X-linked hypophosphatemia (XLH) is a rare disease of elevated fibroblast growth factor 23 (FGF23) production that leads to hypophosphatemia and impaired mineralization of bone and teeth. The clinical manifestations of XLH include a high prevalence of dental abscesses and periodontal disease, likely driven by poorly formed structures of the dentoalveolar complex, including the alveolar bone, cementum, dentin, and periodontal ligament. Our previous studies have demonstrated that sclerostin antibody (Scl-Ab) treatment improves phosphate homeostasis, and increases long bone mass, strength, and mineralization in the Hyp mouse model of XLH. In the current study, we investigated whether Scl-Ab impacts the dentoalveolar structures of Hyp mice. Male and female wild-type and Hyp littermates were injected with 25 mg·kg^-1 of vehicle or Scl-Ab twice weekly beginning at 12 weeks of age and euthanized at 20 weeks of age. Scl-Ab increased alveolar bone mass in both male and female mice and alveolar tissue mineral density in the male mice. The positive effects of Scl-Ab were consistent with an increase in the fraction of active (nonphosphorylated) β-catenin, dentin matrix protein 1 (DMP1) and osteopontin stained alveolar osteocytes. Scl-Ab had no effect on the mass and mineralization of dentin, enamel, acellular or cellular cementum. There was a nonsignificant trend toward increased periodontal ligament (PDL) attachment fraction within the Hyp mice. Additional PDL fiber structural parameters were not affected by Scl-Ab. The current study demonstrates that Scl-Ab can improve alveolar bone in adult Hyp mice.
Mice ; Male ; Female ; Animals ; Familial Hypophosphatemic Rickets/metabolism* ; Bone and Bones/metabolism* ; Tooth/metabolism* ; Periodontal Ligament/metabolism*

OBJECTIVETo investigate the effects of 17beta-estradiol on the expression of alkaline phosphatase (ALP) and osteoprotegerin in human periodontal ligament cells.

METHODSHuman periodontal ligament cells (hPDLC) were obtained from periodontal tissue explants of teeth extracted for orthodontic treatment ALP activity was determined by PNPP, and OPG protein and corresponding mRNA levels were quantitatively detected by ELISA and RT-PCR RESULTS: ALP activity was significantly increased at 14 days and 21 days (P <0.05). 17beta-E2 of physiological concentration promoted secretion of OPG protein and expression of OPG mRNA (P <0.05). 17beta-E2 with high-dose showed no effect on OPG protein secretion and decrease OPG mRNA expression.

CONCLUSIONS17beta-E2 may have a positive impact on periodontium through promoting expression of ALP and OPG in hPDLC.

Alkaline Phosphatase ; metabolism ; Cells, Cultured ; Estradiol ; pharmacology ; Humans ; Osteoprotegerin ; metabolism ; Periodontal Ligament ; cytology ; drug effects ; metabolism

OBJECTIVETo study the integrin beta1 mRNA changes after orthodontic tooth movement in normal teeth and periodontitis teeth of rats.

METHODSThe OD of positively stained osteoclasts for integrin beta1 mRNA using in situ hybridzation was detected after orthodontic tooth movement in normal teeth and periodontitis teeth groups.

RESULTSIntegrin beta1 mRNA expression were detected on all osteoclasts in tooth movement samples of normal and periodontitis teeth. There were stronger positive signals after given orthodontic force in both of the two groups. But no differences were found after 0.5, 1, 2, 3, 5, 7, 10 days since orthodontic tooth movement. The integrin beta1 mRNA signals in normal tooth movement group were not different from that in periodontitis group.

CONCLUSIONThe integrin beta1 of osteoclasts may play a role in the stability and remodeling of periodontal ligament in orthodontic tooth movement. There were no difference in the OD of integrin beta1 mRNA staining in orthodontic tooth movement between normal teeth group and periodontitis teeth group.

