This study investigated the effects of SIRT1 gene knock-out on osteoarthritis in mice, and the possible roles of SREBP2 protein and the PI3K/AKT signaling pathway in the effects. Mice were randomly divided into a normal group and a SIRT1 gene knock-out group (6 mice in each group). In these groups, one side of the knee anterior cruciate ligament was traversed, and the ipsilateral medial meniscus was cut to establish an osteoarthritis model of knee joint. The countralateral synovial bursa was cut out, serving as controls. The knee joint specimens were then divided into four groups: SIRT1control group (group A, n=6); SIRT1osteoarthritis group (group B, n=6); SIRT1control group (group C, n=6); SIRT1osteoarthritis group (group D, n=6). HE staining, Masson staining, Safranin O-Fast Green staining and Van Gieson staining were used to observe the morphological changes in the articular cartilage of the knee. Immunohistochemical staining was employed to detect the expression of SIRT1, SREBP2, VEGF, AKT, HMGCR and type II collagen proteins. SA-β-gal staining was utilized to evaluate chondrocyte aging. The results showed clear knee joint cartilage destruction and degeneration in the SIRT1osteoarthritis group. The tidal line was twisted and displaced anteriorly. Type II collagen was destroyed and distributed unevenly. Compared with the SIRT1osteoarthritis group and SIRT1control group, SIRT1 protein expression was not obviously changed in the SIRT1osteoarthritis group (P>0.05), while the expression levels of the SREBP2, VEGF and HMGCR proteins were significantly increased (P<0.05) and the levels of AKT and type II collagen proteins were significantly decreased (P<0.05). SIRT1 gene knock-out may aggravate cartilage degeneration in osteoarthritis by activating the SREBP2 protein-mediated PI3K/AKT signalling pathway, suggesting that SIRT1 gene may play a protective role against osteoarthritis.
Animals ; Cartilage ; pathology ; Chondrocytes ; metabolism ; Collagen Type II ; metabolism ; Disease Models, Animal ; Humans ; Knee Joint ; metabolism ; pathology ; Mice ; Mice, Knockout ; Oncogene Protein v-akt ; genetics ; Osteoarthritis ; genetics ; pathology ; Phosphatidylinositol 3-Kinases ; genetics ; Signal Transduction ; genetics ; Sirtuin 1 ; genetics ; Sterol Regulatory Element Binding Protein 2 ; biosynthesis ; genetics ; Vascular Endothelial Growth Factor A ; biosynthesis

SRT1720, a new discovered drug, was reported to activate silent information regulator 1 (SIRT1) and inhibit the chondrocyte apoptosis. However, the underlying mechanism remains elusive. In the present study, the chondrocytes were extracted from the cartilage tissues of New Zealand white rabbits, cultured in the presence of sodium nitroprusside (SNP) (2.5 mmol/L) and divided into five groups: 1, 5, 10, and 20 μmol/L SRT1720 groups and blank control group (0 μmol/L SRT1720). MTT assay was used to detect the chondrocyte viability and proliferation, and DAPI staining and flow cytometry to measure the chondrocyte apoptosis. The expression levels of SIRT1, p53, NF-κB/p65, Bax, and peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) were detected by Western blotting and the expression levels of SIRT1, type II collagen, and aggrecan mRNA by RT-PCR. The results showed that in the SRT1720-treated groups, the nuclei of chondrocytes were morphologically intact and had uniform chromatin. In the blank control group, nuclear rupture into debris was observed in chondrocytes. With the SRT1720 concentration increasing, the chondrocyte viability increased, the apoptosis rate decreased, the protein expression levels of SIRT1 and PGC-1α and the mRNA expression levels of type II collagen and aggrecan increased ({ptP}<0.05), and the expression levels of p53, NF-κB and bax decreased (P<0.05). It was suggested that SRT1720 inhibits chondrocyte apoptosis by activating the expression of SIRT1 via p53/bax and NF-κB/PGC-1α pathways.
Aggrecans ; genetics ; metabolism ; Animals ; Apoptosis ; drug effects ; Cartilage, Articular ; cytology ; drug effects ; metabolism ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Chondrocytes ; cytology ; drug effects ; metabolism ; Chromatin ; chemistry ; drug effects ; metabolism ; Collagen Type II ; genetics ; metabolism ; Gene Expression Regulation ; Heterocyclic Compounds, 4 or More Rings ; pharmacology ; Nitroprusside ; toxicity ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; genetics ; metabolism ; Primary Cell Culture ; Rabbits ; Signal Transduction ; drug effects ; genetics ; Sirtuin 1 ; genetics ; metabolism ; Transcription Factor RelA ; genetics ; metabolism ; Tumor Suppressor Protein p53 ; genetics ; metabolism ; bcl-2-Associated X Protein ; genetics ; metabolism

