Early elevation in circulating levels of C‐telopeptides of type II collagen predicts structural damage in articular cartilage in the rodent model of collagen‐induced arthritis

Objective

To investigate changes in the circulating levels of the C‐telopeptide of type II collagen (CTX‐II) with relation to disease onset and structural damage of cartilage in a rodent model of collagen‐induced arthritis (CIA), and to investigate immunolocalization of the CTX‐II epitope in the articular cartilage of affected joints.

Methods

Seven‐week‐old female Lewis rats were immunized with type II collagen and monitored using blood sampling at weekly intervals. At study termination (day 23), the animals were killed, synovial fluid was collected, and the affected joints were scored macroscopically for disease severity and underwent immunohistochemical evaluation.

Results

At the time of disease onset (day 15), which was characterized by redness and swelling of the affected joints (mean ± SD macroscopic severity score 9.1 ± 1.6), there was a 355% increase in serum CTX‐II levels. The early change in serum CTX‐II from day 0 to day 15 showed a significant association with the severity of cartilage damage (r = 0.61, P < 0.01). Immunostaining revealed extensive presence of the CTX‐II epitope in the damaged, uncalcified cartilage tissue.

Conclusion

The elevation in serum CTX‐II concomitant with the onset of disease and proportional to cartilage damage demonstrates that CTX‐II is a sensitive diagnostic tool for monitoring joint disease in the rodent model of CIA. Furthermore, the immunohistochemical findings are consistent with the concept that the major source of serum CTX‐II is the damaged articular cartilage.

     

Cartilage destruction in collagen induced arthritis assessed with a new biochemical marker for collagen type II C-telopeptide fragments

OBJECTIVE: To assess the ability of a marker of collagen type II degradation (CTX-II) to quantify cartilage turnover in vitro in cartilage explants and in vivo in rats with collagen induced arthritis (CIA). METHODS: Bovine articular cartilage explants were cultured in the presence of interleukin 1a, oncostatin M, and plasminogen to induce cartilage degradation. CTX-II, CTX-I (C-telopeptide fragment of collagen type I), glycosaminoglycan, and hydroxyproline contents in culture supernatants were measured. CIA was induced in 12-week-old female Lewis rats by immunization with bovine type II collagen. The incidence and severity of arthritis were monitored by measuring paw swelling, and urinary levels of CTX-II and CTX-I were determined. The knee joints of rats were histopathologically examined after sacrifice. Results. CTX-II but not CTX-I levels correlated well with collagen degradation in bovine articular cartilage in vitro quantified by hydroxyproline release. Urinary CTX-II levels as well as paw volume of CIA rats were significantly higher than normal rats on Days 21, 28, and 42 and were apparently correlated with cartilage destruction, assessed histopathologically. Urinary CTX-I level began to increase on Day 21, but only on Day 42 was it significantly different between CIA and normal rats. The elevation in CTX-I level appeared to occur later than that of CTX-II, in accord with the more delayed onset of bone erosion in the CIA model of rheumatoid arthritis. CONCLUSION: Urinary CTX-II may be a useful marker for evaluation of dynamics of cartilage destruction in CIA rats.     

Effects of ovariectomy and estrogen therapy on type II collagen degradation and structural integrity of articular cartilage in rats: implications of the time of initiation

