Experimental Osteoarthritis In Rats Research Articles

Effects of Etanercept on Experimental Osteoarthritis in Rats: Role of Histone Deacetylases.

Mounting evidence suggests that histone deacetylases (HDAC) inhibitors reduce cartilage destruction in animal models of osteoarthritis (OA). Tumor necrosis factor (TNF)-α-blocking treatment for OA may provide effective joint protection by slowing joint damage. To investigate the effects of intraperitoneal administration of etanercept (a TNF-α inhibitor) on OA development in rats and changes in the nociceptive behavior of rats and expression of HDACs, RUNX2, and MMP13 in cartilage. Induction of OA in Wistar rats was accomplished through anterior cruciate ligament transection (ACLT). One or five milligrams (mg) of etanercept was administered intraperitoneally for 5 consecutive weeks after ACLT to the ACLT + etanercept (1 and 5 mg/kg) groups. Nociceptive behavior and changes in knee joint width were analyzed. Cartilage was evaluated histologically and immunohistochemically. ACLT + etanercept significantly improved mechanical allodynia and weight-bearing distribution compared to ACLT alone. In OA rats treated with etanercept, cartilage degeneration and synovitis were significantly less pronounced than those in ACLT rats. OA-affected cartilage also showed reduced expression of HDAC 6, 7, RUNX-2, and MMP-13 in response to etanercept but increased expression of HDAC4. Our study demonstrated that etanercept therapy (1) attenuated the development of OA and synovitis in rats, (2) reduced nociception, and (3) regulated chondrocyte metabolism, possibly by inhibiting cell HDAC6 and HDAC7, RUNX2, and MMP13 and increasing HDAC4 expression. Based on new evidence, etanercept may have therapeutic potential in OA.

Comparison of the protective effect of the upper zone of the growth plate and unique cartilage matrix-associated protein with hyaluronic acid and corticosteroids on an experimental rat osteoarthritis model.

This study sought to compare the protective effect of the upper zone of the growth plate and unique cartilage matrix-associated protein (UCMA) with hyaluronic acid (HA) and corticosteroids (CS) in a rat model of osteoarthritis (OA). In the experimental animal study, 40 adult male rats were randomly assigned into five groups: control, monosodium iodoacetate (MIA) + vehicle (MIA+V), MIA+HA, MIA+CS, and MIA+UCMA. The OA model was induced by an intra-articular MIA injection to the right knee, and intra-articular injections into the right knee were performed on the treatment groups seven times every three days for 21 days. The knee joints were taken for histopathology and immunohistochemistry (IHC) analyses after the rats were sacrificed. All sections were stained with hematoxylin-eosin, safranin O and fast green FCF, and toluidine blue, and bone morphogenetic protein 2 (BMP-2) and nuclear factor-kappa B (NF-κB) expressions were analyzed with IHC. The Mankin scoring was utilized to determine the histopathological changes in the joint tissues. Mankin score was significantly higher in the MIA group compared to the control group. Histopathologically, in the UCMA-, HA-, and CS-treated groups, degenerations in the articular cartilage were milder than in the MIA+V group. Mankin score was found to be decreased significantly in the UCMA-, HA-, and CS-treated groups compared to the MIA group. Furthermore, IHC analyses revealed that NF-κB and BMP-2 expressions elevated in the MIA-induced OA model, while they were downregulated after UCMA, HA, and CS treatments. Our data revealed that UCMA could be used as a potential protective molecule in the prevention and treatment of OA. Furthermore, the protective effect of UCMA was similar to HA and CS, and its possible beneficial roles against OA may be linked to the reduced BMP-2 and NF-κB levels. Further experimental research would make significant contributions to a better understanding of the therapeutic effect of UCMA on degenerative cartilage tissues.

