Spatiotemporal Characterization of Microstructure Morphology, Mechanical Properties and Bone Remodeling of Rat Tibia Under Uniaxial Compressive Overload Loading.

Bone tissue is subjected to increased mechanical stress during high-intensity work. Inadequate bone remodeling reparability can result in the continuous accumulation of microdamage, leading to stress fractures. The aim of this work was to investigate the characteristics and repair mechanisms of tibial microdamage under several degrees of overload.

Morphological and mechanical alterations in articular cartilage and subchondral bone during spontaneous hip osteoarthritis in guinea pigs.

This study aimed to investigate the morphological and mechanical changes in articular cartilage and subchondral bone during spontaneous hip osteoarthritis in guinea pigs. Hip joints of guinea pigs were investigated at 1, 3, 6, and 9 months of age (hereafter denoted as 1 M, 3 M, 6 M, and 9 M, respectively; = 7 in each group). Morphological and mechanical alterations during spontaneous hip osteoarthritis in guinea pigs were investigated.

Effects of whole-body vibration at different periods on lumbar vertebrae in female rats.

The current study aimed to investigate the effects of whole-body vibration (WBV) before and after ovariectomy on lumbar vertebrae, and to observe whether the positive effects of WBV before and after ovariectomy on lumbar vertebrae in rats could be maintained after vibration stopped. Three-month-old female rats were divided into four groups (n = 45/group): control (CON), ovariectomy (OVA), WBV before ovariectomy (WBV-BO), and WBV after ovariectomy (WBV-AO) groups. For 1-8 weeks, WBV-BO group was subjected to vertical WBV.

Additively Manufactured Multilevel Voronoi-Lattice Scaffolds with Bonelike Mechanical Properties.

Irregular porous scaffold through Voronoi tessellation based on global modeling demonstrated randomness to a certain degree and susceptibility to producing large processing deviations. A modeling method for new types of scaffolds based on periodic arrays of Voronoi unit cell was proposed in this study. These porous scaffolds presented controllable local cells and satisfactory mechanical properties.

The adaptive response of rat tibia to different levels of peak strain and durations of experiment.

The osteogenic response of bone to compressive load is affected by peak strain and duration of experiment, however, combined effect of peak load and duration of experiment on the rat tibia axial loading model remains unclear. In this study, rat tibia axial loading models with different levels of peak strains and durations of experiments were established (peak loads: 10 N, 20 N and 40 N, experimental duration: 2 weeks and 4 weeks). Microcomputer tomography scanning (Micro-CT), compression mechanical test and bone tissue alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) staining were used to investigate the effects of cyclic loading with different levels of peak strains and durations of experiments on osteogenic response of tibia in adult female Sprague-Dawley (SD) rats.

[Design of new gradient scaffolds based on triply periodic minimal surfaces and study on its mechanical, permeability and tissue differentiation characteristics].

In order to establish a bone scaffold with good biological properties, two kinds of new gradient triply periodic minimal surfaces (TPMS) scaffolds, i.e., two-way linear gradient G scaffolds (L-G) and D, G fusion scaffold (N-G) were designed based on the gyroid (G) and diamond (D)-type TPMS in this study.

Strain Distribution Evaluation of Rat Tibia under Axial Compressive Load by Combining Strain Gauge Measurement and Finite Element Analysis.

This study is aimed at providing an effective method for determining strain-load relationship and at quantifying the strain distribution within the whole tibia under axial compressive load on rats. Rat tibial models with axial compressive load were designed. Strains in three directions (0°, 45°, and 90°) at the proximal shaft of the tibia were measured by using a strain gauge rosette, which was used to calculate the maximum and minimum principal strains.

Effects of treadmill with different intensities on bone quality and muscle properties in adult rats.

Background: Bone is a dynamically hierarchical material that can be divided into length scales of several orders of magnitude. Exercise can cause bone deformation, which in turn affects bone mass and structure. This study aimed to study the effects of treadmill running with different intensities on the long bone integrity and muscle biomechanical properties of adult male rats.

Multiscale experimental study on the effects of different weight-bearing levels during moderate treadmill exercise on bone quality in growing female rats.

Background: Bone tissue displays a hierarchical organization. Mechanical environments influence bone mass and structure. This study aimed to explore the effects of different mechanical stimuli on growing bone properties at macro-micro-nano scales.

Finite Element Investigation of the Effects of the Low-Frequency Vibration Generated by Vehicle Driving on the Human Lumbar Mechanical Properties.

Long-term exposure to low-frequency vibration generated by vehicle driving impairs human lumbar spine health. However, few studies have investigated how low-frequency vibration affects human lumbar mechanical properties. This study established a poroelastic finite element model of human lumbar spinal segments L2-L3 to perform time-dependent vibrational simulation analysis and investigated the effects of different vibrational frequencies generated by normal vehicle driving on the lumbar mechanical properties in one hour.

Whole body vibration with rest days could improve bone quality of distal femoral metaphysis by regulating trabecular arrangement.

Low-magnitude, high-frequency vibration (LMHFV) with rest days (particularly seven rest days) was considerably effective in improving the morphological and mechanical properties of rat proximal femur. However, current knowledge is limited regarding the possible benefit of this mechanical regimen to other bone sites and whether the optimal rest days are the same. This study followed our previous experiment on LMHFV loading with rest days for three-month-old male Wistar rats.

