Protective effects of emodin on subchondral bone and articular cartilage in osteoporotic osteoarthritis rats: A preclinical study.

BACKGROUND: Osteoporotic osteoarthritis (OP-OA) is a severe pathological form of OA, urgently requiring precise management strategies and more efficient interventions. Emodin (Emo), an effective ingredient found in the traditional Chinese medicine rhubarb, has been dEmonstrated to promote osteogenesis and inhibit extracellular matrix degradation. In this study, we aimed to investigate the interventional effects of Emo on the subchondral bone and cartilage of the knee joints in OP-OA model rats. METHODS: Thirty-two SD rats were randomly and equally divided into sham, OP-OA, Emo low-dose, and Emo high-dose groups. Micro-CT scanning was conducted to examine the bone microstructure of the rat knee joints. H&E and Safranin O and Fast Green staining (SO&FG) were performed for the pathomorphological evaluation of the rat cartilage tissues. ELISA was used to estimate the rat serum expression levels of inflammatory factors, including interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α). Additionally, the CCK-8 assay was utilized for determining the viability of Emo-treated BMSCs. Western blot and real-time PCR analyses were also employed to measure the bone formation indexes and cartilage synthesis and decomposition indexes. Lastly, the osteogenic and chondrogenic differentiation efficiency of the BMSCs was investigated via Alizarin Red and Alcian Blue staining. RESULTS: Emo intervention alleviated the bone microstructural disruption of the subchondral bone and articular cartilage in the OP-OA rats and up-regulated the expression of bone and cartilage anabolic metabolism indicators, decreased the expression of cartilage catabolism indicators, and diminished the expression of inflammatory factors in the rat serum (P<0.05). Furthermore, Emo reversed the decline in the osteogenic and chondrogenic differentiation ability of the BMSCs (P<0.05). CONCLUSION: Emo intervention mitigates bone loss and cartilage damage in OP-OA rats and promotes the osteogenic and chondrogenic differentiation of BMSCs.

Duhuo Jisheng Decoction regulates intracellular zinc homeostasis by enhancing autophagy via PTEN/Akt/mTOR pathway to improve knee cartilage degeneration.

BACKGROUND: Articular cartilage and cartilage matrix degradation are key pathological changes occurring in the early stage of knee osteoarthritis (KOA). However, currently, there are limited strategies for early prevention and treatment of KOA. Duhuo Jisheng Decoction (DHJSD) is a formula quoted in Bei Ji Qian jin Yao Fang, which was compiled by Sun Simiao in the Tang Dynasty of China. As a complementary therapy, it is widely used to treat early-stage KOA in China; however, its mechanism has not been completely elucidated. OBJECTIVE: This study investigated the potential role of DHJSD in preventing cartilage degradation and the underlying mechanism. METHODS: A rat model of KOA model was established via the Hulth method. Subsequently, 25 rats were randomized into sham (saline), model control (saline), high-DHJSD (1.9g/mL of DHJSD), medium-DHJSD (1.2g/mL of DHJSD), and low-DHJSD groups (0.6g/mL of DHJSD). After 4 weeks of treatment, all rats were sacrificed and the severity of the cartilage degeneration was evaluated by a series of histological methods. The autophagosome was observed using transmission electron microscopy, and the related functional proteins were detected by the western blotting and real-time polymerase chain reaction. Next, the mechanism by which DHJSD improves knee cartilage degeneration was further clarified the in vitro by gene silencing technology combined with a series of functional experiments. The proteins levels of PTEN, Akt, p-Akt, mTOR, and p-mTOR, as well as the marker proteins of autophagy and apoptosis were determined. Zinc levels in chondrocytes were determined using inductively coupled plasma mass spectrometry. RESULTS: Histopathological staining revealed that DHJSD had a protective effect on the cartilage. DHJSD increased autophagosome synthesis and the expression of autophagy proteins LC3 and Beclin-1 in chondrocytes. Moreover, it reduced the phosphorylation levels of Akt and mTOR and the levels of zinc, MMP-13, Bax, and Bcl-2. Following PTEN silencing, this DHJSD-mediated reduction in Akt and mTOR phosphorylation and Bax, Bcl-2, and zinc levels were further decreased; in addition, DHJSD-mediated increase in LC3 and Beclin-1 levels was decreased. CONCLUSION: DHJSD inhibits the Akt/mTOR signaling pathway by targeting PTEN to promote autophagy in chondrocytes, which may help reduce MMP-13 production by regulating zinc levels in chondrocytes.

