Studies on carbohydrate moieties of glycoproteins in established adjuvant induced arthritis

Identification of Molecular Signatures from Different Vaccine Adjuvants in Chicken by Integrative Analysis of Microarray Data

The present study compared the differential functions of two groups of adjuvants, Montanide incomplete Seppic adjuvant (ISA) series and Quil A, cholesterol, dimethyl dioctadecyl ammonium bromide, and Carbopol (QCDC) formulations, in chicken by analyzing published microarray data associated with each type of vaccine adjuvants. In the biological function analysis for differentially expressed genes altered by two different adjuvant groups, ISA series and QCDC formulations showed differential effects when chickens were immunized with a recombinant immunogenic protein of Eimeria. Among the biological functions, six categories were modified in both adjuvant types. However, with respect to “Response to stimulus”, no biological process was modified by the two adjuvant groups at the same time. The QCDC adjuvants showed effects on the biological processes (BPs) including the innate immune response and the immune response to the external stimulus such as toxin and bacterium, while the ISA adjuvants modified the BPs to regulate cell movement and the response to stress. In pathway analysis, ISA adjuvants altered the genes involved in the functions related with cell junctions and the elimination of exogenous and endogenous macromolecules. The analysis in the present study could contribute to the development of precise adjuvants based on molecular signatures related with their immunological functions.

Therapeutic effect of irradiation of magnetic infrared laser on osteoarthritis rat model

Osteoarthritis (OA) is a degenerative joint disease caused by articular cartilage loss. Many complementary and alternative medicines for OA have been reported so far, but the effectiveness is controversial. Previously, we have shown anti-inflammatory effects of low level laser therapy with static magnetic field, magnetic infrared laser (MIL), in various animal models. Therefore, the beneficial effects were examined in OA rat model. Rats were divided by six groups; no treatment controls of sham and OA model, three MIL treatment groups of OA model at 6.65, 2.66 and 1.33 J cm(-2), and Diclofenac group of OA model with 2 mg kg(-1) diclofenac sodium. The OA control exhibited typical symptoms of OA, but 4-week MIL treatment improved the functional movement of knee joint with reduced edematous changes. In addition, cartilage GAGs were detected more in all MIL treatment groups than OA control. It suggests that 4-week MIL irradiation has dose-dependent anti-inflammatory and chondroprotective effects on OA. Histopathological analyses revealed that MIL treatment inhibits the cartilage degradation and enhances chondrocyte proliferation. The fact that MIL has an additional potential for the cartilage formation and no adverse effects can be regarded as great advantages for OA treatment. These suggest that MIL can be useful for OA treatment.

Comparative study of sialyl glycoprotein with multiple glycosylation sites using isotope labeling and capillary liquid chromatography/mass spectrometry

RATIONALE

A comparative strategy has been demonstrated using RNase B, a single-site N-linked high-mannose glycoprotein. Glycoproteins are more common with multiple glycosylation sites and with complex glycans. A strategy capable of differentiating the changes caused by glycoprotein concentration, glycosylation site occupancy, and a glycoform profile of complex glycoproteins would be beneficial.

METHODS

Tryptic-digested glycoproteins were labeled using ¹² C,H-formaldehyde and ¹³ C, D-formaldehyde, purified, and then analyzed using capillary reversed-phase liquid chromatography/mass spectrometry (RPLC/MS). The relative intensity of non-glycosylated peptides provided information on glycoprotein concentration variation. A site-specific glycoform profile variation was obtained by comparing the glycoform profile of CH₂ and ¹³ CD₂ glycopeptides. Determining the protein concentration and glycoform profile variations allows the glycosylation site occupancy variation to be calculated.

RESULTS

A strong correlation between the observed and prepared ratios for fetuin glycopeptides from 0.2 to 5 was obtained. Two fetuin samples with different glycoprotein concentrations (4-fold change), glycoform profiles (normal and modified), and glycosylation site occupancies (100% and 50%) were prepared, labeled, mixed, purified, and analyzed using RPLC/MS. The results of the comparative study had a strong correlation with the prepared values.

CONCLUSIONS

In this report, we demonstrated a comparative analysis of fetuin, a glycoprotein with multiple glycosylation sites and complex sialyl glycans. Compared to our previous approach, we made several modifications including the use of RPLC, a larger mass difference isotope tag, and isotope overlapping correction. The modified approach is expected to be applicable to most glycoproteins. Copyright © 2013 John Wiley & Sons, Ltd.

