scholarly journals Exercise mitigates the stunting effect of cold temperature on limb elongation in mice by increasing solute delivery to the growth plate

2010 ◽  
Vol 109 (6) ◽  
pp. 1869-1879 ◽  
Author(s):  
Maria A. Serrat ◽  
Rebecca M. Williams ◽  
Cornelia E. Farnum
Keyword(s):  
Growth Plate ◽  
Bone Growth ◽  
Wheel Running ◽  
Multiphoton Microscopy ◽  
Tail Length ◽  
Limb Lengthening ◽  
Cold Temperature ◽  
Bone Lengthening ◽  
Bone Elongation

Ambient temperature and physical activity modulate bone elongation in mammals, but mechanisms underlying this plasticity are a century-old enigma. Longitudinal bone growth occurs in cartilaginous plates, which receive nutritional support via delivery of solutes from the vasculature. We tested the hypothesis that chronic exercise and warm temperature promote bone lengthening by increasing solute delivery to the growth plate, measured in real time using in vivo multiphoton microscopy. We housed 68 weanling female mice at cold (16°C) or warm (25°C) temperatures and allowed some groups voluntary access to a running wheel. We show that exercise mitigates the stunting effect of cold temperature on limb elongation after 11 days of wheel running. All runners had significantly lengthened limbs, regardless of temperature, while nonrunning mice had shorter limbs that correlated with housing temperature. Tail length was impacted only by temperature, indicating that the exercise effect was localized to limb bones and was not a systemic endocrine reaction. In vivo multiphoton imaging of fluoresceinated tracers revealed enhanced solute delivery to tibial growth plates in wheel-running mice, measured under anesthesia at rest. There was a minimal effect of rearing temperature on solute delivery when measured at an intermediate room temperature (20°C), suggesting that a lasting increase in solute delivery is an important factor in exercise-mediated limb lengthening but may not play a role in temperature-mediated limb lengthening. These results are relevant to the study of skeletal evolution in mammals from varying environments and have the potential to fundamentally advance our understanding of bone elongation processes.

scholarly journals Temperature alters solute transport in growth plate cartilage measured by in vivo multiphoton microscopy

2009 ◽  
Vol 106 (6) ◽  
pp. 2016-2025 ◽  
Author(s):  
Maria A. Serrat ◽  
Rebecca M. Williams ◽  
Cornelia E. Farnum
Keyword(s):  
Solute Transport ◽  
Growth Plate ◽  
Quantitative Methods ◽  
Multiphoton Microscopy ◽  
Growth Plates ◽  
Absolute Growth ◽  
Body Core ◽  
Intracardiac Injection ◽  
Bone Elongation

Solute delivery to avascular cartilaginous plates is critical to bone elongation, and impaired transport of nutrients and growth factors in cartilage matrix could underlie many skeletal abnormalities. Advances in imaging technology have revolutionized our ability to visualize growth plates in vivo, but quantitative methods are still needed. We developed analytical standards for measuring solute delivery, defined by amount and rate of intravenous tracer entry, in murine growth plates using multiphoton microscopy. We employed an acute temperature model because of its well-established impact on bone circulation and tested the hypothesis that solute delivery changes positively with limb temperature when body core and respiration are held constant (36°C, 120 breaths/min). Tibial growth plates were surgically exposed in anesthetized 5-wk-old mice, and their hindlimbs were immersed in warm (36°C) or cool (23°C) saline ( n = 6/group). After 30 min of thermal equilibration, we administered an intracardiac injection of fluorescein (50 μl, 0.5%) and captured sequentially timed growth plate images spanning 10 min at standardized depth. Absolute growth plate fluorescence was normalized to vascular concentrations for interanimal comparisons. As predicted, more fluorescein infiltrated growth plates at 36°C, with standardized values nearly double those at 23°C. Changing initial limb temperature did not alter baseline values, suggesting a sustained response period. These data validate the sensitivity of our system and have relevance to strategies for enhancing localized delivery of therapeutic agents to growth plates of children. Applications of this technique include assessment of solute transport in models of growth plate dysfunction, particularly chondrodysplasias with matrix irregularities.

scholarly journals Effect of Pulsed Electromagnetic Field Stimulation on the Growth Plate of the Tibia Bone of Rats: An In Vivo Study

2021 ◽  
Vol 11 (16) ◽  
pp. 7571
Author(s):  
Yoon-Young Sung ◽  
Jae-Woo Shin ◽  
Won-Kyung Yang ◽  
Min-Jin Kim ◽  
Ja-Ik Koo ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Growth Plate ◽  
Bone Growth ◽  
Articular Chondrocytes ◽  
Growth Promotion ◽  
Control Group ◽  
Pulsed Electromagnetic Field ◽  
Tibia Bone ◽  
Pulsed Electromagnetic

