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PubMed1989

First bone formation and the dissection of an osteogenic lineage in the embryonic chick tibia is revealed by monoclonal antibodies against osteoblasts.

Detailed studies of the origin and differentiation of osteogenic cells can be facilitated by cell-specific markers. To this end, we immunized mice with a heterogeneous population of chick embryonic bone cells and subsequently generated and selected for monoclonal antibodies against cell surface determinants. Supernatants from growing hybridoma colonies were screened immunohistochemically against frozen sections of embryonic stage 35 (day 9.5) chick tibiae. Three cell lines, SB-1, SB-2, and SB-3, which each secrete a different antibody against osteogenic cells, have been successfully cloned, stabilized, and immortalized. Antibody SB-1 reacts with a family of cells in embryonic bone, liver, kidney, and intestine, which are identically stained by the histochemical stain for alkaline phosphatase. The SB-2 antigen is present only on osteoblasts, while the SB-3 antigen is expressed on the surface of osteoblasts, ependymal cells and ventricular myoblasts. Studies on the developmental progression of osteoblasts in the embryonic tibia indicate that the determinants recognized by SB-1, SB-2, and SB-3 are temporally coupled to the appearance of the pre-osteoblast marker alkaline phosphatase. Detailed morphologic analyses reveal that SB-1 reacts with a large family of osteogenic cells residing between the surface of newly formed bone and the overlying periosteal osteoprogenitor cells. By contrast, SB-2 and SB-3 appear to react with those mature osteoblasts involved in the secretion and mineralization of osteoid. Cells which are imprisoned within bone matrix (osteocytes) of the developing tibia are not recognized by these antibodies, but are immunostained by an osteocyte-specific monoclonal antibody which does not react with SB-1, SB-2 or SB-3 positive cells. The results reported here suggest the existence of an osteogenic cell lineage which is characterized by a series of discrete cell states prior to the overt expression of the Secretory Osteoblastic phenotype. We propose that the emergence and abatement of phenotypically distinct osteogenic cell surface antigens follows a precise spatial and temporal sequence which reflects the position of cells within the osteogenic lineage.

Alkaline Phosphatase↗

PubMed1991

Mechanical properties and biochemical composition of rat cortical femur and tibia after long-term treatment with biosynthetic human growth hormone.

The influence of biosynthetic human growth hormone (b-hGH) on female rat cortical femur and tibia was studied after administration of hormone doses of 0.16, 1.10, or 8.33 mg/kg body weight/day for 90 days. The mechanical properties, dimensions, real density, ash weight, and the mineral and collagen concentrations of the bones were measured. In both femur and tibia a positive linear relation was found between the dose of hormone and ultimate load, ultimate stiffness, energy absorption at ultimate load, load at failure, energy absorption at failure, and deflection at failure. In the femur a positive correlation between dose and deflection at ultimate load was also found. After normalizing the mechanical data for the dimensions of the bones, no differences were found in the hormone treated groups compared to placebo, except for the elastic modulus (Young's modulus), which was decreased in the femur in the group given 8.33 mg b-hGH. The mineral and collagen concentration were unaffected in both femur and tibia, whereas the real density was decreased in the femur. The growth-hormone-induced changes in the mechanical properties seem to be caused mainly by increased dimensions of the bones.

Analysis of Variance↗

PubMedDate not supplied

The aminobisphosphonate alendronate inhibits bone loss induced by thyroid hormone in the rat. Comparison between effects on tibiae and vertebrae.

The aims of this study were to develop a rat model of hyperthyroidism and to determine the efficacy of alendronate in the prevention of thyroid hormone-induced bone loss. Ten week-old Sprague-Dawley rats injected with thyroxine 250 micrograms/kg/day (+T4) or vehicle (-T4) were treated with alendronate (+ALN) or vehicle (-ALN) orally 0.5 mg/kg/day. After 3 weeks of treatment histomorphometric parameters of cancellous bone remodeling were assessed in the proximal tibia and in the first lumbar vertebra. In the secondary spongiosa of the tibia T4 treatment caused significant bone loss, associated with increased bone turnover; trabecular bone volume, trabecular thickness and trabecular number were significantly decreased. Osteoid and osteoclast surfaces increased in +T4/-ALN as compared to control. Alendronate prevented the increase in bone turnover and increased bone volume above control values without interfering with the recruitment of osteoclasts. These changes were not apparent in the vertebra. It is concluded that excess thyroid hormone in the rat induces high turnover bone loss in the tibia which can be prevented by alendronate through an inhibition of osteoclastic activity. The lack of effects of thyroid hormone on the vertebra may be ascribed to a lower rate of basal bone turnover at that site.