Ameliorative effect of p-coumaric acid, a common dietary phenol, on adjuvant-induced arthritis in rats

p-Coumaric acid (3-(4-hydroxyphenyl)-2-propenoic acid), a common dietary polyphenol, is widely distributed in cereals, fruits and vegetables with antioxidant property. Numerous studies have enlightened the ability of dietary phenols to be considered as potential therapeutics against arthritis. In this study, we aimed to investigate the ameliorative effect of plant phenolic p-coumaric acid on adjuvant-induced arthritis in rats. The reference drug indomethacin was used for comparison purposes. Arthritis was induced in rats by a single intradermal injection of complete freund's adjuvant (0.1 mL) into the foot pad of right hind paw. p-Coumaric acid (100 mg/kg b wt) and indomethacin (3 mg/kg b wt) were administered intraperitoneally for 8 days from day 11 to 18 after adjuvant injection. An increase in the activities/levels of lysosomal enzymes, tissue marker enzymes, glycoproteins and paw thickness was observed in the arthritic rats, on the contrary, the body weight was found to be reduced in arthritic rats when compared to normal control rats. Administration of p-coumaric acid (100 mg/kg b wt) to the arthritic rats reverted back the altered physical and biochemical parameters to near normal levels comparable to indomethacin treatment. Histopathological evaluation of ankle joints in arthritic rats also revealed the anti-inflammatory effect of p-coumaric acid by the reduction in leukocytes infiltration. Thus, the present study clearly demonstrates the anti-inflammatory potential of the p-coumaric acid against adjuvant-induced arthritis in rats.

Efficacy of Siddha formulation Kalpaamruthaa in ameliorating joint destruction in rheumatoid arthritis in rats

BACKGROUND

Rheumatoid arthritis (RA) is a kind of chronic inflammatory autoimmune disease. The degradation of extracellular matrix and cartilage pave way in understanding the molecular mechanisms in RA. Degradation of cartilage is a more complex event involving the local release of metallaoproteases and lysosomal enzymes that mediate inflammation in joints and in the synovial fluid in RA.

OBJECTIVES

In the present study, the efficacy of a Siddha preparation named Kalpaamruthaa (KA) in ameliorating the disease process via markedly reducing the joint destruction was demonstrated in adjuvant induced arthritis rat model. KA consists of Semecarpus anacardium nut milk extract (SA), dried powder of Emblica officinalis fruit and honey.

MATERIAL AND METHODS

Both SA and KA were administered at dose of 150 mg/kg b.wt. for 14 days after 14 days of adjuvant injection in rats. The activity of lysosomal enzymes, the level of collagen, glycosaminoglycans (GAGs) and its degradative products were analyzed in control and experimental animals.

RESULTS AND CONCLUSION

The study revealed that KA exhibited a profound reduction (p<0.05) in the activities of lysosomal enzymes and thereby decreasing (p<0.05) the levels of GAGs and its fractions when compared to arthritis rats. The latter was confirmed by Safrannin O staining for GAGs in the interphalangeal joints of control and experimental animals. The effect of KA was found to be improved than SA and this might be due to the combined interactions of phytoconstituents present in KA.

Antiinflammatory effect of the Indian Ayurvedic herbal formulation Triphala on adjuvant-induced arthritis in mice

In the present study, attempts have been made to evaluate the antiarthritic effect of the Indian Ayurvedic herbal formulation Triphala on adjuvant-induced arthritis in mice and to compare it with that of the non-steroidal antiinflammatory drug indomethacin. Arthritis was induced by intradermal injection of complete Freund's adjuvant (0.1 mL) into the right hind paw of Swiss albino mice. Triphala (1 g/kg/bxwt) and indomethacin (3 mg/kg/bxwt) were administered orally for 8 days (from day 11 to 18) after adjuvant injection. The levels of lysosomal enzymes, tissue marker enzymes, glycoproteins and paw thickness were increased in adjuvant-induced arthritic animals. The body weight was found to be reduced when compared with the control animals. These physical and biochemical changes observed in arthritic animals were altered significantly to near normal conditions after oral administration of Triphala (1 g/kg/bxwt). The results obtained clearly indicate the fact that the Indian Ayurvedic herbal formulation Triphala has promising antiinflammatory activity.

