OBJECTIVE: To investigate the effects of melatonin (MT) on bone mass and serum inflammatory factors in rats received ovariectomy (OVX) and to investigate the effects of MT on the levels of inflammatory factors in culture medium and osteogenic ability of bone marrow mesenchymal stem cells (BMSCs) stimulated by lipopolysaccharide. METHODS: Fifteen 12-week-old Sprague Dawley (SD) rats were randomly divided into 3 groups. The rats in Sham group only received bilateral lateral abdominal incision and suture, the rats in OVX group received bilateral OVX, and the rats in OVX+MT group received 100 mg/(kg·d) MT oral intervention after bilateral OVX. After 8 weeks, the levels of serum inflammatory factors [interleukin-1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α)] were detected using ELISA assay. Besides, the distal femurs were detected by Micro-CT to observe changes in bone mass and microstructure, and quantitatively measured bone volume fraction, trabecular thickness, and trabecular number. The BMSCs were extracted from the femurs of three 3-week-old SD rats using whole bone marrow culture method and passaged. The 3rd-5th passage BMSCs were cultured with different concentrations of MT (0, 1, 10, 100, 1 000 µmol/L), and the cell viability was then detected using cell counting kit 8 (CCK-8) to select the optimal concentration of MT for subsequent experiments. Cells were devided into osteogenic induction group (group A) and osteogenic induction+1/5/10 μg/mL lipopolysaccharide group (group B-D). The levels of inflammatory factors (IL-1β, IL-6 and TNF-α) in cell culture medium were detected using ELISA assay after corresponding intervention. According to the results of CCK-8 method and ELISA detection, the cells were intervened with the most significant concentration of lipopolysaccharide for stimulating inflammation and the optimal concentration of MT with osteogenic induction, defining as group E, and the cell culture medium was collected to detect the levels of inflammatory factors by ELISA assay. After that, alkaline phosphatase (ALP) staining and alizarin red staining were performed respectively in groups A, D, and E, and the expression levels of osteogenic related genes [collagen type Ⅰ alpha 1 chain (Col1a1) and RUNX family transcription factor 2 (Runx2)] were also detected by real time fluorescence quantitative PCR (RT-qPCR). RESULTS: ELISA and Micro-CT assays showed that compared with Sham group, the bone mass of the rats in the OVX group significantly decreased, and the expression levels of serum inflammatory factors (IL-1β, IL-6, and TNF-α) in OVX group significantly increased (P<0.05). Significantly, the above indicators in OVX+MT group were all improved (P<0.05). Rat BMSCs were successfully extracted, and CCK-8 assay showed that 100 µmol/L was the maximum concentration of MT that did not cause a decrease in cell viability, and it was used in subsequent experiments. ELISA assays showed that compared with group A, the expression levels of inflammatory factors (IL-1β, IL-6, and TNF-α) in the cell culture medium of groups B-D were significantly increased after lipopolysaccharide stimulation (P<0.05), and in a concentration-dependent manner. Moreover, the expression levels of inflammatory factors in group D were significantly higher than those in groups B and C (P<0.05). After MT intervention, the expression levels of inflammatory factors in group E were significantly lower than those in group D (P<0.05). ALP staining, alizarin red staining, and RT-qPCR assays showed that compared with group A, the percentage of positive area of ALP and alizarin red and the relative mRNA expressions of Col1a1 and Runx2 in group D significantly decreased, while the above indicators in group E significantly improved after MT intervention (P<0.05). CONCLUSION MT may affect the bone mass of postmenopausal osteoporosis by reducing inflammation in rats; MT can reduce the inflammation of BMSCs stimulated by lipopolysaccharide and weaken its inhibition of osteogenic differentiation of BMSCs.
Female ; Rats ; Animals ; Tumor Necrosis Factor-alpha ; Osteogenesis ; Rats, Sprague-Dawley ; Core Binding Factor Alpha 1 Subunit ; Melatonin/pharmacology* ; Interleukin-6/genetics* ; Lipopolysaccharides/pharmacology* ; Coloring Agents ; Inflammation

