Mechanical Properties Of Tibia Research Articles

Insulin Therapy on Bone Macroscopic, Microarchitecture, and MechanicalProperties of Tibia in Diabetic Rats.

This study evaluated tibia's macroscopic structure, mechanical properties, and bone microarchitecture in rats with type 1 diabetes mellitus (T1DM). Eighteen animals were divided into three groups (n=6): Non-diabetic (ND), diabetic (D), and diabetic+insulin (DI). T1DM was induced by streptozotocin; insulin was administered daily (4IU). The animals were euthanized 35 days after induction. The tibiae were removed and analyzed using macroscopic, micro-computed tomography (micro-CT) and three-point bending. The macroscopic analysis measured proximal-distal length (PD), antero-posterior thickness (AP) of proximal (AP-P) and distal (AP-D) epiphysis, and lateral-medial thickness (LM) of proximal (LM-P) and distal (LM-D) epiphysis. Micro-CT analysis closed porosity, tissue mineral density, and cortical thickness. The three-point bending test measured maximum strength, energy, and stiffness. The macroscopic analysis showed that D presented smaller measures of length and thickness (AP and AP-P) than ND and DI. More extensive measurements were observed of LM and AP-D thickness in DI than in D. In micro-CT, DI showed larger cortical thickness than D. Mechanical analysis showed lower strength in D than in other groups. T1DM reduces bone growth and mechanical strength. Insulin therapy in diabetic rats improved bone growth and fracture resistance, making diabetic bone similar to normoglycemic animals.

Effect of collagen fiber orientation on mechanical properties of bone and myofascia in hindlimb unloading rats

It is well known that the bone loss which may lead to bone fracture risk occurs under microgravity and disuse. Besides bone mineral density (BMD), the role of collagen as the main component of bone in the mechanism has unknown. In addition, myofascia, which is also mainly composed of collagen, plays an important role in the force transmission in musculoskeletal system. In this study, the collagen alternations of hindlimb tibia and myofascia in tail-suspension rats, which hindlimb unloading as a model to simulate microgravity and/or disuse, were investigated and further the correlations with the mechanical properties were analyzed. The collagen fiber orientations were observed by second-harmonic generation (SHG) microscopy and quantitatively analyzed in MATLAB. Bone mechanical properties were measured by three-point-bending test and nanoindentation. Myofascial mechanical properties were explored by tensile test. The results showed: 1) the collagen fibers orientation both in bone and myofascia were dispersed, as standard deviation of collagen fiber orientation increased .2) the mechanical properties of tibia were decreased by unloading both at macro level (maximum load, breaking load and stiffness, etc.) and micro level (hardness). In myofascia, the yield strain and ultimate strain were significantly decreased. 3) correlation analysis showed bone collagen orientation was related to bone hardness/elastic modulus, and myofascial collagen orientation was related to myofascial elastic modulus and yield limit. Additionally, myofascial mechanical properties were related to bone mechanical properties. These suggested disordered collagen orientation may be related to the deterioration of mechanical properties in both bone and myofascia under simulated microgravity. The alternation of myofascial mechanical property may have a certain impact on the deterioration of bone mechanical properties through affecting the force transmission from muscle to bone.

The effect of periodic stretching on countering bone loss in hindlimb unloading rat

IntroductionConventional exercises could not prevent the deterioration of astronaut's bone and muscle effectively during space flight. On the ground, stretching is widely used to improve the joint range of motion (ROM) and muscle performance. However, study on how stretching affected bone mass and bone quality was rarely reported and the animal stretching modes were not ideal. Therefore, the aim of this study was to develop a device that stretching the hindlimb of rats to study the effects of stretching on bone in hindlimb unloading rats. MethodsThe ankle joint angel of conscious rat was kept at 30° for periodical stretching by this device. 32 Sprague Dawley rats were randomly divided into 4 groups (n = 8, each): control group (CON); CON plus stretching group (CONS); tail-suspension group (TS); TS plus stretching group (TSS). On the 29th day of the experiment, the bone mineral density (BMD) and trabecular microstructure were analyzed by μCT, the mechanical properties of tibia were determined by three-point bending test and the muscle performance was measured by multi-channel physiological signal tester. ResultsThe data showed that the muscle strength and wet weight in TSS group were significantly higher than TS group. After stretching, the BMD, trabecular microstructure and mechanical properties of tibia in TSS group were also significantly better than TS group. In addition, these results of bone showed no significant difference between TSS group and CON group. ConclusionsThis device we developed could quantitatively stretch the hindlimb of rat and prevent the bone and muscle degeneration induced by tail-suspension. Our results suggested that stretching could be a useful exercise mode to keep bone and muscle healthy for astronauts or people who could not do conventional exercise.