Animals ; Integrin beta1 ; metabolism ; Osteoclasts ; Periodontal Ligament ; Periodontitis ; physiopathology ; RNA, Messenger ; metabolism ; Rats ; Tooth Movement Techniques

OBJECTIVES: This work aimed to investigate the molecular mechanism of cyclic tensile stress (CTS) stimulating autophagy in human periodontal ligament cells (hPDLCs). METHODS: hPDLCs were isolated and cultured from normal periodontal tissues. hPDLCs were loaded with tensile stress by force four-point bending extender to simulate the autophagy of hPDLCs induced by orthodontic force du-ring orthodontic tooth movement. XMU-MP-1 was used to inhibit the Hippo signaling pathway to explore the role of the Hippo-YAP signaling pathway in activating hPDLC autophagy by tensile stress. The expression levels of autophagy-related genes (Beclin-1, LC3, and p62) in hPDLCs were detected by real-time quantitative polymerase chain reaction. Western blot was used to detect the expression levels of autophagy-related proteins (Beclin-1, LC3-Ⅱ/LC3-Ⅰ, and p62) and Hippo-YAP pathway proteins (active-YAP and p-YAP) in hPDLCs. Immunofluorescence was used to locate autophagy-related proteins (LC3-Ⅱand p62) and Hippo-YAP pathway proteins (active-YAP) of hPDLCs. RESULTS: CTS-activated autophagy in hPDLCs and expression of autophagy-related proteins initially increased and then decreased; it began to increase at 30 min, peaked at 3 h, and decreased (P<0.05). CTS increased the expression of active-YAP protein and decreased the expression of p-YAP protein (P<0.05). When XMU-MP-1 inhibited the Hippo-YAP signaling pathway (P<0.05), active-YAP protein was promoted to enter the nucleus and autophagy expression was enhanced (P<0.05). CONCLUSIONS The Hippo-YAP signaling pathway is involved in the regulation of autophagy activation in hPDLCs under CTS.
Humans ; Hippo Signaling Pathway ; Periodontal Ligament/metabolism* ; Beclin-1/metabolism* ; Cells, Cultured ; Autophagy

OBJECTIVETo investigate the influence of high mobility group box 1 (HMGB1) on the expression of interleukin 6 (IL-6), receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG) on periodontal ligament fibroblasts.

METHODSHuman periodontal ligament fibroblasts were stimulated with HMGB1 at concentrations of 10, 30, and 100 ng x mL(-1) for 24 h. RT-PCR and Western blot analysis were performed to check mRNA and protein expression of IL-6, RANKL and OPG on the cells.

RESULTSThe ratio of RANKL/OPG was increased at both mRNA and protein level after HMGB1 stimulation at 10, 30, 100 ng x mL(-1). Inflammatory cytokine IL-6 was upregulated by HMGB1 at the concentration of 100 ng x mL(-1).

CONCLUSIONIncreased ratio of RANKL/OPG and IL-6 on periodontal ligament fibroblasts suggests that HMGB1 might play a role in the pathogenesis and progression of periodontal disease.

Cells, Cultured ; Fibroblasts ; metabolism ; HMGB1 Protein ; metabolism ; Humans ; Interleukin-6 ; metabolism ; Osteoprotegerin ; metabolism ; Periodontal Ligament ; cytology ; RANK Ligand ; metabolism

Magnetic attachments have flux leakages, thus they will exert certain magnetic fields on the adjacent tissues when used in the patients' oral cavities. There are few research reports on the biological effects of the magnetic fields generated by magnetic attachments on human body. A cellular static magnetic field (SMF) loading system was developed in this study. By using this system, in vitro cultured human periodontal ligament cells (HPDLCs) were loaded with SMF simulating those of magnetic attachments. The cellular SMF loading system could produce constant SMF and the strength of the SMF is adjustable. The system is small and is able to exert SMF to cells cultured in different culture vessels such as culture dishes and culture plates, thus is suitable to researches in multiple biological items of cells. The results of the SMF loading experiment on HPDLCs showed that this cellular SMF loading system could effectively load cells with SMF of different strengths for different time in vitro. The development of this system has provided a useful tool for the researches on the cellular hiologioal effects of SMF.
Cells, Cultured ; Electromagnetic Fields ; adverse effects ; Humans ; Magnetics ; Periodontal Ligament ; cytology ; metabolism ; radiation effects

Epigenetics is defined as a change in gene expression without the alteration of the genetic sequence. Such a change would be inherited by offspring. Histone acetylation is a type of epigenetics. Existing studies proposed that chronic periodontitis is related to epigenetic modification. In this review, we summarised the influence of chronic periodontitis on periodontal ligament stem cells by histone acetylation.
Acetylation ; Cell Differentiation ; Cells, Cultured ; Histones ; metabolism ; Osteogenesis ; Periodontal Ligament ; Stem Cells ; physiology

