DPSCs regulate epithelial-T cell interactions in oral submucous fibrosis.

BACKGROUND: Oral submucous fibrosis (OSF) is a precancerous lesion characterized by fibrous tissue deposition, the incidence of which correlates positively with the frequency of betel nut chewing. Prolonged betel nut chewing can damage the integrity of the oral mucosal epithelium, leading to chronic inflammation and local immunological derangement. However, currently, the underlying cellular events driving fibrogenesis and dysfunction are incompletely understood, such that OSF has few treatment options with limited therapeutic effectiveness. Dental pulp stem cells (DPSCs) have been recognized for their anti-inflammatory and anti-fibrosis capabilities, making them promising candidates to treat a range of immune, inflammatory, and fibrotic diseases. However, the application of DPSCs in OSF is inconclusive. Therefore, this study aimed to explore the pathogenic mechanism of OSF and, based on this, to explore new treatment options. METHODS: A human cell atlas of oral mucosal tissues was compiled using single-cell RNA sequencing to delve into the underlying mechanisms. Epithelial cells were reclustered to observe the heterogeneity of OSF epithelial cells and their communication with immune cells. The results were validated in vitro, in clinicopathological sections, and in animal models. In vivo, the therapeutic effect and mechanism of DPSCs were characterized by histological staining, immunohistochemical staining, scanning electron microscopy, and atomic force microscopy. RESULTS: A unique epithelial cell population, Epi1.2, with proinflammatory and profibrotic functions, was predominantly found in OSF. Epi1.2 cells also induced the fibrotic process in fibroblasts by interacting with T cells through receptor-ligand crosstalk between macrophage migration inhibitory factor (MIF)-CD74 and C-X-C motif chemokine receptor 4 (CXCR4). Furthermore, we developed OSF animal models and simulated the clinical local injection process in the rat buccal mucosa using DPSCs to assess their therapeutic impact and mechanism. In the OSF rat model, DPSCs demonstrated superior therapeutic effects compared with the positive control (glucocorticoids), including reducing collagen deposition and promoting blood vessel regeneration. DPSCs mediated immune homeostasis primarily by regulating the numbers of KRT19 + MIF + epithelial cells and via epithelial-stromal crosstalk. CONCLUSIONS: Given the current ambiguity surrounding the cause of OSF and the limited treatment options available, our study reveals that epithelial cells and their crosstalk with T cells play an important role in the mechanism of OSF and suggests the therapeutic promise of DPSCs.

[A study on quality of life and related factors among HIV-infected men who have sex with men based on latent profile analysis].

Objectives: To investigate the potential classification of quality of life in HIV-infected men who have sex with men (HIV-infected MSM) and to analyze possible influencing factors of different categories. Methods: A questionnaire survey was conducted among HIV-infected MSM who received antiretroviral treatment (ART) in an infectious disease hospital in Ji'nan, Shandong Province from October to December 2020. The quality of life scores in six domains were analyzed by latent profile analysis (LPA), and possible related factors of potential classification were explored by ordinal logistic regression analysis. Results: A total of 584 HIV-infected MSM were included in this study. LPA divided their quality of life into three categories, named low score, medium score and high score groups, accounting for 34.4% (201/584), 49.8% (291/584), and 15.8% (92/584), respectively. Multivariate ordinal logistic regression analysis showed that age above 40 years (aOR=1.77, 95%CI:1.11-2.80), monthly average income of 3 000 Yuan and below (aOR=3.15, 95%CI:1.72-5.76), monthly average income of 3 001-5 000 Yuan (aOR=2.26, 95%CI:1.41-3.62), distance to the hospital to receive drugs farer than 40 kms (aOR=1.76, 95%CI:1.07-2.89), and adverse reactions after taking drugs (aOR=2.31, 95%CI:1.65-3.23) were factors associated with low level of quality of life. Conclusions: The qualities of life of HIV-infected MSM showed group heterogeneity and were at high levels. Attention should be focused on HIV-infected MSM who are at older age, with low income, and long distance to access the health facilities. The measures should be taken to reduce the adverse reactions of ART drugs and improve the quality of life.

