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Objective To explore the potential role of alpinumisoflavone (AIF) in the treatment of temporomandibular joint osteoarthritis (TMJOA) cell model through network pharmacology and molecular docking and to provide a research basis for AIF in the treatment of TMJOA. Methods GeneCards, OMIM, DisGeNET, and PharmGKB databases were used to screen TMJOA disease targets, and PharmMapper and HERB were used to retrieve AIF-related targets. The intersection targets of the compounds and diseases were uploaded to the STRING database to obtain the key targets for GO and KEGG enrichment analysis, while the key targets in related signaling pathways were evaluated through molecular docking. Approval was obtained from the Ethics Committee to extract condylar chondrocytes from 3-week-old SD rats. The CCK-8 assay was used to detect AIF cytotoxicity on condylar chondrocytes. Condylar chondrocytes were induced with 10 ng/mL interleukin 1β (IL-1β) for 24 h to construct a TMJOA cell model. The experiment was divided into three groups: control group, comprising condylar chondrocytes cultured in DMEM for 48 h; IL-1β group, comprising condylar chondrocytes pre-cultured in DMEM for 24 h, after which IL-1β was added to the original culture medium to obtain a medium concentration of 10 ng/mL and allowed to culture for 24 h; and the IL-1β+10 μmol/L AIF group, comprising condylar chondrocytes pre-cultured in DMEM medium containing 10 μmol/L AIF for 24 h, after which IL-1β was added to the original culture medium to obtain a medium concentration of 10 ng/mL and allowed to culture for 24 h. The effect of AIF on condylar chondrocyte apoptosis in the TMJOA cell model was detected by flow cytometry. The experiment was divided into four groups: control group, IL-1β group, IL-1β+10 μmol/L AIF group, and IL-1β+30 μmol/L AIF group. The IL-1β+30 μmol/L AIF group was pre-cultured in DMEM containing 30 μmol/L AIF for 24 h, after which IL-1β was added to the original culture medium to obtain a medium concentration of 10 ng/mL and allowed to culture for 24 h. The remaining three groups were cultured in the same manner as before. The mRNA and protein expression of apoptosis-associated B-cell leukemia/lymphoma-2 (Bcl2), cysteinyl aspartate specific protease 3 (caspase-3), matrix degradation-associated a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS4), matrix metalloproteinase 3 (MMP3), and matrix metalloproteinase 13 (MMP13) were detected by qPCR and western blot, by AIF in the TMJOA cell model. Results The PharmMapper and HERB database search yielded 300 AIF compound targets. The GeneCards, OMIM, DisGeNET, and PharmGKB databases yielded 378 TMJOA disease targets. Thirty-three potential common targets were obtained by intersecting compounds with disease targets. The common targets were uploaded into the STRING database to obtain 31 key targets that were mainly associated with apoptosis and extracellular matrix degradation. This process may be associated with the MAPK, estrogen, and TNF signaling pathways. The molecular docking results showed that AIF has good binding activity with extracellular signal-regulated kinase 1/2 (ERK1/2) and estrogen receptor gene 1/2 (ESR1/2), which are key targets in the MAPK and estrogen signaling pathways. The CCK-8 assay showed that AIF had no obvious cytotoxicity to condylar chondrocytes. The cell experiments showed that AIF inhibited apoptosis in the IL-1β+10 μmol/L AIF group compared to the IL-1β group. Compared to the IL-1β group in the IL-1β+10 μmol/L AIF group and the IL-1β+30 μmol/L AIF group, AIF upregulated Bcl2 and downregulated caspase-3 mRNA and protein expression and inhibited ADAMTS4, MMP3, and MMP13 mRNA and protein expression. Conclusion AIF inhibited apoptosis in the TMJOA cell model by upregulating Bcl2 and downregulating caspase-3 mRNA and protein expression, and inhibited extracellular matrix degradation induced by IL-1β, thereby delaying TMJOA progression.