Alendronate↗

PubMedDate not supplied

The response of rat tibiae to incremental bouts of mechanical loading: a quantum concept for bone formation.

To investigate the minimum number of loading bouts necessary to produce new lamellar or woven bone formation, and the time required for its initiation, bone formation was measured in 32 retired breeder female Sprague-Dawley rats following one, two, three, or five bouts of applied loading. Bending forces of 54 N were applied to right tibiae using a four-point loading apparatus, and left tibiae served as contralateral controls. Loading was applied as a sine wave with a frequency of 2 Hz for 18 s (36 cycles) per loading bout. Rats were injected with alizarin on day 1 and calcein on days 5 and 12, and were killed on day 19. One bout of loading was sufficient to increase the periosteal woven bone surface (Wb.Pm/B.Pm) from 0% to 40% (p < 0.01), and to 80% after five bouts of loading (p < 0.01), with a dose-response relationship for increases in Wb.Pm/B.Pm (p < 0.0001), mineral apposition rate (Wb.AR; p = 0.002), and bone formation rate (Wb.BFR/BS; p = 0.0001). In the first labeling period (days 1-5), the endocortical lamellar bone forming surface (BSf/BS) was increased slightly (p < 0.05), but no significant differences were shown for BFR/BS or MAR. From days 5 to 19, right tibiae showed a dose-response increase in BFR/BS (p = 0.002) and BSf/BS (p = 0.008), but not MAR. These results are consistent with a "quantum" model of bone formation such that a "quantum" of bone cells is activated in response to the loading bout and the strain magnitude dictate the size or microstructural organization of a given packet of new bone. Conversely, the distributed nature of loading may define the recruitment, rather than size, of new packets of bone.

Analysis of Variance↗

PubMed2006

Biomechanical study of prophylactic internal fixation of the radial osteocutaneous donor site using the sheep tibia model.

This study investigated the strengthening effect of different types of plate and position after osteotomy of the sheep tibia, which is a model for the radial osteocutaneous donor site. Fifty matched pairs of adult sheep tibias were tested in torsion and four-point bending. Firstly, the weakening effect of an osteotomy was compared with the intact bone. Then pairs of bones with an osteotomy were compared with and without reinforcement with different types of 3.5mm plate. The plate was placed in either the anterior (over the defect) or posterior (on the intact cortex) position. In torsion the mean strength of the intact bone was 45% greater than after osteotomy (P=0.02). The reinforced bone was on average 61% stronger than the unreinforced bone (P<0.001). In bending the mean strength of the intact bone was 188% greater than after osteotomy (P=0.02). The reinforced bone was on average 184% stronger then the unreinforced bone (P<0.001). The tibia was able to withstand much greater loads in bending. The dynamic compression plate was the strongest reinforcement in both torsion and bending. The position of the plate did not alter the strengthening effect in torsion but the posterior position resisted greater bending loads (P=0.01). This may not be relevant in clinical practice as the radius is likely to fracture first as a result of lower torsional forces.

Analysis of Variance↗

PubMed2004

Reproducibility and error sources of micro-MRI-based trabecular bone structural parameters of the distal radius and tibia.

The mechanical competence of trabecular bone is significantly determined, next to material density, by its three-dimensional (3D) structure. Recent advances in micromagnetic resonance imaging (micro-MRI) acquisition and processing techniques allow the 3D trabecular structure to be analyzed in vivo at peripheral sites such as the distal radius and tibia. The practicality of micro-MRI-based noninvasive virtual bone biopsy (VBB) for longitudinal studies of patients hinges on the reproducibility of the derived structural parameters, which largely determine the size of the effect that can be detected at a given power and significance level. In this paper, the reproducibility of micro-MRI-derived trabecular bone structure measures was examined by performing repeat studies in six healthy subjects in whom the distal aspects of the radius and tibia were scanned with a 3D spin-echo sequence at 137 x 137 x 410 microm3 voxel size. Bone volume fraction (BV/TV) and digital topological analysis (DTA) structural parameters including the topological bone surface-to-curve ratio (SCR) and topological erosion index (TEI) were evaluated after subjecting the raw images to a cascade of processing steps. The average coefficient of variation was 4-7% and was comparable for the two anatomic sites and for all parameters measured. The reliability expressed in terms of the intraclass correlation coefficient ranged from 0.95 to 0.97 in the radius and 0.68 to 0.92 in the tibia. Error analysis based on simulations suggests involuntary patient motion, primarily rotation, to be the chief source of imprecision, followed by failure to accurately match the analysis volumes in repeat studies.