Пространственное распределение протеогликанов суставного хряща бедренных мыщелков и тибиального плато при экспериментальном остеоартрозе у крыс

Introduction. Very few works have studied the spatial distribution of proteoglycans of the articular cartilage of femoral condyles (FCs) and the tibial plateau (TP) in normal and experimental osteoarthritis (OA). The aim of the paper was to analyze the spatial distribution of lubricin and aggrecan in the articular cartilage of FCs and the TP in normal and experimental OA in rats. Materials and methods. We divided 15 male Wistar rats (weight 250–300 g) into three groups: intact, undergone sham surgery, and having experimental OA. Sham surgery was done with intra-articular injection of saline solution, and experimental OA was modeled by intra-articular injection of medical talc. We performed morphological and immunohistochemical studies using antibodies to Aggrecan and Lubricin to assess the spatial distribution of proteoglycans. Results. After 3 weeks in the group with OA, the thickness of the articular cartilage of FCs and the TP was 15% greater and 11% less, respectively, in comparison with that in the intact rats (p<0.05). In the intact group, the numerical density of chondrocytes of the superficial zone of the articular cartilage of the TP was 2.6 times higher compared to that of FCs; after 3 weeks, the group with OA showed the opposite trend. A similar pattern was in the middle and deep zones. Immunohistochemistry revealed the presence of intense staining on lubricin of isogenic groups of chondrocytes and extracellular matrix (ECM) of the middle zone of the articular cartilage of the TP in experimental OA. Conclusion. In experimental OA, we observed interstitial growth in the articular cartilage of FCs and signs of ECM destruction in superficial and middle zones of the articular cartilage of the TP. In experimental OA, the distribution of lubricin synthesis changes. For the middle zone chondrocytes, localized close to the surface zone, the color on lubricin is characteristic. Keywords: morphology, articular cartilage, aggrecan, lubricin, femoral condyles, tibial plateau, osteoarthritis, rat

Zinc finger E-box binding homebox 2 alleviated experimental osteoarthritis in rats

ABSTRACT Aims Osteoarthritis (OA) is a chronic inflammatory disease, characterized by degradation of extracellular matrix, apoptosis of chondrocytes and inflammation in articular cartilage. Zinc finger E-box binding homebox 2 (ZEB2), a transcription repressor, has been demonstrated with anti-inflammatory role in some cells. The analysis from GEO data reveals that ZEB2 expression is upregulated in articular cartilage of OA patients and experimental OA rodents. This study aims to confirm the function of ZEB2 in OA process. Material and methods The experimental OA was induced by anterior cruciate ligament transaction (ACLT) in rats, and the adenovirus loaded with ZEB2 coding sequence was intra-articularly injected into rats (1 × 10 PFU). The primary articular chondrocytes were stimulated by interleukin-1β (IL-1β) (10 ng/ml) to mimic the osteoarthritic injury, and transfected with the adenovirus carrying ZEB2 coding or silencing sequence. The apoptosis, content of extracellular matrix, inflammation, and the activity of NFκB signaling in chondrocytes and cartilage were determined. Results ZEB2 was highly expressed in osteoarthritic cartilage tissues and IL-1β-treated chondrocytes. The overexpression of ZEB2 restrained ACLT- or IL-1β administration-induced apoptosis, matrix degradation and inflammation in vivo or in vitro, evidenced by changed levels of cleaved caspase-3/PARP, collagen-II, aggrecan, matrix metalloproteinase 3/13, tumor necrosis factor-α and interleukin-6. Additionally, the phosphorylation of NFκB p65, IκBα and IKKα/β, and the nuclear translocation of p65 was blocked by ZEB2, implying inactivation of this signaling. Conclusions ZEB2 mitigated osteoarthritic symptoms in rats and chondrocytes, and NFκB signaling might be involved. These findings may provide novel insights for clinical treatment of OA.

Evaluation of Protective Effect of Metformin in Rats with Experimental Osteoarthritis

Objective: The objective of this study is to evaluate metformin proposed protective effect against the development of osteoarthritis (OA) in rats. Materials and Methods: A total of 40 male Sprague–Dawley rats were included, divided into four groups: negative control (n = 10), positive control (OA induced by monoiodoacetate [MIA]) (n = 10), metformin 200mg/kg group (n = 10) preinduction of OA, and metformin 200 mg/kg group (n = 10) postinduction of OA. Serum C-telopeptide type II collagen (CTX-II), inflammatory biomarkers were evaluated for each group. For data analysis, SPSS version 26.00 was used. Results: Metformin-treated groups showed a significant reduction in inflammatory biomarkers and CTX-II serum levels compared with OA group (P < 0.05). Pretreatment with 200 mg/kg metformin imparted extra cartilage protective effect and further decreased inflammatory cytokines compared to posttreated (P < 0.05). Conclusion: Metformin produced a beneficial protective effect in experimental OA in rats. It attenuates the inflammatory reactions progression by preventing the release of pro-inflammatory cytokines in rats with experimental OA. Furthermore, metformin reduced cartilage degradation evidenced by lowering CTX-II serum levels experimental OA in rats.

