The Experimental Production of Arthritis: A Review

Methods for Testing Immunological Factors

Hypersensitivity reactions can be elicited by various factors: either immunologically induced, i.e., allergic reactions to natural or synthetic compounds mediated by IgE, or non-immunologically induced, i.e., activation of mediator release from cells through direct contact, without the induction of, or the mediation through immune responses. Mediators responsible for hypersensitivity reactions are released from mast cells. An important preformed mediator of allergic reactions found in these cells is histamine. Specific allergens or the calcium ionophore 48/80 induce release of histamine from mast cells. The histamine concentration can be determined with the o-phthalaldehyde reaction.

Preclinical Assessment of Inflammatory Pain

While acute inflammation is a natural physiological response to tissue injury or infection, chronic inflammation is maladaptive and engenders a considerable amount of adverse pain. The chemical mediators responsible for tissue inflammation act on nociceptive nerve endings to lower neuronal excitation threshold and sensitize afferent firing rate leading to the development of allodynia and hyperalgesia, respectively. Animal models have aided in our understanding of the pathophysiological mechanisms responsible for the generation of chronic inflammatory pain and allowed us to identify and validate numerous analgesic drug candidates. Here we review some of the commonly used models of skin, joint, and gut inflammatory pain along with their relative benefits and limitations. In addition, we describe and discuss several behavioral and electrophysiological approaches used to assess the inflammatory pain in these preclinical models. Despite significant advances having been made in this area, a gap still exists between fundamental research and the implementation of these findings into a clinical setting. As such we need to characterize inherent pathophysiological pathways and develop new endpoints in these animal models to improve their predictive value of human inflammatory diseases in order to design safer and more effective analgesics.

Evaluation of disease modifying activity of Coriandrum sativum in experimental models

BACKGROUND & OBJECTIVES

Coriandrum sativum (CS), has been widely used in traditional systems of medicine for treatment of rheumatoid arthritis. However, the mechanism of action for its antiarthritic effects is not clearly known. Therefore, the present study was carried out to evaluate the antiarthritic activity of CS in rats in two experimental models.

METHODS

The antiarthritic activity of CS seed hydroalcoholic extract (CSHE) was evaluated in adult Wistar rats by using two experimental models, viz. formaldehyde and Complete Freund's adjuvant (CFA) induced arthritis. The expression of pro-inflammatory cytokines (predominantly contributed by macrophages) was also evaluated. TNF- α level was estimated in serum by ELISA method. TNF-R1, IL-1 β and IL-6 expression in the synovium was analysed by immunohistochemistry.

RESULTS

CSHE produced a dose dependent inhibition of joint swelling as compared to control animals in both, formaldehyde and CFA induced arthritis. Although there was a dose dependent increase in serum TNF-α levels in the CSHE treated groups as compared to control, the synovial expression of macrophage derived pro-inflammatory cytokines/cytokine receptor was found to be lower in the CSHE treated groups as compared to control.

INTERPRETATION & CONCLUSIONS

Our results demonstrate that the antiarthritic activity of CSHE may be attributed to the modulation of pro-inflammatory cytokines in the synovium. In further studies CSHE could be explored to be developed as a disease modifying agent in the treatment of RA.

Anti-arthritic and disease modifying activity of Terminalia chebula Retz. in experimental models

OBJECTIVE

This study evaluates the anti-arthritic effect of Terminalia chebula hydroalcoholic extract (TCHE) in experimental models and attempts to correlate the effect of treatment on macrophage-derived pro-inflammatory cytokine expression and extent of disease activity.

METHODS

Arthritis was induced in rats by subplantar administration of either formaldehyde or complete Freund's adjuvant (CFA). Joint size was measured at regular intervals by using a micrometer screw gauge. Serum and ankle joints of rats immunized with CFA were collected and subjected to ELISA for estimation of TNF-α level and immuno-histochemistry for detection of IL-1β, IL-6 and TNF-R1, respectively. An acute and 28-day oral toxicity study was carried out to evaluate the safety of the test drug.

KEY FINDINGS

TCHE produced a significant inhibition of joint swelling as compared with control in both formaldehyde-induced and CFA-induced arthritis. TCHE treatment also reduced serum TNF-α level and synovial expression of TNF-R1, IL-6 and IL-1β. Results of acute toxicity study showed that the oral LD50 of TCHE was >2000 mg/kg. Chronic administration also did not produce any significant physiological changes as compared with normal rats.