An integrated network pharmacology approach reveals that Darutigenol reduces inflammation and cartilage degradation in a mouse collagen-induced arthritis model by inhibiting the JAK-STAT3 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Darutigenol (DL) is a natural active product derived from the Chinese herbal medicine Sigesbeckia glabrescens (Makino) Makino. It is administered as a traditional Chinese medicine (TCM) to dispel rheumatism, benefit the joints, and detoxify. However, its potential mechanism in the treatment of rheumatoid arthritis (RA) remains unknown. AIMS OF THE STUDY: The objectives of this research were to determine the effects and elucidate the modes of action of DL on RA-related joint inflammation. MATERIALS AND METHODS: Network pharmacology and molecular docking were used to screen and validate candidate DL targets for RA treatment, respectively. A DBA/1 mouse rheumatoid arthritis model was induced with bovine type II collagen. Intragastric DL administration was followed by the calculation of the clinical arthritis index. A section of the ankle joint was excised and stained and the pathological changes in it were observed. Enzyme-linked immunosorbent assays (ELISA) and western blotting (WB) were used to clarify the mechanisms of DL in RA treatment. RESULTS: DL effectively attenuated the inflammation, mitigated the articular cartilage degradation, and bone erosion, and alleviated the inflammatory joints associated with RA. Network pharmacology screened six key targets of DL while molecular docking revealed that it docked well with its protein targets. The DL treatment group presented with significantly less ankle joint redness and swelling, a lower arthritis index scores and serum and bone marrow supernatant IL-6 levels, more complete ankle joint surfaces, and less synovial inflammation, cartilage degradation, and bone erosion than the collagen-induced arthritis (CIA) group. The DL treatment also substantially downregulated the Janus kinase (JAK)1, JAK3, matrix metalloproteinase (MMP)2, MMP9, and phospho-signal transducer and activator of transcription (p-STAT)3 proteins in the joints. CONCLUSIONS: To the best of our knowledge, the present work was the first to demonstrate that DL has significant anti-inflammatory efficacy and reduces cartilage degradation and bone erosion. It also demonstrated that the anti-RA effect of DL may be explained by its ability to inhibit joint inflammation and reduce articular cartilage degradation through the interleukin (IL)-6/JAK1,3/STAT3 axis and downregulate MMP2 and MMP9. Hence, DL might play a therapeutic role in a mouse RA model.

Tick tock, the cartilage clock.

Osteoarthritis (OA) is the most common age-related joint disease, affecting articular cartilage and other joint structures, causing severe pain and disability. Due to a limited understanding of the underlying disease pathogenesis, there are currently no disease-modifying drugs for OA. Circadian rhythms are generated by cell-intrinsic timekeeping mechanisms which are known to dampen during ageing, increasing disease risks. In this review, we focus on one emerging area of chondrocyte biology, the circadian clocks. We first provide a historical perspective of circadian clock discoveries and the molecular underpinnings. We will then focus on the expression and functions of circadian clocks in articular cartilage, including their rhythmic target genes and pathways, links to ageing, tissue degeneration, and OA, as well as tissue niche-specific entrainment pathways. Further research into cartilage clocks and ageing may have broader implications in the understanding of OA pathogenesis, the standardization of biomarker detection, and the development of novel therapeutic routes for the prevention and management of OA and other musculoskeletal diseases.

An injectable copolymer of fatty acids (ARA 3000 BETA) as a promising treatment for osteoarthritis.

Osteoarthritis (OA) is the most prevalent rheumatic disease and a fast growing cause of disability. Current pharmacological treatments include antalgics and non-steroid anti-inflammatory drugs to control pain and inflammation as well as slow acting drugs such as intra-articular (IA) administration of hyaluronic acid. Oral supplementation or diet rich in polyunsaturated free fatty acids are proposed but evidence for benefit is still under debate. We here investigated the therapeutic potential of ARA 3000 BETA, an injectable copolymer of fatty acids, at the structural level in OA. Collagenase-induced osteoarthritis model was induced in C57BL/6 mice by collagenase injection into knee joint. Mice were treated with one or two IA or four intra-muscular injections (IM) of ARA 3000 BETA. At sacrifice, knee joints were recovered for cartilage analysis by confocal laser scanning microscopy (CLSM) and bone analysis by micro-computed tomography system. OA histological scoring was performed after safranin O/fast green staining. Histological analysis revealed a protective effect against cartilage degradation in treated knee joints after IM and IA administration. This was confirmed by CLSM with a significant improvement of all articular cartilage parameters, including thickness, volume and surface degradation whatever the administration route. A slight protective effect was also noticed on subchondral bone parameters and knee joint calcification after IM administration and to a lesser extent, two IA injections. We demonstrated the therapeutic efficacy of injectable ARA 3000 BETA in OA with a protection against cartilage and bone alterations providing the proof-of-concept that clinical translation might be envisioned to delay disease progression.

