scholarly journals Osteocyte Apoptosis Contributes to Cold Exposure-induced Bone Loss

2021 ◽  
Vol 9 ◽  
Author(s):  
Jingke Du ◽  
Zihao He ◽  
Junqi Cui ◽  
Hanjun Li ◽  
Mingming Xu ◽  
...  
Keyword(s):  
Bone Mass ◽  
Bone Remodeling ◽  
Cold Exposure ◽  
Volume Fraction ◽  
Cold Temperature ◽  
Brown Adipocyte ◽  
Control Group ◽  
Dependent Manner ◽  
Bone Volume Fraction ◽  
Exposure To Cold

Emerging evidence indicates that bone mass is regulated by systemic energy balance. Temperature variations have profound effects on energy metabolism in animals, which will affect bone remodeling. But the mechanism remains unclear. 2-month-old C57BL/6J male mice were exposed to cold (4°C) and normal (23°C) temperatures for 28 days and the effects of cold exposure on bone mass was investigated. Micro-computed tomography results showed that bone volume fraction was significantly reduced after 14 days of exposure to cold temperature, and it was recovered after 28 days. Ploton silver staining and immunohistochemical results further revealed that exposure to cold decreased canalicular length, number of E11-and MMP13-positive osteocytes after 14 days, but they returned to the baseline levels after 28 days, different from the normal temperature control group. In addition, change of Caspase-3 indicated that exposure to cold temperature augmented apoptosis of osteocytes. In vitro results confirmed the positive effect of brown adipocytes on osteocyte‘s dendrites and E11 expression. In conclusion, our findings indicate that cold exposure can influence bone mass in a time-dependent manner, with bone mass decreasing and recovering at 2 and 4 weeks respectively. The change of bone mass may be caused by the apoptosis osteocytes. Brown adipocyte tissue could influence bone remodeling through affecting osteocyte.

scholarly journals Alpha-Ketoglutarate: An Effective Feed Supplement in Improving Bone Metabolism and Muscle Quality of Laying Hens: A Preliminary Study

Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2420
Author(s):  
Ewa Tomaszewska ◽  
Sylwester Świątkiewicz ◽  
Anna Arczewska-Włosek ◽  
Dorota Wojtysiak ◽  
Piotr Dobrowolski ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Laying Hens ◽  
Volume Fraction ◽  
Basal Diet ◽  
Cholesterol Content ◽  
Muscle Quality ◽  
Control Group ◽  
Bone Volume Fraction ◽  
Trabecular Thickness ◽  
Laying Performance

The aim of the experiment was to assess the effect of dietary alpha-ketoglutarate (AKG) supplementation on performance, serum hormonal indices, duodenum and jejunum histomorphometry, meat quality characteristics, bone quality traits and cartilage degradation in laying hens with a mature skeletal system. Forty-eight 30 week-old Bovans Brown laying hens were randomly assigned to a control group or the group fed the basal diet plus 1.0% AKG. The experimental trial lasted 30 weeks. The supplementation of AKG increases blood serum content of leptin, ghrelin, bone alkaline phosphatate and receptor activator of nuclear factor kappa-Β ligand, while osteoprotegerin and osteocalcin decrease. While dietary AKG was given to laying hens negatively influenced villus length, crypt depth, villus/crypt ratio and absorptive surface area in duodenum and jejunum, these changes have no effect on feed intake, weight gain, nor laying performance. In breast muscles, no significant changes in skeletal muscle fatty acid composition were observed, however, a higher shear force and decreased cholesterol content following AKG supplementation were noted, showing the improvement of muscle quality. While dietary AKG supplementation did not affect the general geometric and mechanical properties of the tibia, it increased collagen synthesis and enhanced immature collagen content. In medullary bone, an increase of bone volume fraction, trabecular thickness, fractal dimension and decrease of trabecular space were observed in AKG supplemented group. The trabeculae in bone metaphysis were also significantly thicker after AKG supplementation. AKG promoted fibrillogenesis in articular cartilage, as indicated by increased cartilage oligomeric matrix protein immunoexpression. By improving the structure and maintaining the proper bone turnover rate of highly reactive and metabolically active medullar and trabecular bones AKG showed its anti-osteoporotic action in laying hens.