CONCLUSION

Results indicate that the anti-arthritic activity of TCHE was at least in part due to its modulatory effect on pro-inflammatory cytokine expression in the synovium. We believe that TCHE has the potential to be used as a disease-modifying agent in treatment of rheumatoid arthritis.

CHEMOTHERAPY OF ARTHRITIS INDUCED IN RATS BY MYCOBACTERIAL ADJUVANT

Arthritis induced in rats by mycobacterial adjuvant has been used for the study of compounds of known value in the treatment of rheumatoid arthritis in man. The development of the arthritic syndrome in treated and control rats was followed by measuring the changes in foot thickness of both hind-feet with a micrometer. This method allowed the effect of anti-inflammatory compounds to be expressed quantitatively. Anti-inflammatory activity was readily observed in certain steroids, pyrazolidines, salicylates and sodium aurothiomalate. Chloroquine and hydroxychloroquine were inactive. The inhibition obtained by daily treatment with the steroid paramethasone disappeared when treatment was withdrawn.

Animal models for osteoarthritis: processes, problems and prospects

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Inflammatory polyarthritis in mice transgenic for human T cell leukemia virus type I

OBJECTIVE

We have recently reported that arthropathy develops in high incidence among transgenic mice carrying the pX region of human T cell leukemia virus type I (HTLV-I). In the present study, the histopathologic features of the joints in these mice were examined in order to compare the animal disease with rheumatoid arthritis (RA) in humans.

METHODS

Paraffin sections of limbs (right and left fingers, wrists, elbows, shoulders, toes, knees, and ankles) were stained with hematoxylin and eosin, periodic acid-Schiff, azan-Mallory, or phosphotungstic acid hematoxylin, and examined by light microscopy.

RESULTS

Abnormalities of the limbs began to occur as early as 3 weeks of age, and the incidence gradually increased until the mice were 12 months old. The incidence of arthropathy was 22% (48 of 217) at 3 months of age and 28% (18 of 64) at 6 months. The severity of the histopathologic changes in the joints of the transgenic mice ranged from grade I to grade IV.

CONCLUSION

The major histopathologic features in the joints of HTLV-I transgenic mice are similar to those in humans with RA. Thus, these mice may represent a useful model for the study of the disease in humans.

Histopathological observation of joint lesions of extremities in mice transferred genome

Pathological examination of arthritic lesions in transgenic mice produced by the pX region of the human T-cell leukemia virus type-1 (HTLV-1) was carried out. Clinically, erythema, swelling and/or ataxia of the limb joints were observed in many transgenic mice about 1 month-old. Histopathologically, proliferation of synovial lining cells, infiltration of inflammatory cells with lymphoid structures and formation of pannus with cartilage and/or subchondral bone destructions were observed in various joints of transgenic mice. The frequency of abnormalities in the joints was higher in females than in males. These histopathological findings were very similar to those of human rheumatoid arthritis (RA). Present results indicate that the pX genome of the HTLV-1 is an etiological agent for the incidence of arthritic lesions in the transgenic mice.

Cellular basis and oncogene expression of rheumatoid joint destruction

A new animal model for human rheumatoid arthritis is described, and the unsolved questions regarding the mechanism of primary joint destruction are discussed. Following an analysis of the types of cells and antibodies found in joints affected by rheumatoid arthritis, it is concluded that both expression of oncogenes and the presence of retroviral sequences detectable by monoclonal antibodies to HTLV I p19 and p24 sequences are associated with early abnormal proliferation of apparently transformed cells at the site of initial cartilage and/or bone destruction.

Experimental models of osteoarthritis: the role of immobilization

Evidence is reviewed from animal experiments supporting the hypothesis that immobilization, for whatever reason, is one of the pathogenetic factors in musculo-skeletal degeneration. It shows beyond reasonable doubt that immobilization is not only a cause of osteoarthritis but that it delays the healing process.