Currently, many children undergo precocious puberty, resulting in short stature due to premature closure of the growth plate. Pulsed electromagnetic field (PEMF) stimulation induces cell proliferation of articular chondrocytes. We developed a method for growth promotion using equipment with PEMF. In this study, we aimed to evaluate the effects of PEMF on the growth rate of growth plates using an animal model. An experimental study was conducted on 16 3-week-old rats to validate the effects of the growth care device on growth and development by PEMF stimulation at 28 Hz and 20 Gauss. The tibia bones of the groups with and without PEMF administration were dissected after 10 days, and then, the length of the growth plate of the knee and levels of insulin-like growth factor (IGF)-1 hormone in serum were measured. The length of the growth plate on the tibia bone and the levels of circulating IGF-1 were significantly increased by 25.6% and 13.6%, respectively, in the experimental group to which PEMF was applied compared to those of the control group, without any side effects. These results suggest that PEMF can safely stimulate growth of the growth plate in a non-invasive manner to promote bone growth.

scholarly journals Hindlimb heating increases vascular access of large molecules to murine tibial growth plates measured by in vivo multiphoton imaging

2014 ◽  
Vol 116 (4) ◽  
pp. 425-438 ◽  
Author(s):  
Maria A. Serrat ◽  
Morgan L. Efaw ◽  
Rebecca M. Williams
Keyword(s):  
Growth Plate ◽  
Vascular Access ◽  
Multiphoton Microscopy ◽  
Molecular Transport ◽  
Vessel Diameter ◽  
Cartilage Growth ◽  
Multiphoton Imaging ◽  
Growth Plates ◽  
Large Molecules

Advances in understanding the molecular regulation of longitudinal growth have led to development of novel drug therapies for growth plate disorders. Despite progress, a major unmet challenge is delivering therapeutic agents to avascular-cartilage plates. Dense extracellular matrix and lack of penetrating blood vessels create a semipermeable “barrier,” which hinders molecular transport at the vascular-cartilage interface. To overcome this obstacle, we used a hindlimb heating model to manipulate bone circulation in 5-wk-old female mice ( n = 22). Temperatures represented a physiological range of normal human knee joints. We used in vivo multiphoton microscopy to quantify temperature-enhanced delivery of large molecules into tibial growth plates. We tested the hypothesis that increasing hindlimb temperature from 22°C to 34°C increases vascular access of large systemic molecules, modeled using 10, 40, and 70 kDa dextrans that approximate sizes of physiological regulators. Vascular access was quantified by vessel diameter, velocity, and dextran leakage from subperichondrial plexus vessels and accumulation in growth plate cartilage. Growth plate entry of 10 kDa dextrans increased >150% at 34°C. Entry of 40 and 70 kDa dextrans increased <50%, suggesting a size-dependent temperature enhancement. Total dextran levels in the plexus increased at 34°C, but relative leakage out of vessels was not temperature dependent. Blood velocity and vessel diameter increased 118% and 31%, respectively, at 34°C. These results demonstrate that heat enhances vascular carrying capacity and bioavailability of large molecules around growth plates, suggesting that temperature could be a noninvasive strategy for modulating delivery of therapeutics to impaired growth plates of children.

scholarly journals Imaging IGF-I uptake in growth plate cartilage using in vivo multiphoton microscopy

2017 ◽  
Vol 123 (5) ◽  
pp. 1101-1109 ◽  
Author(s):  
Maria A. Serrat ◽  
Gabriela Ion
Keyword(s):  
Real Time ◽  
Growth Plate ◽  
Multiphoton Microscopy ◽  
Biologically Active ◽  
Growth Plate Chondrocytes ◽  
Growth Plates ◽  
Metatarsal Bones ◽  
Wide Range ◽  
Igf I