Local vibration enhanced the efficacy of passive exercise on mitigating bone loss in hindlimb unloading rats

Spaceflight induced bone loss is seriously affecting astronauts. Mechanical stimulation from exercise has been shown to restrain bone resorption as well as improve bone formation. Current exercise countermeasures in space cannot prevent it completely. Active exercise may convert to passive exercise in some ways because of the loss of gravity stimulus and inertia of exercise equipment. The aim of this study was to compare the efficacy of passive exercise or/and local vibration on counteracting the deterioration of the musculoskeletal system, including bone, muscle and tendons in tail-suspended rats. We hypothesized that local vibration could enhance the efficacy of passive exercise on countering bone loss. 40 Sprague Dawley rats were randomly distributed into five groups (n = 8, each): tail-suspension (TS), TS+35 Hz vibration (TSV), TS + passive exercise (TSP), TS + passive exercise coupled with 35 Hz vibration (TSPV) and control (CON). Passive exercise or/and local vibration was performed for 21 days. On day 0 and 21, bone mineral density (BMD) was observed by dual energy X-ray absorptiometry (DXA), and trabecular microstructure was evaluated by microcomputer tomography (μCT) analysis in vivo. Mechanical properties of tibia and tendon were determined by a mechanical testing system. Soleus and bone ash weight was tested by an electronic balance. Results showed that the passive exercise could not prevent the decrease of trabecular BMD, microstructure and bone ash weight induced by TS, whereas vibration and passive exercise coupled with local vibration (PV) could. Biomechanical properties of the tibia and tendon in TSPV group significantly increased compared with TS group. In summary, PV in this study was the best method in preventing weightlessness-induced bone loss. Consistent with our hypothesis, local vibration partly enhanced the effect of passive exercise. Furthermore, this study will be useful in improving countermeasure for astronauts, but also for the rehabilitation of disused or aged osteoporosis.

Puerarin enhances bone mass by promoting osteoblastogenesis and slightly lowering bone marrow adiposity in ovariectomized rats.

We investigated the effect of puerarin on bone mass and marrow adiposity in ovariectomy (OVX)- induced osteoporosis. The rats were divided into four groups: control; OVX; OVX+estradiol (OVX-E); and OVX+puerarin treatment (OVX-GE). In vivo, bone mineral density (BMD) and histomorphometry were measured under microCT. The mechanical properties of tibia were obtained in 3-point bending test. Plasma osteocalcin and adiponectin were determined using enzyme-linked immunosorbent assay (ELISA). Alkaline phosphatase (ALP) were measured using biochemical methods. In vitro, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Oil Red O staining were used to compare osteoblast proliferation and adipocyte differentiation, respectively. Osteocalcin and adiponectin in culture supernatants were determined using ELISA. The results showed that puerarin significantly enhanced bone volume density and trabecular number compared with OVX and OVX-E groups (p<0.05, p<0.05, respectively). Puerarin increased energy to ultimate load, plasma osteocalcin and ALP (p<0.01). However, BMD in OVX-GE group was less than that in control (p<0.01) and OVX-E groups (p<0.05). The culture supernatants from OVX-GE group showed increased osteocalcin compared with those from OVX (p<0.01) and OVX-E groups (p<0.05). Puerarin lowered adiponectin in culture supernatant compared with supernatant from OVX group and inhibited the increase in adipocytes caused by OVX (p<0.01). However, the amount of lipids did not differ between OVX-GE and OVX groups. These findings suggest that puerarin likely enhances bone formation by stimulating the proliferation and differentiation of osteoblasts while slightly inhibiting the adipotic differentiation.

Interrelationships between densitometric, morphometric and mechanical properties of Tibia in polish landrace pigs

Interrelationships between densitometric, morphometric and mechanical properties of Tibia in polish landrace pigs

Effect of β‐hydroxy‐β‐methylbutyrate (HMB) administration on volumetric bone mineral density, and morphometric and mechanical properties of tibia in male turkeys

This study was performed to investigate the effects of β-hydroxy-β-methylbutyrate (HMB) administration on skeletal system properties in turkeys. Thirty-two males were randomly divided into two groups at the age of 35 days of life. The first group included control turkeys (n = 16) treated with placebo, while the second group of birds (HMB group; n = 16) was administered orally with calcium salt of HMB during the last 15 weeks of life. The turkeys were sacrificed at the age of 20 weeks and tibia was isolated for analysis of bone geometrical parameters, volumetric bone mineral density (vBMD) and mechanical properties. Furthermore, assessment of free amino acid concentrations in plasma was performed. The results showed a 6.3% increase of vBMD of tibia in response to HMB treatment (p < 0.01). Cross-sectional area, second moment of inertia, maximum elastic strength and ultimate strength of tibia were significantly increased in HMB-treated turkeys by 21.3%, 49.0%, 27.2% and 28.3%, respectively (p ≤ 0.01). β-hydroxy-β-methylbutyrate administration increased plasma concentrations of proline,glutamate, leucine, isoleucine, valine, alanine, aspartate, phenylalanine and cysteic acid (p < 0.05). These results indicate that long-term administration of HMB improves vBMD, and geometrical and mechanical properties of skeletal system in turkeys, and that these effects are associated with improved plasma amino acid concentrations.