Adipose-Derived Extract Suppresses IL-1β-Induced Inflammatory Signaling Pathways in Human Chondrocytes and Ameliorates the Cartilage Destruction of Experimental Osteoarthritis in Rats.

We investigated the effects of adipose-derived extract (AE) on cultured chondrocytes and in vivo cartilage destruction. AE was prepared from human adipose tissues using a nonenzymatic approach. Cultured human chondrocytes were stimulated with interleukin-1 beta (IL-1β) with or without different concentrations of AE. The effects of co-treatment with AE on intracellular signaling pathways and their downstream gene and protein expressions were examined using real-time PCR, Western blotting, and immunofluorescence staining. Rat AE prepared from inguinal adipose tissues was intra-articularly delivered to the knee joints of rats with experimental osteoarthritis (OA), and the effect of AE on cartilage destruction was evaluated histologically. In vitro, co-treatment with IL-1β combined with AE reduced activation of the p38 and ERK mitogen-activated protein kinase (MAPK) pathway and nuclear translocation of the p65 subunit of nuclear factor-kappa B (NF-κB), and subsequently downregulated the expressions of matrix metalloproteinase (MMP)-1, MMP-3, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, IL-6, and IL-8, whereas it markedly upregulated the expression of IL-1 receptor type 2 (IL-1R2) in chondrocytes. Intra-articular injection of homologous AE significantly ameliorated cartilage destruction six weeks postoperatively in the rat OA model. These results suggested that AE may exert a chondroprotective effect, at least in part, through modulation of the IL-1β-induced inflammatory signaling pathway by upregulation of IL-1R2 expression.

LEVEL OF MIDDLE MOLECULAR PEPTIDES IN THE ARTICULAR CARTILAGE OF RATS UNDER EXPERIMENTAL OSTEOARTHRITIS AND ADMINISTRATION OF PROBIOTIC COMPOSITION

The question regarding clarification the mechanisms that link changes in the musculoskeletal system with changes in the microbiome, in recent few years has become particularly relevant. The investigation of the biological effect of probiotics on cartilage metabolism under osteoarthritis (OA) opens the perspectives for their use in complex therapy and prevention of joint pathology. The aim of the research was to analyze the quantitative and qualitative composition of the peptide component of the middle-mass molecules (MMM) of different fractions in the articular cartilage of rats with experimental OA under the introduction of multiprobiotic (PB) composition. The experiments were conducted on white male non-linear rats weighing 180-200 g. Experimental osteoarthritis in rats was induced by a single injection of sodium monoiodacetate (MIA; Sigma, USA) in the knee patellar ligament. The animals of therapeutic group received oral administration of live probiotic composition Multiprobiotic Simbiter® acidophilic concentrated ("O.D. Prolisok", Ukraine) at a dose of 140 mg/kg daily for 14 days. Euthanasia of animals was performed on the 30th day of the experiment. The level of MMM was assessed spectrophotometrically. Fractionation at the peptide level was performed using the method of chromatography, which is separated by size on Sephadex G 15 column. Our findings showed an increase in the MMM content of all studied fractions in cartilage tissue of rats with experimental OA and changes in the qualitative and quantitative composition of their the peptide component, that could indicate the development of endogenous intoxication, as a result of impaired cartilage metabolism, inflammation and destructive processes in the knee joint during the pathology. Administration to animals with MIA-induced OA PB composition had a favorable effect on the studied parameters, which was expressed in a decrease of MMM content and restored redistribution of the peptide pool of cartilage tissue. The obtained results provide grounds for further research aimed at studying the biological effect of PB on cartilage metabolism, which may contribute to the development of new strategies for the treatment and prevention of joint diseases.