Protective effect of Withania somnifera root powder in relation to lipid peroxidation, antioxidant status, glycoproteins and bone collagen on adjuvant-induced arthritis in rats

The present investigation was carried out to evaluate the protective effect of Withania somnifera Linn. Dunal (family-Solanaceae), commonly known as Ashwagandha, on adjuvant-induced arthritic rats. Results were compared with those for Indomethacin, a nonsteroidal anti-inflammatory drug. Arthritis was induced by intradermal injection of complete Freund's adjuvant (0.1 mL) into the right hind paw of Wistar albino rats. Withania somnifera root powder (1000 mg/kg/day) and Indomethacin (3 mg/kg/day) were orally administered for 8 days (from 11th to 18th day) after adjuvant injection. The anti-arthritic effect of W. somnifera root powder was assessed by measuring changes in lipid peroxidation, antioxidant status, and glycoprotein levels in plasma and spleen of arthritic animals. In addition, cartilage degradation was also assessed by estimating bone collagen, and urinary constituents in arthritic animals. Results of the present investigation showed significant increase in the level of lipid peroxides, glycoproteins, and urinary constituents with the depletion of antioxidant status and bone collagen in arthritic animals. These biochemical alterations observed were ameliorated significantly by oral administration of W. somnifera root powder (1000 mg/kg body weight) in arthritic animals. The results of this study clearly indicate that W. somnifera root powder is capable of rectifying the above biochemical changes in adjuvant arthritis.

Anti-inflammatory and lysosomal stability actions of Cleome gynandra L. studied in adjuvant induced arthritic rats

The present study was aimed to assess the anti-arthritic nature of Cleome gynandra L. (Cat's whiskers) against Freund's complete adjuvant induced arthritis in rats. The ethanolic extract of C. gynandra was administered orally at a dose of 150 mg/kg body weight for 30 days to the experimental rats after the induction of adjuvant arthritis. The anti-inflammatory activity of C. gynandra leaves was assessed by paw volume measurement, and its capacity to stabilize lysosomal enzyme activities in the plasma and liver of control and experimental rats. The activity of pathophysiological enzymes such as AST, ALT, ALP, cathepsin-D, beta-glucuronidase, N-acetyl-beta-glucosaminidase LDH and the levels of glycoproteins were also estimated in plasma and liver. The increased levels of both lysosomal enzymes and protein-bound carbohydrates in arthritic rats were significantly suppressed to near normal level by the administration of C. gynandra extract. Further, the significantly elevated plasma levels of TNF-alpha found in arthritic rats were found to be significantly restored back to near normal levels by the extract in experimental animals. The membrane stabilizing activity of the extract was further evidenced by histological observations made on the limb tissue. Recently, we have reported the presence of many biologically active phyto chemicals such as triterpenes, tannins, anthroquinones, flavonoids, saponins, steroids, resins, lectins, glycosides, sugars, phenolic compounds, and alkaloids in the extract of C. gynandra and these compounds might be responsible for the anti-arthritic properties observed in the present study. The possible mechanism of action of the C. gynandra extract may be through its stabilizing action on lysosomal membranes and there by preventing the spread of inflammation.

Antinociceptive and antiarthritic activity of Cissampelos pareira roots

In the present study, 50% aqueous ethanolic extract of Cissampelos pareira (Menispermaceae) roots (C. pareira) at the dose levels of 100-400 mg/kg, once daily for 3 days exhibited significant (P < 0.001) resistance against mechanical pain after 30 min in analgesymeter induced pain in mice. In acetic acid (0.6%; i.p.) inducing writhing, Cissampelos pareira significantly (P < 0.05) decreased the writhing episodes; the degree of percent protection at 200 and 400 mg/kg was 22.73 and 51.63. The hot plate reaction time was increased by 2.07 (P < 0.05) and 2.70 (P < 0.001) folds. respectively. Further Cissampelos pareira showed the dose dependent significant protective effect against complete Freund's adjuvant induced arthritis. The percentage protection on the 18th day was 40.54 (P < 0.01) and 71.52 (P < 0.001) at 200 and 400 mg/kg respectively. Lysosomal enzymes (acid phosphatase and N-acetyl glucosaminidase) were decreased by 50% (P < 0.01) and 26.26% (P < 0.05) by using Cissampelos pareira, dextramethasone decreased them 56.56% (P < 0.01) and 31.82% (P < 0.01) and the glycoprotein contents (total hexose and sialic acid) were increased by 1.55-folds (P < 0.01) and 1.51-folds (P < 0.05) by using Cissampelos pareira while dextramethasone increases them by 1.51-folds (P < 0.001) and 1.60-folds (P < 0.01) respectively in stomach homogenate with respect to arthritic group. The increased pain threshold and protective effect against CFE by Cissampelos pareira vindicated its medicinal value in treatment of pain and arthritis.