[Correlation between alcohol drinking and high risk sexual behaviors in HIV negative clients of female sex workers].

Objective: To explore the correlation between alcohol drinking and high-risk sexual behaviors in HIV negative clients of female sex workers and provide scientific evidence for prevention of HIV sexual transmission. Methods: A cross-sectional survey was conducted in HIV negative clients in Ji'nan and Haikou from December 2018 to May 2019. The estimated sample size was 337, the information about their demographic characteristics, AIDS knowledge awareness, sexual behaviors and alcohol drinking habit were collected through convenience sampling. The data were analyzed by using SPSS 24.0 software. Results: A total of 381 clients were included in this study. Most of them were less than 40 years old, accounting for 89.2% (340/381); 85.3% of them (325/381) reported an education level of high school and above; the clients who were married, had cohabitation with females or had girl friends accounted for 53.2% (202/380). The overall awareness rate of AIDS knowledge was 83.7% (318/380). Of all participants, 80.8% (308/381) had commercial sex in the past year, 79.8% (304/381) had non-commercial sex partners, 62.7% (239/381) had high-risk sexual behaviors. The results of logistic regression showed that compared with those with alcohol drinking frequency ≤2 times per month in last year, the clients with alcohol drinking frequency more than once a week (aOR=3.22, 95%CI: 1.25-8.27) were more likely to have high risk sexual behaviors after adjustment for age, living area, location type of residence, time of local residence, education level, monthly income level, occupation, marital status, knowledge awareness of AIDS and HIV related services, the number of commercial or non-commercial sexual partners in the past year, cost of commercial sex and HIV test frequency. Conclusions: Alcohol drinking is related to high risk sexual behaviors in HIV negative clients, and will increase the risk of HIV transmission. To control AIDS, the intervention of alcohol drinking should be combined with other preventions to improve the correct use of condoms.

MicroRNA-29b Promotes Subchondral Bone Loss in TMJ Osteoarthritis.

Abnormal subchondral bone remodeling plays important roles during osteoarthritis (OA) pathology. Recent studies show that bone marrow mesenchymal stem cells (BMSCs) in osteoarthritic subchondral bones exhibit a prominent pro-osteoclastic effect that contributes to abnormal subchondral bone remodeling; however, the pathologic mechanism remains unclear. In the present study, we used a mouse model with OA-like change in the temporomandibular joint (TMJ) induced by an experimentally unilateral anterior crossbite (UAC) and found that the level of microRNA-29b (miR-29b), but not miR-29a or miR-29c, was markedly lower in BMSCs from subchondral bones of UAC mice as compared with that from the sham control mice. With an intra-articular aptamer delivery system, BMSC-specific overexpression of miR-29b by aptamer-agomiR-29b rescued subchondral bone loss and osteoclast hyperfunction in UAC mice, as demonstrated by a significant increase in bone mineral density, bone volume fraction, trabecular thickness, and the gene expression of osteocalcin and Runx2 but decreased trabecular separation, osteoclast number and osteoclast surface/bone surface, and the gene expression of cathepsin K, Trap, Wnt5a, Rankl, and Rank as compared with those in the UAC mice treated by aptamer-NC (all P < 0.05). In addition, BMSC-specific inhibition of miR-29b by aptamer-antagomiR-29b exacerbated those responses in UAC mice. Notably, although it primarily affected miR-29b levels in the subchondral bone (but not in cartilage and synovium), BMSC-specific overexpression of miR-29b in UAC mice largely rescued OA-like cartilage degradation, including decreased chondrocyte density, cartilage thickness, and the percentage areas of proteoglycans and type II collagen, while BMSC-specific inhibition of miR-29b aggravated these characteristics of cartilage degradation in UAC mice. Moreover, we identified Wnt5a, but not Rankl or Sdf-1, as the direct target of miR-29b. The results of the present study indicate that miR-29b is a key regulator of the pro-osteoclastic effects of BMSCs in TMJ-OA subchondral bones and plays important roles in the TMJ-OA progression.