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Abstract Background Temporomandibular joint osteoarthritis (TMJOA) has a high incidence rate, but its pathogenesis remains unclear. Circadian rhythm is an important oscillation in the human body and influences various biological activities. However, it is still unclear whether circadian rhythm affects the onset and development of TMJOA. Methods We disrupted the normal rhythm of rats and examined the expression of core clock genes in the mandibular condylar cartilage of the jaw and histological changes in condyles. After isolating rat mandibular condylar chondrocytes, we upregulated or downregulated the clock gene Per1, examined the expression of cartilage matrix-degrading enzymes, tested the activation of the GSK3β/β-CATENIN pathway and verified it using agonists and inhibitors. Finally, after downregulating the expression of Per1 in the mandibular condylar cartilage of rats with jet lag, we examined the expression of cartilage matrix-degrading enzymes and histological changes in condyles. Results Jet lag led to TMJOA-like lesions in the rat mandibular condyles, and the expression of the clock gene Per1 and cartilage matrix-degrading enzymes increased in the condylar cartilage of rats. When Per1 was downregulated or upregulated in mandibular condylar chondrocytes, the GSK3β/β-CATENIN pathway was inhibited or activated, and the expression of cartilage matrix-degrading enzymes decreased or increased, which can be rescued by activator and inhibitor of the GSK3β/β-CATENIN pathway. Moreover, after down-regulation of Per1 in mandibular condylar cartilage in vivo, significant alleviation of cartilage degradation, cartilage loss, subchondral bone loss induced by jet lag, and inhibition of the GSK3β/β-CATENIN signaling pathway were observed. Circadian rhythm disruption can lead to TMJOA. The clock gene Per1 can promote the occurrence of TMJOA by activating the GSK3β/β-CATENIN pathway and promoting the expression of cartilage matrix-degrading enzymes. The clock gene Per1 is a target for the prevention and treatment of TMJOA.

Background: Temporomandibular joint osteoarthritis (TMJOA) has a high incidence rate, but its pathogenesis remains unclear. Circadian rhythm is an important oscillation in the human body and influences various biological activities. However, it is still unclear whether circadian rhythm affects the onset and development of TMJOA. Methods: We disrupted the normal rhythm of rats and examined the expression of core clock genes in the mandibular condylar cartilage of the jaw and histological changes in condyles. After isolating rat mandibular condylar chondrocytes, we upregulated or downregulated the clock gene Per1, examined the expression of cartilage matrix-degrading enzymes, tested the activation of the GSK3β/β-CATENIN pathway and verified it using agonists and inhibitors. Finally, after downregulating the expression of Per1 in the mandibular condylar cartilage of rats with jet lag, we examined the expression of cartilage matrix-degrading enzymes and histological changes in condyles. Results: Jet lag led to TMJOA-like lesions in the rat mandibular condyles, and the expression of the clock gene Per1 and cartilage matrix-degrading enzymes increased in the condylar cartilage of rats. When Per1 was downregulated or upregulated in mandibular condylar chondrocytes, the GSK3β/β-CATENIN pathway was inhibited or activated, and the expression of cartilage matrix-degrading enzymes decreased or increased, which can be rescued by activator and inhibitor of the GSK3β/β-CATENIN pathway. Moreover, after down-regulation of Per1 in mandibular condylar cartilage in vivo, significant alleviation of cartilage degradation, cartilage loss, subchondral bone loss induced by jet lag, and inhibition of the GSK3β/β-CATENIN signaling pathway were observed. Circadian rhythm disruption can lead to TMJOA. The clock gene Per1 can promote the occurrence of TMJOA by activating the GSK3β/β-CATENIN pathway and promoting the expression of cartilage matrix-degrading enzymes. The clock gene Per1 is a target for the prevention and treatment of TMJOA. [ABSTRACT FROM AUTHOR]

