Effects of ADAM12 abnormal expression on chondrocyte injury and IGFBP-related genes in patients with Kashin-Beck disease / 中华地方病学杂志

Objective:To investigate the role of a disintegrin and metalloprotease 12 (ADAM12) gene in chondrocyte injury in patients with Kashin-Beck disease (KBD) and its impact on genes related to insulin-like growth factor binding protein (IGFBP).Methods:Articular cartilage samples were obtained from 5 patients with KBD and 5 control subjects admitted to Honghui Hospital Affiliated to Xi'an Jiaotong University. Chondrocytes were extracted and cultured in vitro. Quantitative real-time PCR (qRT-PCR) and Western blotting were used to detect the expression levels of ADAM12 mRNA and protein in chondrocytes of patients with KBD and control subjects, respectively. Subsequently, ADAM12 gene overexpression was performed using lentivirus in chondrocytes of patients with KBD. MTT assay was used to detect changes in cell viability after ADAM12 gene overexpression, and qRT-PCR was used to detect the mRNA expression levels of chondrocyte differentiation related genes SRY-box transcription factor 9 (SOX9) and type Ⅱ collagen (COLⅡ), apoptosis-related gene B-cell lymphoma/leukaemia-2-associated X protein (BAX), and anabolic related genes IGFBP3 and IGFBP5. Results:The expression levels of ADAM12 mRNA and protein in chondrocytes of patients with KBD (0.57 ± 0.05, 0.81 ± 0.07) were significantly lower than those of control subjects (1.00 ± 0.00, 1.00 ± 0.00), and the differences were statistically significant ( t = - 24.50, - 3.61, P < 0.05). The results of MTT assay showed that the cell viability of chondrocytes in ADAM12 overexpression group (1.09 ± 0.05) was higher than that in empty vector control group (1.00 ± 0.08), and the difference was statistically significant ( t = 4.12, P = 0.031). The results of qRT-PCR showed that compared with empty vector control group, the mRNA expression levels of IGFBP3 (2.35 ± 0.79 vs 0.96 ± 0.25), IGFBP5 (2.13 ± 0.30 vs 0.98 ± 0.34), SOX9 (2.92 ± 0.51 vs 0.94 ± 0.36) and COLⅡ (6.45 ± 2.81 vs 0.87 ± 0.19) in ADAM12 overexpression group were significantly increased, and the differences were statistically significant ( t = 3.19, 5.16, 6.27, 4.10, P < 0.05); while the expression level of BAX mRNA (0.31 ± 0.06 vs 1.02 ± 0.22) was significantly decreased, and the difference was statistically significant ( t = - 11.16, P < 0.001). Conclusion:The ADAM12 gene may have a role in inhibiting apoptosis and promoting differentiation in chondrocyte injury in patients with KBD, and its overexpression can increase expression of IGFBP3 and IGFBP5.

The role of E3 ubiquitin ligases in bone homeostasis and related diseases

The ubiquitin-proteasome system (UPS) dedicates to degrade intracellular proteins to modulate demic homeostasis and functions of organisms. These enzymatic cascades mark and modifies target proteins diversly through covalently binding ubiquitin molecules. In the UPS, E3 ubiquitin ligases are the crucial constituents by the advantage of recognizing and presenting proteins to proteasomes for proteolysis. As the major regulators of protein homeostasis, E3 ligases are indispensable to proper cell manners in diverse systems, and they are well described in physiological bone growth and bone metabolism. Pathologically, classic bone-related diseases such as metabolic bone diseases, arthritis, bone neoplasms and bone metastasis of the tumor, etc., were also depicted in a UPS-dependent manner. Therefore, skeletal system is versatilely regulated by UPS and it is worthy to summarize the underlying mechanism. Furthermore, based on the current status of treatment, normal or pathological osteogenesis and tumorigenesis elaborated in this review highlight the clinical significance of UPS research. As a strategy possibly remedies the limitations of UPS treatment, emerging PROTAC was described comprehensively to illustrate its potential in clinical application. Altogether, the purpose of this review aims to provide more evidence for exploiting novel therapeutic strategies based on UPS for bone associated diseases.

