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OBJECTIVE: To determine the in vivo effects of intraarticular MMP-13. METHODS: Human recombinant MMP-13 was injected intraarticularly (i.a. ) into the hamster knee joint. MMP-13 activity, collagen and proteoglycan fragments, and hyaluronan were measured in synovial fluid. Antibody 9A4 was used to localize collagen damage. Western blotting was used to determine the size of type II collagen fragments. RESULTS: MMP-13 activity measurements showed greater than 98% of MMP-13 to be cleared instantly from the joint cavity. The remainder was cleared with a t(1/2)of 2 h. Immunohistochemical staining demonstrated collagen cleavage was limited to a thin superficial band on the surface of the articular cartilage whereas collagen damage extended more deeply into the synovial capsule and the menisci. The elevation of proteoglycan and hyaluronan in synovial fluid after MMP-13 was modest. Collagen fragments appeared in synovial fluid within 15 min following MMP-13. They were cleared with a half-life of circa 1.8 h and the predominant fragment was 32 kDa. CONCLUSIONS: Activated MMP-13 leads to tissue collagen damage with the release of collagen fragments. These fragments are measurable and could provide a method for assessment of cartilage collagen damage.

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To determine whether the collagen network is compromised by collagenase during acute inflammation, a monoclonal antibody (9A4) was developed with specificity for the C-terminal neoepitope sequence generated by collagenase-cleavage of type II collagen (Gly-Pro-Pro-Gly-Pro-Gln-Gly-COOH). 9A4 was shown to detect the collagen collagenase-cleavage neoepitope with a K = 1.7 x 10(-7) M (type II) and K = 2 x 10(-6) M (type I). It does not recognize uncleaved native or denatured collagen. Articular cartilage from control animals is unstained by 9A4. During acute inflammation elicited in hamsters by intra-articular LPS, positive staining for the 9A4 neoepitope indicated the collagen was damaged. Wheel running exercise was used to apply stress to control cartilage and cartilage from animals with damaged collagen. After 6 months of running, the cartilage from normal animals was unaffected. By contrast, in the group with damaged collagen, the cartilage was fibrillated in all animals and in half of those, the cartilage failed and bony eburnation resulted.

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OBJECTIVE: It has been reported that osteoarthritis can occur in hamsters. The present study was undertaken to determine the effects of exercise on the composition of articular cartilage and synovial fluid and on the development of cartilage degeneration in these animals. METHODS: Young (2.5-month-old) group-housed hamsters were compared with 5.5-month-old hamsters that had undergone 3 months of daily wheel running exercise (6-12 km/day) or 3 months of sedentary, individually housed living. The condition of the femoral condyles was determined by scanning electron microscopy in 12 exercising hamsters, 12 sedentary hamsters, and 6 of the young controls. The content of proteoglycan, hyaluronic acid, hydroxyproline, and proline in synovial fluid and patellar cartilage was measured. RESULTS: By scanning electron microscopy, the femoral articular cartilage was smooth and undulating in young controls and older exercising hamsters. In contrast, the femoral condyles were fibrillated in all 12 of the sedentary hamsters. There was no difference in the patellar cartilage collagen content between the 3 groups, but proteoglycan content and synthesis were lower in the patellar cartilage of the sedentary group. Synovial fluid volume was also decreased in the sedentary group compared with the young controls or the older exercising hamsters. CONCLUSION: A sedentary lifestyle in the hamster leads to a lower proteoglycan content in the cartilage and a lower synovial fluid volume. These changes are associated with cartilage fibrillation, pitting, and fissuring. Daily exercise prevents early cartilage degeneration and maintains normal articular cartilage.