Experimental arthritis induced by polysaccharide macromolecules

Several polysaccharide macromolecules are capable of inducing synovial inflammation. Characteristics of polysaccharides that have this capacity were studied in an in vivo rabbit model. The ability to induce synovial inflammation was positively correlated with the presence of sulfate and with high molecular weight. Understanding the characteristics of molecules that produce inflammation may help in the investigation to determine what mechanisms initiate the inflammatory response.

Ankylosing spondylitis and trauma: the medicolegal implications. A comparative study of patients with non-specific back pain

Ankylosing spondylitis (AS) arising as a result of injury was reported by five of 113 hospital patients who completed questionnaires on the historical and symptomatic features of their disease. Identical questionnaires were given to a group of 51 patients with non-specific back pain (NSBP) attending an orthopaedic clinic. Five of these patients developed their first symptoms after trauma. A further four patients with ankylosing spondylitis believed that their disease was initiated by injury, however, x-ray photographs showed that they had already developed AS at the time of their injuries. It is suggested that injury does not cause AS but brings it to the patient's attention, possibly through immobilisation, in 7% of hospital cases.

Induction of chronic polyarthritis in rabbits by hyperimmunization with Escherichia coli. I. Pathologic and serologic features in two breeds of rabbits

Hyperimmunization of 147 rabbits (outbred Japanese white rabbits and New Zealand white [NZW] rabbits bred in a closed colony) with heat-killed Escherichia coli 0:14 in Freund's incomplete adjuvant resulted in the animals developing a chronic polyarthritis resembling rheumatoid arthritis (RA). While both Japanese white and NZW rabbits showed a high incidence of the induced arthritis, a higher proportion of NZW rabbits developed the disease, suggesting that genetic influence is important in the development of RA-like illness. This experimental model may be useful for the study of RA.

Growth disturbances in experimental juvenile arthritis of the dog knee

In the study of pathophysiological mechanisms in growth abnormalities of the juvenile knee in arthritis an animal model in dogs was developed. Arthritis was induced by intra-articular injections of Carrageenan. Prominent growth changes were enlargement of the distal femoral epiphysis, patellar squaring and decreased endochondral and appositional growth of the distal femur. Generalized osteoporosis of the arthritic limb was present. The induced growth disturbances bear resemblance to the growth abnormalities in juvenile chronic arthritis and hemophilic arthropathy of the knee.

Sequential appearance of fibronectin and collagen fibres in experimental arthritis in rabbits

The sequential changes in the presence of fibronectin in the synovial membrane during the development of antigen-induced arthritis in rabbits were studied using an indirect immunoperoxidase technique on the tissue specimens fixed in formaldehyde, embedded in paraffin and pre-treated with pepsin and testicular hyaluronidase. The relation to the distribution of fibronectin and connective tissue fibres, demonstrated as either argyrophilic or red by van Gieson method, was studied. Initial after the induction of the arthritis the synoviocytes became increased in size and number. The subsynoviocytial tissue was invaded by granulocytes and the number of vessels was increased. Fibronectin in increased amount was seen around the lining cells. After 2-4 weeks a markedly reduced amount of granulocytes were seen together with an increase in the number of macrophages. At this stage, fibronectin was also found together with argyrophilic fibres in the subsynoviocytial connective tissue. After 8-13 weeks the synovial membrane was found hypertrophic and folded. The lining layer was unchanged, but in the subsynoviocytial tissue lymphocytes and plasma cells were more focally arranged. At that time fine fibres, stained by the van Gieson method, were present together with fibronectin and argyrophilic fibres in the subsynoviocytial tissue. The morphological change and the distribution of fibronectin in experimentally induced arthritis correlated temporally to the morphological change and the presence of fibronectin found in experimentally induced granulation tissue.

Immunogenicity of xenogeneic cartilage matrix components in a rabbit model

Purified xenogeneic cartilage matrix components, including proteoglycan subunits, chondroitin 4 sulfate, and chondroitin 6 sulfate, were inoculated into the knee joint of rabbits, and local as well as systemic responses were evaluated. proteoglycan was associated with synovial hyperplasia and infiltrates of eosinophils and lymphocytes and with rising titers of antiproteoglycan antibodies in a tanned sheep rbc hemagglutination assay over a six-week period of weekly intra-articular injections and observations. Chondroitin sulfates failed to evoke detectable changes in the joint or serum. Immunogenicity of cartilage matrix components may play a role in allogeneic and xenogeneic osteochondral grafts, and it is also possible that autogenous matrix immunogens exist and contribute to progression of degenerative joint disease. The immunogenicity of allogeneic and autogenous cartilage matrix components remains undefined.