Research progress on the role of chondrocyte mitochondrial homeostasis imbalance in the pathogenesis of osteoarthritis / 中国修复重建外科杂志

OBJECTIVE@#To summarize the role of chondrocyte mitochondrial homeostasis imbalance in the pathogenesis of osteoarthritis (OA) and analyze its application prospects.@*METHODS@#The recent literature at home and abroad was reviewed to summarize the mechanism of mitochondrial homeostasis imbalance, the relationship between mitochondrial homeostasis imbalance and the pathogenesis of OA, and the application prospect in the treatment of OA.@*RESULTS@#Recent studies have shown that mitochondrial homeostasis imbalance, which is caused by abnormal mitochondrial biogenesis, the imbalance of mitochondrial redox, the imbalance of mitochondrial dynamics, and damaged mitochondrial autophagy of chondrocytes, plays an important role in the pathogenesis of OA. Abnormal mitochondrial biogenesis can accelerate the catabolic reaction of OA chondrocytes and aggravate cartilage damage. The imbalance of mitochondrial redox can lead to the accumulation of reactive oxygen species (ROS), inhibit the synthesis of extracellular matrix, induce ferroptosis and eventually leads to cartilage degradation. The imbalance of mitochondrial dynamics can lead to mitochondrial DNA mutation, decreased adenosine triphosphate production, ROS accumulation, and accelerated apoptosis of chondrocytes. When mitochondrial autophagy is damaged, dysfunctional mitochondria cannot be cleared in time, leading to ROS accumulation, which leads to chondrocyte apoptosis. It has been found that substances such as puerarin, safflower yellow, and astaxanthin can inhibit the development of OA by regulating mitochondrial homeostasis, which proves the potential to be used in the treatment of OA.@*CONCLUSION@#The mitochondrial homeostasis imbalance in chondrocytes is one of the most important pathogeneses of OA, and further exploration of the mechanisms of mitochondrial homeostasis imbalance is of great significance for the prevention and treatment of OA.

Effect of needle-knife on chondrocyte apoptosis of knee joint in rabbits with knee osteoarthritis based on CircSERPINE2-miR-1271-5P-ERG axis / 中国针灸

OBJECTIVE@#To observe the effect of needle-knife on the chondrocyte apoptosis of knee joint in rabbits with knee osteoarthritis (KOA) based on the CircSERPINE2-miR-1271-5P-E26 specific transformation-related gene (ERG) axis, and to explore the mechanism of needle-knife for KOA.@*METHODS@#Thirty-six New Zealand white rabbits were randomly divided into a normal group, a model group, a needle-knife group and a sham needle-knife group, 9 rabbits in each group. The rabbits in the model group, the needle-knife group and the sham needle-knife group were treated with modified Videman method to prepare KOA model. After successful modeling, the rabbits in the needle-knife group were treated with needle-knife at cord adhesion and nodules near quadriceps femoris tendon and internal and external collateral ligament on the affected knee joint; the rabbits in the sham needle-knife group were treated with sham needle-knife baside the needle insertion point of the needle-knife group (needle-knife was only inserted, without any operation). The treatment was given once a week, 3 times in total. The Lequesne MG behavioral score was used to evaluate the knee joint damage in each group before and after intervention. After intervention, HE staining and transmission electron microscopy were used to observe the cartilage tissue morphology and ultrastructure of chondrocytes in the knee joint in each group; TUNEL method was used to detect the level of chondrocyte apoptosis in the knee joint; real-time fluorescence quantitative PCR was used to detect the expression of CircSERPINE2, miR-1271-5P and ERG mRNA in knee cartilage tissue in each group.@*RESULTS@#After intervention, compared with the normal group, the Lequesne MG behavioral score in the model group was increased (P<0.01). Compared with the model group and the sham needle-knife group, the Lequesne MG behavioral score in the needle-knife group was decreased (P<0.01). In the model group and the sham needle-knife group, the number of chondrocytes and organelles was decreased, the cell nucleus was shrunk, mitochondria was swelling or disappeared; in the needle-knife group, the number of chondrocytes and organelles was increased, the cell nucleus was not obviously shrunk and the mitochondria was not obviously swelling. Compared with the normal group, the level of chondrocyte apoptosis in the model group was increased (P<0.01); compared with the model group and the sham needle-knife group, the level of chondrocyte apoptosis in the needle-knife group was decreased (P<0.01, P<0.05). Compared with the normal group, the expression of CircSERPINE2 and ERG mRNA in the model group was decreased (P<0.01), and the expression of miR-1271-5P mRNA was increased (P<0.01); compared with the model group and the sham needle-knife group, the expression of CircSERPINE2 and ERG mRNA in the needle-knife group was increased (P<0.01), and the expression of miR-1271-5P mRNA was decreased (P<0.01).@*CONCLUSION@#Needle-knife could reduce the knee joint damage and chondrocyte apoptosis in KOA rabbits, which may be related to up-regulating the expression of CircSERPINE2 and ERG mRNA, and inhibiting the expression of miR-1271-5P mRNA.