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OBJECTIVE AND DESIGN: The limitation of activity and its modification by therapy in an experimental arthritis was studied. SUBJECTS: Female hamsters in groups of six per treatment were used. TREATMENT: An acute arthritis was induced by intraarticular injection of 0.1 microgram lipopolysaccharide (LPS) in hamsters with free access to running wheels. Tenidap at 100 mg%, and piroxicam and indomethacin at 30 mg% were administered in the hamster's normal diet. METHODS: Activity was monitored and analysed by computer. Plasma blood levels of drugs were determined by high pressure liquid chromatographic (HPLC) analysis. RESULTS: Hamsters normally run 10-15 km/day. That distance was reduced to less than 2 km/day after arthritis induction. Speed of movement, essentially the equivalent of walking time, was reduced 40% by the arthritis. However, the time spent in movement (activity time) was more severely affected by arthritic disease. Therapy gave a modest 1.3-fold increase in speed of movement, but a highly significant 2-fold increase in activity time. CONCLUSIONS: The effects of arthritis on activity in this animal model suggest that time spent in movement (activity time) should be considered as an outcome measure in clinical studies. These observations may also help explain why the modest disease improvements obtained with cyclooxygenase inhibition are valued. From a patient perspective, a doubling of activity time is a highly significant improvement in quality-of-life.

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In vitro pharmacologic measures of drug specificity are well established, i.e. drug interaction with a specific target such as an enzyme, receptor, or ion channel. However, in vitro measures of drug selectivity, defined as effects on secondary targets, are lacking. Two-dimensional gel electrophoresis (2-D gel) was examined as a measure of drug selectivity by comparing the effects of three drugs, tenidap, piroxicam, and dexamethasone, on the synthesis of intracellular proteins in lipopolysaccharide (LPS)-stimulated murine macrophages. A set of 902 35S-methionine-labeled proteins were separated consistently, identified by their coordinates of apparent isoelectric point and molecular weight, and quantified. LPS altered the concentrations of 45 proteins. Tenidap, at 10 microM, affected a total of five proteins (suppressed three; stimulated two), whereas piroxicam, at 10 microM, suppressed two proteins. Dexamethasone at 0.01 microM suppressed eight proteins and stimulated one. Thus, none of the drugs reversed the LPS-induced changes. Two of the eight proteins suppressed by dexamethasone were also suppressed by tenidap and were identified as proIL-1 alpha and proIL-1 beta. Since the subset of affected proteins provided a unique protein "fingerprint" for each drug, the three drugs were mechanistically differentiated by 2-D gel analysis. Compared to LPS (5% affected proteins), all three drugs were selective (< or = 1% affected) with piroxicam > tenidap > dexamethasone. With identification of affected proteins, this technique can provide a useful in vitro assessment of drug selectivity.

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The effect of running activity on normal and inflamed knees was determined by light microscopic (LM) and scanning electron microscopic (SEM) observations on hamster articular cartilage. Animals were split into two groups; one housed in standard cages and one given free access to running wheels. Twenty-one days prior to analysis, half of each group was given an intra-articular injection of lipopolysaccharide (LPS) to cause an inflammation, the other half were uninjected. No remarkable changes were observed by LM in either the control running or nonrunning groups. In contrast, cartilage proteoglycan depletion, and pannus and synovial hyperplasia were equally observed in both groups of LPS-injected animals. SEM observations on the patellae from control animals found them to be free from damage to the articular cartilage. The joints of both the LPS nonrunning and running animals contained synovial hypertrophy with villus projection from the synovial lining. However, only the LPS-injected running hamsters had cartilage fraying over large areas of the articular surface, as well as areas in which the villus projections had been flattened. These results demonstrated that mechanical stress applied to a proteoglycan-depleted cartilage enhances the breakdown of the collagen matrix as judged by fibrillation, and may aggravate the inflammation by crushing the swollen synovial lining where it encroaches on the joint space.