1,25-Dihydroxyvitamin D Deficiency Accelerates Aging-related Osteoarthritis via Downregulation of Sirt1 in Mice.

Emerging observational data suggest that vitamin D deficiency is associated with the onset and progression of knee osteoarthritis (OA). However, the relationship between vitamin D level and OA and the role of vitamin D supplementation in the prevention of knee OA are controversial. To address these issues, we analyzed the articular cartilage phenotype of 6- and 12-month-old wild-type and 1α(OH)ase-/- mice and found that 1,25(OH)2D deficiency accelerated the development of age-related spontaneous knee OA, including cartilage surface destruction, cartilage erosion, proteoglycan loss and cytopenia, increased OARSI score, collagen X and Mmp13 positive chondrocytes, and increased chondrocyte senescence with senescence-associated secretory phenotype (SASP). 1,25(OH)2D3 supplementation rescued all knee OA phenotypes of 1α(OH)ase-/- mice in vivo, and 1,25(OH)2D3 rescued IL-1ß-induced chondrocyte OA phenotypes in vitro, including decreased chondrocyte proliferation and cartilage matrix protein synthesis, and increased oxidative stress and cell senescence. We also demonstrated that VDR was expressed in mouse articular chondrocytes, and that VDR knockout mice exhibited knee OA phenotypes. Furthermore, we demonstrated that the down-regulation of Sirt1 in articular chondrocytes of 1α(OH)ase-/- mice was corrected by supplementing 1,25(OH)2D3 or overexpression of Sirt1 in mesenchymal stem cells (MSCs) and 1,25(OH)2D3 up-regulated Sirt1 through VDR mediated transcription. Finally, we demonstrated that overexpression of Sirt1 in MSCs rescued knee OA phenotypes in 1α(OH)ase-/- mice. Thus, we conclude that 1,25(OH)2D3, via VDR-mediated gene transcription, plays a key role in preventing the onset of aging-related knee OA in mouse models by up-regulating Sirt1, an aging-related gene that promotes articular chondrocyte proliferation and extracellular matrix protein synthesis, and inhibits senescence and SASP.

No adverse effects on periarticular tissue by intra-articular vitamin D analogue calcipotriol in a reduced-dose zymosan-induced arthritis model in rats.

Calcipotriol, a vitamin D analogue, is an antiproliferative and anti-inflammatory drug currently used in psoriasis. Here, our aim was to analyse the safety of calcipotriol for cartilage and bone in alleviated-dose (0.1 mg instead of usual ≥1mg dose) zymosan-induced arthritis in rats. Theoretically, high doses of vitamin D or analogues could have detrimental effects on bone or cartilage. The rats were divided into four groups: vehicle (n = 9), dexamethasone 0.1 mg/kg (n = 9), calcipotriol 0.1 mg/kg (n = 8) and negative control (n = 10) with no injections. Arthritic rats were given phosphate-buffered saline (PBS) injections to left knees as a control. After euthanasia on day 8, all knees were imaged with micro-computed tomography for surface lesions and decalcified for histological analyses. Contrary to our expectations, no significant changes could be observed in the tomography data and histological scores among the three treatment groups or between the vehicle-treated and non-arthritic group. Calcipotriol did not cause adverse effects on cartilage or subchondral bone within a week, suggesting that it could be safely used in local treatment of arthritis. The alleviated model caused synovitis with local and systemic inflammatory response without cartilage erosions, which might be useful in studying self-limiting synovitis where cartilage or bone effects are not of primary interest.

Estrogen antagonizes ASIC1a-induced chondrocyte mitochondrial stress in rheumatoid arthritis.