Tolerance of estrogen-treated rats to acute cold exposure

1979 ◽  
Vol 47 (1) ◽  
pp. 59-66 ◽  
Author(s):  
M. J. Fregly ◽  
D. L. Kelleher ◽  
D. J. Black
Keyword(s):  
Oxygen Consumption ◽  
Cold Exposure ◽  
Previous Experiment ◽  
Female Rats ◽  
Control Group ◽  
Maximal Rate ◽  
Acute Cold Exposure ◽  
Exposure To Cold ◽  
Rate Of Oxygen Consumption ◽  
Rate Of Cooling

Female rats treated chronically with ethynylestradiol (36 micrograms/kg per day) alone, and in combination with the progestational agent, norethynodrel (253 micrograms/kg per day), cooled significantly faster than controls when lightly restrained and exposed to air at 5 degrees C. Rate of cooling of rats given only norethynodrel was similar to that of the control group. In other studies, rate of oxygen consumption was determined for all groups during acute exposure to cold (14 degrees C). All estrogen-treated groups achieved the same maximal rate of oxygen consumption as control and norethynodrel-treated groups during cold exposure, but cooled significantly faster. Two groups of female rats were treated chronically with ethynylestradiol at two separate doses (36 and 61 micrograms/kg per day). An untreated group served as controls. Rate of oxygen consumption of all animals were measured during restraint and exposure to cold (18 degrees C). The estrogen-treated groups again achieved the same maximal rate of oxygen consumption as the control group, but also cooled significantly faster despite the fact that the cold stress was less severe than in the previous experiment. That estrogen-treated rats cooled faster than controls in both studies despite achieving a maximal rate of heat production which did not differ from controls suggests that reduced cold tolerance of estrogen-treated rats may be related to increased heat loss.

scholarly journals Osteopenia and Osteoporosis Assessed by Dual X Absorptiometry in Sickle Cell Anemia Adults Subjects

2019 ◽  
Vol 3 (3) ◽  
pp. p153
Author(s):  
Joseph Médard Kabeya Kabenkama ◽  
Minouche Bukumba ◽  
Orly Kazadi ◽  
Frederic Tshibasu ◽  
Angele Mbongo Tanzia ◽  
...  
Keyword(s):  
Bone Mass ◽  
Bone Remodeling ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Characteristic Curve ◽  
Sub Saharan Africa ◽  
High Rate ◽  
Control Group ◽  
Normal Children ◽  
T Score

Background: Sickle cell anemia is the most common genetic disease in sub-Saharan Africa. It is an inherited autosomal recessive disorder characterized by chronic hemolysis secondary to falciformation of red blood cells, also responsible of ischemia, bone infarction and accompanied by serious infections and organic lesions.Normal for weight at birth, Sickle cell anemia subjects have low pre puberty growth compared to normal children and also have compromised bone remodeling balance which results in decrease of bone mass and increase of bone fragility. Several studies have established that 37% to 50% of SCA patients were osteopenic or osteoporotic. This study aims to confirm the existence of bone remodeling disorders with osteoporotic translation and to compare the values found in Congolese sickle cell adults subjects to the general population.Methods: Spine and hip DXA were conducted on 270 SS homozygotes aged 18 to 50 years (121 men and 149 women) and 359 AA homozygotes as controls (138 men and 221 women), aged from 18 to 50 years old, who agreed to participate in the study, considered as a control group. AS heterozygotes were not included in the study.Results: AA subjects shows higher density (BMD) and Bone mineral content (BMC) values. Both SCA and AA controls showed the characteristic curve with peak bone mass at the fourth decade of life, followed by a decay with age. The difference in BMD and BMC with the control population ranged from 7.94% to 26.34% (average of 16.02%) which means -0.8 to -2.7 standard deviations, whereas, compared to the T -score in the Congolese population, was 11.6% to 22.15% less (average of -17.5%) equivalent of -0.9 to -2 standard deviations.The overall decrease in bone mass rate for -2.5 DS of the T-score was: -28.4% and 33.2% for -2 DS of T-score.Conclusion: SCA subjects shows high rate of osteopenia and osteoporosis and are more likely at risk for fractures.

Effects of cold exposure on inhibition by isoproterenol of release of alanine in the rat

1988 ◽  
Vol 64 (3) ◽  
pp. 906-912 ◽  
Author(s):  
T. Yamada ◽  
M. Shiota ◽  
T. Sugano
Keyword(s):  
Cold Exposure ◽  
Complex Medium ◽  
Control Group ◽  
Bicarbonate Buffer ◽  
Exposure To Cold ◽  
Flow Through