Adult↗

PubMed2004

Relative motions of the tibia, talus, and calcaneus during the stance phase of gait: a cadaver study.

The motions of the tibia, talus, and calcaneus during walking were analyzed three-dimensionally using a dynamic cadaver model that recreates the stance phase of walking. Rigid marker clusters were attached to each of the three bones, and the rotations of the talus and calcaneus with respect to the tibia and the calcaneus with respect to the talus were analyzed for eight right cadaver feet. The talus rotated primarily in plantarflexion/dorsiflexion about the talocrural joint, with an average range of 18 degrees +/- 4.7 degrees. The calcaneus began in inversion and internal rotation with respect to the tibia, moved into the neutral position at 28% of the stance phase and rotated primarily in plantarflexion from that point onward. Rotation of the calcaneus with respect to the talus at the subtalar joint occurred about all three axes, with approximately 5 degrees of relative dorsiflexion and 7 degrees of relative internal rotation. After 25% of stance, the talus and calcaneus moved together as one body into plantarflexion, providing a rigid lever as toe-off was approached.

Aged↗

PubMed2006

Tibia and rearfoot motion and ground reaction forces in subjects with patellofemoral pain syndrome during walking.

Abnormal subtalar joint function and the consequent rotation of the tibia during walking are thought to contribute to patellofemoral pain syndrome (PFPS). The purpose of this study was to measure rearfoot and tibia motion, and the ground reaction force (GRF) during the stance phase of walking in subjects with PFPS and compare them to healthy subjects. A four camera motion analysis system with a single force plate was used to investigate rearfoot motion relative to the tibia in three planes, the tibial transverse plane rotation and the GRF during the stance phase of walking in 13 female subjects diagnosed with PFPS and 14 healthy females. Analysis showed significantly delayed peak rearfoot eversion (p=0.02), and earlier occurrence of peak dorsiflexion (p=0.02) for the PFPS group. Furthermore, significantly lower peak medial GRF (p=0.03), minimum vertical GRF trough (p=0.02) and the second vertical GRF peak (p=0.01) were found in the PFPS group. Tibial transverse rotation was not shown to be different in PFPS subjects. However, there was prolonged rearfoot eversion during the stance phase of walking. The earlier appearance of rearfoot dorsiflexion as well as the lower GRFs indicate altered propulsive function of the foot during supination.

Adult↗

PubMed2006

Bone mineral density of the proximal tibia relates to axial torsion in the lower limb.

This study sought to determine the relationship between bone mineral density distribution in the proximal tibia and tibial and femoral torsions, hip-knee-ankle angle, hip rotation index (internal-external rotation), knee abduction moments, and the foot progression angle. Simple linear regression found that the hip rotation index (r=-0.59, p<0.001), tibial torsion (r=-0.41, p=0.004), and knee abduction moments (r=0.39, p=0.005) were significantly related to medial-lateral BMD ratio for all subjects. The three variables were then studied together to determine their relationship to the bone mineral distribution in the proximal tibia using multiple linear regression (r=0.80, p<0.001). These findings suggest that higher medial knee joint loads, loss of internal rotation of the hip, and internal tibial torsion may lead to increased medial versus lateral BMD of the proximal tibia of healthy knees. Similar bone distribution patterns are found in knees with osteoarthritis; therefore, we suggest these may be risk factors.

Adult↗

PubMed2005

Expression of bone morphogenic protein 2/4, transforming growth factor-beta1, and bone matrix protein expression in healing area between vascular tibia grafts and irradiated bone-experimental model of osteonecrosis.