Targeted glycoproteomics: serial lectin affinity chromatography in the selection of O-glycosylation sites on proteins from the human blood proteome

Although lectin selection is gaining increasing acceptance as a tool for targeting glycosylation in glycoproteomics, most of the work has been directed at N-glycosylation. The work reported here focuses on the use of lectins in the study of O-glycosylation. The problem with using lectins for studying O-glycosylation is that they are not sufficiently specific. This paper reports that through the use of serial lectin affinity chromatography (SLAC) it is possible to select predominantly O-glycosylated peptides from tryptic digests of human serum. Jacalin is relatively specific for O-glycosylation but has the problem that it also selects high mannose N-type glycans. This problem was addressed by using a concanavalin A affinity column to first remove high mannose, hybrid-type and biantennary complex-type N-type glycans before application of the Jacalin columns. When used in a serial format, concanavalin A and Jacalin together provide essentially O-glycosylated peptides. The glycoprotein parents of glycopeptides were identified by deglycosylating the selected O-glycopeptides by oxidative elimination. These peptides were then separated by RPC and further analyzed using ESI-MS/MS and MALDI-MS/MS. Using this approach all the O-glycosylated sites in a model protein (fetuin) and over thirty glycoprotein parents from human serum were identified. It is concluded that a serial combination of Con A and Jacalin can be of utility in the study of O-glycosylation in glycoproteomics.

Therapeutic effects of Semecarpus anacardium Linn. nut milk extract on the changes associated with collagen and glycosaminoglycan metabolism in adjuvant arthritic Wistar rats

The effect of milk extract of Semecarpus anacardium Linn. nut milk extract (SA) was studied to gain some insight into this intriguing disease with reference to collagen metabolism. Arthritis was induced in rats by injecting Freund's complete adjuvant containing 10mg of heat killed mycobacterium tuberculosis in 1 ml paraffin oil (0.1 ml) into the left hind paw of the rat intradermally. After 14 days of induction, SA (150 mg/kg body weight/day) was administered orally by gastric intubations for 14 days. Decreased levels of collagen and glycosaminoglycans (GAGS) components (chondroitin sulphate, heparan sulphate, hyaluronic acid) and increase in the levels of connective tissue degrading lysosomal glycohydrolases such as acid phosphatase, beta-glucuronidase, beta-N-acetyl glucosaminidase and cathepsin-D observed in arthritic animals were reverted back to near normal levels upon treatment with SA. The drug effectively regulated the uriniray markers of collagen metabolism namely hexosamine, hexuronic acid, hydroxyproline and total GAGS. Electron microscopic studies also revealed the protective effect of SA. Hence, it can be suggested that SA very effectively regulate the collagen metabolism that derange during arthritic condition.

Biochemical evaluation of the inflammatory changes in cardiac, hepatic and renal tissues of adriamycin-administered rats and the modulatory role of exogenous heparin-derivative treatment

The aim of the present work is to evaluate the role of a heparin derivative, low molecular weight heparin (LMWH), certoparin on the inflammatory changes in adriamycin (ADR) cytotoxicity on a biochemical basis. Male Wistar rats (140+/-10g) were divided into four groups: untreated control, ADR group (a single dose intravenous injection of 7.5 mg/kg ADR), LMWH control (300 microg/(day rat) s.c. for 1 week) and ADR plus LMWH group (7.5 mg/kg ADR on day 1 of study period followed by LMWH treatment, 300 microg/(day rat) commencing on day 8 and continued for 1 week). At the end of the 2-week experimental period, biochemical assessment of the inflammatory status was carried out in the plasma, cardiac, hepatic and renal tissues. Increased concentrations of plasma C-reactive protein (CRP) and fibrinogen indicated severe inflammation in the ADR cytotoxic rats. These acute-phase inflammatory markers diminished significantly in the LMWH treated group, when compared with the cytotoxic group (p<0.001). Tissue damage was marked by elevated levels of plasma and tissue hexose, hexosamine, hexuronic acid and sialic acid, which were reversed on LMWH administration (p<0.001). The activities of lysosomal enzymes was measured in the experimental groups, and it was observed that the ADR induced rats showed a marked increase in the enzymic activities, while LMWH treated rats revealed normal activities. The present study throws light on the inflammatory changes in the ADR-challenged heart, liver and kidney tissues, and projects the biochemical basis for the anti-inflammatory property of the LMWH, certoparin.