Effect of pulsed electromagnetic fields on mesenchymal stem cell-derived exosomes in inhibiting chondrocyte apoptosis / 生物医学工程学杂志

The study aims to explore the effect of mesenchymal stem cells-derived exosomes (MSCs-Exo) on staurosporine (STS)-induced chondrocyte apoptosis before and after exposure to pulsed electromagnetic field (PEMF) at different frequencies. The AMSCs were extracted from the epididymal fat of healthy rats before and after exposure to the PEMF at 1 mT amplitude and a frequency of 15, 45, and 75 Hz, respectively, in an incubator. MSCs-Exo was extracted and identified. Exosomes were labeled with DiO fluorescent dye, and then co-cultured with STS-induced chondrocytes for 24 h. Cellular uptake of MSC-Exo, apoptosis, and the protein and mRNA expression of aggrecan, caspase-3 and collagenⅡA in chondrocytes were observed. The study demonstrated that the exposure of 75 Hz PEMF was superior to 15 and 45 Hz PEMF in enhancing the effect of exosomes in alleviating chondrocyte apoptosis and promoting cell matrix synthesis. This study lays a foundation for the regulatory mechanism of PEMF stimulation on MSCs-Exo in inhibiting chondrocyte apoptosis, and opens up a new direction for the prevention and treatment of osteoarthritis.

GPRC5B protects osteoarthritis by regulation of autophagy signaling

Osteoarthritis (OA) is one of the most common chronic diseases in the world. However, current treatment modalities mainly relieve pain and inhibit cartilage degradation, but do not promote cartilage regeneration. In this study, we show that G protein-coupled receptor class C group 5 member B (GPRC5B), an orphan G-protein-couple receptor, not only inhibits cartilage degradation, but also increases cartilage regeneration and thereby is protective against OA. We observed that Gprc5b deficient chondrocytes had an upregulation of cartilage catabolic gene expression, along with downregulation of anabolic genes in vitro. Furthermore, mice deficient in Gprc5b displayed a more severe OA phenotype in the destabilization of the medial meniscus (DMM) induced OA mouse model, with upregulation of cartilage catabolic factors and downregulation of anabolic factors, consistent with our in vitro findings. Overexpression of Gprc5b by lentiviral vectors alleviated the cartilage degeneration in DMM-induced OA mouse model by inhibiting cartilage degradation and promoting regeneration. We also assessed the molecular mechanisms downstream of Gprc5b that may mediate these observed effects and identify the role of protein kinase B (AKT)-mammalian target of rapamycin (mTOR)-autophagy signaling pathway. Thus, we demonstrate an integral role of GPRC5B in OA pathogenesis, and activation of GPRC5B has the potential in preventing the progression of OA.

Research progress of chondrocyte mechanotransduction mediated by TRPV4 and PIEZOs / 生物医学工程学杂志

Mechanical signal transduction are crucial for chondrocyte in response to mechanical cues during the growth, development and osteoarthritis (OA) of articular cartilage. Extracellular matrix (ECM) turnover regulates the matrix mechanical microenvironment of chondrocytes. Thus, understanding the mechanotransduction mechanisms during chondrocyte sensing the matrix mechanical microenvironment can develop effective targeted therapy for OA. In recent decades, growing evidences are rapidly advancing our understanding of the mechanical force-dependent cartilage remodeling and injury responses mediated by TRPV4 and PIEZOs. In this review, we highlighted the mechanosensing mechanism mediated by TRPV4 and PIEZOs during chondrocytes sensing mechanical microenvironment of the ECM. Additionally, the latest progress in the regulation of OA by inflammatory signals mediated by TRPV4 and PIEZOs was also introduced. These recent insights provide the potential mechanotheraputic strategies to target these channels and prevent cartilage degeneration associated with OA. This review will shed light on the pathogenesis of articular cartilage, searching clinical targeted therapies, and designing cell-induced biomaterials.