Ornithine alpha-ketoglutarate increases mineralization and mechanical properties of tibia in turkeys

Skeletal disorders in rapidly growing poultry are commonplace. This study was performed to investigate the effect of ornithine alpha-ketoglutarate (OKG) administration during the last 7 weeks of life on structural properties, mineralization, and mechanical endurance of skeleton in turkeys at slaughter. Healthy HB Medium Bronze female turkeys were randomly assigned to two weight-matched groups at the age of 12 weeks. OKG was administered orally to the experimental group ( N = 17) at the dose of 0.4 g/kg body weight per day, while the control group ( N = 16) received an equal dose of the vehicle. The turkeys were slaughtered at the age of 19 weeks and the tibiae were isolated for analysis. The effect of OKG on skeletal system development in turkeys was evaluated in relation to both geometrical and mechanical properties as well as quantitative computed tomography (QCT). Free amino acids concentrations were assessed with the use of ion-exchange chromatography. Significantly increased bone mineral density of the trabecular and the cortical bone of tibia in the turkeys given OKG for the last 7 weeks of production cycle were observed ( P < 0.05). OKG administration improved mechanical endurance of the tibia estimated by the three-point bending test ( P < 0.01). Plasma amino acid analyses showed increased level of aspartate, proline, alanine, valine, isoleucine, leucine, and ornithine (all P < 0.05) after OKG treatment, whereas cystathionine concentration was decreased ( P = 0.03). Obtained results indicate that oral OKG administration has beneficial effects on skeletal development in fast growing turkeys and this effect is connected with increased amino acid synthesis. These observations may serve to improve skeletal properties in birds, especially when considering that skeletal disorders often affect the tibia and the proper function of the skeletal system plays an essential role in animal welfare and poultry production.

Effect of family housing of farmed silver foxes (Vulpes vulpes) in outdoor enclosures on some behavioural and physiological parameters

Group housing of silver foxes in large housing systems has been claimed to promote the welfare of the species since it provides foxes with the possibility to express species-specific social and locomotor behaviour. In our study, silver foxes were housed in outdoor enclosures in family units consisting of a vixen and her four cubs. Foxes housed alone in traditional fox cages were used as control animals. Light hour activity, rectal temperature during human handling and restraint, activity of the HPA axis, heart and gastrocnemius muscle mass, succinate-dehydrogenase activity in gastrocnemius muscle and mechanical properties of tibia were determined from the foxes. The effect of different housing systems was more pronounced in the cubs than in the vixens, indicating the importance of earlier experiences on animals' performance. Both the increased rectal temperature and the increased activity of the HPA axis especially in the cubs housed in enclosures show that the foxes housed in enclosures had a greater fear level towards man than the foxes housed in cages. Furthermore, the foxes, especially the male cubs, raised in groups may have experienced stress due to social tension. Although the exercise-related parameters may indicate that a larger available space could be beneficial for the foxes' physical endurance, these parameters had no clear correlation with physiological welfare parameters. Key words: Behaviour, fear, physical endurance, HPA axis, stress-induced hyperthermia, Vulpes vulpes

Differential response of rat limb bones to strenuous exercise

We examined the influence of a strenuous exercise regimen on tibial and metatarsal bones to show not only how the geometric, histological, and mechanical properties of immature bone respond to strenuous exercise but also how long bones within the same limb may respond differentially to exercise. Female Sprague-Dawley rats (8 wk old) were divided randomly into two groups: a sedentary control (n = 15) and an exercised group (n = 15). The exercise intensity was 80-90% of maximum oxygen capacity 5 days/wk for 10 wk. Mechanical properties of tibia and second metatarsus (MT) were determined with three-point bending, and contralateral bones were used for geometric and histological analyses. Length and middiaphyseal cross-sectional geometry of the exercised tibiae were significantly less than controls, but material properties were not different. The exercised tibiae had significantly lower structural properties (e.g., loads at the proportional limit and maximum and energy at failure load). The middiaphyseal dorsal cortex of exercised MT was significantly thicker than controls, but tensile stress at the proportional limit and elastic modulus of exercised MT were significantly less than controls. The average number of osteons and osteocytes per unit area of the tibial middiaphysis was significantly greater in the exercised group--especially in lateral and posterior cortices. The number of osteons and osteocytes per unit area in the MT, however, was significantly less in the exercised group. The differential effects of strenuous exercise on tibia and MT suggest that local loading and bone-specific responses have important roles in modulating the response of immature bone to strenuous exercise.