OBJECTIVETo establish a reliable model for drug screening and therapy by culturing rat femoral head and inducing cartilage degeneration quickly in vitro.

METHODSThe femoral heads from the same SD rats of two-month old were divided into control group and experimental group respectively. They were cultured with DMEM medium plus 10% fetal bovine serum or DMEM medium plus 10% fetal bovine serum plus 50 ng/ml IL-1β for three days. Femoral heads were fixed in 4% paraformaldehyde, decalcified, dehydrated, embedded in paraffin and cut into slices. Specimens were stained with Toluidine blue and Safranine O-Fast Green FCF. The protein expression levels of type II collagen, MMP13, Sox9 and ADAMTS5 were analyzed by immunofluorescence.

RESULTSBoth the Toluidine blue and Safranine O staining were pale in the margin of femoral heads which were stimulated with IL-1β for three days compared to that in control group. The Fast Green FCF staining was positive at the edge of the femoral head in experimental group, which indicated that cartilage became degenerated. The expression levels of both type H collagen and Sox9 were decreased significantly while the expression levels of MMP13 and ADAMTS5 were increased in experimental group.

CONCLUSIONThe model of cartilage degeneration is established by culturing and inducing the degeneration of the femoral heads quickly in vitro.

Animals ; Cartilage Diseases ; genetics ; metabolism ; Collagen Type II ; genetics ; metabolism ; Disease Models, Animal ; Femur Head ; metabolism ; Humans ; In Vitro Techniques ; Interleukin-1beta ; genetics ; metabolism ; Male ; Matrix Metalloproteinase 13 ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; SOX9 Transcription Factor ; genetics ; metabolism

OBJECTIVEAlthough chondroprotective activities have been documented for polysaccharides, the potential target of different polysaccharide may differ. The study was aimed to explore the effect of glucan HBP-A in chondrocyte monolayer culture and chondrocytes-alginate hydrogel constructs in vivo, especially on the expression of type II collagen.

METHODSChondrocytes isolated from rabbit articular cartilage were cultured and verified by immunocytochemical staining of type II collagen. Chondrocyte viability was assessed after being treated with HBP-A in different concentrations. Morphological status of chondrocytes-alginate hydrogel constructs in vitro was observed by scanning electron microscope (SEM). The constructs were treated with HBP-A and then injected to nude mice subcutaneously. Six weeks after transplantation, the specimens were observed through transmission electron microscopy (TEM). The mRNA expressions of disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTs-5), aggrecan and type II collagen in both monolayer culture and constructs were determined by real time polymerase chain reaction (PCR). The expression of type II collagen and matrix metalloproteinases-3 (MMP-3) in chondrocyte monolayer culture was also tested through Western blot and enzyme linked immunosorbent assay (ELISA), respectively.

RESULTSMMP-3 secretion and ADAMTs-5 mRNA expression in vitro were inhibited by HBP-A at 0.3 mg/mL concentration. In morphological study, there were significant appearance of collagen in those constructs treated by HBP-A. Accordingly, in both chondrocyte monolayer culture and chondrocytes-alginate hydrogel constructs, the expression of type II collagen was increased significantly in HBP-A group when compared with control group (P<0.001).

CONCLUSIONSThe study documented that the potential pharmacological target of glucan HBP-A in chondrocytes monolayer culture and tissue engineered cartilage in vivo may be concerned with the inhibition of catabolic enzymes MMP-3, ADAMTs-5, and increasing of type II collagen expression.