Effects of dexmedetomidine on ADAMTS5 mediated matrix degradation in chondrocytes and expressions of related factors / 西安交通大学学报(医学版)

【Objective】 To investigate the effects of dexmedetomidine (DEX) intervention on the expressions of chondrocytes and related factors in vitro and its possible molecular mechanisms. 【Methods】 C28/I2 normal human chondrocyte lines were cultured in vitro, and dexmedetomidine at the concentration of 1 μmol/L was selected to intervene for 24 h and 48 h, respectively. The morphology and cell density of chondrocytes were observed after DEX culture at different time points. Immunofluorescence technique was used to detect the expression levels of disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) in chondrocytes in each group. The expression levels of Adamts5, aggrecan (Acan), versican (Vcan), Furin, proprotein convertase subtilisin/kexin type 6 (Pcsk6), collagen type Ⅰ alpha 1 (Col1a1), collagen type Ⅱ alpha 1 (Col2a1), collagen type X alpha 1 (Col10a1), and SRY2 related high mobility group box gene9 (Sox9) were detected by RT-PCR. Adamts5 gene knockout chondrocytes were constructed by lentivirus transfection technology and treated with DEX; RT-PCR was used to detect the effects of DEX on the expression levels of Acan, Vcan, Furin, Pcsk6 and Sox9 after Adamts5 gene knockout. 【Results】 After 24 and 48 h of intervention with 1 μmol/L DEX, the morphology and size of chondrocytes did not change significantly, but the cell density increased slightly. Immunofluorescence assay showed that the expression of ADAMTS5 increased at first and then decreased after DEX treatment for 24 and 48h, respectively (P=0.032). RT-PCR results showed that with the extension of intervention time, the expression of Adamts5 first increased and then decreased. The expression difference between 48 and 24 h after culture was statistically significant (P=0.032). The change trend of Pcsk6 was the same as that of Adamts5, while the change trend of Acan expression was opposite that of Adamts5. Chondrocytes knocked out Adamts5 gene and intervened with DEX for 24 and 48 h. The results of RT-PCR showed that the expression of Pcsk6 decreased while that of Acan increased and the changes were significant. 【Conclusion】 Dexmedetomidine may activate ADAMTS5 zymogen through Pcsk6, thereby promoting proteoglycan degradation in chondrocytes.

Progress in research on PI3K/ AKT signaling pathway in autophagy and injury of chondrocytes in osteoarticular diseases / 西安交通大学学报(医学版)

This paper reviews the status quo of recent years’ research on autophagy and damage of chondrocytes in Kashin-Beck disease （KBD） and osteoarthritis （OA）. PI3K/AKT signaling pathway and mTOR regulate the autophagy activity of chondrocytes. PI3K/AKT signaling pathway can promote the proliferation of chondrocytes and cause their damage by inhibiting their autophagy activity. This might play an important role in the occurrence and progression of bone and joint diseases such as KBD and OA， and provide scientific basis for revealing the pathogenesis and treatment plan of them.

Deeper Understanding the Pathogenesis of Osteoarthritis from Matrix Viscoelasticity and Calcium Signaling / 医用生物力学

Generally, extracellular matrix (ECM) has the characteristics of viscoelasticity. In osteoarthritis (OA), catabolic processes alter the viscoelastic properties of functional pericellular matrix (PCM) of chondrocytes. Chondrocytes sense and respond to their mechanical microenvironment via an array of mechanosensitive receptors and channels that activate a complex network of downstream signaling pathways to regulate several cell processes central to OA pathology. Advances in understanding the specific mechanosignalling mechanisms in articular cartilage will promote the development of cell microenvironment construction in cartilage tissue engineering and the targeted precision therapeutics for OA. In this review, the work on the mechanism of matrix viscoelasticity regulating chondrocytes mechanotransduction by Agarwal et al. was briefly commented, and the recent advances related with their work was also discussed.