BACKGROUND: Destruction of articular cartilage and bone is the main cause of joint dysfunction in rheumatoid arthritis (RA). Acid-sensing ion channel 1a (ASIC1a) is a key molecule that mediates the destruction of RA articular cartilage. Estrogen has been proven to have a protective effect against articular cartilage damage, however, the underlying mechanisms remain unclear. METHODS: We treated rat articular chondrocytes with an acidic environment, analyzed the expression levels of mitochondrial stress protein HSP10, ClpP, LONP1 by q-PCR and immunofluorescence staining. Transmission electron microscopy was used to analyze the mitochondrial morphological changes. Laser confocal microscopy was used to analyze the Ca2+, mitochondrial membrane potential (Δψm) and reactive oxygen species (ROS) level. Moreover, ASIC1a specific inhibitor Psalmotoxin 1 (Pctx-1) and Ethylene Glycol Tetraacetic Acid (EGTA) were used to observe whether acid stimulation damage mitochondrial function through Ca2+ influx mediated by ASIC1a and whether pretreatment with estrogen could counteract these phenomena. Furthermore, the ovariectomized (OVX) adjuvant arthritis (AA) rat model was treated with estrogen to explore the effect of estrogen on disease progression. RESULTS: Our results indicated that HSP10, ClpP, LONP1 protein and mRNA expression and mitochondrial ROS level were elevated in acid-stimulated chondrocytes. Moreover, acid stimulation decreased mitochondrial membrane potential and damaged mitochondrial structure of chondrocytes. Furthermore, ASIC1a specific inhibitor PcTx-1 and EGTA inhibited acid-induced mitochondrial abnormalities. In addition, estrogen could protect acid-stimulated induced mitochondrial stress by regulating the activity of ASIC1a in rat chondrocytes and protects cartilage damage in OVX AA rat. CONCLUSIONS: Extracellular acidification induces mitochondrial stress by activating ASIC1a, leading to the damage of rat articular chondrocytes. Estrogen antagonizes acidosis-induced joint damage by inhibiting ASIC1a activity. Our study provides new insights into the protective effect and mechanism of action of estrogen in RA.

Nodakenin attenuates cartilage degradation and inflammatory responses in a mice model of knee osteoarthritis by regulating mitochondrial Drp1/ROS/NLRP3 axis.

Osteoarthritis (OA) is a common degenerative disease with few treatments. In traditional Chinese medicine (TCM), Radix Angelicae biseratae (RAB) is commonly used to treat OA. Nodakenin (Nod) is one main coumarin active component in RAB and exhibits anti-inflammatory, anti-oxidative, and anti-apoptotic effects. Reactive oxygen species (ROS) produced by mitochondria play a vital role in the pathogenesis of OA. We hypothesized that Nod might ameliorate cartilage degradation and inflammatory responses by regulating the mitochondrial Drp1/ROS/NLRP3 axis. With this, the effects of Nod on a mouse model of knee OA and activated primary chondrocytes were assessed. The results showed that Nod intervention improved bone volume, lowered trabecular separation, and increased trabecular number in the subchondral bone. Nod decreased the Osteoarthritis Research Society International (OARSI) scores and increased collagen II-positive areas in the articular cartilage of the tibial plateau. Compared with OA mice, Nod-treated animals exhibited lower levels of inflammatory factors in the serum and synovitis of the knee joint. In vitro results indicated that Nod suppressed dynamin-related protein 1 (Drp1) phosphorylation and massive ROS production by Drp1-dependent mitochondrial fission in lipopolysaccharide-stimulated chondrocytes. Moreover, Nod inhibited the mRNA levels of inflammatory cytokines (COX 2, IL-1ß, and TNF-α), nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, and matrix metalloproteinase 13 expression in activated chondrocytes. In conclusion, Nod attenuates cartilage degradation and inflammatory responses in mice with OA by regulating the mitochondrial Drp1/ROS/NLRP3 axis, suggesting its potential for OA therapy.

Effects of Combined Allogenic Adipose Stem Cells and Hyperbaric Oxygenation Treatment on Pathogenesis of Osteoarthritis in Knee Joint Induced by Monoiodoacetate.