[3H]proline incorporation and hydroxyproline concentration in articular cartilage during the development of osteoarthritis caused by immobilization. A study in vivo with rabbits

Proline metabolism in vivo was studied during the development of immobilization osteoarthritis in rabbits. Collagen content was measured as the hydroxyproline concentration of the tissue in question. The incorporation of [3H]proline was used as the indicator for total protein synthesis; collagen synthesis rate was estimated from measurements of the specific radioactivity of hydroxyproline. Cartilage samples from knee and hip joints were analysed after 3, 7, 11, 18, 35 and 56 days of immobilization. The total protein and collagen synthesis rates of the immobilized legs increased and reached a maximum after 11-35 days. Although they decreased thereafter, these rates remained elevated to the end of the experiment. A slight increase in the synthetic activity of the non-immobilized contralateral legs was also detected after 7--18 days of immobilization. The isotope incorporation was markedly higher in tibial marginal tissue than in weight-bearing cartilage. In spite of the increased synthesis, no clear changes were found in the collagen content of the tissues studied during the experiment.

Trypsin-induced mitosis in the articular cartilage of adult rabbits

Full-grown rabbits were injected in the knee joints with solutions of trypsin of various concentrations. The animals were sacrificed 2 weeks after the trypsin injection. Twenty-four hours before sacrifice they received 40 muCi 3H-thymidine intra-articularly. The changes in the knee joints were then studied by histological and autoradiographical methods. The injection of trypsin did not result in the development of osteoarthritis. However, autoradiography revealed that the chondrocytes started to divide after the injection. The mitosis of the chondrocytes can thus not be due to degeneration of the cartilage. The explanation put forward is that the mitosis of the chondrocytes may be the result of a decrease in the concentration of a growth controlling factor (chalone) initiated by the administration of trypsin.

Recent concepts on the pathogenesis of rheumatoid arthritis

The evidence implicating an immune pathogenesis of the lesions of rheumatoid arthritis is presented under four headings: clinical, histopathological, serological and experimental. This leads to the conclusion that the disease occurs in two phases, an initial phase associated with the presence of an exogenous initiating agent and a chronic, apparently self-prepetuating phase maintained by the presence of an autoanitgen. The microbial nature of the initiating agent is considered and it is concluded that present evidence does not exclude the possibility that no single agent is responsible.

Antigen-induced arthritis in mice. I. Induction of arthritis in various strains of mice

Antigen-induced arthritis was established in the mouse by immunizaiton with methylated bovine serum albumin (mBSA) in complete Freund's adjuvant with B pertusis vaccine. The knee joint was injected after 21 days with mBSA in saline. The arthritis was chronic, antigen-specific, and T-cell dependent in hypothmic nu/nu mice. C57BL and balb/c mice were susceptible, whereas CBA mice were relatively resistant. Susceptibility was dominant; one gene was loosely linked to the "b" allele of the H-2 complex of C57BL mice.

The effect of impact loading on rabbit knee joints

Eighteen mature male Whiteland rabbits received repetitive impulse loads slightly larger than body weight (4 kp) through one knee joint for periods from 1 to 6 weeks. Mechanical compression of subchondral bone cores from impacted tibiae showed progressive increased deformation under a constant force. Cartilage degeneration occurred concurrently with alterations in the mechanical properties of the subchondral bone. The cartilage degeneration may be explained by: (i) the deleterious effect of repetitive mechanical compression, (ii) the decreased mechanical support of the underlying subchondral bone.

Histochemical investigation of adjuvant-induced arthritis

Rats with adjuvant-induced arthritis were observed to have increased alkaline phosphatase, acid phosphatase (two isozymes), and ATPase activity in the radial zone of articular cartilage, at the osteochondral junction, and in the bone marrow elements. A qualitative and quantitative reduction azure A, PAS colloidal iron, alcian blud critical electrolyte concentration staining (0.4 and 0.9 M (mg Cl2) was also observed in corresponding areas. These findings suggest the degradation of the articular cartilage matrix with possible simultaneous or resultant calcification.