OBJECTIVES: To investigate the effect of recombinant human fibroblast growth factor 21 (rhFGF21) on the proliferation and mineralization of cementoblasts and its mechanism. METHODS: Hematoxylin eosin, immunohistochemical staining, and immunofluorescence were used to detect the expression and distribution of fibroblast growth factor 21 (FGF21) in rat periodontal tissues and cementoblasts (OCCM-30), separately. Cell Counting Kit-8 was used to detect the proliferation of OCCM-30 under treatment with rhFGF21. Alkaline phosphatase staining and Alizarin Red staining were used to detect the mineralization state of OCCM-30 after 3 and 7 days of mineralization induction. The transcription and protein expression of the osteogenic-related genes Runx2 and Osterix were detected by real-time quantitative polymerase chain reaction (PCR) and Western blot analysis. The expression levels of genes of transforming growth factor β (TGFβ)/bone morphogenetic protein (BMP) signaling pathway in OCCM-30 were detected through PCR array analysis. RESULTS: FGF21 was expressed in rat periodontal tissues and OCCM-30. Although rhFGF21 had no significant effect on the proliferation of OCCM-30, treatment with 50 ng/mL rhFGF21 could promote the mineralization of OCCM-30 cells after 7 days of mineralization induction. The transcriptional levels of Runx2 and Osterix increased significantly at 3 days of mineralization induction and decreased at 5 days of mineralization induction. Western blot analysis showed that the protein expression levels of Runx2 and Osterix increased during mineralization induction. rhFGF21 up-regulated Bmpr1b protein expression in cells. CONCLUSIONS rhFGF21 can promote the mineralization ability of OCCM-30. This effect is related to the activation of the TGFβ/BMP signaling pathway.
Humans ; Rats ; Animals ; Dental Cementum ; Core Binding Factor Alpha 1 Subunit/metabolism* ; Cell Differentiation ; Bone Morphogenetic Proteins/metabolism* ; Transforming Growth Factor beta/pharmacology*

OBJECTIVE: To construct a luciferase reporter gene vector carrying human nuclear factor of activated T cells 2 (NFATc2) gene promoter and examine the effects of metformin and lipopolysaccharide (LPS) on the transcriptional activity of NFATc2 gene. METHODS: The promoter sequence of human NFATc2 gene was acquired from UCSC website for PCR amplification. NFATc2 promoter fragment was inserted into pGL3-basic plasmid double cleaved with Kpn Ⅰ and Hind Ⅲ. The resultant recombinant plasmid pGL3-NFATC2-promoter was co-transfected with the internal reference plasmid pRL-TK in 293F cells, and luciferase activity in the cells was detected. Reporter gene vectors of human NFATc2 gene promoter with different fragment lengths were also constructed and assayed for luciferase activity. The changes in transcription activity of NFATc2 gene were assessed after treatment with different concentrations of metformin and LPS for 24 h. We also examined the effect of mutation in RUNX2-binding site in NFATC2 gene promoter on the regulatory effects of metformin and LPS on NFATc2 transcription. RESULTS: We successfully constructed pGL3-NFATc2-promoter plasmids carrying different lengths (2170 bp, 2077 bp, 1802 bp, 1651 bp, 1083 bp, 323 bp) of NFATc2 promoter sequences as verified by enzymatic digestion and sequencing. Transfection of 293F cells with the plasmid carrying a 1651 bp NFATc2 promoter (pGL3-1651 bp) resulted in the highest transcriptional activity of NFATc2 gene, and the luciferase activity was approximately 3.3 times that of pGL3-2170 bp (1.843 ± 0.146 vs 0.547 ± 0.085). Moderate (5 mmol/L) and high (10 mmol/L) concentrations of metformin significantly upregulated the transcriptional activity of pGL3-1651 bp by up to 2.5 and 3 folds, respectively. LPS at different doses also upregulated the transcriptional activity of pGL3-1651 bp by at least 1.6 folds. The mutation in the RUNX2 binding site on pGL3-1651 bp obviously reduced metformin- and LPS-induced enhancement of pGL3-1651bp transcription by 1.7 and 2 folds, respectively. CONCLUSION pGL3-NFATc2-promoter can be transcribed and activated in 293F cells, and LPS and metformin can activate the transcription of pGL3- NFATc2-promoter in a RUNX2-dependent manner.
Core Binding Factor Alpha 1 Subunit/genetics* ; Humans ; Lipopolysaccharides/pharmacology* ; Luciferases/genetics* ; Metformin/pharmacology* ; NFATC Transcription Factors/genetics* ; Promoter Regions, Genetic ; T-Lymphocytes ; Transcription, Genetic/drug effects* ; Transfection