The beneficial effects of HBO in inflammatory processes make it an attractive type of treatment for chronic arthritis. In addition, the effects of combination therapy based on adipose stem cells and HBO on OA progression have not been fully investigated. The current study explored the efficacy of intra-articular injection of allogeneic adipose-derived mesenchymal stem cells (ADMSCs) combined with hyperbaric oxygenation treatment (HBO) in a rat osteoarthritis (OA) model. The rat OA model was induced by intra-articular injection of monoiodoacetate (MIA) and 7 days after application of MIA rats were divided into five groups: healthy control (CTRL), osteoarthritis (OA), ADMSCs (ADS), the HBO+ADS21day and HBO+ADS28day groups. A single dose of 1 × 106 allogeneic ADMSCs suspended in sterile saline was injected into the knee joint alone or in combination with HBO treatment. Rats were sacrificed at 3 or 4 weeks after MIA injection. Treatment outcomes were evaluated by radiographic, morphological and histological analysis and by specific staining of articular cartilage. We also measured the level of inflammatory and pro/antioxidative markers. We confirmed that combined treatment of ADMSCs and HBO significantly improved the regeneration of cartilage in the knee joint. Rtg score of knee joint damage was significantly decreased in the HBO+ADS21day and HBO+ADS28day groups compared to the OA. However, the positive effect in the HBO+ADS28day group was greater than the HBO+ADS21day group. The articular cartilage was relatively normal in the HBO+ADS28day group, but moderate degeneration was observed in the HBO+ADS21day compared to the OA group. These findings are in line with the histopathological results. A significantly lower level of O2-. was observed in the HBO+ADS28day group but a higher NO level compared to the HBO+ADS21day group. Moreover, in the HBO+ADS28day group significantly higher concentrations of IL-10 were observed but there was no significant difference in proinflammatory cytokine in serum samples. These results indicate that a single intra-articular injection of allogeneic ADMSCs combined with HBO efficiently attenuated OA progression after 28 days with greater therapeutic effect compared to alone ADMSCs or after 3 weeks of combined treatment. Combined treatment might be an effective treatment for OA in humans.

Intra-articular ozone slows down the process of degeneration of articular cartilage in the knees of rats with osteoarthritis.

BACKGROUND: Osteoarthritis (OA) is a joint disease of multifactorial etiology, affecting mainly the knees. We aimed to evaluate the effects of two different doses of gaseous ozone intra-articularly on the knee cartilage morphology of rats with osteoarthritis (OA). METHODS: The articular lesion was induced by sodium monoiodoacetate (MIA). 40 Wistar rats were divided into 4 groups: G1 control (without lesion and without treatment), G2 articular lesion (AL) (only lesion MIA-induced), G3 AL + treatment with 5 µg/mL of ozone intra-articular, and G4 AL + treatment with 10 µg/mL of ozone intra-articular. The experiment was carried out for 60 days. RESULTS: Both doses of ozone intra-articular demonstrated less reduction in joint space (G3 and G4) compared to the G2, formation of osteophytes, but without subchondral sclerosis. Ozone decreased the volumetric density of the articular lesion (VV(AL)) of tibial. The treatments recovered VV(AL) of the femur similar to G1. Ozone lower dose (G3) showed lower tibia and femur macroscopic scores. CONCLUSION: Intra-articular gaseous ozone can delay the degeneration of articular cartilage and can represents an integrative therapy in the OA treatment of knee after 60 days of treatment. For the first time the role of ozone in articular cartilage degeneration was evaluated helping to understand this therapy.

Effects of photobiomodulation therapy in chondrocyte response by in vitro experiments and experimental model of osteoarthritis in the knee of rats.

The purpose of this study is to evaluate the effects of photobiomodulation (PBM) therapy in chondrocyte response by in vitro experiments and cartilage repair using an experimental model of osteoarthritis (OA) in the knee of rats. The in vitro experiment was performed with chondrocyte cells, and they were divided into two groups: non-irradiated and irradiated with PBM (808 nm; 0.8 J or 1.4 J). Then, cell proliferation was evaluated after 1, 3, and 5 days. The experimental model of osteoarthritis (OA) was performed in the knee of 64 Wistar rats, and they were assorted into control group (CG), PBM (808 nm; 1.4 J). The results of in vitro showed that PBM 1.4 J increased cell proliferation, on days 1 and 5. However, after 3 days was demonstrated a significant increase in cell proliferation in PBM 0.8 J. The in vivo experiment results demonstrated, on histological analysis, that PBM presented less intense signs of tissue degradation with an initial surface discontinuity at the superficial zone and disorganization of the chondrocytes in the cartilage region when compared to CG, after 4 and 8 weeks. These findings were confirmed by immunohistochemistry and qRT-PCR analysis which showed that PBM increased IL-4, IL-10, COL-2, Aggrecan, and TGF-ß which are anabolic factors and acts on extracellular matrix. Also, PBM reduces the IL1-ß, an inflammatory marker that operates as a catabolic factor on articular cartilage. In conclusion, these results suggest that PBM may have led to a return to tissue homeostasis, promoting chondroprotective effects and stimulating the components of the articular tissue.