OBJECTIVE: To investigate how the time of initiation influences the effects of estrogen therapy on type II collagen (CII) turnover and the structural integrity of articular cartilage in ovariectomized rats and to determine whether estrogen exerts direct effects on the catabolic function of chondrocytes ex vivo. METHODS: A total of 46 Sprague-Dawley rats were distributed into 1 of the following treatment groups: 1) ovariectomy, 2) ovariectomy plus early estrogen therapy, 3) ovariectomy plus delayed estrogen therapy, or 4) sham operation. Cartilage turnover was estimated by measuring the serum levels of C-telopeptide of type II collagen (CTX-II). Cartilage lesions at week 9 were quantified using a published scoring technique. The presence of the CTX-II epitope in articular cartilage was assessed by immunohistochemistry. The effects of estrogen (1-100 nM) on chondrocytes were investigated in bovine cartilage explants subjected to catabolic cytokines (tumor necrosis factor alpha [TNFalpha] and oncostatin M [OSM]). RESULTS: In ovariectomized rats, estrogen therapy evoked significant decreases in serum CTX-II independently of the time of initiation; yet, delayed initiation resulted in diminished efficacy in terms of preventing cartilage lesions. CTX-II fragments were present in articular cartilage, colocalizing with early lesions at the cartilage surface. In untreated animals, the early relative increases in serum CTX-II were proportional to the severity of cartilage lesions at week 9 (r = 0.73, P < 0.01). Estrogen significantly and dose-dependently countered CTX-II release from TNFalpha plus OSM-stimulated cartilage explants ex vivo. CONCLUSION: Our results suggest that estrogen counters the acceleration of CII degradation and related structural alterations, and these benefits can be maximized by early initiation after menopause. The protective effect of estrogen seems to involve direct inhibition of the catabolic function of chondrocytes.     

The effect of oral calcitonin on cartilage turnover and surface erosion in an ovariectomized rat model

OBJECTIVE: To investigate whether oral calcitonin treatment influences the increases in type II collagen (CII) degradation and related surface erosions of articular cartilage in ovariectomized rats. METHODS: Fifty rats were randomly allocated into 1 of the 5 following intervention groups: sham-operated, ovariectomy, ovariectomy plus subcutaneously implanted 17beta-estradiol pellet, ovariectomy plus 2 mg/kg salmon calcitonin plus 50 mg/kg 5CNAC (carrier), or ovariectomy plus 50 mg/kg 5CNAC. Each treatment was administered for 9 weeks after the ovariectomy. Blood samples for biochemical marker analysis were collected from fasting animals at baseline, on day 3, and after 1, 2, 4, 6, and 9 weeks. CII degradation was quantified by specific immunoassay, and the changes in severity scores of articular cartilage erosions were visualized and scored in histologic sections of the knees. RESULTS: Ovariectomy resulted in a marked increase in serum levels of C-telopeptide of type II collagen (CTX-II) (P < 0.001), which could be effectively reversed by 17beta-estradiol supplementation. Oral administration of calcitonin elicited similar decreases in serum levels of CTX-II (P < 0.001). Histologic scoring of cartilage erosion showed significantly less cartilage erosion in calcitonin-treated ovariectomized rats versus control ovariectomized rats that were untreated or treated with 5CNAC alone. (P < 0.01). CONCLUSION: The in vivo effects of calcitonin in rats suggest that calcitonin is able to counteract CII degradation and the accompanying structural disintegration of articular cartilage promoted by estrogen deficiency. Clinical assessment of the chondroprotective potential of calcitonin in postmenopausal women seems warranted.     

Urinary CTX-II and glucosyl-galactosyl-pyridinoline are associated with the presence and severity of radiographic knee osteoarthritis in men

OBJECTIVE: To investigate the association between biochemical markers of bone, cartilage, and synovial turnover with the presence and severity of knee osteoarthritis (OA) in men. METHODS: 176 men aged 59-70 years from the MRC Hertfordshire Cohort were studied. Weightbearing anteroposterior and lateral semiflexed radiographs were taken of both knees. A lifestyle questionnaire including basic demographic details and a questionnaire detailing knee pain was completed. This random sample was stratified based on the Kellgren and Lawrence (K&L) score, and the following biochemical markers were analysed: serum osteocalcin, serum C-terminal crosslinked telopeptide of type I collagen (CTX-I), urinary C-terminal crosslinked telopeptide of type II collagen (CTX-II), and urinary glucosyl-galactosyl-pyridinoline (Glc-Gal-Pyd). RESULTS: Age, body mass index (BMI), social class, smoking, and alcohol consumption were similar across K&L grades. Only one subject had a grade 4 K&L score, and was amalgamated with grade 3 subjects. A strong significant association was found between the presence of knee OA and urinary CTX-II and urinary Glc-Gal-Pyd (p=0.0001 and p=0.009), which persisted after adjustment for age and BMI. A significant positive association was also found between urinary CTX-II and urinary Glc-Gal-Pyd and the severity of K&L grade, joint space narrowing, and osteophytes scores, which persisted after adjustment for age and BMI. No associations between the presence and severity of knee OA were found for serum CTX-I or serum osteocalcin. CONCLUSIONS: Urinary CTX-II and Glc-Gal-Pyd, but not systemic markers of bone turnover, are strongly associated with disease severity and the presence of OA at the tibiofemoral and patellofemoral joints in men.     