OBJECTIVES: To explore the physicochemical characteristics and biocompatibility of calcium peroxide (CPO)-loaded polycaprolactone (PCL) microparticle. METHODS: The CPO/PCL particles were prepared. The morphology and elemental distribution of CPO, PCL and CPO/PCL particles were observed with scanning electron microscopy and energy dispersive spectroscopy, respectively. Rat adipose mesenchymal stem cells were isolated and treated with different concentrations (0.10%, 0.25%, 0.50%, 1.00%) of CPO or CPO/PCL particles. The mesenchymal stem cells were cultured in normal media or osteogenic differentiation media under the hypoxia/normoxia conditions, and the amount of released O₂ and H₂O₂ after CPO/PCL treatment were detected. The gene expressions of alkaline phosphatase (ALP), Runt-associated transcription factor 2 (RUNX2), osteopontin (OPN) and osteocalcin (OCN) were detected by realtime RT-PCR. SD rats were subcutaneously injected with 1.00% CPO/PCL particles and the pathological changes and infiltration of immune cells were observed with HE staining and immunohistochemistry at day 7 and day 14 after injection. RESULTS: Scanning electron microscope showed that CPO particles had a polygonal structure, PCL particles were in a small spherical plastic particle state, and CPO/PCL particles had a block-like crystal structure. Energy dispersive spectroscopy revealed that PCL particles showed no calcium mapping, while CPO/PCL particles showed obvious and uniform calcium mapping. The concentrations of O₂ and H₂O₂ released by CPO/PCL particles were lower than those of CPO group, and the oxygen release time was longer. The expressions of Alp, Runx2, Ocn and Opn increased with the higher content of CPO/PCL particles under hypoxia in osteogenic differentiation culture and normal culture, and the induction was more obvious under osteogenic differentiation conditions (all P<0.05). HE staining results showed that the muscle tissue fibers around the injection site were scattered and disorderly distributed, with varying sizes and thicknesses at day 7 after particle injection. Significant vascular congestion, widened gaps, mild interstitial congestion, local edema, inflammatory cell infiltration, and large area vacuolization were observed in some tissues of rats. At day 14 after microparticle injection, the muscle tissue around the injection site and the tissue fibers at the microparticle implantation site were arranged neatly, and the gap size was not thickened, the vascular congestion, local inflammatory cell infiltration, and vacuolization were significantly improved compared with those at day 7. The immunohistochemical staining results showed that the expressions of CD3 and CD68 positive cells significantly increased in the surrounding muscle tissue, and were densely distributed in a large area at day 7 after particle injection. At day 14 of microparticle injection, the numbers of CD3 and CD68 positive cells in peripheral muscle tissue and tissue at the site of particle implantation were lower than those at day 7 (all P<0.01). CONCLUSIONS CPO/PCL particles have good oxygen release activity, low damage to tissue, and excellent biocompatibility.
Rats ; Animals ; Osteogenesis ; Core Binding Factor Alpha 1 Subunit ; Rats, Sprague-Dawley ; Hydrogen Peroxide/pharmacology* ; Cell Differentiation ; Oxygen ; Hypoxia ; Cells, Cultured

OBJECTIVE: To investigate the effect of teriparatide on the differentiation of MC3T3-E1 cells in high-glucose microenvironment and explore the possible mechanism. METHODS: MC3T3-E1 cells cultured in normal glucose or high-glucose (25 mmol/L) medium were treated with 10 nmol/L teriparatide with or without co-treatment with H-89 (a PKA inhibitor). CCK-8 assay was used to detect the changes in cell proliferation, and cAMP content in the cells was determined with ELISA. Alkaline phosphatase (ALP) activity and mineralized nodules in the cells were detected using ALP kit and Alizarin red staining, respectively. The changes in cell morphology were detected by cytoskeleton staining. Real-time PCR was used to detect the mRNA expressions of PKA, CREB, RUNX2 and Osx in the treated cells. RESULTS: The treatments did not result in significant changes in proliferation of MC3T3-E1 cells (P > 0.05). Compared with the cells in routine culture, the cells treated with teriparatide showed significantly increased cAMP levels (P < 0.05) with enhanced ALP activity and increased area of mineralized nodules (P < 0.05). Teriparatide treatment also resulted in more distinct visualization of the cytoskeleton in the cells and obviously up-regulated the mRNA expressions of PKA, CREB, RUNX2 and Osx (P < 0.05). The opposite changes were observed in cells cultured in high glucose. In cells exposed to high glucose, treatment with teriparatide significantly increased cAMP levels (P < 0.05), ALP activity and the area of mineralized nodules (P < 0.05) and enhanced the clarity of the cytoskeleton and mRNA expressions of PKA, CREB, RUNX2 and Osx; the effects of teriparatide was strongly antagonized by co-treatment with H-89 (P < 0.05). CONCLUSION Teriparatide can promote osteoblast differentiation of MC3T3-E1 cells in high-glucose microenvironment possibly by activating the cAMP/PKA/CREB signaling pathway.
Cell Differentiation ; Core Binding Factor Alpha 1 Subunit ; Glucose/pharmacology* ; Osteoblasts/drug effects* ; RNA, Messenger ; Signal Transduction ; Teriparatide ; Animals ; Mice ; Cell Line