Warming moxibustion attenuates inflammation and cartilage degradation in experimental rabbit knee osteoarthriti.

OBJECTIVE: To explore the molecular mechanism of warming moxibustion (WM) in knee osteoarthritis (KOA). METHODS: The knee joints of 40 New Zealand rabbits were placed in a plaster cast in an extended position to establish a KOA model. The animals were randomly divided into four groups: the control group, model group, WM group, and diclofenac (DF) group. Hematoxylin-eosin staining and the modified Mankin score were applied to evaluate the histopathological changes. Chondrocyte apoptosis was determined by the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Western blotting and real-time quantitative polymerase chain reaction were performed to measure the expression of interleukin-1α (IL-1ß), prostaglandin E receptor 3 (PTGER3), a disintegrin-like and metalloproteinase with thrombospondin type-1 motifs-5 (ADAMTS-5), matrix metalloproteinase-13 (MMP-13), and C-terminal telopeptides of collagen type II (CTX-II) in cartilage tissues of the different groups. The concentrations of IL-1ß, PTGER3, and CTX-II in serum were detected by the enzyme-linked immunosorbent assay. RESULTS: Rabbits with KOA in the WM and DF groups showed significantly reduced cartilage erosion and Mankin scores, compared with the untreated rabbits. The number of TUNEL-positive cells observed in the WM group was much fewer than that in the model group. The expression of PTGER3, MMP-13, CTX-II IL-1ß, and ADAMTS-5 in cartilage tissues was remarkably downregulated following therapy with WM and DF. Moreover, a marked reduction was observed in the serum levels of IL-1ß, PTGER3, and CTX-II in the WM and DF groups. CONCLUSION: WM exerts favorable therapeutic effects on articular injuries of KOA by regulating the expression of inflammatory and cartilage degradation-related cytokines.

Evaluation of electroacupuncture for symptom modification in a rodent model of spontaneous osteoarthritis.

OBJECTIVE: Faced with the frustration of chronic discomfort and restricted mobility due to osteoarthritis (OA), many individuals have turned to acupuncture for relief. However, the efficacy of acupuncture for OA is uncertain, as much of the evidence is inconclusive. The purpose of this study was to evaluate electroacupuncture (EA) in a rodent model of OA such that conclusions regarding its effectiveness for symptom or disease modification could be drawn. METHODS: Ten 12-month-old male Hartley guinea pigs-which characteristically have moderate to advanced OA at this age-were randomly assigned to receive EA for knee OA (n = 5) or anesthesia only (control group, n = 5). Treatments were performed three times weekly for 3 weeks, followed by euthanasia 2 weeks later. Gait analysis and enclosure monitoring were performed weekly to evaluate changes in movement. Serum was collected for inflammatory biomarker testing. Knee joints were collected for histology and gene expression. RESULTS: Animals receiving EA had significantly greater changes in movement parameters compared to those receiving anesthesia only. There was a tendency toward decreased serum protein concentrations of complement component 3 (C3) in the EA group compared to the control group. Structural and antioxidant gene transcripts in articular cartilage were increased by EA. There was no significant difference in total joint histology scores between groups. CONCLUSION: This study provides evidence that EA has a positive effect on symptom, but not disease, modification in a rodent model of OA. Further investigations into mechanistic pathways that may explain the efficacy of EA in this animal model are needed.

Pretreatment with mechano growth factor E peptide attenuates osteoarthritis through improving cell proliferation and extracellular matrix synthesis in chondrocytes under severe hypoxia.

Osteoarthritis (OA) is characterized by pain and declining gait function associated with degeneration of cartilage. A severe hypoxic environment occurs due to tissue injury in the joint cavity and may aggravate the development of OA. In this study, the effects of severe hypoxia and treatment with mechano growth factor (MGF) E peptide on metabolism of the extracellular matrix (ECM) during the progression of OA were determined. The results showed that cell viability, cell proliferation, and type II collagen expression in chondrocytes were significantly inhibited by cobalt chloride (CoCl2)-simulated severe hypoxia, whereas cell apoptosis and expression levels of hypoxia inducible factor 1 alpha, type I collagen, and matrix metalloproteinases 1/13 were clearly induced. Pretreatment with MGF E peptide reduced the abovementioned adverse effects induced by CoCl2-simulated severe hypoxia in chondrocytes. Pretreatment also upregulated the proliferation of chondrocytes under severe hypoxia through the PI3K-Akt and MEK-ERK1/2 signaling pathways. In a rat model of monosodium iodoacetate (MIA)-induced OA. MIA treatment induced tissue necrosis and cartilage degeneration, and histological score was significantly decreased. The levels of type II collagen and aggrecan were reduced after MIA treatment for 4 or 6 weeks, and abnormal distribution of ECM occurred in the inner epicondyle after 6 weeks. MGF E peptide also reduced the progression of MIA-induced OA by retarding cartilage degeneration, upregulating type II collagen synthesis, and improving ECM distribution after 4 or 6 weeks. Our findings suggest that MGF attenuates the progression of OA, and thus may be applied for the treatment of OA in the clinic.

