaramurthy

Mao

2005

Journal Orthopaedic Research

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Although previous theoretical modeling studies have predicted that various mechanical stresses accelerate or inhibit the ossification process of the neonatal chondroepiphysis, there is a paucity of experimental data to verify these models. The present study was designed to provide experimental evidence on whether the ossification of the chondroepiphysis is modulated by mechanical loading on the distal femoral condyle explant of the neonatal (5-day-old) rabbit in organ culture. Upon aseptic dissection, the right condyle explant was immersed in and fixated to an organ culture system, and received cyclic forces at 200 mN and 1 Hz for 12 h (N ¼ 8) directly on its slightly convex articular surface, whereas the contralateral, left condyle explant was immersed separately in organ culture (N ¼ 8). Subsequently, both loaded and control explants were placed in a bioreactor rotating at 20 rpm for 72 h. In each mechanically loaded specimen, a structure reminiscent of the secondary ossification center (SOC) appeared with an average area of 1.17 AE 0.13 mm 2 , or 15.2 AE 8.2% of the total epiphysis area. In contrast, no SOC was detected in any of the unloaded contralateral control specimens. The SOC in mechanically loaded specimens was stained intensively with fast green, whereas either the rest of the loaded epiphysis or the entire control epiphysis was stained intensely to safranin-O but lacked fast green staining. Immunolocalization revealed that the SOC of the mechanically loaded specimens expressed Runx 2 and osteopontin, both of which were absent in the unloaded control specimens. Type X collagen was expressed surrounding hypertrophic chondrocytes adjacent to the SOC, but was absent in the control specimen. Type II collagen and decorin were absent in the SOC of the loaded specimen, but were expressed throughout the rest of the loaded epiphysis and the unloaded control epiphysis. The intensity of type II collagen and decorin expression was significantly stronger among hypertrophic chondrocytes surrounding the SOC than the control. The numbers of hypertrophic chondrocytes surrounding the SOC and superior to metaphyseal bone were significantly higher in the loaded specimens than the unloaded controls. Taken together, mechanical stresses accelerate the formation of the secondary ossification center, and therefore modulate endochondral ossification. ß

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“…This increase in body height is, in some part, due to the increase of intervertebral disc height [21]. However, numerous reports have shown inconsistent effects of weightlessness or unloading on longitudinal bone growth: it can inhibit bone formation [18], have no effect at all on bone size [18], or suppress bone enlargement [20,24,28,30,32]. The reported effects of excess loading, as in the case of competitive athletes, are also contradictory, showing induction or reduction of longitudinal growth, most likely due to variations in the type and rate of the physical activity [4,15,27].…”

Section: Introductionmentioning

confidence: 99%

Effect of long-term axial spinal unloading on vertebral body height in adult thoracolumbar spine

Kermani

Soroush

2008

Eur Spine J

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The human spine is influenced by mechanical loads. To our knowledge, this is the first study to assess the effect of long-term axial unloading on morphology of healthy vertebras in adults. The objective of this study is to quantify the effects of long-term relative axial unloading on thoracolumbar vertebral body height in adults. In this study, 218 vertebras on 200 plain lateral radiograms of patients with thoracolumbar vertebral body fracture, which underwent long segment instrumentation and fusion and had a relative axial unloading on five vertebrae of thoracolumbar spine were evaluated. Anterior vertebral body height (AVBH) and posterior vertebral body height (PVBH) proximal and distal to the fractured vertebrae were measured before and at least 1 year after the unloading operative procedures. AVBH of the first distal adjacent vertebrae and summative AVBHs of the first distal and proximal adjacent vertebras to the fractured vertebrae were significantly increased after 1 year of unloading, whereas the PVBH changes were not noticeable and the mean of cumulative height of two levels of proximal and distal adjacent vertebras to the fractured vertebrae did not show significant difference. Vertebral body height of lumbar was more influenced by unloading when compared with thoracic spine. Long-term relative axial unloading can affect the height of healthy vertebral bodies in adult spine.

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The Effects of Dynamic Axial Loading on the Rat Growth Plate

Cited by 105 publications

References 38 publications

Endochondral growth in growth plates of three species at two anatomical locations modulated by mechanical compression and tension

Endochondral growth in growth plates of three species at two anatomical locations modulated by mechanical compression and tension

Modulation of endochondral development of the distal femoral condyle by mechanical loading

Effect of long-term axial spinal unloading on vertebral body height in adult thoracolumbar spine

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