The effects of isoproterenol on the release of alanine during perfusion with pyruvate and valine were studied in perfused hindlimbs from rats that had been kept for 5 or 20 days at 4 degrees C. In hindlimbs perfused with Krebs bicarbonate buffer in a flow-through mode, the rate of release of alanine during perfusion with 2 mM pyruvate plus 5 mM valine was 250 nmol.min-1.leg-1, a rate that is comparable with that reported in hindlimbs perfused with complex medium. Neither the pyruvate-stimulated nor valine plus pyruvate-stimulated rates of release of alanine changed after 20 days of exposure to cold. Isoproterenol inhibited the release of alanine during perfusion with pyruvate, with valine, and with valine plus pyruvate in hindlimbs from a control group of rats. However, in hindlimbs from cold-exposed groups, isoproterenol failed to inhibit the release of alanine during perfusion with valine plus pyruvate and stimulated the release of alanine during perfusion with valine. Aminooxyacetate inhibited the effects of valine, pyruvate, and isoproterenol. The results obtained suggested that cold exposure decreases the responses to isoproterenol of the mechanism of alanine release and causes an increased supply of alanine to the liver.

scholarly journals Radioprotective Effect of Sodium Selenite on Mandible of Irradiated Rats

2019 ◽  
Vol 30 (3) ◽  
pp. 232-237
Author(s):  
Mayra Cristina Yamasaki ◽  
Rocharles CavalcanteFontenele ◽  
Yuri Nejaim ◽  
Deborah Queiroz Freitas
Keyword(s):  
Sodium Selenite ◽  
Volume Fraction ◽  
Bone Microarchitecture ◽  
Bone Volume ◽  
Radioprotective Effect ◽  
Control Group ◽  
X Rays ◽  
Bone Volume Fraction ◽  
Trabecular Thickness ◽  
Significant Difference

Abstract The purpose of this study was to test the radioprotective effect of selenium in the bone microarchitecture of irradiated rats mandibles. Forty rats were separated into 4 groups with 10 animals: control group (CG), irradiated group (IG), sodium selenite group (SSG) and sodium selenite irradiated group (SSIG). A single dose of 0.8 mg/kg sodium selenite was administered intraperitoneally in the SSG and SSIG groups. One hour later, animals of IG and SSIG groups were irradiated with 15 Gy of x-rays. Forty days after radiation a bilateral extraction of the mandibular first molars was performed. After the extraction procedure, five rats were killed after fifteen days and others five after thirty days. Micro- computed tomography was used to evaluate cortical and trabecular bone of each rat. The mean and standard deviation of each bone microarchitecture parameter were analyzed using the statistical test of two-way Analysis of Variance (ANOVA). At 15 days, the bone volume presented higher values in the CG and SSG groups (p=0.001). The same groups presented statistically significant higher values when bone volume fraction (p<0.001) and trabecular thickness (p<0.001) were analyzed. At 30 days, it was observed that in relation to the bone volume fraction, SSG group presented the highest value while SSIG group had the lowest value, with statistically significant difference (p=0.016). Sodium selenite demonstrated a median radioprotective effect in the bone microarchitecture of irradiated mandibles, which indicates the substance may be a potential radioprotective agent against chronic effects of high doses of ionizing radiation.

scholarly journals Raloxifene administration enhances retention in an orthodontic relapse model

2020 ◽  
Vol 42 (4) ◽  
pp. 371-377
Author(s):  
Niloufar Azami ◽  
Po-Jung Chen ◽  
Shivam Mehta ◽  
Zana Kalajzic ◽  
Eliane H Dutra ◽  
...  
Keyword(s):  
Alveolar Bone ◽  
Tooth Movement ◽  
Volume Fraction ◽  
Orthodontic Tooth Movement ◽  
Bone Volume ◽  
Resin Cement ◽  
Control Group ◽  
Tartrate Resistant Acid Phosphatase ◽  
Bone Volume Fraction ◽  
Tissue Density