A single intra-articular dose of vitamin D analog calcipotriol alleviates synovitis without adverse effects in rats.

1,25-dihydroxyvitamin-D3 and its derivatives have shown anti-arthritic and chondroprotective effects in experimental animal models with prophylactic dosing. The purpose of this preliminary study was to test the efficacy and safety of calcipotriol, vitamin D analog, as a treatment for a fully-developed knee arthritis in Zymosan-induced arthritis (ZIA) model. Forty 5-month-old male Sprague-Dawley rats were randomized into three arthritis groups and a non-arthritic control group with no injections (10 rats/group). A day after Zymosan (0.1 mg) had been administrated into the right knee joints, the same knees were injected with calcipotriol (0.1 mg/kg), dexamethasone (0.1 mg/kg) or vehicle in a 100 µl volume. The left control knees were injected with saline (PBS) on two consecutive days. All injections, blood sampling and measurements were performed under general anesthesia on days 0, 1, 3 and 8. Internal organs and knees were harvested on day 8 and the histology of the whole knees was assessed blinded. Joints treated with calcipotriol showed a milder histological synovitis than those treated with vehicle (p = 0.041), but there was no statistically significant difference between the dexamethasone and vehicle groups. The clinical severity of arthritis did not differ between the arthritis groups measured by body temperature, swelling of the knee, thermal imaging, clinical scoring or cytokine levels on days 1, 3 and 8. Weight loss was bigger in rats treated with dexamethasone, propably due to loss of appetite,compared to other arthritis groups on days 2-3 (p<0.05). Study drugs did not influence serum calcium ion and glucose levels. Taken together, this preliminary study shows that a single intra-articular injection of calcipotriol reduces histological grade of synovitis a week after the local injection, but dexamethasone did not differ from the vehicle. Calcipotriol may have an early disease-modifying effect in the rat ZIA model without obvious side effects.

Decursin alleviates the aggravation of osteoarthritis via inhibiting PI3K-Akt and NF-kB signal pathway.

Osteoarthritis (OA) is a common joint disease that takes joint degeneration or aging as its pathological basis, and joint swelling, pain or dysfunction as its main clinical manifestations. Decursin (DE), the major active component isolated from Angelica gigas Nakai, has been demonstrated to possess anti-inflammatory effect in many diseases. But, the specific physiological mechanism of DE on OA is not clear yet. Therefore, the object of this study was to assess the therapeutic effect of DE on OA, and to explore its potential anti-inflammatory mechanisms. In vitro cell experiments, the inflammatory response in chondrocytes is mediated via interleukin-1ß (IL-1ß), which led to abnormal secretion of pro-inflammatory factors, such as prostaglandin E2 (PGE2), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX-2), nitric oxide (NO) and inducible nitric oxide synthase (iNOS). These cytokines were all decreased by the preconditioning of DE in a dose-dependent form of 1, 5, and 10 µM. Moreover, DE could restrain IL-1ß-mediated inflammatory reaction and the collapse of extracellular matrix (ECM) via reducing the secretion of ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) and MMPs (matrix metalloproteinases). In short, DE restrained IL-1ß-mediated abnormal excitation of PI3K/AKT/NF-κB axis. Furthermore, molecular docking analysis showed that DE has a strong binding affinity with the inhibitory targets of PI3K. In vivo animal studies, DE treatment could helped to improve destruction of articular cartilage and decreased the serum inflammatory factor levels in an operationally induced mouse OA model. To sum up, these data obtained from the experiment indicate that DE has good prospects for the treatment of osteoarthritis.

ß-Hydroxy-ß-Methylbutyrate (HMB) Supplementation Prevents Bone Loss during Pregnancy-Novel Evidence from a Spiny Mouse (Acomys cahirinus) Model.