MiR-378a-5p inhibits angiogenesis of oral squamous cell carcinoma by targeting KLK4.

Oral squamous cell carcinoma (OSCC) is still a leading cause of cancer death owing to distant metastasis, which is largely facilitated by tumor angiogenesis. MicroRNA (miR)-378a-5p and Kallikrein-related peptidase 4 (KLK4) participate in tumorigenesis and tumor metastasis according to previous studies, yet the exact role they play in tumor angiogenesis remains poorly understood. The aim of the present study is to investigate the effect of miR-378a-5p and KLK4 on angiogenesis of OSCC. MTT assay showed that the expression level of miR-378a-5p was negatively correlated with the proliferation of OSCC cells. ELISA and Western blot assay showed that down-regulation of miR-378a-5p promotes VEGF expression. Tube formation and in vivo chicken chorioallantoic membrane (CAM) assay showed that inhibition of miR-378a-5p reduced tube formation of human umbilical vein endothelial cells (HUVECs) and newly formed microvessel. On the contrary, over-expression of KLK4 enhanced angiogenesis of OSCC cells with increased VEGF expression, tube formation activity of HUVECs and newly formed microvessel. Moreover, the dual-luciferase assay validated that KLK4 was a target gene of miR-378a-5p. MiR-378a-5p silencing induced tube formation was suppressed by the downregulation of KLK4. Besides, the activation of Wnt/ß-catenin signaling pathway in miR-378a-5p antagomir transfected cells was also blocked by the KLK4 shRNA. To sum up, our study suggests that miR-378a-5p suppressed angiogenesis of OSCC at least partly by the regulation of KLK4.

Contribution of biomimetic collagen-ligand interaction to intrafibrillar mineralization.

Contemporary models of intrafibrillar mineralization mechanisms are established using collagen fibrils as templates without considering the contribution from collagen-bound apatite nucleation inhibitors. However, collagen matrices destined for mineralization in vertebrates contain bound matrix proteins for intrafibrillar mineralization. Negatively charged, high-molecular weight polycarboxylic acid is cross-linked to reconstituted collagen to create a model for examining the contribution of collagen-ligand interaction to intrafibrillar mineralization. Cryogenic electron microscopy and molecular dynamics simulation show that, after cross-linking to collagen, the bound polyelectrolyte caches prenucleation cluster singlets into chain-like aggregates along the fibrillar surface to increase the pool of mineralization precursors available for intrafibrillar mineralization. Higher-quality mineralized scaffolds with better biomechanical properties are achieved compared with mineralization of unmodified scaffolds in polyelectrolyte-stabilized mineralization solution. Collagen-ligand interaction provides insights on the genesis of heterogeneously mineralized tissues and the potential causes of ectopic calcification in nonmineralized body tissues.

Simultaneous control of blood glucose, blood pressure, and lipid among drug-treated Type 2 diabetes patients from Shaanxi province, North-Western China: A multicenter study.

AIM: To investigate the percentage of patients with Type 2 diabetes mellitus (T2DM) who achieved simultaneous control of glycated hemoglobin (HbA1c), blood pressure (BP), and low-density lipoprotein cholesterol (LDL-C) and also to assess its determinants in Shaanxi province, North-Western China. MATERIALS AND METHODS: This cross-sectional survey was conducted between March and June 2012 in six tertiary hospitals across Shaanxi province. Subjects with known T2DM who had at least one antidiabetic medicine were invited. A questionnaire was used to collect basic information and blood samples were drawn for laboratory measurements. Simultaneous control was defined as HbA1c <7%, BP <130/80 mmHg, and LDL-C <2.6 mmol/L. RESULTS: A total of 2274 individuals were included, of which 588 individuals (25.9%) achieved good glycemic control (HbA1c <7%) and only 102 (4.5%) attained simultaneous control. The percentage of individuals (24.2%) achieving simultaneous control increased with less stringent goals (HbA1c <8%, BP <140/90 mmHg, and LDL-C <2.8 mmol/L). In addition, multivariate analyses showed that body mass index of 24-28 kg/m2 (odds ratio [OR]: 0.577, 95% confidence interval [CI]: 0.376-0.886), HbA1c above 8% at diagnosis (pooled OR: 0.392, 95% CI: 0.254-0.531), and insulin treatment (pooled OR: 0.412, 95% CI: 0.225-0.594) were the independent predictors of simultaneous control. CONCLUSION: Simultaneous control among drug-treated Type 2 diabetes patients was amazingly low in North-Western China. Our present study confirmed the gap between guideline and practice and provided evidence of the need for aggressive diabetes management.