Combined detection of COMP and CS846 biomarkers in experimental rat osteoarthritis: a potential approach for assessment and diagnosis of osteoarthritis

BackgroundTo comprehensively evaluate the diagnostic value of serum cartilage oligomeric matrix protein (COMP) and chondroitin sulfate 846 epitope (CS846) biomarkers in osteoarthritis (OA), longitudinal and combined measurement of serum COMP and CS846 were performed at different stages in the pathological process of OA in a rat model of anterior cruciate ligament transection (ACLT).MethodsSixty male Sprague-Dawley rats were randomly divided into two groups, including a model group (n = 30) and a control group (n = 30). Rat models were established by ACLT surgery, and sham operations were performed on rats in the control group. Prior to surgery and at 2, 4, 6, 8, and 10 weeks after ACLT surgery, serum levels of COMP and CS846 biomarkers were determined using an enzyme-linked immunosorbent assay approach. Five rats per group were euthanized at 2, 4, 6, 8, and 10 weeks after surgery, after which tibial plateau specimens were collected. Macroscopic observation and histological examination were employed for rat tibial plateau. Histological changes in articular cartilage were evaluated according to Osteoarthritis Research Society International (OARSI) scoring criteria. The area under the curve (AUC) of COMP, CS846, and combined biomarkers was compared using receiver operating characteristic (ROC) curve.ResultsWithin 10 weeks after surgery, serum levels of COMP and CS846 in the model group were significantly higher when compared to those in the control group. Moreover, a significant correlation was observed between changes in COMP and CS846 levels. At each time point, macroscopic observations and OARSI scores were significantly increased in the development of OA. The AUC of combined biomarkers was higher compared to that of COMP and CS846 alone. Finally, a positive relationship was found between levels of COMP and CS846 and the OARSI score.ConclusionsIn this study, we found that combined detection of serum CS846 and COMP levels can be used for diagnosis and monitoring of OA progression.

Culture-expanded allogenic adipose tissue-derived stem cells attenuate cartilage degeneration in an experimental rat osteoarthritis model.

Mesenchymal stem cell (MSC)-based cell therapy is a promising avenue for osteoarthritis (OA) treatment. In the present study, we evaluated the efficacy of intra-articular injections of culture-expanded allogenic adipose tissue-derived stem cells (ADSCs) for the treatment of anterior cruciate ligament transection (ACLT) induced rat OA model. The paracrine effects of major histocompatibility complex (MHC)-unmatched ADSCs on chondrocytes were investigated in vitro. Rats were divided into an OA group that underwent ACLT surgery and a sham-operated group that did not undergo ACLT surgery. Four weeks after surgery mild OA was induced in the OA group. Subsequently, the OA rats were randomly divided into ADSC and control groups. A single dose of 1 × 106 ADSCs suspended in 60 μL phosphate-buffered saline (PBS) was intra-articularly injected into the rats of the ADSC group. The control group received only 60 μL PBS. OA progression was evaluated macroscopically and histologically at 8 and 12 weeks after surgery. ADSC treatment did not cause any adverse local or systemic reactions. The degeneration of articular cartilage was significantly weaker in the ADSC group compared to that in the control group at both 8 and 12 weeks. Chondrocytes were co-cultured with MHC-unmatched ADSCs in trans-wells to assess the paracrine effects of ADSCs on chondrocytes. Co-culture with ADSCs counteracted the IL-1β-induced mRNA upregulation of the extracellular matrix-degrading enzymes MMP-3 and MMP-13 and the pro-inflammatory cytokines TNF-α and IL-6 in chondrocytes. Importantly, ADSCs increased the expression of the anti-inflammatory cytokine IL-10 in chondrocytes. The results of this study indicated that the intra-articular injection of culture-expanded allogenic ADSCs attenuated cartilage degeneration in an experimental rat OA model without inducing any adverse reactions. MHC-unmatched ADSCs protected chondrocytes from inflammatory factor-induced damage. The paracrine effects of ADSCs on OA chondrocytes are at least part of the mechanism by which ADSCs exert their therapeutic activity.

Evaluation of the effect of oral administration of collagen peptides on an experimental rat osteoarthritis model.

