OBJECTIVE: To compare the effects of different concentrations of linolenin on inhibiting apoptosis of chondrocytes in the growth plate, and to screen the optimal concentration of linolenin, so as to provide theoretical support for delaying epiphyseal closure and promoting long bone growth in rats. METHODS: Two 4-week-old male SD rats (SPF grade) with a body mass of 80 g were selected. The growth plate cartilage of rat tibia and femur was dissected and isolated in vitro to obtain growth plate chondrocytes for culture. The chondrocytes were observed and identified by inverted phase contrast microscope and typeⅡ collagen immunofluorescence test, and then 20 ng/ml IL-1β was used to induce apoptosis of growth plate chondrocytes as model group, and added with 1, 10, 20, 40 μM linolenin as the experimental group, and 5 μM letrozole as the positive control group. The cells were cultured for 24 and 48 hours respectively. The drug promoted cell proliferation was observed by MTT method, and the drug inhibited cell apoptosis was detected by flow cytometry. RESULTS: Contents 1, 10, 20, 40 μM could promote cell proliferation in varying degrees, and the principle was that the drug inhibits IL-1β induced chondrocyte apoptosis in the growth plate, and the optimal concentration of drugs to inhibit apoptosis was 20 μM. CONCLUSION The appropriate concentration of linseed lignans can significantly inhibit the apoptosis of chondrocytes in the growth plate of rats, and the optimal drug concentration is 20 μM. It provides possibility for delayed bone closure and longer growth time to promote bone growth during development.
Male ; Rats ; Animals ; Growth Plate ; Chondrocytes ; Flax ; Rats, Sprague-Dawley ; Apoptosis ; Lignans/pharmacology*

OBJECTIVE: To investigate the effects of continuous pumping of teriparatide (TPTD) on bone metabolism in ovariectomized and normal mice and provide experimental evidence for the selection of animal models for studying the effects of TPTD and its related peptides on osteoclasts. METHODS: Twenty-four female C57BL mice (6-weeks old) were subjected to ovariectomy (OVX) or sham operation followed 7 days later by continuous pumping of TPTD or the solvent vehicle (VEH) a micropump (SHAM-VEH, SHAM-TPTD, OVX-VEH, and OVX-TPTD groups; =6). Two weeks later, the tibial and femoral bones were harvested for micro-CT scanning to measure the parameters of the tibia and the femoral cortical bone. Histopathological examinations of the tibial tissue were conducted using HE staining and TRAP staining and the number of osteoclasts and the growth plate thickness were determined. The serum Ca2 + levels of the mice were measured. The primary osteoblasts from the cranial bone were treated with estradiol (E2) and TPTD for 48 h, and the expressions of β-catenin and RANKL protein in the cells were analyzed. RESULTS: The trabecular bone mass of OVX mice was significantly lower than that of sham-operated mice ( < 0.05). Continuous TPTD pumping significantly reduced tibial cancellous bone mass and femoral cortical bone area in the sham-operated mice, while in the castrated mice, TPTD pumping increased the cancellous bone mass without changing the cortical bone area. TRAP staining showed that cancellous osteoblasts in the tibia increased significantly in the castrated mice as compared with the sham-operated mice, and TPTD pumping significantly increased the number of cancellous osteoblasts in the sham-operated mice ( < 0.05). In the primary cultured osteoblasts, treatment with both E2 and TPTD obviously lowered the expression of β-catenin and increased the expression of RANKL as compared with TPTD treatment alone. CONCLUSIONS Continuous pumping of TPTD promotes bone resorption in normal mice but does not produce obvious bone resorption effect in the ovariectomized mice, suggesting that castrated mice are not suitable models for studying the effect of TPTD and the related peptides on the osteoclasts.
Animals ; Bone Density ; Bone Density Conservation Agents ; administration & dosage ; pharmacology ; Bone Resorption ; drug therapy ; Bone and Bones ; drug effects ; metabolism ; Female ; Growth Plate ; drug effects ; Mice ; Mice, Inbred C57BL ; Osteoclasts ; drug effects ; Ovariectomy ; RANK Ligand ; metabolism ; Teriparatide ; administration & dosage ; pharmacology ; beta Catenin ; metabolism