The Role and Mechanisms of Mechanical Stimulation in Degeneration of Vertebral Cartilage Endplates / 医用生物力学

The important function of the endplate is to transmit stress and supply nutrition. Endplate degeneration might induce or promote degeneration of the intervertebral disc, causing a series of spine diseases that seriously impair people’s health and life quality. Endplate chondrocytes can respond to mechanical stimulation, which is an important factor affecting endplate degeneration. Inappropriate mechanical stimulation will accelerate endplate degeneration. This review summarized the effects of mechanical stimulation on vertebral endplate chondrocyte apoptosis, synthesis inhibition, calcification, and extracellular matrix degradation. The endplate degeneration induced by mechanical stimulation is regulated by a complex network of signal pathways composed of various signal transduction factors. The signal pathways involved in this review included NF-κB, Wnt, Hedgehog, MAPK, RhoA/Rock-1, AKT/mTOR, TGF-β signaling pathway and miRNA related signals. The interconnection of these pathways was highlighted and summarized. Multiple signaling pathways work together to regulate endplate chondrocyte metabolism, which ultimately leads to the endplate degeneration. This review might shed light on early diagnosis and precise treatment of cartilage endplate degeneration.

Development of fibrocartilage layers in Achilles tendon enthesis in rabbits / Journal of Rural Medicine

Objective: The details regarding the development of fibrocartilage layers in Achilles tendon (AT) enthesis are unknown. Therefore, we evaluated the development of fibrocartilage layers in AT enthesis using a rabbit model.Materials and Methods: Forty-eight male Japanese white rabbits were used in this study. Six of them were euthanized at different stages (day 1, and 1, 2, 4, 6, 8, 12, and 24 weeks of age). The proliferation, apoptosis, Sox9-positivity rates, and chondrocyte number were evaluated. Additionally, safranin O-stained glycosaminoglycan (GAG) areas, width of AT enthesis, and calcaneus length were assessed. All parameters were compared to those at 24 weeks of age.Results: The level of chondrocyte apoptosis was high from 1 to 8 weeks of age, and high expression level of Sox9 was maintained from day 1 to 6 weeks of age, which decreased gradually. Safranin O-stained GAG areas increased up to 12 weeks, calcaneus length increased up to 6 weeks, and the width of AT enthesis increased up to 1 week of age.Conclusion: The changes in chondrocyte and extracellular matrix were completed by 8 and 12 weeks of age, respectively. The development of fibrocartilage layers in AT enthesis was completed by 12 weeks of age. Our results contribute to the administration of appropriate treatments based on age and aid in the development of novel methods for regenerating AT enthesis.

Effect of 17β-estradiol on the proliferation of condylar chondrocytes / 华西口腔医学杂志

OBJECTIVES@#To study the effects of 17β-estradiol (E2) on the regulation of the proliferation of condylar chondrocytes and provide a preliminary discussion on the role of phosphorylate-mammalian target of rapamycin (p-mTOR) in this regulatory process.@*METHODS@#Condylar chondrocytes were isolated from 6-week-old female rats for primary culture. Drug treatment with different concentrations of E2 and/or rapamycin (RAPA) was carried out on second-generation cells. Cell Counting Kit 8 was used to measure the cell viability of condylar chondrocytes after culture for 24, 48, or 72 h, and reverse transcription-polymerase chain reaction (RT-PCR) was applied to detect the relative gene expression of estrogen receptor alpha (ERα), estrogen receptor beta (ERβ), collagen type Ⅱ (COLⅡ), autophagy-related gene 6 (Beclin-1), and autophagy-related gene 5 (ATG-5). Western blot was employed to determine the relative protein expression of ERα, ERβ, Beclin-1, lipid-modified light chain 3B (LC3-Ⅱ), and p-mTOR.@*RESULTS@#E2 could significantly promote the proliferation of chondrocytes cultured @*CONCLUSIONS@#At a concentration of 10

Chemerin, a pro-inflammatory adipokine, regulates chondrocyte proliferation and metabolism by increasing production of nitric oxide / 中国组织工程研究