Cross sectional evaluation of biochemical markers of bone, cartilage, and synovial tissue metabolism in patients with knee osteoarthritis: relations with disease activity and joint damage

OBJECTIVE: To analyse the relations between the urinary levels of type II collagen C-telopeptide (CTX-II) and glucosyl-galactosyl pyridinoline (Glc-Gal-PYD)-two newly developed biochemical markers of type II collagen and synovial tissue destruction respectively-disease activity and the severity of joint destruction in patients with knee osteoarthritis (OA). The clinical performance of these two new markers was compared with that of a panel of other established biochemical markers of connective tissue metabolism. METHODS: The following biochemical markers were measured in a group of 67 patients with knee OA (mean age 64 years, median disease duration eight years ) and in 67 healthy controls: for bone, serum osteocalcin, serum and urinary C-telopeptide of type I collagen (CTX-I); for cartilage, urinary CTX-II, serum cartilage oligomeric matrix protein (COMP), and serum human cartilage glycoprotein 39 (YKL-40); for synovium, urinary Glc-Gal-PYD, serum type III collagen N-propeptide (PIIINP), serum hyaluronic acid (HA); and for inflammation, serum C reactive protein. Biochemical markers were correlated with pain and physical function (WOMAC index) and with quantitative radiographic evaluation of the joint space using the posteroanterior view of the knees flexed at 30 degrees. RESULTS: All bone turnover markers were decreased in patients with knee OA compared with controls (-36%, -38%, and -52%, p<0.0001 for serum osteocalcin, serum CTX-I and urinary CTX-I, respectively). Serum COMP (+16%, p=0.0004), urinary CTX-II (+25%, p=0.0009), urinary Glc-Gal-PYD (+18%, p=0.028), serum PIIINP (+33%, p<0.0001), and serum HA (+ 233%, p<0.0001) were increased. By univariate analyses, increased urinary Glc-Gal-PYD (r=0.41, p=0.002) and decreased serum osteocalcin (r=-0.30, p=0.025) were associated with a higher total WOMAC index. Increased urinary CTX-II (r=-0.40, p=0.0002) and Glc-Gal-PYD (r=-0.30, p=0.0046) and serum PIIINP (r=-0.29, p=0.0034) were the only markers which correlated with joint surface area. By multivariate analyses, urinary Glc-Gal-PYD and CTX-II were the most important predictors of the WOMAC index and joint damage, respectively. CONCLUSION: Knee OA appears to be characterised by a systemic decrease of bone turnover and increased cartilage and synovial tissue turnover. CTX-II, Glc-Gal-PYD, and PIIINP may be useful markers of disease severity in patients with knee OA.     

Suppressive effects of PG201, an ethanol extract from herbs,on collagen-induced arthritis in mice