OBJECTIVE: To Investigate the effects of lithocholic acid (LCA) on the balance between osteogenic and adipogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). METHODS: Twelve 10-week-old SPF C57BL/6J female mice were randomly divided into an experimental group (undergoing bilateral ovariectomy) and a control group (only removing the same volume of adipose tissue around the ovaries), with 6 mice in each group. The body mass was measured every week after operation. After 4 weeks post-surgery, the weight of mouse uterus was measured, femur specimens of the mice were taken for micro-CT scanning and three-dimensional reconstruction to analyze changes in bone mass. Tibia specimens were taken for HE staining to calculate the number and area of bone marrow adipocytes in the marrow cavity area. ELISA was used to detect the expression of bone turnover markers in the serum. Liver samples were subjected to real-time fluorescence quantitative PCR (RT-qPCR) to detect the expression of key genes related to bile acid metabolism, including cyp7a1, cyp7b1, cyp8b1, and cyp27a1. BMSCs were isolated by centrifugation from 2 C57BL/6J female mice (10-week-old). The third-generation cells were exposed to 0, 1, 10, and 100 μmol/L LCA, following which cell viability was evaluated using the cell counting kit 8 assay. Subsequently, alkaline phosphatase (ALP) staining and oil red O staining were conducted after 7 days of osteogenic and adipogenic induction. RT-qPCR was employed to analyze the expressions of osteogenic-related genes, namely ALP, Runt-related transcription factor 2 (Runx2), and osteocalcin (OCN), as well as adipogenic-related genes including Adiponectin (Adipoq), fatty acid binding protein 4 (FABP4), and peroxisome proliferator-activated receptor γ (PPARγ). RESULTS: Compared with the control group, the body mass of the mice in the experimental group increased, the uterus atrophied, the bone mass decreased, the bone marrow fat expanded, and the bone metabolism showed a high bone turnover state. RT-qPCR showed that the expressions of cyp7a1, cyp8b1, and cyp27a1, which were related to the key enzymes of bile acid metabolism in the liver, decreased significantly ( P<0.05), while the expression of cyp7b1 had no significant difference ( P>0.05). Intervention with LCA at concentrations of 1, 10, and 100 μmol/L did not demonstrate any apparent toxic effects on BMSCs. Furthermore, LCA inhibited the expressions of osteogenic-related genes (ALP, Runx2, and OCN) in a dose-dependent manner, resulting in a reduction in ALP staining positive area. Concurrently, LCA promoted the expressions of adipogenic-related genes (Adipoq, FABP4, and PPARγ), and an increase in oil red O staining positive area. CONCLUSION After menopause, the metabolism of bile acids is altered, and secondary bile acid LCA interferes with the balance of osteogenic and adipogenic differentiation of BMSCs, thereby affecting bone remodelling.
Female ; Mice ; Animals ; Core Binding Factor Alpha 1 Subunit/pharmacology* ; PPAR gamma/metabolism* ; Steroid 12-alpha-Hydroxylase/metabolism* ; Mice, Inbred C57BL ; Cell Differentiation ; Osteogenesis ; Mesenchymal Stem Cells ; Bile Acids and Salts/pharmacology* ; Bone Marrow Cells ; Cells, Cultured ; Azo Compounds

OBJECTIVETo observe the effect of oxymatrine (OMT) on calcification of humans umbilical vein smooth muscle cells and its underlying mechanism.