Copyright of China Journal of Oral & Maxillofacial Surgery is the property of Shanghai Jiao Tong University, College of Stomatology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To investigate the effects of gradient mechanical pressure on chondrocyte proliferation, apoptosis, and the expression of markers of chondrogenesis and chondrocyte hypertrophy. Methods: Mandibular condylar chondrocytes from 5 rabbits were cultured in vitro, and pressed with static pressures of 50 kPa, 100 kPa, 150 kPa and 200 kPa for 3 h, respectively. The chondrocytes cultured without pressure (0 kPa) were used as control. Cell proliferation, apoptosis, and the expression of aggrecan (AGG), collagen II (COL2), collagen X (COL10), alkaline phosphatase (ALP) were investigated. Ultrastructures of the pressurized chondrocytes under transmission electron microscopy (TEM) were observed. Results: Chondrocyte proliferation increased at 100 kPa and decreased at 200 kPa. Chondrocyte apoptosis increased with peak pressure at 200 kPa in a dose-dependent manner. Chondrocyte necrosis increased at 200 kPa. The expression of AGG increased at 200 kPa. The expression of COL2 decreased at 50 kPa and increased at 150 kPa. The expression of COL10 and ALP increased at 150 kPa. Ultrastructure of the pressurized chondrocytes under TEM showed: at 100 kPa, cells were enlarged with less cellular microvillus and a bigger nucleus; at 200 kPa, cells shrank with the sign of apoptosis, and apoptosis cells were found. Conclusions: The mechanical loading of 150 kPa is the moderate pressure for chondrocyte: cell proliferation and apoptosis is balanced, necrosis is reduced, and chondrogenesis and chondrocyte hypertrophy are promoted. When the pressure is lower, chondrogenesis and chondrocyte hypertrophy are inhibited. At 200 kPa, degeneration of cartilage is implied. [ABSTRACT FROM AUTHOR]

This study aimed to explore whether intraflagellar transport protein 88 (IFT88) was associated with polycystin 2 during mechanotransduction of mandibular condylar chondrocytes. Rat mandibular condylar chondrocytes isolated from the condylar bone-cartilage junction were subjected to cyclic tensile strain (0.1 Hz, 10% elongation). Overexpression of IFT88 was achieved by lentiviral vector-mediated transfection. Knockdown of IFT88 and polycystin 2 was achieved by small interfering RNA (siRNA). The prevalence and length of cilia were reflected by immunofluorescence staining. The activities of hedgehog signaling were evaluated by western blot analysis. The interaction between polycystin 2 and IFT88 was evaluated by conducting a co-immunoprecipitation (co-IP) assay. Overexpression of IFT88 increased the length of cilia. Protein levels of polycystin 2, Indian hedgehog (Ihh), Patched 1 (Ptch1), Smoothened (Smo), and Glioma-associated oncogene homolog 1 (Gli1) were elevated in IFT88-overexpressing mandibular condylar chondrocytes under cyclic tensile strain. Knockdown of the protein level of IFT88 reduced the prevalence and length of cilia, and protein levels of polycystin 2, Ihh, Ptch1, Smo, and Gli1. A co-IP assay showed that IFT88 formed a complex with polycystin 2 under cyclic tensile strain. Knockdown of polycystin 2 decreased the protein levels of IFT88, Ihh, Ptch1, Smo, and Gli1 in mandibular condylar chondrocytes following cyclic tensile strain. These findings highlight the vital role of an interaction between IFT88 and polycystin 2 in mechanosensitive hedgehog signaling in mandibular condylar chondrocytes following cyclic tensile strain, which suggest that therapies regulating polycystin 2 may be considered for the disorders of temporomandibular joints. • IFT88 is necessary for mechanosensitive hedgehog signaling in condylar chondrocytes. • Polycystin 2 is required for mechanosensitive hedgehog signaling. • IFT88 co-immunoprecipitated with polycystin 2 under cyclic tensile strain. [ABSTRACT FROM AUTHOR]