Efficacy of PARP inhibition in Pde6a mutant mouse models for retinitis pigmentosa depends on the quality and composition of individual human mutations.

Retinitis pigmentosa (RP), an inherited blinding disease, is caused by a variety of different mutations that affect retinal photoreceptor function and survival. So far there is neither effective treatment nor cure. We have previously shown that poly(ADP-ribose)polymerase (PARP) acts as a common and critical denominator of cell death in photoreceptors, qualifying it as a potential target for future therapeutic intervention. A significant fraction of RP-causing mutations affect the genes for the rod photoreceptor phosphodiesterase 6A (PDE6A) subunit, but it is not known whether they all engage the same death pathway. Analysing three homozygous point mutations (Pde6a R562W, D670G, and V685M) and one compound heterozygous Pde6a (V685M/R562W) mutation in mouse models that match human RP patients, we demonstrate excessive activation of PARP, which correlated in time with the progression of photoreceptor degeneration. The causal involvement of PARP activity in the neurodegenerative process was confirmed in organotypic retinal explant cultures treated with the PARP-selective inhibitor PJ34, using different treatment time-points and durations. Remarkably, the neuroprotective efficacy of PARP inhibition correlated inversely with the strength of the genetically induced insult, with the D670G mutant showing the best treatment effects. Our results highlight PARP as a target for neuroprotective interventions in RP caused by PDE6A mutations and are a first attempt towards personalized, genotype-matched therapy development for RP. In addition, for each of the different mutant situations, our work identifies windows of opportunity for an optimal treatment regimen for further in vivo experimentation and possibly clinical studies.

Clinical analysis on argon plasma coagulation (APC) under painless colonoscopy for treatment of patients with colorectal polyp canceration.

OBJECTIVE: To investigate the clinical effects of argon plasma coagulation combined high frequency electric knife in treating patients with colorectal polyp canceration. PATIENTS AND METHODS: 56 patients diagnosed with colorectal polyp canceration were divided into control group (n=23) and observation group (n=33). Patients in the control group were treated with high frequency electric band ligation electroexcision while patients in observation group were treated with argon coagulation combined high frequency electric knife therapy. The patients were followed up for 6 months and, then, compared for their clinical effects and prognosis. RESULTS: The average diameter of the polyp, the ratios of sessile and flat polyps in observation group were significantly higher than those in the control group with p<0.05. While the differences in the ratio of adenomatous polyp, middle and high differentiated as well as leafless polyps between the two groups had no statistical significance with p>0.05. Further, the differences in operation completion rate and polyp resection rate at one time in observation group was significantly higher than those of control group while operative complication rate and operation time was significantly lower than those in the control group with p<0.05. Also, the differences in recurrence in situ and recurrence time did not differ significantly between the two groups. CONCLUSIONS: Treating colorectal polyps by argon plasma coagulation combined high frequency electric knife could extend polyp resection indication, along with improvement in the operation effect and reduction of complications.

Laparoscopic treatment experience of severe acute pancreatitis complicated by peptic ulcer perforation.