ADAM Proteins ; genetics ; metabolism ; Aggrecans ; genetics ; metabolism ; Alginates ; pharmacology ; Animals ; Cartilage, Articular ; drug effects ; physiology ; Cell Proliferation ; drug effects ; Cell Shape ; drug effects ; Cell Survival ; drug effects ; Chondrocytes ; cytology ; drug effects ; metabolism ; ultrastructure ; Collagen Type II ; genetics ; metabolism ; Female ; Glucans ; pharmacology ; Glucuronic Acid ; pharmacology ; Hexuronic Acids ; pharmacology ; Hydrogel, Polyethylene Glycol Dimethacrylate ; pharmacology ; Immunohistochemistry ; Matrix Metalloproteinase 3 ; metabolism ; Mice, Nude ; RNA, Messenger ; genetics ; metabolism ; Rabbits ; Tissue Engineering ; methods

Eupatilin is the main active component of DA-9601, an extract from Artemisia. Recently, eupatilin was reported to have anti-inflammatory properties. We investigated the anti-arthritic effect of eupatilin in a murine arthritis model and human rheumatoid synoviocytes. DA-9601 was injected into collagen-induced arthritis (CIA) mice. Arthritis score was regularly evaluated. Mouse monocytes were differentiated into osteoclasts when eupatilin was added simultaneously. Osteoclasts were stained with tartrate-resistant acid phosphatase and then manually counted. Rheumatoid synoviocytes were stimulated with TNF-alpha and then treated with eupatilin, and the levels of IL-6 and IL-1beta mRNA expression in synoviocytes were measured by RT-PCR. Intraperitoneal injection of DA-9601 reduced arthritis scores in CIA mice. TNF-alpha treatment of synoviocytes increased the expression of IL-6 and IL-1beta mRNAs, which was inhibited by eupatilin. Eupatilin decreased the number of osteoclasts in a concentration dependent manner. These findings, showing that eupatilin and DA-9601 inhibited the expression of inflammatory cytokines and the differentiation of osteoclasts, suggest that eupatilin and DA-9601 is a candidate anti-inflammatory agent.
Animals ; Anti-Inflammatory Agents/pharmacology/*therapeutic use ; Arthritis, Experimental/chemically induced/*drug therapy ; Arthritis, Rheumatoid/drug therapy/pathology ; Cell Differentiation/*drug effects ; Cells, Cultured ; Collagen Type II ; Cytokines/biosynthesis ; Disease Models, Animal ; Drugs, Chinese Herbal/therapeutic use ; Female ; Flavonoids/pharmacology/*therapeutic use ; Humans ; Inflammation/drug therapy/immunology ; Interleukin-1beta/genetics/metabolism ; Interleukin-6/genetics/metabolism ; Lymph Nodes/cytology ; Mice ; Mice, Inbred DBA ; Monocytes/cytology ; Osteoclasts/*cytology ; Plant Extracts/pharmacology ; RNA, Messenger/biosynthesis ; Synovial Membrane/cytology ; T-Lymphocytes, Regulatory/cytology/immunology ; Tumor Necrosis Factor-alpha/pharmacology

PURPOSE: To investigate the molecular responses of various genes and proteins related to disc degeneration upon treatment with cytokines that affect disc-cell proliferation and phenotype in living human intervertebral discs (IVDs). Responsiveness to these cytokines according to the degree of disc degeneration was also evaluated. MATERIALS AND METHODS: The disc specimens were classified into two groups: group 1 (6 patients) showed mild degeneration of IVDs and group 2 (6 patients) exhibited severe degeneration of IVDs. Gene expression was analyzed after treatment with four cytokines: recombinant human bone morphogenic protein (rhBMP-2), transforming growth factor-beta (TGF-beta), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). Molecular responses were assessed after exposure of cells from the IVD specimens to these cytokines via real-time polymerase chain reaction and immunofluorescence staining. RESULTS: mRNA gene expression was significantly greater for aggrecan, type I collagen, type II collagen, alkaline phosphatase, osteocalcin, and Sox9 in group 1 than mRNA gene expression in group 2, when the samples were not treated with cytokines. Analysis of mRNA levels for these molecules after morphogen treatment revealed significant increases in both groups, which were much higher in group 1 than in group 2. The average number of IVD cells that were immunofluorescence stained positive for alkaline phosphatase increased after treatment with rhBMP-2 and TGF-beta in group 1. CONCLUSION: The biologic responsiveness to treatment of rhBMP-2, TGF-beta, TNF-alpha, and IL-1beta in the degenerative living human IVD can be different according to the degree of degeneration of the IVD.
Adult ; Aggrecans/genetics/metabolism ; Alkaline Phosphatase/genetics/metabolism ; Biological Products/pharmacology/*therapeutic use ; Bone Morphogenetic Protein 2/pharmacology/therapeutic use ; Collagen Type I/genetics/metabolism ; Collagen Type II/genetics/metabolism ; Cytokines/*pharmacology/*therapeutic use ; Female ; Fluorescent Antibody Technique ; Gene Expression Regulation/drug effects ; Humans ; Interleukin-1/pharmacology/therapeutic use ; Intervertebral Disc/*drug effects/*pathology ; Intervertebral Disc Degeneration/*drug therapy/genetics/*pathology ; Male ; Middle Aged ; Osteocalcin/genetics/metabolism ; RNA, Messenger/genetics/metabolism ; Recombinant Proteins/pharmacology/therapeutic use ; SOX9 Transcription Factor/genetics/metabolism ; Transforming Growth Factor beta/pharmacology/therapeutic use ; Tumor Necrosis Factor-alpha/pharmacology