OBJECTIVE: PG201 has been formulated using 12 herbs known to have anti-inflammatory and protective effects on damaged tissue and bone among other functions. The present study was done in order to assess the therapeutic effects of PG201 in collagen-induced arthritis (CIA) in mice. METHODS: DBA/1 mice were immunized with bovine type II collagen. After a second collagen immunization, mice were treated with PG201 orally at 10 mg/kg once a day for 18 days. Paws were evaluated macroscopically for redness, swelling and deformities. The levels of TNF-alpha and IL-1beta in the ankle were examined. The severity of arthritis within the knee joints was evaluated by histological assessment of cartilage destruction and pannus formation. Molecular indicators related to CIA pathology were analysed by measuring the serum levels of matrix metalloproteinase 2 (MMP-2), tissue inhibitor of matrix metalloproteinase 2 (TIMP-2) and the anti-inflammatory cytokines interleukin (IL)-4 and IL-10. RESULTS: Administration of PG201 significantly suppressed the progression of CIA and inhibited the production of TNF-alpha and IL-1beta in the paws. The erosion of cartilage was dramatically reduced in mouse knees after treatment with PG201. In the serum of PG201-treated mice, the level of TIMP-2 and the ratio of TIMP-2 to MMP-2 were significantly elevated, and the level of IL-4, but not of IL-10, was increased. CONCLUSION: Administration of PG201 has therapeutic effects on CIA. Protection of cartilage was particularly prominent. PG201 is a potential therapy for rheumatoid arthritis.     

Uncoupling of type II collagen synthesis and degradation predicts progression of joint damage in patients with knee osteoarthritis

OBJECTIVE: The hallmark of osteoarthritis (OA) is the loss of articular cartilage. This loss arises from an imbalance between cartilage synthesis and cartilage degradation over a variable period of time. The aims of this study were to investigate the rates of these processes in patients with knee OA using two new molecular markers and to investigate whether the combined use of these markers could predict the progression of joint damage evaluated by both radiography and arthroscopy of the joints during a period of 1 year. METHODS: Seventy-five patients with medial knee OA (51 women, 24 men; mean +/- SD age 63 +/- 8 years, mean +/- SD disease duration 4.8 +/- 5.2 years) were studied prospectively. At baseline, we measured serum levels of N-propeptide of type IIA procollagen (PIIANP) and urinary excretion of C-terminal crosslinking telopeptide of type II collagen (CTX-II) as markers of type II collagen synthesis and degradation, respectively. Joint space width (JSW) on radiography and medial chondropathy at arthroscopy (assessed using a 100-mm visual analog scale [VAS]) were measured in all patients at baseline and in 52 patients at 1 year. Progression of joint destruction was defined as a decrease of > or =0.5 mm in JSW on radiography and as increased chondropathy (an increase in the VAS score of >8.0 units) between the baseline and 1-year evaluations. RESULTS: At baseline, compared with 58 healthy age- and sex-matched controls, patients with knee OA had decreased serum levels of PIIANP (20 ng/ml versus 29 ng/ml; P < 0.001) and increased urinary excretion of CTX-II (618 ng/mmole creatinine [Cr] versus 367 ng/mmole Cr; P < 0.001). The highest discrimination between OA patients and controls was obtained by combining PIIANP and CTX-II in an uncoupling index (Z score CTX-II - Z score PIIANP), which yielded a mean Z score of 2.9 (P < 0.0001). Increased baseline values in the uncoupling index were associated with greater progression of joint damage evaluated either by changes in JSW (r = -0.46, P = 0.0016) or by VAS score (r = 0.36, P = 0.014). Patients with both low levels of PIIANP (less than or equal to the mean - 1 SD in controls) and high levels of CTX-II (greater than or equal to the mean + 1 SD in controls) had an 8-fold more rapid progression of joint damage than other patients (P = 0.012 and P < 0.0001 as assessed by radiography and arthroscopy, respectively) and had relative risks of progression of 2.9 (95% confidence interval [95% CI] 0.80-11.1) and 9.3 (95% CI 2.2-39) by radiography and arthroscopy, respectively. CONCLUSION: Patients with knee OA are characterized by an uncoupling of type II collagen synthesis and degradation which can be detected by assays for serum PIIANP and urinary CTX-II. The combination of these two new markers could be useful for identifying knee OA patients at high risk for rapid progression of joint damage.     