OBJECTIVE: To explore the clinical effect of emergency laparoscopic repair of perforation and conventional open surgery in the treatment of severe acute pancreatitis (SAP) complicated with peptic ulcer perforation. PATIENTS AND METHODS: A total of 34 patients diagnosed as severe acute pancreatitis complicated by peptic ulcer perforation were selected as experimental group and a total of 38 patients diagnosed as severe acute pancreatitis complicated by peptic ulcer perforation were selected as control group. The experimental group was treated with emergency laparoscopic perforation repair and the control group was treated with conventional open operation, comparing the difference between the results and the prognosis of the patients. RESULTS: The success rate of the experimental group and the control group are compared was not statistically significant (p > 0.05). While the operation time, postoperative intestinal function recovery time, the time of drainage tube pulled out and the occurrence of complications in experimental group was significantly lower than those in control group. The survival rate of the experimental group was significantly higher than that of the control group, the recurrence rate was significantly lower than that of the control group (p < 0.05). The high sensitive C reactive protein (hs CRP) and tumor necrosis factor TNF-α levels of the experimental group were significantly lower than those of the control group (p < 0.05). CONCLUSIONS: Emergency laparoscopic repair of peptic ulcer perforation in the treatment of SAP complicated with perforation is safe and effective, which can reduce the systemic inflammatory response and better than conventional open surgery.

Systemic administration of strontium or NBD peptide ameliorates early stage cartilage degradation of mouse mandibular condyles.

OBJECTIVE: To determine whether mandibular condylar cartilage degradation induced by experimentally abnormal occlusion could be ameliorated via systemic administration of strontium or NBD peptide. METHODS: Six-week-old female C57BL/6J mice were used. From the seventh day after mock operation or unilateral anterior crossbite (UAC) treatment, the control and UAC mice were further respectively pharmacologically treated for 2 weeks or 4 weeks of saline (CON + Saline and UAC + Saline groups), SrCl2 (CON + SrCl2 and UAC + SrCl2 groups) or NBD peptide (CON + NBD peptide and UAC + NBD peptide groups). Changes in condylar cartilage and subchondral bone were assessed 21 and 35 days after mock operation or UAC procedure by histology and micro-CT. Real-time PCR and/or immunohistochemistry (IHC) were performed to evaluate changes in expression levels of col2a1, aggrecan, ADAMTS-5, tnf-α, il-1ß, nfkbia, nuclear factor-kappaB phospho-p65 in condylar cartilage, and rankl/rank/opg in both condylar cartilage and subchondral bone. RESULTS: Cartilage degradation with decreased col2a1 and aggrecan expression, and increased ADAMTS-5, tnf-α/il1-ß, nfkbia and NF-κB phospho-p65 was observed in UAC + Saline groups. Subchondral bone loss with increased osteoclast numbers and decreased opg/rankl ratio was found in UAC + Saline groups compared to age-match CON + Saline groups. Cartilage degradation and subchondral bone loss were reversed by treatment of SrCl2 or NBD peptide while the same dosage in control mice induced few changes in condylar cartilage and subchondral bone. CONCLUSIONS: The results demonstrate reverse effect of systemic administration of strontium or NBD peptide on UAC-induced condylar cartilage degradation and subchondral bone loss.

Norepinephrine Regulates Condylar Bone Loss via Comorbid Factors.

Degenerative changes of condylar subchondral bone occur frequently in temporomandibular disorders. Although psychologic stresses and occlusal abnormalities have been implicated in temporomandibular disorder, it is not known if these risks represent synergistic comorbid factors that are involved in condylar subchondral bone degradation that is regulated by the sympathetic nervous system. In the present study, chronic immobilization stress (CIS), chemical sympathectomy, and unilateral anterior crossbite (UAC) were sequentially applied in a murine model. Norepinephrine contents in the subjects' serum and condylar subchondral bone were detected by ELISA; bone and cartilage remodeling parameters and related gene expression in the subchondral bone were examined. Subchondral bone loss and increased subchondral bone norepinephrine level were observed in the CIS and UAC groups. These groups exhibited decreased bone mineral density, volume fraction, and bone formation rate; decreased expressions of osterix, collagen I, and osteocalcin; but increased trabecular separation, osteoclast number and surface, and RANKL expression. Combined CIS + UAC produced more severe subchondral bone loss, higher bone norepinephrine level, and decreased chondrocyte density and cartilage thickness when compared to CIS or UAC alone. Sympathectomy simultaneously prevented subchondral bone loss and decreased bone norepinephrine level in all experimental subgroups when compared to the vehicle-treated counterparts. Norepinephrine also decreased mRNA expression of osterix, collagen I, and osteocalcin by mesenchymal stem cells at 7 and 14 d of stimulation and increased the expression of RANKL and RANKL/OPG ratio by mesenchymal stem cells at 2 h. In conclusion, CIS and UAC synergistically promote condylar subchondral bone loss and cartilage degradation; such processes are partially regulated by norepinephrine within subchondral bone.