PURPOSE: For the surgical treatment of osteoradionecrosis after multimodal therapy of head-and-neck cancers, free vascular bone grafts are used to reconstruct osseous structures in the previously irradiated graft bed. Reduced, or even absent osseous healing in the transition area between the vascular graft and the irradiated graft bed represents a clinical problem. Inflammatory changes and fibrosis lead to delayed healing, triggered by bone morphogentic protein 2/4 (BMP2/4) and transforming growth factor (TGF)-beta(1). Given the well-known fibrosis-inducing activity of TGF-beta(1), an osteoinductive effect has been reported for BMP2/4. However, the influence of irradiation (RT) on this cytokine expression remains elusive. Therefore, the aim of the present in vivo study was to analyze the expression of BMP2/4, TGF-beta(1), collagen I, and osteocalcin in the transition area between the bone graft and the graft bed after RT. METHODS AND MATERIALS: Twenty Wistar rats (male, weight 300-500 g) were used in this study. A free vascular tibia graft was removed in all rats and maintained pedicled in the groin region. Ten rats underwent RT with 5 x 10 Gy to the right tibia, the remainder served as controls. After 4 weeks, the previously removed tibia grafts were regrafted into the irradiated (Group 1) and nonirradiated (Group 2) graft beds. The interval between RT and grafting was 4 weeks. After a 4-week osseous healing period, the bone grafts were removed, and the transition area between the nonirradiated graft and the irradiated osseous graft bed was examined histomorphometrically (National Institutes of Health imaging program) and immunohistochemically (avidin-biotin-peroxidase complex) for the expression of BMP2/4, TGF-beta(1), collagen I, and osteocalcin. RESULTS: Absent or incomplete osseous healing of the graft was found in 9 of 10 rats after RT with 50 Gy and in 1 of 10 of the rats with nonirradiated osseous grafts. Histomorphometrically, the proportion of osseous healing in the transition area was 17% in Group 1 and 48% in Group 2 (p = 0.001). Compared with the nonirradiated rats, reduced enchondral and perichondral ossification was found in the healing area after RT, with a reduction of BMP2/4 and osteocalcin expression. TGF-beta(1) and collagen I expression in the transition area to the irradiated osseous graft bed was significantly increased compared with that in the nonirradiated osseous graft bed. CONCLUSION: After RT, osseous healing of vascular bone grafts is significantly reduced and may be a result of radiation-induced inhibition of BMP2/4 and osteocalcin expression. In addition, induction of TGF-beta(1) and collagen I expression occurs. Because the effects of the TGF-beta superfamily are manifold and partially unknown, additional research directions could be in the exogenous application of BMP2/4 and inhibition of TGF-beta(1) by antibody treatment to search for appropriate therapeutic approaches for improving osseous healing in the irradiated graft bed.

Animals↗

PubMed2006

The line of action in the tibia during axial compression of the leg.

Compression of the leg induces bending in the tibia, which can lead to tensile failure of the bone in the midshaft. The purpose of this study was to determine the orientation of the compressive load vector in the human tibia. Five cadaveric lower extremities were instrumented with in situ 6-axis tibial and fibular load cells and subjected to quasistatic axial leg compression tests in two knee positions and nine ankle positions. For each test, the location and angle of the line of action were calculated at the tibial midshaft. The line of action was extended to the bone ends in order to determine the locations of the effective centers of pressure on the tibial plafond and tibial plateau. The effective center of pressure on the tibial plafond consistently migrated anteriorly in dorsiflexion, laterally in eversion, posteriorly in plantarflexion, and medially in inversion. An opposite pattern was observed on the tibial plateau. When the knee was flexed, the effective center of pressure was generally isolated to a small area in the posterior portion of the medial tibial condyle. The percentage of the axial load borne by the fibula varied from -8% to 19%, and was related to the inversion/eversion angle of the ankle (p<0.02), as well as the distance between the fibula and the axial load path at the midshaft (p<0.001). The line of action through the tibia appeared to follow the external load path to the extent allowed by the available joint contact surfaces.

Aged↗

PubMed1998

Tissue reaction to implanted root-end filling materials in the tibia and mandible of guinea pigs.

The purpose of this study was to examine the tissue reaction to implanted mineral trioxide aggregate (MTA), amalgam, Intermediate Restorative Material, and Super-EBA in the tibias and mandibles of guinea pigs. After anesthetizing 20 guinea pigs, raising tissue flaps, and preparing bony cavities, the test materials were placed in Teflon cups and implanted in the tibias and 10 days later in the mandibles. The animals were euthanized 80 days later and the tissues prepared for histological examination. The presence of inflammation, predominant cell type, and thickness of fibrous connective tissue adjacent to each implant were recorded. The tissue reaction to MTA implantation was the most favorable observed at both sites; as in every specimen, it was free of inflammation (p < 0.01). In the tibia, MTA was the material most often observed with direct bone apposition. Based on these results, MTA seems to be a biocompatible material.