Bones elongate through endochondral ossification in cartilaginous growth plates located at ends of primary long bones. Linear growth ensues from a cascade of biochemical signals initiated by actions of systemic and local regulators on growth plate chondrocytes. Although cellular processes are well defined, there is a fundamental gap in understanding how growth regulators are physically transported from surrounding blood vessels into and through dense, avascular cartilage matrix. Intravital imaging using in vivo multiphoton microscopy is one promising strategy to overcome this barrier by quantitatively tracking molecular delivery to cartilage from the vasculature in real time. We previously used in vivo multiphoton imaging to show that hindlimb heating increases vascular access of large molecules to growth plates using 10-, 40-, and 70-kDa dextran tracers. To comparatively evaluate transport of similarly sized physiological regulators, we developed and validated methods for measuring uptake of biologically active IGF-I into proximal tibial growth plates of live 5-wk-old mice. We demonstrate that fluorescently labeled IGF-I (8.2 kDa) is readily taken up in the growth plate and localizes to chondrocytes. Bioactivity tests performed on cultured metatarsal bones confirmed that the labeled protein is functional, assessed by phosphorylation of its signaling kinase, Akt. This methodology, which can be broadly applied to many different proteins and tissues, is relevant for understanding factors that affect delivery of biologically relevant molecules to the skeleton in real time. Results may lead to the development of drug-targeting strategies to treat a wide range of bone and cartilage pathologies. NEW & NOTEWORTHY This paper describes and validates a novel method for imaging transport of biologically active, fluorescently labeled IGF-I into skeletal growth plates of live mice using multiphoton microscopy. Cellular patterns of fluorescence in the growth plate were completely distinct from our prior publications using biologically inert probes, demonstrating for the first time in vivo localization of IGF-I in chondrocytes and perichondrium. These results form important groundwork for future studies aimed at targeting therapeutics into growth plates.

scholarly journals Effect of Allium fistulosum Extracts on the Stimulation of Longitudinal Bone Growth in Animal Modeling Diet-Induced Calcium and Vitamin D Deficiencies

2021 ◽  
Vol 11 (17) ◽  
pp. 7786
Author(s):  
Jin Ah Ryuk ◽  
Hye Jin Kim ◽  
Joo Tae Hwang ◽  
Byoung Seob Ko
Keyword(s):  
Vitamin D ◽  
Growth Plate ◽  
Bone Mineral ◽  
Bone Growth ◽  
Allium Fistulosum ◽  
Mineral Density ◽  
Mg63 Cells ◽  
Alkaline Phosphate

Allium fistulosum is a perennial plant species grown worldwide belonging to the family Liliaceae. In Korean medicine, it is referred to as Chongbaek (CB), and it is prescribed for symptoms associated with the common cold due to its antipyretic properties. This study examined the effects of aqueous (CBW) and 30% ethanol (CBE) extracts on bone growth using a calcium- and vitamin D-deficient animal model. In an in vitro experiment, the alkaline phosphate activities of the extracts were examined using MC3T3-E1 and MG63 cells, and both the aqueous and ethanolic extracts had significant alkaline phosphate activities. In vivo, a serum analysis indicated that the CB extracts promoted bone growth based on the osteogenic markers ALP, calcium, osteocalcin, and collagen type 1 and increased the bone mineral content (BMC), bone mineral density (BMD), and growth plate length. Overall, our results indicate that both CBW and CBE of A. fistulosum can be utilized to facilitate bone growth and increase BMD in children and adolescents by lengthening the growth plate without adverse side effects, such as metabolic disorders or the release of obesity-inducing hormones.

The role of the G protein-coupled receptor GPR30 in the effects of estrogen in ovariectomized mice

2009 ◽  
Vol 296 (3) ◽  
pp. E490-E496 ◽  
Author(s):  
S. H. Windahl ◽  
N. Andersson ◽  
A. S. Chagin ◽  
U. E. A. Mårtensson ◽  
H. Carlsten ◽  
...  
Keyword(s):  
Growth Plate ◽  
Fat Mass ◽  
Bone Growth ◽  
Distal Femur ◽  
Uterine Weight ◽  
Marrow Cellularity ◽  
G Protein Coupled ◽  
Estrogenic Responses

In vitro studies suggest that the membrane G protein-coupled receptor GPR30 is a functional estrogen receptor (ER). The aim of the present study was to determine the possible in vivo role of GPR30 as a functional ER primarily for the regulation of skeletal parameters, including bone mass and longitudinal bone growth, but also for some other well-known estrogen-regulated parameters, including uterine weight, thymus weight, and fat mass. Three-month-old ovariectomized (OVX) GPR30-deficient mice (GPR30−/−) and wild-type (WT) mice were treated with either vehicle or increasing doses of estradiol (E2; 0, 30, 70, 160, or 830 ng·mouse−1·day−1). Body composition [bone mineral density (BMD), fat mass, and lean mass] was analyzed by dual-energy-X ray absorptiometry, while the cortical and trabecular bone compartments were analyzed by peripheral quantitative computerized tomography. Quantitative histological analyses were performed in the distal femur growth plate. Bone marrow cellularity and distribution were analyzed using a fluorescence-activated cell sorter. The estrogenic responses on most of the investigated parameters, including increase in bone mass (total body BMD, spine BMD, trabecular BMD, and cortical bone thickness), increase in uterine weight, thymic atrophy, fat mass reduction, and increase in bone marrow cellularity, were similar for all of the investigated E2 doses in WT and GPR30−/− mice. On the other hand, E2 treatment reduced longitudinal bone growth, reflected by decreased femur length and distal femur growth plate height, in the WT mice but not in the GPR30−/− mice compared with vehicle-treated mice. These in vivo findings demonstrate that GPR30 is not required for normal estrogenic responses on several major well-known estrogen-regulated parameters. In contrast, GPR30 is required for a normal estrogenic response in the growth plate.