Wnt5a/Ror2 mediates temporomandibular joint subchondral bone remodeling.

Increased subchondral trabecular bone turnover due to imbalanced bone-resorbing and bone-forming activities is a hallmark of osteoarthritis (OA). Wnt5a/Ror2 signaling, which can derive from bone marrow stromal cells (BMSCs), takes a role in modulating osteoblast and osteoclast formation. We showed previously that experimentally unilateral anterior crossbites (UACs) elicited OA-like lesions in mice temporomandibular joints (TMJs), displaying as subchondral trabecular bone loss. Herein, we tested the role of BMSC-derived Wnt5a/Ror2 signaling in regulating osteoclast precursor migration and differentiation in this process. The data confirmed the decreased bone mass, increased tartrate-resistant acid phosphatase (TRAP)-positive cell number, and enhanced osteoclast activity in TMJ subchondral trabecular bone of UAC-treated rats. Interestingly, the osteoblast activity in the tissue of TMJ subchondral trabecular bone of these UAC-treated rats was also enhanced, displaying as upregulated expressions of osteoblast markers and increased proliferation, migration, and differentiation capabilities of the locally isolated BMSCs. These BMSCs showed an increased CXCL12 protein expression level and upregulated messenger RNA expressions of Rankl, Wnt5a, and Ror2. Ex vivo data showed that their capacities of inducing migration and differentiation of osteoclast precursors were enhanced, and these enhanced capabilities were restrained after blocking their Ror2 signaling using small interfering RNA (siRNA) assays. Reducing Ror2 expression in the BMSC cell line by siRNA or blocking the downstream signalings with specific inhibitors also demonstrated a suppression of the capacity of the BMSC cell line to promote Wnt5a-dependent migration (including SP600125 and cyclosporine A) and differentiation (cyclosporine A only) of osteoclast precursors. These findings support the idea that Wnt5a/Ror2 signaling in TMJ subchondral BMSCs enhanced by UAC promoted BMSCs to increase Cxcl12 and Rankl expression, in which JNK and/or Ca(2+)/NFAT pathways were involved and therefore were engaged in enhancing the migration and differentiation of osteoclast precursors, leading to increased osteoclast activity and an overall TMJ subchondral trabecular bone loss in the UAC-treated rats.

Bonding of universal adhesives to dentine--Old wine in new bottles?

OBJECTIVE: Multi-mode universal adhesives offer clinicians the choice of using the etch-and-rinse technique, selective enamel etch technique or self-etch technique to bond to tooth substrates. The present study examined the short-term in vitro performance of five universal adhesives bonded to human coronal dentine. METHODS: Two hundred non-carious human third molars were assigned to five groups based on the type of the universal adhesives (Prime&Bond Elect, Scotchbond Universal, All-Bond Universal, Clearfil Universal Bond and Futurabond U). Two bonding modes (etch-and-rinse and self-etch) were employed for each adhesive group. Bonded specimens were stored in deionized water for 24h or underwent a 10,000-cycle thermocycling ageing process prior to testing (N=10). Microtensile bond testing (µTBS), transmission electron microscopy (TEM) of resin-dentine interfaces in non-thermocycled specimens and scanning electron microscopy (SEM) of tracer-infused water-rich zones within hybrid layers of thermocycled specimens were performed. RESULTS: Both adhesive type and testing condition (with/without thermocycling) have significant influences on µTBS. The use of each adhesive in either the etch-and-rinse or self-etch application mode did not result in significantly different µTBS to dentine. Hybrid layers created by these adhesives in the etch-and-rinse bonding mode and self-etch bonding mode were ∼5µm and ≤0.5µm thick respectively. Tracer-infused regions could be identified within the resin-dentine interface from all the specimens prepared. CONCLUSION: The increase in versatility of universal adhesives is not accompanied by technological advances for overcoming the challenges associated with previous generations of adhesives. Therapeutic adhesives with bio-protective and bio-promoting effects are still lacking in commercialized adhesives. CLINICAL SIGNIFICANCE: Universal adhesives represent manufacturers' attempt to introduce versatility in product design via adaptation of a single-bottle self-etch adhesive for other application modes without compromising its bonding effectiveness.