Erythropoietin reduces the degree of arthritis caused by type II collagen in the mouse

OBJECTIVE: Erythropoietin (EPO) is a potent stimulator of erythroid progenitor cells, and its expression is enhanced by hypoxia. The aim of this study was to investigate the effect of EPO on collagen-induced arthritis (CIA) in the mouse. METHODS: CIA was induced by intradermal injection of bovine type II collagen (CII) and Freund's complete adjuvant. Starting on day 25, some of the mice with CIA received daily subcutaneous injections of EPO (1,000 units/kg). Two other groups of mice received sham treatment alone or sham treatment followed by EPO treatment, respectively. Arthritis was assessed clinically, radiologically, and histologically. Cytokine and chemokine levels were measured, and neutrophil infiltration into inflamed joints was quantitated. Immunohistochemistry studies were performed to measure protein nitrosylation. Chondrocyte apoptosis was assessed by TUNEL assay. RESULTS: Macroscopic clinical evidence of CIA first appeared as periarticular erythema and edema in the hind paws. The incidence of CIA was 100% by day 27 in the CII-challenged mice, and the severity of CIA progressed over a 35-day period, with radiographic evaluation revealing focal resorption of bone. Histopathologic features of CIA included erosion of the cartilage at the joint margins. Treatment with EPO starting at the onset of arthritis (day 25) ameliorated the clinical signs on days 26-35 and improved histologic status in the joints and paws. The degree of oxidative and nitrosative damage was significantly reduced in EPO-treated mice as indicated by decreased nitrotyrosine formation and poly(ADP-ribose) polymerase activation. Plasma levels of the proinflammatory cytokine tumor necrosis factor alpha were also significantly reduced by EPO treatment. In addition, EPO reduced the levels of apoptosis in chondrocytes in articular cartilage, as indicated by decreased TUNEL staining. CONCLUSION: These findings demonstrate that EPO exerts an antiinflammatory effect during chronic inflammation and is able to ameliorate the tissue damage associated with CIA.     

Amelioration of collagen-induced arthritis in DBA/1J mice by recombinant TSG-6, a tumor necrosis factor/interleukin-1-inducible protein

OBJECTIVE: To examine the effect of recombinant TSG-6 on collagen-induced arthritis (CIA) in DBA/1J mice. TSG-6 is a tumor necrosis factor (TNF)/ interleukin-1 (IL-1)-inducible hyaluronan-binding protein produced by synovial cells and chondrocytes that is present in synovial fluids of patients with rheumatoid arthritis. METHODS: To determine the effect of TSG-6 on chronic inflammatory joint disease, we induced CIA in DBA/1J mice by immunization with bovine type II collagen. Animals were treated with 12 intraperitoneal doses of 200 microg of recombinant TSG-6, beginning 3 days before the expected onset of disease symptoms. Progression of arthritis was monitored by determining the disease incidence, arthritis index, and footpad swelling. Levels of IgG1, IgG2a, and IgG2b antibodies against bovine and murine type II collagen and serum concentrations of IL-6 were determined at various time points. Histologic examination of affected joints was performed approximately 20 days after the onset of arthritis. RESULTS: Treatment with recombinant TSG-6 protein had a potent ameliorative effect, manifested by decreases in the disease incidence, arthritis index, and footpad swelling. Histologic examination of affected joints in TSG-6-treated animals revealed little pannus formation and cartilage erosion, features which were conspicuous in control mice. Animals treated with recombinant TSG-6 developed significantly reduced levels of IgG1, IgG2a, and IgG2b antibodies against bovine and murine type II collagen. CONCLUSION: The antiinflammatory effect of the TNF/IL-1-inducible TSG-6 protein in murine CIA suggests a role for this protein as an endogenous regulator of the inflammatory process.     