METHODHuman umbilical vein smooth muscle cells (HUSMCs) were calcified by beta-giycerophos-phosphate (beta-GP) and then divided into 6 groups: the control group, the calcification group, the pure OMT group, and lower, middle and higher-dosage OMT groups. Cell calcification were observed by Von Kossa staining, calcium content in HUSMCs were determined by the colorimetric method, the alkaline phosphatase (ALP) activity in HUSMCs were determined by phenyl diphosphate-2-sodium, the osteocalcin (OC) level in HUSMCs were determined by radioimmunossay, the transforming growth factor-beta1 (TGF-beta1) level in HUSMC culture medium and the content changes in psmad2/3 and smad2/3 were determined by the ELISA method, and the expression of Core binding factor alpha1 (Cbfalpha1) protein in HUSMCs were determined by western blot method.

RESULTCompared with the control group, the calcification group showed a great number of black granules among the smooth muscle cells and significant increase in the content of calcium and OC and the activity of ALP; OMT intervention can decrease the content of calcium, OC, TGF-beta1, psmad2/3 and Cbfalpha1 and the activity of ALP. And high-dosage OMT group had better effect than middle and low-dosage groups.

CONCLUSIONOMT can effectively inhibit beta-GP-induced HUSMC calcification and its effect on reducing TGF-beta1, psmad2/3 and Cbfalpha1 may be one of its mechanisms in inhibiting HVSMC calcification.

Alkaline Phosphatase ; metabolism ; Alkaloids ; pharmacology ; Calcification, Physiologic ; drug effects ; Cells, Cultured ; Core Binding Factor Alpha 1 Subunit ; metabolism ; Human Umbilical Vein Endothelial Cells ; drug effects ; metabolism ; Humans ; Quinolizines ; pharmacology ; Radioimmunoassay ; Transforming Growth Factor beta1 ; metabolism

OBJECTIVETo investigate the probabilities of core-biding factor a1 (Cbfa1) expression by human skin fibroblasts induced in vitro.

METHODSThe fibroblasts were isolated, purified from human skin, and were grown in incubation in the media of TNF-alpha, BMP-2, and combined TNF-alpha and BMP-2 at certain concentrations, respectively. The changes in biological features of these fibroblasts correlated with osteogenesis were detected by immunohistochemistry and RT-PCR assay.

RESULTSTNF-alpha could switch phenotype of collagen in fibroblasts from Type I and III to Type I and induce fibroblasts to express Ras and BMP type I receptor (BMPR-IA). TNF-alpha in combination with BMP-2 could induce fibroblasts to express Cbfa1 and osteocalcin mRNA.

CONCLUSIONHuman skin fibroblast could be induced into pro-osteoblast expressing Cbfa1, an osteoblast-specific transcription factor and a regulation of osteoblast differentiation, and combined use of TNF-alpha and BMP-2 was one of the regulating factors.

Bone Morphogenetic Protein 2 ; Bone Morphogenetic Protein Receptors, Type I ; Bone Morphogenetic Proteins ; pharmacology ; Cells, Cultured ; Collagen ; biosynthesis ; Core Binding Factor Alpha 1 Subunit ; Core Binding Factors ; Fibroblasts ; metabolism ; Humans ; Neoplasm Proteins ; Osteocalcin ; biosynthesis ; Protein-Serine-Threonine Kinases ; biosynthesis ; RNA, Messenger ; analysis ; Receptors, Growth Factor ; biosynthesis ; Skin ; cytology ; Transcription Factors ; biosynthesis ; genetics ; Transforming Growth Factor beta ; Tumor Necrosis Factor-alpha ; pharmacology

OBJECTIVETo probe the effects of dexamethasone (DEX) combined with histone deacetylase (HDAC) inhibitor vorinostat on inhibiting proliferation and inducing differentiation and apoptosis in Kasumi-1 leukemia cells, and its possible mechanisms in order to provide a theoretical basis for the treatment of AML1-ETO positive AML.

METHODSThe cell survival, differentiation and apoptosis rates were tested by MTT or flow cytometry analysis after Kasumi-1 cells were treated by DMSO, DEX (20 nmol/L), vorinostat (1 μmol/L) or DEX (20 nmol/L) in combination with vorinostat (1 μmol/L). WB and IP-WB were performed to detect AML1-ETO and its ubiquitination.