BACKGROUND: The key pathological characteristics of osteoarthritis are manifested in the degeneration of the cartilage caused by inflammation, and chondrocytes are the only cells in cartilage tissues. Studies have shown that Chemerin can stimulate the migration of leukocytes to the inflammation site and increase the inflammation signal of chondrocytes, suggesting that Chemerin can play a role in arthritis. Our previous research indicated that the serum Chemerin level in patients with osteoarthritis was significantly increased, and the Chemerin level in the synovial fluid was related to the severity of osteoarthritis based on the Kellgren-Lawrence classification. Chemerin may be used as an inflammatory factor in osteoarthritis. OBJECTIVE: To investigate the effect of Chemerin on the proliferation and metabolism of chondrocytes. METHODS: The chondrocytes from neonatal mice were isolated by collagenase type II digestion, and then cultured. Cell growth curves were established and the range of concentrations of Chemerin that exhibited toxicity to normal chondrocytes was screened using an MTT assay. Subsequently, 10 μg/L interleukin-1β was used to stimulate the chondrocytes in order to establish an in vitro model of osteoarthritis induction. After the chondrocytes had been cultured in the presence of the drug for 2 days, cell morphology, proliferation and metabolism were evaluated by hematoxylin-eosin staining and diacetate fluorescein/ propidium iodide staining. In addition, the expression of inducible nitric oxide polymerase was analyzed by measuring the secretion of nitric oxide. Furthermore, qRT-PCR was used to quantify mRNA expression of proteoglycan, type II collagen α1, matrix metalloprotease-13 and nitric oxide synthase 2. RESULTS AND CONCLUSION: The chondrocytes cultured in vitro exhibited healthy activity and morphology. Furthermore, chemerin (50 μg/L) and interleukin-1β (10 μg/L) were able to reduce the synthesis of extracellular matrix, enhance the secretion of nitric oxide and increase chondrocyte apoptosis. More importantly, the qRT-PCR results indicated that Chemerin and interleukin-1β caused similar effects, by which the expression of cartilage-specific genes was downregulated and catabolism-related genes upregulated. As a pro-inflammatory factor, Chemerin can increase the generation of nitric oxide in chondrocytes, regulate cell metabolism, stimulate cell apoptosis and act synergistically with interleukin-1β.

Role and application of bone morphogenetic proteins in articular cartilage regeneration / 中国组织工程研究

BACKGROUND: Articular cartilage degeneration is the main cause of osteoarthritis. Bone morphogenetic proteins play an important role in cartilage regeneration and repair. OBJECTIVE: To review the research progress of bone morphogenetic protein in the process of articular cartilage regeneration. METHODS: A computer-based online search of PubMed and Elsevier databases was performed using the keywords “bone morphogenetic proteins, BMPs, arthritis, osteoarthritis, OA, cartilage, chondrocyte” in English. A total of 272 papers were retrieved, 96 of which were included in final analysis. Another 27 papers related to concepts were also included. Therefore, 123 papers are finally included. RESULTS AND CONCLUSION: Bone morphogenetic proteins participate in many biological processes including cell proliferation, differentiation, migration, and apoptosis, and play an important role in the formation of bone and cartilage. Bone morphogenetic proteins participate in a variety of signaling pathway cascades by binding to different receptors, which can protect articular cartilage from cartilage destruction caused by inflammation and trauma. Bone morphogenetic proteins alone or in combination with other cytokines can repair cartilage defects improve degenerative lesions, and promote the differentiation and regeneration of articular chondrocytes. However, there are still some practical problems that need to be solved for the widespread use of bone morphogenetic proteins in cartilage regeneration, such as the safety of drug transporters, the lack of effective biological scaffold materials, the optimal dosage and time point of use of biological agents, and their toxic and side effects. Future research will focus on how to solve the above problems. The widespread application of bone morphogenetic proteins will open a new era for targeted treatment of cartilage damage and cartilage degenerative diseases represented by osteoarthritis.