This study aims to investigate the effect of total flavones of Fructus Chorspondiatis (TFFC) on the mRNA and protein expression of collagen type I and III of rat cardiac fibroblasts (CFs) induced by angiotensin II (Ang II), and explore its anti-myocardial fibrosis molecular mechanism. Neonatal rat CFs were prepared from Sprague-Dawley rats (1-3 d after birth). The expression of collagen type I and III mRNA and protein were measured by RT-PCR and Western blotting, respectively. The study showed that stimulation of neonatal rat CFs with 100 nmol.L-1 of Ang II for 72 h resulted in a significant increase of the expression of collagen type I and III mRNA and protein. The changes on the expression level were blocked by TFFC. The results demonstrated that TFFC can inhibit myocardial fibrosis induced by Ang II in rats, which is probably associated with the collagen type I and III mRNA and protein levels up-regulated by Ang II, and TFFC was shown to decrease the expression levels of collagen type I and III mRNA and protein.
Anacardiaceae ; chemistry ; Angiotensin II ; pharmacology ; Animals ; Animals, Newborn ; Cells, Cultured ; Collagen Type I ; genetics ; metabolism ; Collagen Type III ; genetics ; metabolism ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; administration & dosage ; isolation & purification ; pharmacology ; Fibroblasts ; cytology ; metabolism ; Flavones ; administration & dosage ; isolation & purification ; pharmacology ; Fruit ; chemistry ; Myocardium ; cytology ; metabolism ; Plants, Medicinal ; chemistry ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley

It is widely known that hypoxia can promote chondrogenesis of human bone marrow derived mesenchymal stem cells (hMSCs) in monolayer cultures. However, the direct impact of oxygen tension on hMSC differentiation in three-dimensional cultures is still unknown. This research was designed to observe the direct impact of oxygen tension on the ability of hMSCs to "self assemble" into tissue-engineered cartilage constructs. hMSCs were cultured in chondrogenic medium (CM) containing 100 ng/mL growth differentiation factor 5 (GDF-5) at 5% (hypoxia) and 21% (normoxia) O2 levels in monolayer cultures for 3 weeks. After differentiation, the cells were digested and employed in a self-assembly process to produce tissue-engineered constructs under hypoxic and normoxic conditions in vitro. The aggrecan and type II collagen expression, and type X collagen in the self-assembled constructs were assessed by using immunofluorescent and immunochemical staining respectively. The methods of dimethylmethylene blue (DMMB), hydroxyproline and PicoGreen were used to measure the total collagen content, glycosaminoglycan (GAG) content and the number of viable cells in each construct, respectively. The expression of type II collagen and aggrecan under hypoxic conditions was increased significantly as compared with that under normoxic conditions. In contrast, type X collagen expression was down-regulated in the hypoxic group. Moreover, the constructs in hypoxic group showed more significantly increased total collagen and GAG than in normoxic group, which were more close to those of the natural cartilage. These findings demonstrated that hypoxia enhanced chondrogenesis of in vitro, scaffold-free, tissue-engineered constructs generated using hMSCs induced by GDF-5. In hypoxic environments, the self-assembled constructs have a Thistological appearance and biochemical parameters similar to those of the natural cartilage.
Aggrecans ; genetics ; metabolism ; Bone Marrow Cells ; drug effects ; metabolism ; Cartilage ; cytology ; metabolism ; Cell Differentiation ; drug effects ; genetics ; Cell Hypoxia ; Cells, Cultured ; Chondrogenesis ; drug effects ; genetics ; Collagen Type II ; genetics ; metabolism ; Collagen Type X ; metabolism ; Female ; Gene Expression ; drug effects ; Glycosaminoglycans ; metabolism ; Growth Differentiation Factor 5 ; pharmacology ; Humans ; Immunohistochemistry ; Male ; Mesenchymal Stromal Cells ; drug effects ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Tissue Engineering ; methods