RESULTSTreatment with the combination of DEX and vorinostat for 48 h led to statistically significant differences of inhibited proliferation [(42.06±8.20)%], increased differentiation [(52.83±8.97)%] and apoptosis [(52.92±2.53)%] of Kasumi-1 cells when compared with vorinostat [(33.82±9.41)%, (43.93±9.04)% and (42.98±3.01)%, respectively], DEX [(17.30±3.49)%, (22.53±4.51)% and (19.57±2.17)%, respectively] or control [(6.96±0.39)%, (21.73±2.03)% and (6.96±0.39)%, respectively]. Also significant ubiquitination and decreased AML1-ETO protein in Kasumi-1 cells after the combination treatment over single agent or control were observed.

CONCLUSIONThe results indicated that DEX and vorinostat could synergistically inhibit the Kasumi-1 cells proliferation, induce Kasumi-1 cells differentiation and apoptosis through ubiquitination and degradation of AML1-ETO.

Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Differentiation ; drug effects ; Cell Line, Tumor ; Core Binding Factor Alpha 2 Subunit ; metabolism ; Dexamethasone ; pharmacology ; Drug Synergism ; Humans ; Hydroxamic Acids ; pharmacology ; Oncogene Proteins, Fusion ; metabolism ; RUNX1 Translocation Partner 1 Protein ; Ubiquitination

OBJECTIVETo determine the activity of endoplasmic reticulum stress (ERS) and its effect on osteogenic differentiation of periodontal ligament stem cells (PDLSC) in inflammatory microenvironment.

METHODSPDLSC were obtained from the primary culture of the human tooth and cloned with limited diluted method. Real-time reverse transcription (RT)-PCR was used to examine the different expression of thapsigargin (TG) treated PDLSC and lipopolysaccharide (LPS) treated PDLSC. Real-time RT-PCR, alizarin red staining and cetyl pyridine chloride quantitative analyze were used to examine the osteogenic differentiation of PDLSC, TG + PDLSC, LPS + PDLSC and LPS + PDLSC + 4-PBA.

RESULTSProtein kinase receptor like endoplasmic reticulum kinase (PERK), glucose regulated protein 78 (GRP78), transcription activation factor 4(ATF4), CCAAT/enhancer-binding protein-homologous protein (CHOP) mRNA expression in group PDLSC + TG in 6 h were respectively 1.49 ± 0.24, 2.77 ± 0.60, 1.75 ± 0.16, 2.16 ± 0.32, which were all greater than that in group PDLSC (P < 0.05). PERK, CHOP mRNA expression reached the peak at 6 h (1.76 ± 0.08, 2.31 ± 0.17) and were greater than group PDLSC (P < 0.05). ERS could suppress osteogenic differentiation of TG + PDLSC and LPS + PDLSC. The runt-related transcription factor-2 (RUNX2), alkaline phosphatase (ALP), osteocalcin (OCN) mRNA expression of group TG + PDLSC was respectively 0.73 ± 0.06, 0.01 ± 0.00, 0.20 ± 0.06 (P < 0.05). The RUNX2, ALP, OCN mRNA expression of group LPS + PDLSC was respectively 0.80 ± 0.06, 0.48 ± 0.05, 0.29 ± 0.04 (P < 0.05). The RUNX2, ALP, OCN mRNA expression of group PDLSC + TG + 4-PBA was respectively 1.10 ± 0.09, 0.74 ± 0.05, 0.67 ± 0.13, which were greater higher than that of group LPS + PDLSC (P < 0.05).

CONCLUSIONSERS was activated in PDLSC and suppressed osteogenic differentiation of PDLSC, which can simulate inflammatory microenvironment in vitro. This effect can be recovered by using ERS inhibitor 4-PBA.

Alkaline Phosphatase ; metabolism ; Butylamines ; pharmacology ; Cell Differentiation ; Cellular Microenvironment ; Core Binding Factor Alpha 1 Subunit ; metabolism ; Endoplasmic Reticulum Stress ; physiology ; Humans ; Osteocalcin ; metabolism ; Osteogenesis ; Periodontal Ligament ; cytology ; metabolism ; Polysaccharides ; pharmacology ; RNA, Messenger ; metabolism ; Stem Cells ; drug effects ; physiology ; Thapsigargin ; pharmacology