Linear growth occurs at the growth plate. Therefore, genetic defects that interfere with the normal function of the growth plate can cause linear growth disorders. Many genetic causes of growth disorders have already been identified in humans. However, recent genome-wide approaches have broadened our knowledge of the mechanisms of linear growth, not only providing novel monogenic causes of growth disorders but also revealing single nucleotide polymorphisms in genes that affect height in the general population. The genes identified as causative of linear growth disorders are heterogeneous, playing a role in various growth-regulating mechanisms including those involving the extracellular matrix, intracellular signaling, paracrine signaling, endocrine signaling, and epigenetic regulation. Understanding the underlying genetic defects in linear growth is important for clinicians and researchers in order to provide proper diagnoses, management, and genetic counseling, as well as to develop better treatment approaches for children with growth disorders.
Child ; Diagnosis ; Epigenomics ; Extracellular Matrix ; Genetic Counseling ; Genome-Wide Association Study ; Growth Disorders ; Growth Plate ; Humans ; Paracrine Communication ; Polymorphism, Single Nucleotide

BACKGROUND AND OBJECTIVES: Mesenchymal stem cells (MSCs) become hypertrophic in long term despite chondrogenic differentiation following the pathway of growth plate chondrocytes. This terminal differentiation leads to phenotypically unstable cartilage and was mirrored in vitro by addition of hypertrophy inducing medium. We investigated how intrinsic TGF-β signaling is altered in pro-hypertrophic conditions. METHODS AND RESULTS: Human bone marrow derived MSC were chondrogenically differentiated in 3D culture. At day 14 medium conditions were changed to 1. pro-hypertrophic by addition of T3 and withdrawal of TGF-β and dexamethasone 2. pro-hypertrophic by addition of BMP 4 and withdrawal of TGF-β and dexamethasone and 3. kept in prochondrogenic medium conditions. All groups were treated with and without TGFβ-type-1-receptor inhibitor SB431542 from day 14 on. Aggregates were harvested for histo- and immunohistological analysis at d14 and d28, for gene expression analysis (rt-PCR) on d1, d3, d7, d14, d17, d21 and d28 and for Western blot analysis on d21 and d28. Induction of hypertrophy was achieved in the pro-hypertrophic groups while expression of TGFβ-type-1- and 2-receptor and Sox 9 were significantly downregulated compared to pro-chondrogenic conditions. Western blotting showed reduced phosphorylation of Smad 2 and 3 in hypertrophic samples, reduced TGF-β-1 receptor proteins and reduced SOX 9. Addition of SB431542 did not initiate hypertrophy under pro-chondrogenic conditions, but was capable of enhancing hypertrophy when applied simultaneously with BMP-4. CONCLUSIONS: Our results suggest that the enhancement of hypertrophy in this model is a result of both activation of pro-hypertrophic BMP signaling and reduction of anti-hypertrophic TGFβ signaling.
Blotting, Western ; Bone Marrow ; Cartilage ; Chondrocytes ; Chondrogenesis ; Dexamethasone ; Down-Regulation ; Gene Expression ; Growth Plate ; Humans ; Hypertrophy ; In Vitro Techniques ; Mesenchymal Stromal Cells ; Phosphorylation