The destruction evaluation in different foot joints: new ideas in collagen-induced arthritis rat model

Collagen-induced arthritis (CIA) has been widely used as the animal model of rheumatoid arthritis since 1977, while till now, no paper has depicted the destruction characteristics in different foot joints. In this study, we observed the differences among the foot joint destruction process of CIA to elucidate further the pathological process of this model. CIA was induced in male Wistar rat immunized with bovine type II collagen and Freund’s incomplete adjuvant. Radiological studies were performed 1, 2, 4, 6, and 8 months after the second immunization to follow the development of disease. At last, all the animals were killed and histological research was performed. In the histological observation, three main types of joint destructions such as subchondral side erosion, external joint erosion and the cartilaginous fusion of articular cartilage were identified. All these destruction forms exist in one joint or several different joints. Furthermore, we found that tartrate-resistant acid phosphatase (TRAP) stain-positive cells participated in the destruction of articular cartilage. These new findings showed that in the disease process of the CIA model, different foot joints show different destruction characteristics and cartilaginous fusion of foot joints is another typical pathological characteristic. Our research was supported by Shanghai Key Laboratory of Orthopaedic Implant (08DZ2230300).     

Increased collagen and aggrecan degradation with age in the joints of Timp3(-/-) mice

OBJECTIVE: To investigate the in vivo effect of an imbalance between metalloproteinases and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs), in mouse articular cartilage. METHODS: Hind joints of Timp3(-/-) and wild-type mice were examined by routine staining and by immunohistochemical analysis using antibodies specific for type X collagen and for the neoepitopes produced on proteolytic cleavage of aggrecan (... VDIPEN and ... NVTEGE) and type II collagen. The neoepitope generated on cleavage of type II collagen by collagenases was quantitated in sera by enzyme-linked immunosorbent assay. RESULTS: Articular cartilage from Timp3-knockout animals (ages > or =6 months) showed reduced Safranin O staining and an increase in ...VDIPEN content compared with cartilage from heterozygous and wild-type animals. There was also a slight increase in ... NVTEGE content in articular cartilage and menisci of Timp3(-/-) animals. Chondrocytes showed strong pericellular staining for type II collagen cleavage neoepitopes, particularly in the superficial layer, in knockout mice. Also, there was more type X collagen expression in the superficial zone of articular cartilage, especially around clusters of proliferating chondrocytes, in the knockout mice. More type II collagen cleavage product was found in the serum of Timp3(-/-) mice compared with wild-type animals. This increase was significant in 15-month-old animals. CONCLUSION: These results indicate that TIMP-3 deficiency results in mild cartilage degradation similar to changes seen in patients with osteoarthritis, suggesting that an imbalance between metalloproteinases and TIMP-3 may play a pathophysiologic role in the development of this disease.     

Early degradation of type IX and type II collagen with the onset of experimental inflammatory arthritis

OBJECTIVE: To determine whether following the onset of intraarticular inflammation, there is early damage to articular cartilage, specifically to types II and IX collagen, and the proteoglycan (PG) aggrecan, and whether measurement of the degradation products of these molecules in synovial fluid (SF) and serum may permit the detection of cartilage damage. METHODS: A rabbit model of rheumatoid arthritis, antigen (ovalbumin)-induced arthritis, was studied. Articular cartilage samples were analyzed by immunoassays for total type II collagen content, its denaturation and cleavage by collagenases, and for type IX collagen content. PG content was determined by colorimetric assay. In serum and SF, total PG content and collagenase-generated peptides of type II collagen were measured. RESULTS: After 6 days, both the PG content and the NC4 domain of type IX collagen were reduced in femoral and tibial cartilage, concomitant with the onset of arthritis. In only the tibial cartilage did this reduction in PG persist up to day 20. However, denatured type II collagen was increased in all cartilage samples, but only on day 20. In SF, the PG content was significantly reduced on day 20, and products of type II collagen cleavage by collagenase were significantly increased on both day 6 and day 20. CONCLUSION: This study, which is the first of its kind examining changes in both types II and IX collagen and PG content, reveals early damage to both types of collagen as well as to PG in articular cartilage samples following induction of joint inflammation. SF analyses reveal this early damage and may be of value in the study and treatment of inflammatory arthritic diseases such as rheumatoid arthritis.     

Increased resistance to collagen-induced arthritis in CD44-deficient DBA/1 mice.