The aim of this study was to determine the effects of ß-hydroxy-ß-methylbutyrate (HMB) supplementation during pregnancy on postpartum bone tissue quality by assessing changes in trabecular and compact bone as well as in hyaline and epiphyseal cartilage. The experiment was carried out on adult 6-month-old female spiny mice (Acomys cahirinus) divided into three groups: pregnant control (PregCont), pregnant HMB-treated (supplemented with 0.02 g/kg b.w of HMB during the second trimester of pregnancy, PregHMB), and non-pregnant females (NonPreg). Cross-sectional area and cortical index of the femoral mid-shaft, stiffness, and Young modulus were significantly greater in the PregHMB group. Whole-bone mineral density was similar in all groups, and HMB supplementation increased trabecular number. Growth plate cartilage was the thinnest, while the articular cartilage was the thickest in the PregHMB group. HMB supplementation increased the content of proteoglycans in the articular cartilage and the percentage of immature collagen content in metaphyseal trabeculae and compact bone. In summary, dietary HMB supplementation during the second trimester of pregnancy intensifies bone metabolic processes and prevents bone loss during pregnancy.

Associations of blood pressure and arterial stiffness with knee cartilage volume in patients with knee osteoarthritis.

OBJECTIVE: To describe the associations of blood pressure and arterial stiffness with knee cartilage volume in patients with knee OA. METHODS: A secondary analysis was performed on the data from participants in a randomized controlled trial that identified the effects of vitamin D supplementation on knee structures and symptoms among patients with symptomatic knee OA. Brachial and central blood pressure, arterial stiffness indicators and knee cartilage volume were measured at baseline and the 2 year follow-up. Associations were assessed using generalized estimating equations. RESULTS: Among 231 participants (average age 63.2 years), 48.9% were females. Higher supine systolic and diastolic pressures were significantly associated with lower tibial cartilage volume (systolic: lateral ß -6.23, medial ß -5.14, total ß -11.35 mm3/mmHg; diastolic: lateral ß -10.25, medial ß -11.29, total ß -21.50 mm3/mmHg). Higher supine systolic pressure was associated with lower femoral cartilage volume (lateral ß -17.35, total ß -28.31 mm3/mmHg). Central systolic pressure and arterial stiffness indicators (including pulse wave velocity, central pulse pressure and peripheral pulse pressure) were largely not associated with knee cartilage volume; however, higher augmentation index was associated with lower tibial and femoral cartilage volume (tibial: medial ß -8.24, total ß -19.13 mm3/%; femoral: lateral ß -23.70, medial ß -26.42, total ß -50.12 mm3/%). CONCLUSIONS: Blood pressure and arterial stiffness are associated with knee cartilage volume at several sites in knee OA patients. This supports that blood pressure and arterial stiffness may involve in the progression of knee OA.

Quantitative proteomics reveal the protective effects of EDS against osteoarthritis via attenuating inflammation and modulating immune response.

ETHNOPHARMACOLOGICAL RELEVANCE: Epimedium brevicornu Maxim, Dioscorea nipponica Makino, and Salvia miltiorrhiza Bunge formula (EDS) are three traditional Chinese medicines commonly combined and used to treat osteoarthritis (OA). However, the mechanism of its therapeutic effect on OA is still unclear. AIM OF THE STUDY: The aim of this study was to investigate the potential anti osteoarthritis mechanism of EDS in the treatment of OA rats' model by quantitative proteomics. MATERIALS AND METHODS: A papain-induced rat OA model was established, and then EDS was intragastrically administered for 28 days. A label-free quantification proteomics was performed to evaluate the holistic efficacy of EDS against OA and identify the possible protein profiles mechanisms. The expression levels of critical changed proteins were validated by RT-qPCR and Western blotting. The effects of EDS were then assessed by evaluating pathologic changes in the affected knee joint and measuring pressure pain threshold, acoustic reflex threshold, angle of joint curvature. RESULTS: Proteomics analysis showed that 62 proteins were significantly upregulated and 208 proteins were downregulated in OA group compared to control group. The changed proteins were involved in activation of humoral immunity response, complement cascade activation, leukocyte mediated immunity, acute inflammatory response, endocytosis regulation, and proteolysis regulation. The EDS treatment partially restored the protein profile changes. The protective effects of EDS on pathologic changes in OA rats' knee joint and pain threshold assessment were consisted with the proteomics results. CONCLUSIONS: The results suggest that EDS exerted synergistic therapeutic efficacies to against OA through suppressing inflammation, modulating the immune system, relieving joint pain, and attenuating cartilage degradation.