Ultrastructural changes of the white zone cells of the meniscus in a rat model of early osteoarthritis / 中国组织工程研究

BACKGROUND: The research focuses of knee osteoarthritis are on mainly articular cartilage, subchondral bone and synovium. There are few studies on the ultrastructure of the meniscus in animal models. OBJECTIVE: On the basis of observing the ultrastructure and types of chondrocytes in the white zone of the meniscus, to observe the ultrastructural changes of the white zone cells of the meniscus in an animal model of early osteoarthritis, in order to explore the relationship between the microstructural changes and the physiological functional changes in the meniscus. METHODS: Sprague-Dawley rats were randomly divided into a control group and a model group. Rats in the model group were made into the model of early knee osteoarthritis by intraarticular injection of papain. After 5 weeks, the meniscuses of three rat models in each group were taken, located and observed for the ultrastructure of the white zone cells through a transmission electron microscope. An ethics approval was obtained from the Animal Ethics Committee of Fujian University of Traditional Chinese Medicine. RESULTS AND CONCLUSION: In the control group, most of cells were fusiform in the superficial layer of meniscus and were triangular-like in the deeper layer. They were rich in rough endoplasmic reticulum and mitochondria, with presence of Golgi and other organelles. Extracellular collagen fibrils were mainly type II collagen fibrils. The cells in the white zone of meniscus were chondrocytes. In the model group, the meniscal surface became rough, the cells were swollen, cytoplasmic organelles were reduced and swollen, glycogen was accumulated, and most of nuclei were abnormal with heterochromatin agglutination. Extracellular collagen fibrils became disordered and sparse. These findings indicate that the mild degeneration of chondrocytes and matrix in the meniscus can reduce the ability of cells to synthesize and secrete matrix components, which may lead to the physiological hypofunction.

Mangiferin attenuates IL / 中南大学学报(医学版)

OBJECTIVES@#Chondrocyte apoptosis is an important process in the pathogenesis of osteoarthritis. Mangiferin exerts multiple pharmacological effects such as anti-inflammatory and anti-apoptosis. However, the role of mangiferin in chondrocyte apoptosis is not clear. In this study, we aimed to explore the role of mangiferin in IL-1β-induced chondrocyte apoptosis.@*METHODS@#ATDC5 cells were randomly divided into a control group, a IL-1β group, a MFN-L group, a MFN-M group, a MFN-H group and a MFN+LY294002 group. Cells in the control group were treated with IL-1β (10 ng/mL) for 24 h; cells in the MFN-L group, the MFN-M group and the MFN-H group were pretreated with 5, 10 and 20 μmol/L mangiferin for 1 h respectively, and then they were treated with IL-1β (10 ng/mL) for 24 h; cells in the MFN+LY294002 group were treated with LY294002 (25 μmol/L) for 1 h, then mangiferin (20 μmol/L) and IL-1β (10 ng/mL) for 1 h and 24 h, respectively. Cell viability was detected by CCK-8 assay and cell apoptosis was measured by flow cytometry. Colorimetric assay was conducted to measure the caspase-3 activity. The protein levels of Bcl-2, Bax, and phosphoinositide 3-kinase (PI3K)/Akt signaling pathway related proteins were detected by Western blotting.@*RESULTS@#Compared to the control group, cell viability was significantly decreased; cell apoptosis, caspase-3 activity and Bax protein expression were significantly increased; the protein levels of Bcl-2, p-PI3K, and p-Akt were significantly decreased in the IL-1β group (all @*CONCLUSIONS@#Mangiferin could attenuate IL-1β-induced apoptosis of the mice chondrocytes, which is mediated by the activation of PI3K/Akt signaling pathway.

Effect of quercetin on chondrocyte phenotype and extracellular matrix expression / 中国天然药物

Due to the poor repair ability of cartilage tissue, regenerative medicine still faces great challenges in the repair of large articular cartilage defects. Quercetin is widely applied as a traditional Chinese medicine in tissue regeneration including liver, bone and skin tissues. However, the evidence for its effects and internal mechanisms for cartilage regeneration are limited. In the present study, the effects of quercetin on chondrocyte function were systematically evaluated by CCK8 assay, PCR assay, cartilaginous matrix staining assays, immunofluorescence assay, and western blotting. The results showed that quercetin significantly up-regulated the expression of chondrogenesis genes and stimulated the secretion of GAG (glycosaminoglycan) through activating the ERK, P38 and AKT signalling pathways in a dose-dependent manner. Furthermore, in vivo experiments revealed that quercetin-loaded silk protein scaffolds dramatically stimulated the formation of new cartilage-like tissue with higher histological scores in rat femoral cartilage defects. These data suggest that quercetin can effectively stimulate chondrogenesis in vitro and in vivo, demonstrating the potential application of quercetin in the regeneration of cartilage defects.