Collagen is an extracellular matrix protein present in the skin, tendon, cartilage and bone. Collagen peptides (CP) are produced by the hydrolysis of gelatin (heat-denatured collagen) by proteases and are utilized as a component of nutraceuticals. The current study investigated the effect of CP on the articular cartilage of OA by evaluating the serum levels of biomarkers (CTX–II for type II collagen degradation and CPII for type II collagen synthesis), histopathological changes (Mankin score, based on the toluidine blue staining of proteoglycans), and immunohistochemical staining of matrix metalloproteinase (MMP)-13 and type II collagen, using a rat experimental osteoarthritis (OA) model. Anterior cruciate ligament transection (ACLT) was performed on the right knee joint to surgically induce OA. Animals were divided into four groups: Control group (Control), sham-operated group (Sham), ACLT group without collagen peptide (ACLT group) and ACLT group with oral administration of CP (CP group). ACLT induced histological damages and significantly increased the Mankin score (P<0.05). However, CP administration markedly suppressed the Mankin score, although this difference was not significant. In addition, serum CTX-II levels were significantly decreased in CP group compared with those in the ACLT group (P<0.05). By contrast, serum CPII levels did not differ significantly among the four groups. Moreover, immunohistochemical staining of type II collagen and MMP-13 (an important type II collagen-degrading enzyme) indicated that the amount of type II collagen increased, whereas the number of MMP-13 positive chondrocytes decreased in the CP group compared with ACLT group. These observations suggest that CP has the potential to exert chondroprotective action on OA by inhibiting MMP-13 expression and type II collagen degeneration.

Mefenamic acid decreases inflammation but not joint lesions in experimental osteoarthritis.

Mefenamic acid is a non-steroidal anti-inflammatory drug able to control the symptoms of osteoarthritis (OA), but its effects on protection of cartilage and bone are still unclear. This study aimed to investigate whether the control of inflammation by mefenamic acid translates into decreased joint lesions in experimental OA in rats. OA was induced by injecting 1mg of monosodium iodoacetate (MIA) into the joints of rats. The animals were treated with mefenamic acid (50mg/kg, daily, oral gavage) either pre-MIA injection (preventive) or post-MIA injection (therapeutic). Joint swelling and hyperalgesia were evaluated at baseline and 1, 3, 14 and 28days after induction of OA. Intra-articular lavage and kinetics of cell migration into the synovium were measured 3 and 28days after OA induction. Histopathological analysis, Osteoarthritis Research Society International (OARSI) score, total synovium cells count, cartilage area and levels of proteoglycans in joints were also evaluated. Mefenamic acid prevented joint oedema and hyperalgesia induced by MIA in the acute phase (3days) of the disease. In the chronic phase (28days), preventive and therapeutic regimens decreased the number of mononuclear cells in the joint cavity. In contrast, thickening of the synovium, bone resorption, loss of cartilage and levels of proteoglycans were unaffected by mefenamic acid when it was administered either preventively or therapeutically. Thus, mefenamic acid had anti-inflammatory effects but did not reduce the progression of OA lesions, thereby indicating that it is only effective for symptomatic control of OA.

Destabilization of the medial meniscus leads to subchondral bone defects and site-specific cartilage degeneration in an experimental rat model

This study aimed to investigate subchondral bone changes using micro-computed tomography (micro-CT) and regional differences in articular cartilage degeneration, focusing on changes of cartilage covered by menisci, in the early phase using a destabilization of the medial meniscus (DMM) model. The DMM model was created as an experimental rat osteoarthritis (OA) model (12 weeks old; n = 24). At 1, 2, and 4 weeks after surgery, the rats were sacrificed, and knee joints were scanned using a Micro-CT system. Histological sections of the medial tibial plateau, which was divided into inner, middle, and outer regions, were prepared and scored using the modified OARSI scoring system. The cartilage thickness was also calculated, and matrix metalloproteinase 13 (MMP13), Col2-3/4c, and vascular endothelial growth factor (VEGF) expression was assessed immunohistochemically. Subchondral bone defects were observed in the middle region, in which the cartilage thickness decreased over time after surgery, and these defects were filled with MMP13- and VEGF-expressing fibrous tissue. The OARSI score increased over time in the middle region, and the score was significantly higher in the middle region than in the inner and outer regions at 1, 2, and 4 weeks after surgery. Col2-3/4c and MMP13 expression was observed primarily in the meniscus-covered outer region, in which the cartilage thickness increased over time. Loss of meniscal function caused cartilage degeneration and subchondral bone defects in the early phase site-specifically in the middle region. Furthermore, our results might indicate cartilage covered by menisci is easily degraded resulting in osmotic swelling of the cartilage in early OA.