PURPOSE: This pilot study assessed changes in the growth plate and growth rates in children during a 6-month period. METHODS: The study included 31 healthy children (17 boys, 14 girls) under evaluation for growth retardation. Height, weight, bone age, insulin like growth factor-1 (IGF-1), and insulin like growth factor binding protein 3 (IGF-BP3) were measured at baseline and after 6 months. In addition, the diameter, thickness, and volume of the femoral and tibial growth plates were measured using magnetic resonance imaging. RESULTS: The mean bone age in boys and girls was 11.7 and 10.7 years, respectively. In boys, height (z score) (−0.2 vs. 0.0), weight (z score) (0.8 vs. 1.1), body mass index (BMI) (z score) (1.27 vs. 1.5), IGF-1 (ng/mL) (343.6 vs. 501.8), and IGF-BP3 (ng/mL) (5,088.5 vs. 5,620.0) were significantly higher after 6 months. In girls, height (z score) (−1.0 vs. −0.7), weight (z score) (−0.5 vs. 0.1), BMI (z score) (−0.02 vs. 0.3), IGF-1 (ng/mL) (329.3 vs. 524.6), and IGF-BP3 (ng/mL) (4,644.4 vs. 5,593.6) were also significantly higher after 6 months. In both sexes, the mean diameter and volume of the femoral and tibial growth plates were significantly increased 6 months later. CONCLUSION: No significant correlation was found between changes in the growth plate and clinical parameters in children with growth retardation in this study, other than correlations of change in femoral diameter with weight and BMI. A larger, long-term study is needed to precisely evaluate the correlation between change in the growth plate and growth.
Body Mass Index ; Carrier Proteins ; Child* ; Female ; Growth Plate* ; Humans ; Insulin ; Insulin-Like Growth Factor I ; Magnetic Resonance Imaging* ; Pilot Projects

PURPOSE: Growth hormone secretagogues (GHSs) possess the ability to release growth hormone (GH) in the body. This study aimed to investigate the effects of MK-677, an orally active GHS, on somatic growth in rats. MATERIALS AND METHODS: The serum levels of GH were measured after oral administration of MK-677 to confirm GH stimulatory effects. Body weight, body length, tibia length, epiphyseal plate width, and serum levels of insulin-like growth factor (IGF)-I were measured after oral administration of 4 mg/kg of MK-677 for 6 weeks to investigate growth-promoting effects. RESULTS: Oral administration of MK-677 at 4 mg/kg increased peak GH concentrations by 1.8-fold, compared to baseline. However, oral administration of MK-677 for 6 weeks did not increase body growth or serum levels of IGF-I. At 6 weeks after treatment, the GH response to MK-677 was abolished. Pituitary GH mRNA and hypothalamic GH-releasing hormone mRNA, and GH secretagogue receptor (GHSR) mRNA expression in the pituitary and hypothalamus did not differ between the control and treatment group. Somatostatin (SST) mRNA expression in the hypothalamus was markedly increased in the treatment group, whereas SST receptor (SSTR)-2 mRNA expression in the pituitary gland was decreased. Protein expression of hypothalamic GHSR, SST, and pituitary SSTR-2 showed patterns similar to those for mRNA expression. CONCLUSION: Our results suggest that prolonged administration of MK-677 in rats does not promote growth despite the GH stimulatory effect of MK-677, which may be related to increased expression of SST in the hypothalamus. Further studies are needed to overcome the observed desensitization to GHS.
Administration, Oral ; Animals ; Body Weight ; Growth Hormone* ; Growth Plate ; Hypothalamus ; Insulin-Like Growth Factor I ; Pituitary Gland ; Rats* ; RNA, Messenger ; Somatostatin ; Tibia

Tibial dyschondroplasia (TD) cases has not been reported in Tibetan chickens (TBCs), but it is commonly seen in commercial broilers characterized by lameness. The underlying mechanism remains unclear. Hypoxia-inducible factors (HIFs) are important regulators of cellular adaptation to hypoxic conditions. In this study, we investigated the role of HIF-1α,
Anoxia ; Blotting, Western ; Chickens ; Growth Plate ; Osteochondrodysplasias ; Poultry ; Reverse Transcriptase Polymerase Chain Reaction ; RNA ; Thiram