scholarly journals The potential role of VEGF-induced vascularisation in the bony repair of injured growth plate cartilage

2014 ◽  
Vol 221 (1) ◽  
pp. 63-75 ◽  
Author(s):  
Rosa Chung ◽  
Bruce K Foster ◽  
Cory J Xian
Keyword(s):  
Blood Vessel ◽  
Growth Plate ◽  
Bone Growth ◽  
Fracture Repair ◽  
Bone Lengthening ◽  
Bony Tissue ◽  
Injury Site ◽  
Repair Tissue ◽  
Anti Vegf ◽  
Growth Plate Injury

Growth plate injuries often result in undesirable bony repair causing bone growth defects, for which the underlying mechanisms are unclear. Whilst the key importance of pro-angiogenic vascular endothelial growth factor (VEGF) is well-known in bone development and fracture repair, its role during growth plate bony repair remains unexplored. Using a rat tibial growth plate injury repair model with anti-VEGF antibody, Bevacizumab, as a single i.p. injection (2.5 mg/kg) after injury, this study examined the roles of VEGF-driven angiogenesis during growth plate bony repair. Histology analyses observed isolectin-B4-positive endothelial cells and blood vessel-like structures within the injury site on days 6 and 14, with anti-VEGF treatment significantly decreasing blood-vessel-like structures within the injury site (P<0.05). Compared with untreated controls, anti-VEGF treatment resulted in an increase in undifferentiated mesenchymal repair tissue, but decreased bony tissue at the injury site at day 14 (P<0.01). Consistently, microcomputed tomography analysis of the injury site showed significantly decreased bony repair tissue after treatment (P<0.01). RT-PCR analyses revealed a significant decrease in osteocalcin (P<0.01) and a decreasing trend in Runx2 expression at the injury site following treatment. Furthermore, growth plate injury-induced reduced tibial lengthening was more pronounced in anti-VEGF-treated injured rats on day 60, consistent with the observation of a significantly increased height of the hypertrophic zone adjacent to the growth plate injury site (P<0.05). These results indicate that VEGF is important for angiogenesis and formation of bony repair tissue at the growth plate injury site as well as for endochondral bone lengthening function of the uninjured growth plate.

scholarly journals Theobroma cacao improves bone growth by modulating defective ciliogenesis in a mouse model of achondroplasia

2021 ◽  
Author(s):  
L. Martin ◽  
N. Kaci ◽  
C. Benoist-Lasselin ◽  
M. Mondoloni ◽  
S. Decaudaveine ◽  
...  
Keyword(s):  
Mouse Model ◽  
Primary Cilium ◽  
Theobroma Cacao ◽  
Primary Cilia ◽  
Bone Growth ◽  
Ex Vivo ◽  
Growth Factor Receptor ◽  
Drug Candidates ◽  
Bone Elongation

AbstractA gain-of-function mutation in the fibroblast growth factor receptor 3 gene (FGFR3) results in achondroplasia (ACH), the most frequent form of dwarfism. The constitutive activation of FGFR3 impaired bone formation and elongation and many signaling transduction pathways. Identification of new and relevant compounds targeting the FGFR3 signaling pathway is of broad importance for the treatment of ACH. Natural plant compounds are the prime sources of drug candidates. Here, we found that the phenol compound (-)-epicatechin isolated from Theobroma cacao effectively inhibits FGFR3’s downstream signaling pathways. Transcriptomic analysis in Fgfr3 mouse model showed that ciliary mRNA expression was modified and influenced significantly by the Indian hedgehog and PKA pathways. (-)-Epicatechin is able to rescue impairments in the expression of these mRNA that control both the structural organization of the primary cilium and ciliogenesis-related genes. In femurs isolated from a mouse model (Fgfr3Y367C/+) of ACH, we showed that (-)-epicatechin countered the bone growth impairment during 6 days of ex vivo cultures. We confirmed in vivo that daily subcutaneous injections of (-)-epicatechin in Fgfr3Y367C/+ mice increased bone elongation and rescued the primary cilium defect observed in chondrocytes. This modification of the primary cilia promoted the typical columnar arrangement of flat proliferative chondrocytes and thus enhanced bone elongation. The results of the present proof-of-principle study illustrated (-)-epicatechin’s ability may facilitate the development of (-)-epicatechin as a treatment for patients with ACH.

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