Evaluation of the effect of glucosamine on an experimental rat osteoarthritis model

Aims To investigate the in vivo effect of glucosamine on articular cartilage in osteoarthritis (OA), we evaluated serum biomarkers such as CTX-II (type II collagen degradation) and CPII (type II collagen synthesis) as well as histopathological changes (Mankin score, toluidine blue staining of proteoglycans in an experimental OA model using rats. Main methods OA was surgically induced in the knee joint by anterior cruciate ligament transection (ACLT) in rats. Animals were divided into three groups: sham-operated group (Sham), ACLT group without GlcN administration (− GlcN) and ACLT group with oral administration of glucosamine hydrochloride (+ GlcN; 1000 mg/kg/day for 56 days). Key findings ACLT induced macroscopic erosive changes on the surfaces of articular cartilage and histological damages such as increase of Mankin score. Of note, glucosamine administration substantially suppressed the macroscopic changes, although the effect on Mankin score was not significant. In addition, serum CTX-II levels were elevated in −GlcN group compared to that in Sham group after the operation. Of importance, the increase of CTX-II was significantly suppressed by GlcN administration. Moreover, serum CP-II levels were substantially increased in + GlcN group compared to those in Sham and − GlcN groups after the operation. Significance GlcN has a potential to exert a chondroprotective action on OA by inhibiting type II collagen degradation and enhancing type II collagen synthesis in the articular cartilage.

Diacerein mutual prodrug for osteoarthritis: synthesis, in vitro kinetic studies and preliminary pharmacological screening

Abstract A gastro-sparing diacerein mutual prodrug was designed and synthesized by linking it to D-glucosamine as a promoiety with an objective of increasing the potential of its anti-inflammatory activity and improving its hydrophilic characteristics so as to make its parenteral administration feasible. Diacerein was linked with D-glucosamine through amide linkage and was subjected to in vitro release studies in aqueous buffers of varied pH range. 97% release of diacerein was achieved in phosphate buffer (pH 7.4) with a half-life of 48 min, following first order kinetics. Preliminary screening was carried in a one-month study in experimental osteoarthritis in rats induced by mono-iodoacetate and therapeutic efficacy of the conjugate was evaluated for changes in knee-diameter, spontaneous locomotor activity, alkaline phosphatase and glucosaminoglycan levels. The prodrug was also tested for anti-inflammatory activity in Freund’s adjuvant arthritis and local irritant effect on rat stomach by Rainsford’s cold stress method. The prodrug exhibited quicker onset of action than diacerein with respect to reduction in knee diameter, improved locomotor activity, better anti-inflammatory and gastro-sparing activity. The preliminary results are promising. In vivo kinetic studies and evaluation in mono-iodoacetate induced osteoarthritis over a period of three months is in progress to establish its effectiveness in the management of osteoarthritis.

Transcriptional profiling and pathway analysis of monosodium iodoacetate-induced experimental osteoarthritis in rats: relevance to human disease

The objective of this study was to characterize the rat monosodium iodoacetate (MIA)-induced model for osteoarthritis (OA) and determine the translatability of this model to human disease. This was accomplished through pathway, network and system level comparisons of transcriptional profiles generated from animal and human disease cartilage. An OA phenotype was induced in rat femorotibial joints following a single injection of 200mug MIA per knee joint for a period of 2 or 4 weeks. Lesion formation in the rat joints was confirmed by histology. Gene expression changes were measured using the Agilent rat whole genome microarrays. Cartilage was harvested from human knees and gene expression changes were measured using the Agilent human arrays. One thousand nine hundred and forty-three oligos were differentially expressed in the MIA model, of these, approximately two-thirds were up-regulated. In contrast, of the 2130 differentially expressed oligos in human disease tissue, approximately two-thirds were down-regulated. This dramatic difference was observed throughout each level of the comparison. The total overlap of genes modulated in the same direction between rat and human was less than 4%. Matrix degradation and inflammatory genes were differentially regulated to a much greater extent in MIA than human disease tissue. This study demonstrated, through multiple levels of analysis, that little transcriptional similarity exists between rat MIA and human OA derived cartilage. As disease modulatory activities for potential therapeutic agents often do not translate from animal models to human disease, this and like studies may provide a basis for understanding the discrepancies.