OBJECTIVE: To study the role of CD44, the principal hyaluronan (HA) receptor, in experimental arthritis. METHODS: We generated CD44 gene deficiency in arthritis-susceptible DBA/1LacJ mice to study the role of CD44 directly in collagen-induced arthritis (CIA). Wild-type and CD44-deficient mice were immunized with chicken type II collagen, and the onset and severity of CIA were monitored up to day 64. The immune status of immunized mice was determined at the end of the experiments. Cell transfer experiments were performed to monitor lymphocyte traffic to the inflamed joints. RESULTS: Mice homozygous for the CD44 mutation developed normally and showed no phenotypic defects. Although they showed a normal response to immunization with type II collagen and had Th1/Th2 ratios comparable with those in wild-type animals, CD44-deficient mice exhibited significant reductions in both the incidence and severity of CIA. This was accompanied by altered serum levels of HA, reduced expression of L-selectin, and a delayed entry of intravenously injected CD44-deficient donor lymphocytes into the arthritic joints of recipient mice. CONCLUSION: While CD44 is not essential for morphogenesis and autoimmunity, this cell surface receptor seems to play an important role in the development of arthritis, most likely by directing leukocyte traffic to the site of inflammation.     

The quantitation of a native chondroitin sulfate epitope in synovial fluid lavages and articular cartilage from canine experimental osteoarthritis and disuse atrophy

Objective. Previous studies have shown the presence of a native chondroitin sulfate epitope in articular cartilage proteoglycans from canine knee joints with experimental early osteoarthritis (OA), but not in normal cartilage. The objective of this study was to quantitate the native epitope recognized by monoclonal antibody 3-B-3 in synovial fluids and articular cartilage of diseased joints. Methods. An immunoassay with monoclonal antibody 3-B-3, which recognizes a native chondroitin-6-sulfate structure, was developed and used to analyze synovial fluid lavage material and extracts of articular cartilage from canine knee joints with early experimental OA or with mild disuse atrophy, and from control animals. Results. The concentration of epitope in the OA fluids was elevated 33–35-fold, and in the OA articular cartilage extracts it was elevated > 200-fold, compared with samples from the control group. No significant difference was detected in the levels of 3-B-3 epitope in the synovial fluid lavage material or cartilage extracts from the joints of the disuse group versus the control group. Conclusion. The native 3-B-3 epitope in articular cartilage and synovial fluids may be a specific marker of ongoing anabolic events in early degenerative joint disease.     

Beneficial effects of tempol, a membrane-permeable radical scavenger, in a rodent model of collagen-induced arthritis

OBJECTIVE: To investigate the effects of tempol, a membrane-permeable radical scavenger, in rats with collagen-induced arthritis (CIA). METHODS: CIA was induced in Lewis rats by intradermal injection of 100 microl of an emulsion of 100 microg of bovine type II collagen (CII) in complete Freund's adjuvant (FCA) at the base of the tail. On day 21, a second injection of CII in FCA was administered. RESULTS: Lewis rats developed an erosive arthritis of the hind paws when immunized with CII in FCA. Macroscopic evidence of CIA first appeared as periarticular erythema and edema in the hind paws. The incidence of CIA was 100% by day 27 in the CII-challenged rats, and the severity of CIA progressed over a 35-day period. Radiographs revealed focal resorption of bone, with osteophyte formation in the tibiotarsal joint, and soft tissue swelling. The histopathologic features included erosion of the cartilage at the joint margins. Treatment of rats with tempol (10 mg/kg/day intraperitoneally) starting at the onset of arthritis (day 23) delayed the development of the clinical signs on days 24-35 and improved the histologic status of the knee and paw. Immunohistochemical analysis for nitrotyrosine and poly(ADP-ribose) synthetase (PARS) revealed positive staining in the inflamed joints of CII-treated rats. The degree of nitrotyrosine and PARS staining was markedly reduced in tissue sections obtained from CII-treated rats that had received tempol. Furthermore, radiographs revealed protection against bone resorption and osteophyte formation in the joints of tempol-treated rats. CONCLUSION: This study is the first to provide evidence that tempol, a small molecule that permeates biologic membranes and scavenges reactive oxygen species, attenuates the degree of chronic inflammation and tissue damage associated with CIA in the rat.     