Aggrecan is a proteoglycan in the extracellular matrix of growth plate and cartilaginous tissues. Aggrecanopathy has been reported as a genetic cause not only for severe skeletal dysplasia but also for autosomal dominant short stature with normal to advanced bone age. We report a novel heterozygous mutation of ACAN in a Korean family with proportionate short stature identified through targeted exome sequencing. We present a girl of 4 years and 9 months with a family history of short stature over three generations. The paternal grandmother is 143 cm tall (−3.8 as a Korean standard deviation score [SDS]), the father 155 cm (−3.4 SDS), and the index case 96.2 cm (−2.9 SDS). Evaluation for short stature showed normal growth hormone (GH) peaks in the GH provocation test and a mild delayed bone age for chronological age. This subject had clinical characteristics including a triangular face, flat nasal bridge, prognathia, blue sclerae, and brittle teeth. The targeted exome sequencing was applied to detect autosomal dominant growth palate disorder. The novel variant c.910G>A (p.Asp304Asn) in ACAN was identified and this variant was found in the subject's father using Sanger sequencing. This is the first case of Korean familial short stature due to ACAN mutation. ACAN should be considered for proportionate idiopathic short stature, especially in cases of familial short stature.
Aggrecans ; Exome ; Extracellular Matrix ; Family Characteristics ; Fathers ; Female ; Grandparents ; Growth Hormone ; Growth Plate ; Humans ; Palate ; Proteoglycans ; Sclera ; Tooth

Post-menopausal osteoporosis (PMO) is a major global human health concern. Owing to the need for therapeutic drugs without side effects, natural extracts containing various polyphenolic compounds that may exert estrogenic effects have been studied in depth. Rhus verniciflua Stokes (RVS), which has been used as a traditional herbal medicine for centuries in Korea, was recently revealed to exert estrogenic effects attributable to its bioactive ingredients sulfuretin and butein, which have strong estrogen receptor–binding affinities. In this study, the protective potential of RVS in PMO was evaluated by using an experimental animal model of PMO, which was established by ovariectomy (OVX) of female Sprague Dawley rats. The oral administration of RVS at 20 mg/kg or 100 mg/kg for 8 weeks markedly protected against OVX-induced atrophy of the uterine tube and reversed the elevation in the ratio of serum receptor activator of nuclear factor-κB ligand to osteoprotegerin, which is a marker of disease severity. In addition, RVS inhibited OVX-induced tibia bone loss, activated osteogenic activity, and suppressed osteoclastic activity in the tibial epiphyseal plate, a region of bone remodeling. Collectively, these factors indicated that the oral intake of RVS might be beneficial for the prevention of PMO.
Administration, Oral ; Atrophy ; Bone Remodeling ; Estrogens ; Fallopian Tubes ; Female ; Growth Plate ; Herbal Medicine ; Humans ; Korea ; Models, Animal ; Models, Theoretical* ; Osteoclasts ; Osteoporosis, Postmenopausal* ; Osteoprotegerin ; Ovariectomy ; Rats, Sprague-Dawley ; Rhus* ; Tibia

Traditionally, the growth hormone – insulin-like growth factor I (GH – IGF-I) axis is the most important signaling pathway in linear growth, and defects in this axis present as growth hormone deficiencies or IGF-I deficiencies. However, subtle changes in serum levels of GH or IGF-I, caused by gene mutations involved in the GH – IGF-I axis, can present as idiopathic short stature (ISS). This paper briefly discusses GHR and IGFALS. In addition, recent studies have shown that many factors, including paracrine signals, extracellular matrix, and intracellular mechanisms of chondrocytes, regulate the growth plate independent of the GH – IGF-I system. Rapid development of diagnostic technologies has enabled discovery of many genetic causes of ISS. This paper discusses 5 genes, SHOX, NPR2, NPPC, FGFR3, and ACAN, that may lead to better understanding of ISS.
Chondrocytes ; Extracellular Matrix ; Growth Hormone ; Growth Plate ; Insulin-Like Growth Factor I