Analgesic activity of a polysaccharide in experimental osteoarthritis in rats

Viscosupplementation efficacy has been related to the high molecular weight of hyaluronic acid-like compounds, as well as to gel formulation. We evaluated the effect of a galactomannan polysaccharide derived from Guar gum (GG) in joint pain in an osteoarthritis (OA) model. Wistar rats (six animals/group) were subjected to anterior cruciate ligament transection (ACLT-OA group). The OA group was compared to a false-operated group (sham). Joint pain was recorded daily, using the articular incapacitation test, until 7 days after ACLT. Solutions or gel preparations of GG (100 microg) or Hylan G-F 20 (100 microg), used as a comparator, were given intraarticularly (i.a.) at day 4 after ACLT. Controls received saline i.a. The OA group had significantly increased joint pain as compared to sham (P<0.001). GG, either as a gel or solution, significantly inhibited joint pain similar to the inhibition achieved with Hylan G-F20. This is the first demonstration that a galactomannan derived from GG reduces joint pain in experimental OA. This analgesia is independent of the colloidal state. We propose that the analgesic benefit of viscosupplementation may be due to an intrinsic carbohydrate-mediated mechanism rather than to the rheologic properties of the material.

Dose–response relationship for exercise on severity of experimental osteoarthritis in rats: a pilot study

Objective To investigate the influence of a calibrated exercise on the progression of structural lesions in an experimental model of osteoarthritis (OA) in the rat, and to explore the effect of exercise on the level of chondrocyte caspase-dependent apoptosis and of Hsp70. Methods The OA model was induced by anterior cruciate ligament transection (ACLT). Rats were placed in 4 experimental groups: operated (ACLT) free moving rats, and 3 exercise groups (slight, moderate and intense) subjected to running training. Rats were killed 14 and 28 days after surgery. Results On D14 histological assessment demonstrated a beneficial influence of a slight and a moderate exercise vs control ACLT group. Hsp70 increased significantly in the moderate group vs controls. On D28, histological lesions strongly decreased in the slight and moderate exercise groups vs ACLT group, while an intense effort abolished this beneficial trend. Interestingly, the concomitant course of apoptotic events (caspase 3-positive cells) and the co-expression of Hsp70 in the various groups varied, when significant, in an inverse manner. In the intense group this overexpression was not noted, as a “burn out” appeared, thus leading to a loss of this protective effect. Conclusion This study shows that a calibrated slight or moderate exercise exerts a beneficial influence on the severity of chondral lesions in ACLT rats. Conversely, a strong effort abolishes this chondroprotective effect. This effect could be related to a reduced level of chondrocyte apoptosis through anti-apoptotic capacities of stress-induced Hsp70 overexpression.

Regeneration of defects in articular cartilage in rat knee joints by CCN2 (connective tissue growth factor).