Mesenchymal stem cells (MSCs) are multipotent stem cells that differentiate into a variety of cell types. Low frequency pulsed electromagnetic fields (LFPEMFs) therapy can causes biochemical changes at the cellular level to accelerate tissue repair in mammals. So, we tested the hypothesis that LFPEMFs can promote chondrogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) in vitro. The rBMSCs were isolated by adherence method and the third-generation of the rBMSCs were randomly divided into LFPEMFs groups, chondrocyte-induced group and control group. LFPEMFs groups with complete medium were exposed to 50Hz, 1mT PEMFs for 30 min every day, lasting for 10, 15 and 20 d, respectively. Chondrocyte-induced group were treated with chondrogenic media, while control groups were only cultured with complete medium. The mRNA expressions of type II-collagen (Col II) and aggrecan were determined by Real-time fluorescent quantitation PCR. The protein expression of Col II and aggrecan were detected with toluidine blue stain or immunocytochemical stain, respectively. The result showed that the mRNA and protein expression level of Col-II and aggrecan were significantly higher in the LFPEMFs group or chondrocyte-induced group, compared to the control group. It suggest that LFPEMFs could contribute to rBMSCs to differentiate into chondrogenic differentiation in vitro.
Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; radiation effects ; Cells, Cultured ; Chondrocytes ; cytology ; Collagen Type II ; genetics ; metabolism ; Electromagnetic Fields ; Male ; Mesenchymal Stromal Cells ; cytology ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley

IL-17-producing CD4+ T cells (Th17) play important functions in autoimmune diseases and allograft rejection of solid organs. We examined the effects of IL 17 and its mechanism of action on arthritis in a murine collagen-induced arthritis (CIA) model using bone marrow transplantation (BMT) system. DBA/1J mice were administered a lethal radiation dose and then rescued with bone marrow derived from either wild-type (WT) or IL-17-/- mice on C57BL/6 background mice. CIA was induced after the bone marrow transplant, and disease progression was characterized. DBA/1J mice with CIA that received IL-17-/- donor bone marrow showed potently inhibited development and severity of clinical arthritis as compared with CIA mice that received WT bone marrow. Reduced secretion of the pro-inflammatory cytokines tumor necrosis factor-alpha, IL-1beta, and IL-6, and collagen-specific T cell responses were observed in mice that received IL-17-/- bone marrow. IL-17 blockade also inhibited effector T cell proliferation by reciprocally regulating the Treg/Th17 ratio. IL-17 blockade prevented joint destruction in mice with CIA. These findings suggest that CIA with BMT is a viable method of immunological manipulation and that IL-17 deficiency suppresses severe joint destruction and inflammation in CIA mice. There may be clinical benefits in blocking IL-17 and BMT in the treatment of rheumatoid arthritis.
Animals ; Antigens, Differentiation/metabolism ; Arthritis, Experimental/pathology/*prevention & control ; *Bone Marrow Transplantation ; Cell Differentiation ; Cell Proliferation ; Cells, Cultured ; Collagen Type II ; Cytokines/metabolism ; Humans ; Interleukin-17/*deficiency/genetics ; Joints/pathology ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Inbred DBA ; Mice, Knockout ; Osteoclasts/metabolism/physiology ; Signal Transduction ; T-Lymphocytes/metabolism/physiology ; Transplantation, Homologous