Aluminum Compounds↗

PubMed2000

Osseous tissue reaction around hydroxyapatite block implanted into proximal metaphysis of tibia of rat with collagen-induced arthritis.

This study was conducted to investigate the influence of osteoporosis on new bone formation around a hydroxyapatite (HA) block implanted into the proximal metaphysis of the tibia of rats with collagen-induced arthritis (CIA). Ten rats were immunized with an emulsion of bovine type II collagen and Freund's complete adjuvant (arthritis group). Another 10 rats, which were not immunized were used as the control group. Seventeen days after immunization, HA block was implanted into the proximal metaphysis of the tibia. Four weeks after implantation, all rats were killed. The serum level of tetrate-resistant acid phosphatase (TRAP), bone mineral density (BMD) in the proximal metaphysis of the tibia and the affinity index in the arthritis group were 28.0+/-3.5 IU/ml, 130.3+/-28.7 mg/cm2 and 77.6+/-10.8%, respectively, and those in the control group were 24.6+/-5.5 IU/ml, 175.9+/-30.5 mg/cm2 and 56.3+/-14.8%. The serum level of TRAP was higher (P < 0.05) and BMD was lower (P < 0.005) in the arthritis group. The amount of new bone formation around the HA block was larger (affinity index, P < 0.05) in the arthritis group than in the control group. These findings suggest that bone formation around HA block might be enhanced even in conditions associated with highly activated bone resorption and bone formation, such as arthritis.

Animals↗

PubMed2001

The effect of zinc supply on cadmium-induced changes in the tibia of rats.

It has been determined that zinc supplementation (240 microg Zn/ml) during (for 12 weeks) or after (for 2 weeks) cadmium exposure (50 microg Cd/ml for 12 weeks) can prevent the accumulation and toxic action of Cd in the tibia of rats. The exposure to Cd led to disturbances in bone metabolism reflected by changes in the chemical composition of bone and decreased bone mineral density (osteomalacian changes). The Zn supply in conditions of Cd intoxication completely prevented the Cd-induced increase in percentage of water content and decrease in tibia ash weight, ash weight/dry weight, non-org. comp./org. comp., Zn content and concentration. Moreover, Zn partly protected from the decrease in Ca concentration and content, percentage of non-organic components content, Ca/wet weight, Ca/ash weight and Ca/dry weight. Zn administered after Cd exposure partly, but not completely, protected from Cd-induced decrease in percentage of non-organic components content, Ca/wet weight as well as Ca content and concentration. This protective effect on bone was most evident when Zn was administered during Cd exposure. But Zn, independently of the manner of its administration, did not prevent Cd accumulation in the tibia. Our results suggest that Zn supply in conditions of simultaneous exposure can prevent Cd-induced bone loss to some extent, and used after Cd treatment can give therapeutic benefits.

Animals↗

PubMed2002

Endogenous norepinephrine regulates blood flow to the intact rat tibia.

The goal of our study was to determine if endogenous norepinephrine (NE) has a role in the regulation of basal blood flow to intact bone. The experimental plan was to measure bone blood flow before and after pharmacological blockade of alpha-adrenergic receptors. A significant increase in blood flow after receptor blockade would suggest that endogenous norepinephrine exerts a tonic constrictor effect on the vessels supplying blood to the bone. Mature, male rats were anesthetized with Inactin. Arterial blood pressure and left tibia blood flow (laser Doppler flowmetry) were measured. A cannula was inserted into the right iliac artery and advanced to the aortic bifurcation to deliver drugs into the left hindlimb circulation, including the left tibia vasculature. Bolus injection of norepinephrine caused a dose-dependent decrease in bone blood flow (30-40%). Blockade of alpha-adrenergic receptors with phentolamine or phenoxybenzamine attenuated by more than 50% the norepinephrine-induced decrease in bone blood flow. In separate rats that had not received exogenous norepinephrine, injection of phentolamine alone decreased bone vascular resistance by 34+/-3%. Similarly, phenoxybenzamine decreased resistance by 25+/-4%. These results are consistent with the conclusion that alpha-adrenergic receptors mediate a significant constriction of blood vessels which participate in the partial control of basal blood flow to the intact rat tibia.

Adrenergic alpha-Antagonists↗

PubMedDate not supplied

Restoration of tensile properties at tendon insertion to bone by a patellar tendon-tibia autograft: an experimental study with canine infraspinatus.