Abstract Background and objectives Orthodontic relapse is a physiologic process that involves remodelling of the alveolar bone and principle periodontal ligament fibres. Raloxifene is an Food and Drug Administration (FDA)-approved selective oestrogen receptor modulator that inhibits systemic bone loss. In our study, we examined the effects of Raloxifene on alveolar bone modelling and orthodontic relapse in a rodent model. Materials and methods The efficacy of raloxifene was evaluated in 15-week-old male Wistar rats, 8 in each group (Control, Raloxifene, Raloxifene + 7-day relapse, Raloxifene + 14-day relapse) for a total of 42 days. All animals had 14 days of orthodontic tooth movement with a closed nickel–titanium coil spring tied from incisors to right first molar applying 5–8 gm of force. On the day of appliance removal, impression was taken with silicon material and the distance between first molar and second molar was filled with light-cured adhesive resin cement for retention phase. Raloxifene Retention, Raloxifene Retention + 7D, Raloxifene Retention + 14D groups received 14 daily doses of raloxifene (2.0 mg/kg/day) subcutaneously after orthodontic tooth movement during retention. After 14 days of retention, the retainer was removed and right first molar was allowed to relapse for a period of 14 days. Raloxifene injection continued for the Raloxifene + 14-day relapse group during relapse phase too. Control group received saline injections during retention. Animals were euthanized by CO2 inhalation. The outcome measure included percentage of relapse, bone volume fraction, tissue density, and histology analysis using tartrate-resistant acid phosphatase staining and determining receptor activator of nuclear factor-кB-ligand (RANKL) and osteoprotegerin expression. Results Raloxifene Retention + 14D group had significantly less (P &lt; 0.05) orthodontic relapse when compared with other groups. There was a significant increase (P &lt; 0.05) in bone volume fraction and tissue density in the Raloxifene Retention + 14D group when compared with other groups. Similarly, there was significant decrease in number of osteoclasts and RANKL expression in Raloxifene Retention + 14D group when compared with Raloxifene Retention + 7D group (P &lt; 0.05). Conclusion Raloxifene could decrease post-orthodontic treatment relapse by decreasing bone resorption and indirectly enhancing bone formation.

scholarly journals Effect of cyclical forces on the periodontal ligament and alveolar bone remodeling during orthodontic tooth movement

2013 ◽  
Vol 84 (2) ◽  
pp. 297-303 ◽  
Author(s):  
Zana Kalajzic ◽  
Elizabeth Blake Peluso ◽  
Achint Utreja ◽  
Nathaniel Dyment ◽  
Jun Nihara ◽  
...  
Keyword(s):  
Bone Remodeling ◽  
Periodontal Ligament ◽  
Structural Integrity ◽  
Alveolar Bone ◽  
Tooth Movement ◽  
Volume Fraction ◽  
Tartrate Resistant Acid Phosphatase ◽  
Vibratory Stimulus ◽  
Bone Volume Fraction ◽  
Alveolar Bone Remodeling

ABSTRACT Objective: To investigate the effect of externally applied cyclical (vibratory) forces on the rate of tooth movement, the structural integrity of the periodontal ligament, and alveolar bone remodeling. Methods: Twenty-six female Sprague-Dawley rats (7 weeks old) were divided into four groups: CTRL (unloaded), VBO (molars receiving a vibratory stimulus only), TMO (molars receiving an orthodontic spring only), and TMO+VB (molars receiving an orthodontic spring and the additional vibratory stimulus). In TMO and TMO+VB groups, the rat first molars were moved mesially for 2 weeks using Nickel-Titanium coil spring delivering 25 g of force. In VBO and TMO+VB groups, cyclical forces at 0.4 N and 30 Hz were applied occlusally twice a week for 10 minutes. Microfocus X-ray computed tomography analysis and tooth movement measurements were performed on the dissected rat maxillae. Tartrate-resistant acid phosphatase staining and collagen fiber assessment were performed on histological sections. Results: Cyclical forces significantly inhibited the amount of tooth movement. Histological analysis showed marked disorganization of the collagen fibril structure of the periodontal ligament during tooth movement. Tooth movement caused a significant increase in osteoclast parameters on the compression side of alveolar bone and a significant decrease in bone volume fraction in the molar region compared to controls. Conclusions: Tooth movement was significantly inhibited by application of cyclical forces.

scholarly journals Early-Onset Type 2 Diabetes Impairs Skeletal Acquisition in the Male TALLYHO/JngJ Mouse

Endocrinology ◽  
2014 ◽  
Vol 155 (10) ◽  
pp. 3806-3816 ◽  
Author(s):  
M. J. Devlin ◽  
M. Van Vliet ◽  
K. Motyl ◽  
L. Karim ◽  
D. J. Brooks ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Bone Marrow ◽  
Bone Mass ◽  
Early Onset ◽  
Volume Fraction ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Skeletal Acquisition