Urinary collagen type II C-telopeptide fragments are sensitive markers of matrix metalloproteinase-dependent cartilage degradation in rat adjuvant-induced arthritis

OBJECTIVE: To assess the relevance of collagen type II C-telopeptide fragments (CTX-II) as markers of cartilage degradation during adjuvant-induced arthritis in rats. METHODS: Rats were injected with Freund's adjuvant on day 0 and treated orally for 21 days twice a day with vehicle or 10 or 20 mg/kg of a newly designed matrix metalloproteinase inhibitor (MMP-Inh). Urine samples were collected for 24 h between days 19 and 20 and the concentration of the cartilage-derived CTX-II was measured with a 2-site, sandwich-type ELISA. To assess arthritis, inflammatory scores were determined, and changes in paw volumes were measured by plethysmography. RESULTS: On day 21, the inflammation was generalized in rats injected with Freund's adjuvant. The urinary concentration of CTX-II was significantly higher in arthritic rats than in control non-injected rats. Oral treatment of arthritic rats with MMP-Inh dramatically decreased the concentration of CTX-II in urine, with values returning to those of controls. Treatment simultaneously reduced the clinical variables of the disease. CONCLUSION: These results demonstrate that fragments of type II collagen in urine can be used as a measure of cartilage degradation in arthritic rats as well as potent non-invasive markers of the efficacy of chondroprotective treatments.     

Taxol (paclitaxel) involution of articular cartilage destruction in collagen induced arthritis: an ultrastructural demonstration of an increased superficial chondroprotective layer

OBJECTIVE: To determine the ultastructural changes of Taxol (paclitaxel) involution of articular cartilage destruction in collagen induced arthritis (CIA) and to compare with articular cartilage from normal rats. METHODS: Forty-five Louvain rats were randomized to one of 3 protocols for structural analysis: (1) control group, (2) CIA group, and (3) Taxol treated CIA group. The latter group received 10 mg/kg body weight of Taxol at Days 10, 12, and 14 and 7.5 mg/kg body weight of Taxol on Days 16, 18, and 20 postimmunization with collagen type II. Eight days later, each group was examined by light microscopy and scanning and transmission electron microscopy. RESULTS: In Taxol treated rats, the morphology of the articular cartilage reverted to that observed in naive rats except for a striking increase in the thickness of the superficial amorphous layer covering the articular surface. CONCLUSION: The involution of CIA by Taxol suggests that this agent may be useful in the clinical treatment of RA.     

Appearance of calpain correlates with arthritis and cartilage destruction in collagen induced arthritic knee joints of mice.

OBJECTIVES--To determine the relevance of calpain in murine collagen induced arthritis (CIA) and to correlate the presence of m-calpain with the appearance of arthritis and cartilage destruction. METHODS--The immunohistochemical appearance and localisation of m-calpain at different stages of arthritis were analysed and compared with the histological changes occurring during type II CIA. The arthritic knee joint lavage was also examined for m-calpain by immunoelectrophoretic blotting. RESULTS--Immunohistochemical staining demonstrated a clear positive correlation between the appearance of m-calpain and both a histological grade of arthritis and an acute phase of cartilage destruction. Further development of the disease showed continual presence of m-calpain but with reduced intensity. Intra-articular inflammatory cells (mainly polymorphonuclear leucocytes, synovial lining cells, and sublining fibroblasts) were found to be the most positively stained, but extracellular localisation of m-calpain on the surface of cartilage and synovium, and in the articular cartilage matrix and chondrocyte lacunae, was also observed. In the knee joint lavage obtained at the most intensive stage of acute arthritis, m-calpain was detectable by immunoelectrophoretic blotting. CONCLUSIONS--The findings suggest that m-calpain may act at an early phase of CIA as a matrix proteinase and take part in the destruction of articular cartilage or activate other destructive enzymes.