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Arthritis refers to a heterogeneous class of diseases characterized by impairment of movement. Yet animal models of arthritis have traditionally been based on the utilization of animals housed without the capability of extended free movement and without adjunctive measurement of mobility. To define the determinants of mobility impairment, we have established a lipopolysaccharide (LPS)-induced arthritis model in the hamster that prominently features monitoring of mobility and compares mobility changes with histological and biochemical changes during arthritis. Intraarticular LPS induces a dose-dependent inhibition of the hamster's mobility as measured by decreased daily distance on a running wheel (normal distance 9 to 12 km/day). At low concentrations of LPS (0.1 and 1 microgram/knee), daily distances returned to normal after 4 and 6 days, respectively. At higher concentrations, the mobility was still markedly suppressed after 6 days, and, at 100 micrograms/knee, irreversible chondrocyte loss was observed on the femoral condylar margins. Further studies were therefore conducted using 1 microgram LPS/knee. Histological and biochemical changes were examined to determine which resolved at the time of restoration of mobility. At the time of restoration of mobility, the synovial capsule was still edematous and heavily infiltrated with leukocytes; proteoglycan loss from the medial femoral condyle was still increasing. Plasma keratan sulfate failed to correlate with either proteoglycan loss or mobility changes. Proteoglycan synthesis, which was maximally suppressed the second day after LPS, was enhanced over controls at the time of restoration of mobility, suggesting the onset of repair. These results suggest a possible association of mobility inhibition with local cytokine synthesis. This model provides an approach to define the causes of mobility impairment.

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Many studies in animals have examined biochemical, immune and histological changes during arthritis; however, the study of the effects of arthritis on mobility has been largely neglected. Interleukin-1, administered by the intraarticular route into hamster knee joints, resulted in inhibition of spontaneous wheel running activity; however, the effect was transient, lasting only through the evening following IL-1 administration. A further injection of IL-1 2 days later showed still greater inhibition of running. The effect again did not extend beyond the first evening after injection. IL-1alpha and IL-1beta showed equivalent effects on mobility, and no evidence was seen for cooperative interaction between them. A 50% inhibition of running occurred at a dose of approximately 10 ng/knee of IL-1alpha. The effect appeared not to be systemic since intraperitoneal injection required microgram amounts of IL-1 for an equivalent inhibition. At the time mobility had been restored to normal, histological examination showed the continued presence of inflammatory cells, soft tissue swelling and cartilage proteoglycan loss. These results suggest a lack of correlation between inhibition of mobility and histopathological changes in cartilage and soft tissue.

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Mobility is impaired during arthritis. In order to study the causes of the mobility impairment, we have examined hamsters with a LPS arthritis in which running is inhibited over a 4-5 day period. Parameters have been examined to determine which correlate with running impairment. Knee diameter, as well as cell infiltration into the surrounding synovial tissue and the accompanying edema, failed to resolve by the time normal mobility was reestablished. Other factors must be primary determinants of mobility.

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The potential role of interleukin-1 in postoperative adhesion formation was examined. Cecal abrasion gave a consistently higher adhesion score when compared with sham laparotomy, on the basis of adhesion number, density, and vascularity, and so was chosen for use in further studies. The extent of serosal bleeding during cecal abrasion did not affect adhesion scores. Intraperitoneal injection of 10 micrograms murine recombinant interleukin-1 alpha in cecally abraded animals on the day of surgery and on the following 4 days resulted in a significant increase in adhesion scores when compared with those of cecally abraded animals injected with vehicle alone. Adhesions enhanced with murine recombinant interleukin-1 alpha, which were thicker and more vascular, were equivalently enhanced at doses from 10 to 10,000 ng, implying maximal response over that range. Rats not operated on and receiving recombinant interleukin-1 alpha 2 weeks after injury had increased adhesion formation. These results demonstrate that interleukin-1 alpha may be an important short-term mediator of postsurgical adhesion formation.