Abstract Type 2 diabetes (T2D) incidence in adolescents is rising and may interfere with peak bone mass acquisition. We tested the effects of early-onset T2D on bone mass, microarchitecture, and strength in the TALLYHO/JngJ mouse, which develops T2D by 8 weeks of age. We assessed metabolism and skeletal acquisition in male TALLYHO/JngJ and SWR/J controls (n = 8–10/group) from 4 weeks to 8 and 17 weeks of age. Tallyho mice were obese; had an approximately 2-fold higher leptin and percentage body fat; and had lower bone mineral density vs SWR at all time points (P &lt; .03 for all). Tallyho had severe deficits in distal femur trabecular bone volume fraction (−54%), trabecular number (−27%), and connectivity density (−82%) (P &lt; .01 for all). Bone formation was higher in Tallyho mice at 8 weeks but lower by 17 weeks of age vs SWR despite similar numbers of osteoblasts. Bone marrow adiposity was 7- to 50-fold higher in Tallyho vs SWR. In vitro, primary bone marrow stromal cell differentiation into osteoblast and adipocyte lineages was similar in SWR and Tallyho, suggesting skeletal deficits were not due to intrinsic defects in Tallyho bone-forming cells. These data suggest the Tallyho mouse might be a useful model to study the skeletal effects of adolescent T2D.

scholarly journals Bone Remodeling Model Integrating the Biological Function and Damage Influences for the Cortical-Trabecular Interface

2021 ◽  
Vol 9 ◽  
Author(s):  
Imed SOLTANI ◽  
◽  
Imane AIT OUMGHAR ◽  
Abdelwahed BARKAOUI ◽  
Tarek LAZGHAB ◽  
...  
Keyword(s):  
Bone Density ◽  
Bone Remodeling ◽  
Volume Fraction ◽  
Research Work ◽  
Bone Volume ◽  
Bone Volume Fraction ◽  
Saturation Zone ◽  
Damage Repair ◽  
Bone Damage ◽  
Over Time

Bone remodeling process has been widely investigated in literature from an experimental and theoretical viewpoint. Indeed, the biological process of bone remodeling allows a continuous renewal of the microstructure over time and thus, it contributes to decrease the bone damage by repairing it. This research work aims to study the biological function’s (fbio) effects on the bone remodeling process trough bone density evolution. Parameter fbio is one of the important parameters that controls bone volume variation. The biological bone remodeling process is modeled in terms of equations describing the activity of the Basic Multi-cellular Units (BMU). We use a mathematical model to simulate damage repair, based on Garcia Aznar’s model. The results of simulation show a good match with experimental and clinical data: bone porosity decreases over time and decreases also as the biological factors increase. In the same view, the apparent density (ρa) decreases with bone volume fraction increases. We note that the governance of the evolution of bone density leads to consider the evolution of bone volume during youthful and the maturation phase with their saturation zone for adult in terms of growth.

scholarly journals Kindlin-2 regulates skeletal homeostasis by modulating PTH1R in mice

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Xuekun Fu ◽  
Bo Zhou ◽  
Qinnan Yan ◽  
Chu Tao ◽  
Lei Qin ◽  
...  
Keyword(s):  
Bone Mass ◽  
Volume Fraction ◽  
Bone Marrow Cells ◽  
Bone Matrix ◽  
Osteoblastic Cells ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Ovariectomized Mice

AbstractIn vertebrates, the type 1 parathyroid hormone receptor (PTH1R) is a critical regulator of skeletal development and homeostasis; however, how it is modulated is incompletely understood. Here we report that deleting Kindlin-2 in osteoblastic cells using the mouse 10-kb Dmp1-Cre largely neutralizes the intermittent PTH-stimulated increasing of bone volume fraction and bone mineral density by impairing both osteoblast and osteoclast formation in murine adult bone. Single-cell profiling reveals that Kindlin-2 loss increases the proportion of osteoblasts, but not mesenchymal stem cells, chondrocytes and fibroblasts, in non-hematopoietic bone marrow cells, with concomitant depletion of osteoblasts on the bone surfaces, especially those stimulated by PTH. Furthermore, haploinsufficiency of Kindlin-2 and Pth1r genes, but not that of either gene, in mice significantly decreases basal and, to a larger extent, PTH-stimulated bone mass, supporting the notion that both factors function in the same genetic pathway. Mechanistically, Kindlin-2 interacts with the C-terminal cytoplasmic domain of PTH1R via aa 474–475 and Gsα. Kindlin-2 loss suppresses PTH induction of cAMP production and CREB phosphorylation in cultured osteoblasts and in bone. Interestingly, PTH promotes Kindlin-2 expression in vitro and in vivo, thus creating a positive feedback regulatory loop. Finally, estrogen deficiency induced by ovariectomy drastically decreases expression of Kindlin-2 protein in osteocytes embedded in the bone matrix and Kindlin-2 loss essentially abolishes the PTH anabolic activity in bone in ovariectomized mice. Thus, we demonstrate that Kindlin-2 functions as an intrinsic component of the PTH1R signaling pathway in osteoblastic cells to regulate bone mass accrual and homeostasis.

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