Carrageenin-induced arthritis. I. The effect of intraarticular carrageenin on the chemical composition of articular cartilage

A single intraarticular injection of carrageenin into rabbit knee joints initiated a localized synovial inflammatory response. This response was accompanied by a 20% loss of proteoglycan from the articular cartilage within 24 hours and by a further 30-60% loss within 5-7 days. The chondrocytes replaced the lost proteoglycan within 42 days. More than two injections caused only a further small decrease in proteoglycan content; the cartilage was then unable to replace the lost proteoglycan. The absence of recovery coincided with the appearance of erosion of the cartilage surface.

Antigenic profile of the rat chondrocyte

Hetero- and alloantisera were obtained following hyperimmunization of nonsensitized New Zealand rabbits and dark agouti (DA) rats with washed chondrocytes which had been enzymatically isolated from the long bone cartilage of 17-19-day-old rat fetuses of the Fischer strain. Analyses of these antisera by PVP hemagglutination, dye-exclusion cytotoxicity, and indirect immunofluorescence indicated the presence of major histocompatibility antigens, as well as tissue-specific antigens on chronrocytes. Serologic specificity of reactions was demonstrated by serum absorptions and appropriate controls. These findings supprot previous work suggesting that chrondrocytes are endowed with major histocompatibility antigens. The significance of these findings in relation to rheumatoid arthritis is discussed.

A pathogenetic model for erosive synovitis: lessons from animal arthritides

Adjuvant arthritis, streptococcal cell wall-induced arthritis, and Erysipelothrix insidiosa arthritis are laboratory models of relapsing, erosive synovitis. A review of the experimental literature suggests that their pathogenesis is similar. The persistence in macrophages in the pannus of nonbiodegradable microbial cell wall components containing the peptidoglycan moeity is the central event. Based on this experimental literature, a model for the pathogenesis of these arthritides is developed. This model is testable and relevant to erosive synovitis in man.

Thermoanalytical and histological study of intra-articular papain-induced degradation and repair of rabbit cartilage. II. Mature animals

The effect of papain treatment on the cartilage tissue of the knee joint of mature rabbits was studied by histological and thermoanalytical methods. Changes taking place in the composition of cartilage in the course of ageing were shown. As a result of papain treatment a significant irreversible destruction of the ground substance took place. Papain-induced loss of proteoglycans and the intensity of repair reactions and age-related differences are discussed.

Experimental rheumatoid arthritis-like features induced by prolonged sensitization with focal antigens

Prolonged sensitization with emulsion of an autologous or isologous subcutaneous abscess of Arthus type induced by injection of hen egg-white was performed in 34 rabbits which were divided into (high responder and intermediate responder groups (H- and M-groups) according to individual difference of immune responses. The development of a rheumatoid factor-like substance (RFLS) was demonstrated after 30 experimental days and subsequently observed in 21 out of 33 rabbits. There was no significant difference in the incidence of RFLS between both groups. As to the relation between the development of RFLS and types of focal antigens, the group of the autologous W-substance showed a higher incidence of RFLS than the N-substance. Acute and/or chronic synovitis was demonstrated in 13 of 33 rabbits and inflammatory changes were more intensive and extensive in the later period of experiment. Presence of RFLS in the affected synovial tissues, chiefly in the cytoplasm of plasma cells and mononuclear cells, occasionally in a free state was revealed by immunofluorescent study, and depositions positive for IgG and beta 1C were observed in the wall of blood vessels and fibrinous thrombi in the affected synovial tissues.

Thermoanalytical and histological study of intra-articular papain-induced degradation and repair of rabbit cartilage. I. Immature animals

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Polyarthritis associated with Salmonella infection in rats

Rats infected intravenously with Salmonella enteritidis develop a chronic destructive polyarthritis. The joint lesions resemble those of human rheumatoid arthritis in distribution and pathology. On the basis of histological and microbiological studies, involvement does not appear to be the result of intra-articular sepsis. Instead, the data favor the view that transient infection incites an immunological response that localizes in the joint and becomes destructive.

Evidence for a direct effect on articular cartilage and its lysosomal enzymes in filipin-induced arthritis

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Immunofluorescent demonstration of an intra-articular antigen-antibody complex in experimental arthritis of the guinea-pig

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