A free patellar tendon-tibia autograft was performed to reconstruct a tendon insertion to bone of the canine infraspinatus. In this experimental study restoration of mechanical properties at tendon insertion to bone of the patellar tendon-tibia autograft was examined on 0, 42, and 84 postoperative days. Five dogs were used for each time point. Bone union occurred in all grafts by 6 postoperative weeks. The ultimate strength at the tendon insertion to bone recovered from 255.5 N on 0 day to 264.3 N and 439.3 N on 42 and 84 postoperative days, respectively. Stiffness recovered from 141.8 KN/m on 0 day to 201.8 KN/m and 226.3 KN/mN on 42 and 84 postoperative days, respectively. Our results demonstrate that patellar tendon-tibia autograft maintains excellent mechanical properties at tendon insertion to bone in the early healing period. This result suggests that transfer or free graft of tendons with attaching bone plug has a mechanical advantage for reconstruction of the rotator cuff, which may allow the patient to institute early postoperative mobilization.

Animals↗

PubMed2002

Recovery of proximal tibia bone mineral density and strength, but not cancellous bone architecture, after long-term bisphosphonate or selective estrogen receptor modulator therapy in aged rats.

Various bisphosphonates and the selective estrogen receptor modulator (SERM) raloxifene are approved treatments of postmenopausal osteoporosis. They increase bone mineral density (BMD), decrease bone turnover, and reduce vertebral fracture incidence through different cellular mechanisms. We investigated the bone cellular activities, architecture, mineral content/density, and strength of ovariectomized (ovx) rats on a long-term bisphosphonate or SERM treatment, at doses of either agent correcting bone strength. Eleven weeks postovariectomy, 6-month-old rats were treated with the SERM MDL 103,323 or with the bisphosphonate pamidronate for 5 months. Doses of pamidronate and MDL 103,323 were selected from previous studies showing correction of the ovx-induced decrease of ultimate strength of proximal tibia. Ultimate and yield strengths, BMD, and histomorphometric parameters were all quantified at the same site, i.e., the proximal tibia metaphysis. Long-term pamidronate decreases bone turnover and bone formation activity, leading to trabecular thinning. MDL 103,323 decreases bone turnover to a lesser extent, and slightly protects trabecular architecture by uncoupling bone resorption and formation activities. The yield strength is corrected by pamidronate, but not by MDL 103,323 treatment. However, neither compound restores the ovariectomy-induced cancellous bone loss. Total tissue area and cortical thickness are unchanged with pamidronate or MDL 103,323 treatment, indicating that cortical bone mass, thickness, and cross-sectional area are not modified. The discrepancy between proximal tibia BMD and mechanical resistance to fracture modifications, on the one hand, and cancellous bone volume, on the other hand, could be due to changes in the degree of mineralization of bone matrix and/or of the intrinsic properties of the bone matrix.

Aging↗

PubMed2003

Low-intensity, high-frequency vibration appears to prevent the decrease in strength of the femur and tibia associated with ovariectomy of adult rats.

The effect of low-intensity, high-frequency vibration on bone mass, bone strength, and skeletal muscle mass was studied in an adult ovariectomized (OVX) rat model. One-year-old female rats were allocated randomly to the following groups: start control, sham OVX, OVX without vibration, OVX with vibration at 17 Hz (0.5g), OVX with vibration at 30 Hz (1.5g), OVX with vibration at 45 Hz (3.0g). Vibrations were given 30 min/day for 90 days. During vibration each group of rats was placed in a box on top of the vibration motor. The amplitude of the vibration motor was 1.0 mm. The animals were labeled with calcein at day 63 and with tetracycline at day 84. The tibia middiaphysis was studied by mechanical testing and dynamic histomorphometry and the femur distal metaphysis by mechanical compression. OVX without vibration increased the periosteal bone formation rate and increased the medullary cross-sectional area, i.e., increased the endocortical resorption and outward anteromedial and lateral drifts of cortical bone at the tibia middiaphysis. OVX also resulted in a reduced maximum bending stress of the tibia diaphysis and a reduced compressive stress of the femur distal metaphysis. Vibration at the highest intensity, i.e., 45 Hz, of OVX rats induced a further increase in periosteal bone formation rate and inhibited the endocortical resorption seen in OVX rats. Furthermore, vibration at 45 Hz inhibited the decline in maximum bending stress and compressive stress induced by OVX. Neither OVX nor OVX with vibration influenced skeletal muscle mass. In conclusion, the results support the idea of a possible beneficial effect of passive physical loading on the preservation of bone in OVX animals.

Animals↗