CTGF/CCN2, a hypertrophic chondrocyte-specific gene product, possessed the ability to repair damaged articular cartilage in two animal models, which were experimental osteoarthritis and full-thickness defects of articular cartilage. These findings suggest that CTGF/CCN2 may be useful in regeneration of articular cartilage. Connective tissue growth factor (CTGF)/CCN2 is a unique growth factor that stimulates the proliferation and differentiation, but not hypertrophy, of articular chondrocytes in vitro. The objective of this study was to investigate the therapeutic use of CTGF/CCN2. The effects of recombinant CTGF/CCN2 (rCTGF/CCN2) on repair of damaged cartilage were evaluated by using both the monoiodoacetic acid (MIA)-induced experimental rat osteoarthritis (OA) model and full-thickness defects of rat articular cartilage in vivo. In the MIA-induced OA model, quantitative real-time RT-PCR assays showed a significant increase in the level of CTGF/CCN2 mRNA, and immunohistochemical analysis and in situ hybridization revealed that the clustered chondrocytes, in which clustering indicates an attempt to repair the damaged cartilage, produced CTGF/CCN2. Therefore, CTGF/CCN2 was suspected to play critical roles in cartilage repair. In fact, a single injection of rCTGF/CCN2 incorporated in gelatin hydrogel (rCTGF/CCN2-hydrogel) into the joint cavity of MIA-induced OA model rats repaired their articular cartilage to the extent that it became histologically similar to normal articular cartilage. Next, to examine the effect of rCTGF/CCN2 on the repair of articular cartilage, we created defects (2 mm in diameter) on the surface of articular cartilage in situ and implanted rCTGF/CCN2-hydrogel or PBS-hydrogel therein with collagen sponge. In the group implanted with rCTGF/CCN2-hydrogel collagen, new cartilage filled the defect 4 weeks postoperatively. In contrast, only soft tissue repair occurred when the PBS-hydrogel collagen was implanted. Consistent with these in vivo effects, rCTGF/CCN2 enhanced type II collagen and aggrecan mRNA expression in mouse bone marrow-derived stromal cells and induced chondrogenesis in vitro. These findings suggest the utility of CTGF/CCN2 in the regeneration of articular cartilage.

Moderation of iodoacetate-induced experimental osteoarthritis in rats by matrix metalloproteinase inhibitors

Objective To determine the effect of matrix metalloproteinase (MMP) inhibitors in mono-iodoacetate-induced arthritis in rats.Design The ability of compounds to inhibit MMPs in vitro was assessed kinetically using a quenched fluorescent substrate. Rats were injected with iodoacetate intraarticularly in one knee joint and damage to the tibial plateau was evaluated from digitized images captured using an image analyser and by histology. Collagenase and gelatinase activity in cartilage from iodoacetate injected knees were evaluated using3H-rat type I collagen and gelatin zymography, respectively.Results Collagenase and gelatinase activity significantly increased in the knee cartilage of rats injected with iodoacetate with peak activity by day 7. Three MMP inhibitors were examined for their efficacy in the rat iodoacetate-induced arthritis model. Significant (P< 0.05) inhibition of cartilage damage was observed in animals treated orally with 35mg/kg b.i.d. of the three different MMP inhibitors. Inhibition of cartilage damage by the MMP inhibitors ranged from 36–42%.ConclusionMMP inhibitors are partially protective against cartilage and subchondral bone damage induced by iodoacetate. These results support an important role for MMPs in mediating the joint damage in this model of arthritis.

The role of mucopolysaccharide induction in treatment of experimental osteoarthritis in rats by ultrasound.

Therapeutic ultrasound has been used in the treatment of osteoarthritis for the relief of symptom and improvement of functional status. In recent study, we found that ultrasound enhances cartilage repair in experimental early stage osteoarthritis, and prevents deteriorative changes in later stages. In the present study, we further investigate the bioeffects of ultrasound on cartilage matrix of experimental arthritis. Fifty-four rats with three different degrees of papain induced osteoarthritis classified by 99m-Tc pertechnetate bone scan were collected for ultrasound treatment. The changes in their arthritic severity after sonication treatment and two months after treatment were measured using 99m-Tc bone scan. The histopathological changes were evaluated through light microscope after disarticulation sections (H.E. stain), and the changes in mucopolysaccharide density in cartilage matrix were measured using a Optimas scanner analyzer after Alcian blue staining. The results showed that the density of mucopolysaccharide rose in the initial stage of induced arthritis, and decreased progressively in the later stage. The density of mucopolysaccharide increased upon complete sonication more for the treated rats than for the controls, and this was closely related with the improvement in histopathological findings, but inversely with the changes in arthritic severity. In conclusion, therapeutic ultrasound enhances mucopolysaccharide synthesis of arthritic cartilage, and results in the repair of arthritic cartilage in the early stage of induced arthritis and the prevention of deteriorative changes in later stages.