Ethanol extraction technology of Epimedii Folium and protective effect of ethanol extract on chondrocyte / 中国中药杂志

Uniform design-comprehensive scoring method was used to investigate the effects of ethanol dosage, ethanol concentration and extraction time, based on the evaluation index from transfer rates of epimedin A, epimedin B, epimedin C, icariin and baohuoside Ⅰ, which are the main active components in Epimedii Folium. Furthermore, the optimum conditions for the ethanol extraction process were determined by multiple linear stepwise regression and empirical test. Then, the ethanol extract of Epimedii Folium prepared according to the optimized technological conditions was used to intervene the injury model of chondrocyte induced by interleukin-1 beta(IL-1β). Annexin V-FITC/PI staining flow cytometry was used to detect the apoptotic rate of chondrocyte and analyze the effect of ethanol extract of Epimedii Folium on chondrocyte injury model. The optimum conditions of ethanol extraction were as follows. Crude powder of Epimedii Folium was added with 18 times of 70% ethanol solution, and extracted for twice in the refluxing process, for 60 minutes each time. Under the conditions, the extraction rates of the above five active components were 94.21%, 94.76%, 93.85%, 96.17% and 96.85%, respectively. The optimized ethanol extraction process of Epimedii Folium was reasonable, feasible and reproducible. This ethanol extract could significantly reduce the early apoptotic rate, late apoptotic and necrotic rate, total apoptotic rate(P<0.05 or P<0.01) of chondrocyte injury model induced by IL-1β, suggesting that the ethanol extract of Epimedii Folium can inhibit the apoptosis of chondrocytes induced by IL-1β to a certain extent, which lays a foundation for further study on its prevention and treatment of osteoarthritis.

Effect of Duhuo Xuduan Tang for Oral Administration and Iontophoresis on SDF-1/CXCR4 Signaling Pathway and Relevant Factors of Cartilage Degradation in Knee Joint Fluid of Patients with Knee Osteoarthritis with Liver and Kidney Deficiency / 中国实验方剂学杂志

Objective::To observe the clinical efficacy of Duhuo Xuduan Tang for oral administration and iontophoresis in the treatment of knee osteoarthritis (KOA) with liver and kidney deficiency and its effect on stromal cell-derived factor-1 (SDF-1)/C-X-C chemokine receptor type 4 (CXCR4) signaling pathway. Method::Totally 150 KOA patients with deficiency of liver and kidney diagnosed in the Teaching Hospital of Tianjin University of Traditional Chinese Medicine(TCM) were randomly divided into control group, oral TCM group and iontophoresis group, with 50 cases in each group. The control group was given glucosamine sulfate capsule, 0.5 g/time, twice a day, while the oral TCM group was given Duhuo Xuduan Tang, 150 mL/time, twice a day. In the iontophoresis group, Duhuo Xuduan Tang was administered at Kuangu acupoint, Xiguan acupoint, Xiyan acupoint and Dubi acupoint for iontophoresis for 30 minutes, once a day. All of the three groups were treated for 4 weeks. The swelling degree and the pain degree of knee joint before and after treatment were observed, and the clinical efficacy was recorded. The protein contents of SDF-1, CXCR4, matrix metalloproteinase-3 (MMP-3) and matrix metalloproteinase-13 (MMP-13) in knee joint fluid before and after treatment were detected by enzyme-linked immunosorbent assay (ELISA). Result::The efficacy of oral TCM group was better than that of iontophoresis group and control group, and the recurrence rate was the lowest (P<0.05). Compared with before treatment, the tenderness increased, whereas visual analogue scale(VAS) score, knee swelling score, The Western Ontario and McMaste Universities (WOMAC) score and SDF-1, CXCR4, MMP-3 and MMP-13 protein content in knee joint fluid decreased in oral TCM group after treatment, which were better than those in iontophoresis group and control group (P<0.05). Conclusion::Duhuo Xuduan Tang for oral administration and iontophoresis has an obvious effect on KOA with liver and kidney deficiency, with the best effect through oral administration. Its mechanism may be related to the inhibition of SDF-1/CXCR4 inflammatory signaling pathway and cartilage decomposition.