Objective To determine the effects of different estrogen concentrations on the proliferation and differentiation of human embryo mandibular condylar chondrocytes (MCCs). Methods In w'fro-cultured MCCs were incubated and treated with estrogen at different concentrations. The MCCs were identified by toluidine blue and type II collagen immunocytochemical methods, and cell proliferation was monitored using methyl thiazolyl tetrazolium assay. Results The addition of 10-12 or 10-6 mol-L-1 exogenous estrogen inhibited the growth of MCCs, whereas addition of 10-10or 10-8 mol-L-1 exogenous estrogen promoted growth. These estrogen effects were time-dependent. Conclusion Estrogen can affect cellular MCCs proliferation and differentiation in a biphasic manner depending on the concentration. Estrogen may be vital in the maintenance of normal functions of the temporomandibular joint (TMJ) and may be involved in the progression of certain TMJ diseases. [ABSTRACT FROM AUTHOR]

• E2 with CCS has different effects on MCCs proliferation and differentiation. • E2 at physiological concentration with CCS has synergistic effect. • E2 at non-physiological concentration with CCS has no synergistic effect. The aim of this study is to investigate the effects of 17β-Estradiol (E2) at different concentrations combined with cyclical compressive stress on the proliferation and differentiation of mandibular condylar chondrocytes (MCCs). MCCs, isolated from female Sprague-Dawley rats, were exposed to E2 at different concentration, cyclical compressive stress or the combination, effects of which on MCCs proliferation and differentiation were detected. E2 at physiological concentration (10−9 mol/L) has lower proliferative effects on MCCs, compared with non-physiological concentration (10-12 mol/L or 10-6 mol/L). For MCCs differentiation, effects of E2 at different concentration are totally opposite: E2 at 10−9 mol/L promotes MCCs differentiation, but at 10-12 mol/L or 10-6 mol/L, it inhibits MCCs differentiation. When combined with E2 at 10−9 mol/L, cyclical compressive stress shows synergistic effect on proliferation and differentiation. However, when combined with E2 at 10-12 mol/L or 10-6 mol/L cyclical compressive stress reverses the inhibition in MCCs differentiation provoked by E2 at 10-12 mol/L or 10-6 mol/L. Effects of E2 combined with cyclical compressive stress on MCCs proliferation and differentiation are different, which suggests that orthodontist should take fully consideration of the levels of E2 and adopt comprehensive strategies, so as to achieve better orthodontic effect. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of gradient mechanical pressure on chondrocyte proliferation, apoptosis, and the expression of markers of chondrogenesis and chondrocyte hypertrophy., Methods: Mandibular condylar chondrocytes from 5 rabbits were cultured in vitro, and pressed with static pressures of 50kPa, 100kPa, 150kPa and 200kPa for 3h, respectively. The chondrocytes cultured without pressure (0kPa) were used as control. Cell proliferation, apoptosis, and the expression of aggrecan (AGG), collagen II (COL2), collagen X (COL10), alkaline phosphatase (ALP) were investigated. Ultrastructures of the pressurized chondrocytes under transmission electron microscopy (TEM) were observed., Results: Chondrocyte proliferation increased at 100kPa and decreased at 200kPa. Chondrocyte apoptosis increased with peak pressure at 200kPa in a dose-dependent manner. Chondrocyte necrosis increased at 200kPa. The expression of AGG increased at 200kPa. The expression of COL2 decreased at 50kPa and increased at 150kPa. The expression of COL10 and ALP increased at 150kPa. Ultrastructure of the pressurized chondrocytes under TEM showed: at 100kPa, cells were enlarged with less cellular microvillus and a bigger nucleus; at 200kPa, cells shrank with the sign of apoptosis, and apoptosis cells were found., Conclusions: The mechanical loading of 150kPa is the moderate pressure for chondrocyte: cell proliferation and apoptosis is balanced, necrosis is reduced, and chondrogenesis and chondrocyte hypertrophy are promoted. When the pressure is lower, chondrogenesis and chondrocyte hypertrophy are inhibited. At 200kPa, degeneration of cartilage is implied., (Copyright © 2016 Elsevier Ltd. All rights reserved.)