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Tenidap is a new antiarthritic drug of novel chemical structure. This study shows the effects of tenidap on the in vitro synthesis of interleukin 1 (IL-1). IL-1 production by murine peritoneal macrophages was induced either by stimulation with lipopolysaccharide (LPS) or by phagocytosis of zymosan. With either stimulus, tenidap inhibited IL-1 production as measured by a quantitative competitive IL-1 receptor binding assay. Approximately 20 ng/mL of IL-1 was produced by 10(6) macrophages in response to LPS and about half that amount was produced in response to zymosan. Fifty percent inhibition of IL-1 production by tenidap was found at 3 microM for both stimuli. Using goat anti-IL-1 alpha and Western blot analysis, the appearance of intracellular 34 kDa pro-IL-1 alpha was inhibited by tenidap down to 3 microM. Tenidap decreased [35S]Met incorporation into cellular protein at 30 microM but not at 10 or 3 microM, indicating selectivity for IL-1 inhibition relative to total protein synthesis. Because tenidap inhibited IL-1 induction by both zymosan and LPS, it must act subsequently to receptor triggering. As the appearance of IL-1 was inhibited both intracellularly and extracellularly, the primary drug effect cannot be on secretion.

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The lupus of NZB/NZW F1 female mice is associated with immune complex glomerulonephritis and premature death. Cyclophosphamide and 15(S)-15 methyl PGE1 therapy halt disease progression. Fluorescein conjugated antibodies were utilized to label specific leukocytes and the subsets were quantitated using a Fluorescence Activated Cell Sorter. Normal outbred CD-1 female mice showed a decrease in absolute T and B cell numbers with age, but the ratio of T and B cells remained essentially constant through 9 months of age. By contrast the NZB/W female mice showed decreased numbers of total lymphocytes relative to CD-1 controls at all ages. Moreover relative to CD-1s, there was a far greater decrease in T cell numbers (7 x for NZB/W versus 2 x for CD-1) and B cell numbers failed to decrease with age. The characteristic decline in T lymphocyte numbers and relative increase in B cell numbers in NZB/W mice were corrected with cyclophosphamide and PGE1 therapy. However, there was no selective modification of T cell subsets (L3T4+ or Ly2+) with therapy. Our investigation suggests correction of the abnormal T/B cell ratio may be a useful marker of therapeutic activity in NZB/W mice.

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To investigate the potential importance of prostaglandins and thromboxane in systemic lupus erythematosus (SLE), the effects of a nonsteroidal antiinflammatory drug (piroxicam) and a thromboxane synthetase inhibitor (dazmegrel) were examined on survival, proteinuria, food consumption, body weight, and peripheral lymphocyte subset distribution in the NZB/W model of autoimmune lupus disease. The effect of an immunosuppressant (cyclophosphamide) known to be effective in the treatment of murine lupus on these parameters was also examined. Cyclophosphamide at 25 mg/kg ip weekly prolonged survival, inhibited proteinuria and prevented the characteristic decline in peripheral T cells and the relative increase in B cells seen in NZB/W lupus disease while having no apparent effect on body weight or food consumption. Neither dazmegrel at 50 or 200 mg/kg/day in the diet nor piroxicam at 2 mg/kg/day in the diet had any significant effects on these parameters.

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The relationship between functional activity and distribution of lymphocyte surface markers has not been clearly defined. We have examined the relationship between cell surface markers and function under the influence of immunosuppressant therapy. We found that after immunization with EL4 cells, the development of the immune response in the BALB/c mouse was accompanied by a decrease in spleen cells which stained brightly with fluorescein-labeled monoclonal anti-Thy 1 and an increase in cells which stained with rabbit anti-mouse Ig as measured on the FACS. Low doses of azathioprine and cyclophosphamide, which affect functional activity of the cells, do not alter cell surface markers. However, at higher doses of the drugs normalization of immunization-induced marker changes were observed, and the Thy 1+ and Ig+ surface markers were maintained at levels seen in non-immunized mice. In spite of a nearly 3-fold increase in the total number of lymphocytes and an increase in the functional activity of cytotoxic T cells (Lyt 2+) after immunization, no alteration in the percentage of Lyt 2+T cells nor in the intensity of staining with FITC-labeled Lyt2 antibody was seen. Inhibition of the immune response with immunosuppressant also failed to change the Lyt2+-staining cell population. This study demonstrates that lymphocyte functional changes precede cell surface antigen changes, and that functional changes may occur without surface antigen changes. Thus cell surface markers are "late" indicators of functional changes.