Reducing dietary loading decreases mouse temporomandibular joint degradation induced by anterior crossbite prosthesis.

OBJECTIVE: Dietary loading has been reported to have an effect on temporomandibular joint (TMJ) remodeling via periodontal-muscular reflex. We therefore examined whether reducing dietary loading decreased TMJ degradation induced by the unilateral anterior crossbite prosthesis as we recently reported. METHODS: Forty 6-week-old female C57BL/6J mice were randomly divided into two experimental and two control groups. One experimental and one control group received small-size diet and the other two groups received large-size diet. Unilateral anterior crossbite prosthesis was created in the two experimental groups. The TMJ samples were collected 3 weeks after experimental operation. Histological changes in condylar cartilage and subchondral bone were assessed by Hematoxylin & Eosin, toluidine blue, Safranin O and tartrate-resistant acid phosphatase staining. Real-time polymerase chain reaction (PCR) and/or immunohistochemistry were performed to evaluate the expression levels of Collagen II, Aggrecan, a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5) and RANKL/RANK/OPG in TMJ condylar cartilage and/or subchondral bone. RESULTS: Thinner and degraded cartilage, reduced cartilage cellular density, decreased expression levels of Collagen II and Aggrecan, loss of subchondral bone and enhanced osteoclast activity were observed in TMJs of both experimental groups. However, the cartilage degradation phenotype was less severe and cartilage ADAMTS-5 mRNA was lower while OPG/RANKL ratio in cartilage and subchondral bone was higher in the small-size than large-size diet experimental group. No differences of histomorphology and the tested molecules were found between the two control groups. CONCLUSIONS: The current findings suggest that a lower level of functional loading by providing small-size diet could reduce TMJ degradation induced by the biomechanical stimulation from abnormal occlusion.

Overexpressed TGF-ß in subchondral bone leads to mandibular condyle degradation.

Emerging evidence has implied that subchondral bone plays an important role during osteoarthritis (OA) pathology. This study was undertaken to investigate whether abnormalities of the condylar subchondral bone lead to temporomandibular joint (TMJ) OA. We used an osteoblast-specific mutant TGF-ß1 transgenic mouse, the CED mouse, in which high levels of active TGF-ß1 occur in bone marrow, leading to abnormal bone remodeling. Subchondral bone changes in the mandibular condyles were investigated by micro-CT, and alterations in TMJ condyles were confirmed by histopathological and immunohistochemical analysis. Abnormalities in the condylar subchondral bone, characterized as fluctuant bone mineral density and microstructure and increased but uncoupled activity of osteoclasts and osteoblasts, were apparent in the 1- and 4-month CED mouse groups, while obvious cartilage degradation, in the form of cell-free regions and proteoglycan loss, was observed in the 4-month CED group. In addition, increased numbers of apoptotic chondrocytes and MMP9- and VEGF-positive chondrocytes were observed in the condylar cartilage in the 4-month CED group, but not in the 1-month CED group, compared with their respective age-matched controls. This study demonstrated that progressive degradation of mandibular condylar cartilage could be induced by the abnormal remodeling of the underlying subchondral bone during TMJOA progression.

Occlusal effects on longitudinal bone alterations of the temporomandibular joint.