Morphological and Microstructural Alterations of the Articular Cartilage and Bones during Treadmill Exercises with Different Additional Weight-Bearing Levels.

The aim of this study was to investigate the morphological and microstructural alterations of the articular cartilage and bones during treadmill exercises with different exercise intensities. Sixty 5-week-old female rats were randomly divided into 10 groups: five additional weight-bearing groups (WBx) and five additional weight-bearing with treadmill exercise groups (EBx), which were subjected to additional weight bearing of % ( = 0, 5, 12, 19, and 26) of the corresponding body weight of each rat for 15 min/day. After 8 weeks of experiment, the rats were humanely sacrificed and their bilateral intact knee joints were harvested.

Effects of Scan Resolutions and Element Sizes on Bovine Vertebral Mechanical Parameters from Quantitative Computed Tomography-Based Finite Element Analysis.

Quantitative computed tomography-based finite element analysis (QCT/FEA) has been developed to predict vertebral strength. However, QCT/FEA models may be different with scan resolutions and element sizes. The aim of this study was to explore the effects of scan resolutions and element sizes on QCT/FEA outcomes.

Multiscale investigation on the effects of additional weight bearing in combination with low-magnitude high-frequency vibration on bone quality of growing female rats.

This study aimed to explore the effects of additional weight bearing in combination with low-magnitude high-frequency vibration (LMHFV; 45 Hz, 0.3 g) on bone quality. One hundred twenty rats were randomly divided into ten groups; namely, sedentary (SED), additional weight bearing in which the rat wears a backpack whose weight is x% of the body weight (WBx; x = 5, 12, 19, 26), basic vibration (V), and additional weight bearing in combination with LMHFV in which the rat wears a backpack whose weight is x% of the body weight (Vx; x = 5, 12, 19, 26).

Quantification of Age-Related Tissue-Level Failure Strains of Rat Femoral Cortical Bones Using an Approach Combining Macrocompressive Test and Microfinite Element Analysis.

Bone mechanical properties vary with age; meanwhile, a close relationship exists among bone mechanical properties at different levels. Therefore, conducting multilevel analyses for bone structures with different ages are necessary to elucidate the effects of aging on bone mechanical properties at different levels. In this study, an approach that combined microfinite element (micro-FE) analysis and macrocompressive test was established to simulate the failure of male rat femoral cortical bone.

Multi-Level Assessment of Fracture Calluses in Rats Subjected to Low-Magnitude High-Frequency Vibration with Different Rest Periods.

The aim of this study was to investigate the influences of low-magnitude high-frequency vibration (LMHFV) with different rest period regimes (vibrational loading per day [with or without the loading divided into bouts]; or vibrational loading for 7 day followed by 7 day rest [with or without the loading divided into bouts]) on bone healing at multi-levels. Transverse fractures of rat bilateral tibias were established using a Kirschner wire inserted for fixation. The animals were randomly assigned to five groups (n = 7 for each group): four for vibrational groups by LMHFV with different rest period regimes and one for fractured model without mechanical loading.

Age-related regional deterioration patterns and changes in nanoscale characterizations of trabeculae in the femoral head.

This study aimed to investigate the mechanical properties and features of bone materials at the nanoscale level in different regions of the femoral head in elderly patients with femoral neck fracture. Ten femoral heads from female patients with femoral neck fractures were extracted during surgery (five for the Aged group, aged 65-66 years; five for the Advanced aged group, aged 85-95 years). The femoral head was divided into three equal layers (anterior, central, and posterior) in the coronal view, and each layer was segmented into five regions (superior, central, inferior, medial, and lateral).

Seven day insertion rest in whole body vibration improves multi-level bone quality in tail suspension rats.

Objective: This study aimed to investigate the effects of low-magnitude, high-frequency vibration with rest days on bone quality at multiple levels.

Methods: Forty-nine three-month-old male Wistar rats were randomly divided into seven groups, namely, vibrational loading for X day followed by X day rest (VLXR, X = 1, 3, 5, 7), vibrational loading every day (VLNR), tail suspension (SPD), and baseline control (BCL). One week after tail suspension, rats were loaded by vibrational loading (35 Hz, 0.

Relationship between microstructure, material distribution, and mechanical properties of sheep tibia during fracture healing process.

The aim of this study was to investigate the relationship between microstructural parameters, material distribution, and mechanical properties of sheep tibia at the apparent and tissue levels during the fracture healing process. Eighteen sheep underwent tibial osteotomy and were sacrificed at 4, 8, and 12 weeks. Radiographs and micro-computed tomography (micro-CT) scanning were taken for microstructural assessment, material distribution evaluation, and micro-finite element analysis.

An adaptation model for trabecular bone at different mechanical levels.

Background: Bone has the ability to adapt to mechanical usage or other biophysical stimuli in terms of its mass and architecture, indicating that a certain mechanism exists for monitoring mechanical usage and controlling the bone's adaptation behaviors. There are four zones describing different bone adaptation behaviors: the disuse, adaptation, overload, and pathologic overload zones. In different zones, the changes of bone mass, as calculated by the difference between the amount of bone formed and what is resorbed, should be different.