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The role of prostaglandins in the regulation of lipopolysaccharide (LPS)-induced interleukin-1 (IL-1) production by murine C3H/HeN resident peritoneal macrophages was studied. IL-1 production was initially studied in the presence of piroxicam and indomethacin, both inhibitors of prostaglandin biosynthesis. IL-1 was assayed using the IL-1-dependent proliferative response of C3H/HeJ thymocytes. LPS stimulation resulted in 15 to 20 ng/ml of prostaglandin E2 (PGE2) produced in the first hour of culture. IL-1-containing supernatants from drug-treated macrophages at dilutions of up to 1:32 resulted in enhanced thymocyte proliferation compared to control, non-drug-treated cultures and contained less than 2 ng/ml of PGE2. Similar enhancement of proliferation could be obtained by incubating non-drug-treated supernatants with monoclonal anti-PGE2 but not anti-thromboxane B2 (TxB2) antibody. Further dilutions of the drug-treated supernatants gave thymocyte proliferation responses which were indistinguishable from control cultures and, correspondingly, had identical values for IL-1 production. The absence of an effect on IL-1 production was confirmed by quantitation of intracellular IL-1 alpha using goat anti-IL-1 alpha antibody and by quantitation of supernatant IL-1 receptor competition assay. Exogenous PGE2, in the concentration range produced in macrophage supernatants (10-20 ng/ml), directly inhibited IL-1-stimulated thymocyte proliferation. Finally, when macrophages were stimulated with LPS for 24 hr in the presence of added PGE2, thymocyte proliferation was inhibited at the lowest supernatant dilutions, but as the IL-1-containing supernatants were diluted out, the assay curves were indistinguishable from non-PGE2-treated control. Thus, in this system, PGE2 has no effect on IL-1 synthesis, but rather has a direct inhibitory effect on thymocyte proliferation. Nonsteroidal anti-inflammatory drugs are not stimulating IL-1 production but are, in fact, relieving inhibition of the thymocyte IL-1 assay caused by the presence of prostaglandins.

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The acute-phase reactant, C-reactive protein, is a good index of disease activity in patients with rheumatoid arthritis. We examined the murine acute-phase reactant, serum amyloid P, as an index of disease in type II collagen-induced arthritis in 3 mouse strains. The onset of type II collagen-induced arthritis, which is characterized by paw swelling, is associated with a significant, but transient, elevation of serum amyloid P. Anticollagen antibody titers are not temporally associated with the onset of disease. Although murine type II collagen arthritis fails to show the chronic acute-phase reactant elevation that is characteristic of arthritis in humans, the transient elevation of the acute-phase reactant is a reliable indicator of the onset of disease.

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CP-17,193 was examined in vivo for its immunosuppressive effects and for its promotion of E1(4) tumor allograft survival. At a dose of 10 mg/kg p.o., it was shown to suppress the development of both antibody-dependent and cellular cytotoxicity for E1(4) cells. After cessation of drug treatment, and in contrast to what is observed with cyclophosphamide, the humoral immune response was promptly restored. The restoration of cellular cytotoxicity followed a more protracted course, and the tumor allograft was not rejected by day 24. Three possible mechanisms of immunosuppression were examined. CP-17,193 was shown to inhibit the formation of IL-2 sensitive blasts. However, it had no effect on T cell proliferation using performed blasts in the presence of added IL-2, and it did inhibit IL-2 production. Its immunosuppressive effects might therefore be explained by an inhibition of some initial step of lymphocyte activation which interferes with the T lymphocyte's ability to progress on to cell division and IL-2 production after stimulation.

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