Many studies has been conducted concerning prevention of unnecessary complications such as root resorption during orthodontic tooth movement under various mechanical forces. Nowadays, the cause of the root resorption is not thought to be confined only to mechanical forces. But the factor that affects bone metabolism are thought to be major one of the predisposing factors. The light microscope and scanning electron microscope were used to the effects of 60gm, and 100gm of tipping force on root resorption of cats, which were treated with Etidronate disodium. The results were as follows: 1. In the 60gm control group, hyalinization on the compression site of periodontal ligament appeared after first week and second week. In the 60gm experimental group, it appeared after first week with low frequency. In the 100gm control group it appeared with high frequency by first and second week while in 100gm experimental group, it appeared with low frequency. 2. In the 100gm control group, resorption of the cementum and the alveolar bone rapidly increased after second week. In the 60gm experimental group, resorption or formation of alveolar bone and cementum didn't appear all through the experimental period. 3. In the 100gm control group. formation of cementum and alveolar bone appeared after first week while in the 100gm experimental group, formation of cementum and alveolar bone appeared after second week and fourth week respectively. In the 60gm control group, formation of the cementum didn't appear all through the experimental period. 4. In the control group, the root resorption of 100gm group was higher than that of 60gm group after second week, while in experimental group, root resorption didn't appear regardless of the forces.
Animals ; Cats ; Causality ; Dental Cementum ; Etidronic Acid* ; Hyalin ; Metabolism ; Periodontal Ligament ; Root Resorption* ; Tooth Movement* ; Tooth*

Platelet-derived growth factor(PDGF) and lipopolysaccharide(LPS) may be the important regualtors of bone metabolism. Exogenous PDGF is recognized to have a stimulating effect on bone resorption in organ culture, but to stimulate the formation of new bone ultimately. LPS is known to be a stimulating agent on the osteoclastic activity. The purpose of this study was to evaluate the effects and the interaction of PDGF and LPS on periodontal ligament(PDL) cells which have important roles in bone remodeling. Cultured human periodontal ligament cells were treated with various concentration of PDGF and/or LPS. The cellular viability was measured by Microtitration(MTT) assay according to the lapse time of culture. The obtained results were as follows: 1. The viability of PDL cells was not different from the control in O.lng/ml of PDGF, but was significantly increased to be over the level of control in lng/ml of PDGF at the second day of culture, and in lOng/ml of PDGF at the second and the third day of culture. 2. The cellular viability was decreased in O.5microgram/ml or 5microgram/ml of LPS at the third day of culture. 3. Incubation with both 1ng/ml or 10ng/ml of PDGF and 0.5microgram/ml or 5microgram/ml of LPS resulted in the increased cellular viability at the third day, which. was greater than LPS only treated group. It was greater than even the control group in lOng/ml of PDGF. From the above findings, we could summarize that the admixture of PDGF and LPS could not less increase the viability of the human periodontal ligament cells than PDGF only.
Bone Remodeling ; Bone Resorption ; Humans* ; Metabolism ; Organ Culture Techniques ; Osteoclasts ; Periodontal Ligament*

OBJECTIVES: The expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-κB ligand (RANKL) in human periodontal ligament cells (HPDLCs) was investigated by cell culture under continuous static pressure. METHODS: HPDLCs were primarily cultured by tissue explant method and divided into three groups: group A (13-18 years old), group B (19-29 years old), and group C (30-44 years old). CCK-8 was used to detect the proliferation of HPDLCs. The senescence of HPDLCs was detected by senescence-associated β-galactosidase staining. Cells in the three groups were respectively given 0, 1.5, 3, 6, 12, 24, 48, and 72 h of continuous static pressure in vitro. The expression of OPG and RANKL in the supernatant was detected by enzyme-linked immunosorbent assay. RESULTS: After continuous static pressure in vitro for stimulation, the expression of OPG and RANKL changed. The expression of OPG increased with time and age (P<0.01). The expression of RANKL increased with time and decreased with age (P<0.01). The ratio of OPG/RANKL initially decreased, increased with time, and then continued to rise with age (P<0.01). CONCLUSIONS Aging could increase the expression of OPG and the ratio of OPG/RANKL and decrease the expression of RANKL in HPDLCs under continuous static pressure in vitro.
Humans ; Adolescent ; Young Adult ; Adult ; Osteoprotegerin ; RANK Ligand/pharmacology* ; Periodontal Ligament/metabolism* ; Cells, Cultured ; Aging