The pathological changes of subchondral bone during osteoarthritis (OA) development in the temporomandibular joint (TMJ) are poorly understood. In the present study, we investigated the longitudinal alterations of subchondral bone using a rat TMJ-OA model developed in our laboratory. Changes in bone mass were examined by micro-CT, and changes in osteoblast and osteoclast activities were analyzed by real-time PCR, immunohistochemistry, and TRAP staining. Subchondral bone loss was detected from 8 weeks after dental occlusion alteration and reached the maximum at 12 weeks, followed by a repair phase until 32 weeks. Although bone mass increased at late stages, poor mechanical structure and lower bone mineral density (BMD) were found in these rats. The numbers of TRAP-positive cells were increased at 12 weeks, while the numbers of osteocalcin-expressing cells were increased at both 12 and 32 weeks. Levels of mRNA expression of TRAP and cathepsin K were increased at 12 weeks, while levels of ALP and osteocalcin were increased at both 12 and 32 weeks. These findings demonstrated that there is an active bone remodeling in subchondral bone in TMJs in response to alteration in occlusion, although new bone was formed with lower BMD and poor mechanical properties.

Differential expression of IGF1, IGFR1 and IGFBP3 in mandibular condylar cartilage between male and female rats applied with malocclusion.

This study was designed to investigate the expression differences of insulin-like growth factor-1 (IGF1), IGF type 1 receptor (IGFR1) and IGF-binding protein-3 (IGFBP3) in mandibular condylar cartilage between male and female rats with experimentally created malocclusion. A total of 40 male and 40 female rats were used, and malocclusion was created by moving the first molars mesially and the third molars distally in the experimental group. Animals were killed at the end of the second and fourth weeks. Haematoxylin and eosin (HE) staining was performed to monitor the changes in cartilage morphology and thickness. Immunohistochemistry and real-time PCR were used to detect the expression of IGF1, IGFR1 and IGFBP3. Osteoarthritis (OA)-like changes were observed in the experimental groups, with 2-week females showing larger OA-like regions than 2-week males (P < 0·05). Compared to their age- and sex-matched controls, both 2- and 4-week males in the experimental groups displayed increased cartilage thickness in the posterior regions (P < 0·05). Compared to their age- and sex-matched controls, the expression of IGF1 was lower in 2-week female group (P < 0·05), but higher in 4-week female, 2- and 4-week male experimental groups (P < 0.05). Similarly, the expression of IGFR1 was lower in 2-week female experimental group (P < 0.05), but higher in 2-week male experimental group (P < 0.05). The higher expression of IGFBP3 was observed in 2-week female, 2- and 4-week male experimental groups (P < 0·05). These results indicate that condylar cartilage from male and female rats respond differently to the malocclusion in early stage of OA, with more serious degeneration in females.

Localization of MMP-2, MMP-9, TIMP-1, and TIMP-2 in human coronal dentine.

OBJECTIVES: Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play important roles in dentine formation, caries progression and hybrid layer degradation. This study tested the hypothesis that the distribution and concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 are different at different depths of human coronal dentine, including odontoblasts. METHODS: Protein localization was performed using immunohistochemistry. Co-localization of the MMPs and their inhibitors was conducted using immunofluorescence double labelling. Protein concentrations were measured by ELISA and gelatinolytic potential was assessed with gelatine zymography. RESULTS: MMP-2 was the main gelatinase in dentine and was concentrated in the odontoblasts, deep dentine and the dentinoenamel junction. TIMP-2 was co-localized with MMP-2 mainly in the odontoblasts but its concentration was low. Both MMP-9 and TIMP-1 showed a decreasing distribution from the deep to the superficial dentine layers; however, the concentration of TIMP-1 was much higher than that of MMP-9. The gelatinolytic potential of dentine protein extracts decreased gradually from deep to superficial dentine. CONCLUSIONS: The concentrations and distribution patterns of MMP-2, MMP-9, TIMP-1 and TIMP-2, and the gelatinolytic potential of dentine matrix are variable along different dentine depths. Thus, differential collagen degradation potentials may be expected depending upon the depth in which dentine is exposed.