Comparative proteomics of glycoproteins based on lectin selection and isotope coding

Lectins have been widely used in glycan structure analysis. The studies described here exploit this fact to select glycopeptides carrying disease-associated modifications in their oligosaccharides. Coupling lectin affinity selection with recent advances in stable isotope coding for quantitative proteomics allowed a comparative proteomics method to be developed for examining aberrant glycosylation in cancer. Control and experimental samples were individually tryptic digested and differentially coded with stable isotope coding agents before they were mixed and affinity selected with a lectin affinity chromatography column. Glycopeptides carrying an alpha-L-fucose residue were selected with Lotus tetragonolobus agglutinin (LTA) immobilized on a chromatography matrix. Because the oligosaccharides of glycoproteins are generally heterogeneous and often of unknown structure, it was necessary to deglycosylate the selected peptides with PNGase F before they could be compared to sequences in DNA and protein databases. After deglycosylated peptides were transferred to a reversed phase chromatography (RPC) column and fractionated by gradient elution with increasing amounts of acetonitrile. The RPC fractions were then analyzed by both matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) and electrospray ionization mass spectrometry (ESI-MS). When this method was applied to a study of lymphosarcoma in canines, it was found that during chemotherapy, a series of fucosylated proteins in the blood of patients decreased in concentration more than 2-fold. Two of the proteins identified, CD44 and E-selectin, are known to be involved in cell adhesion and cancer cell migration. The observed aberrant fucosylation of these proteins is consistent with the hypothesis that CD44 and E-selectin play a key role in metastasis and the spread of cancer cells to remote sites.

A novel derivative pentacyclic triterpene and omega 3 fatty acid

Adjuvant induced arthritis (AIA) is accompanied by marked changes in the levels of lysosomal enzymes, glycoproteins and metabolic turnover of collagen. The role of a pentacyclic triterpene and eicosapentaenoic acid (EPA) derivative--Lupeol-EPA (50 mg/kg body weight--orally) was tested in vivo in rats. The increased activities of lysosomal enzymes and glycoproteins associated with decreased collagen in arthritic animals were significantly altered to nearly that of controls. Indomethacin (3 mg/kg body weight) was used as a reference compound. The therapeutic usefulness of Lupeol-EPA derivative in inflammatory conditions is attractive and deserves further work in this direction.

Effect of lupeol and lupeol linoleate on lysosomal enzymes and collagen in adjuvant-induced arthritis in rats

Lysosomal enzymes play important roles in the inflammatory process. The pentacyclic triterpenes, lupeol and lupeol linoleate were administered orally (50 mg/kg) for 8 days to arthritic rats, after 11th day of adjuvant injection. The lysosomal enzymes were significantly increased in arthritic condition, which are involved in the destruction of structural macromolecules in connective tissue and cartilage in rheumatoid arthritis. Hence the level of collagen was significantly decreased and the excretion of urinary hydroxyproline, hexosamine, hexuronic acid and glycosaminoglycans were increased in arthritic rats. Treatment of arthritic rats with triterpenes reversed the above changes, which may be due to stabilization of the lysosomal membrane. Out of the two triterpenes tested, lupeol linoleate showed better ameliorating action than lupeol.

Effect of milk extract of Semecarpus anacardium nuts on glycohydrolases and lysosomal stability in adjuvant arthritis in rats

Lysosomal acid hydrolases are thought to play an important role in inflammation associated with rheumatoid arthritis. A Siddha preparation of Semecarpus anacardium nut extract called Serankottai Nei was tested for its capacity to stabilize lysosomes obtained from liver and kidney of adjuvant-induced arthritic animals. Lysosomal membrane stability was measured by determining the release of acid hydrolases from the lysosomes. The drug was administered at a dose level of 150 mg/kg body weight for 14 days to arthritic animals after the adjuvant injection. The total and free activity of lysosomal enzymes were significantly increased in arthritic rats with concomitant increase in plasma levels of protein-bound carbohydrates. Significantly increased lysosomal membrane fragility as observed in arthritic condition was reduced in drug-treated animals. Antiarthritic activity of the drug through its stabilizing action on lysosomal membranes could be inferred from this study.

Effect of the milk extract of Semecarpus anacardium nut on adjuvant arthritis--a dose-dependent study in Wistar albino rats

1. Adjuvant-induced arthritis in rats is used as a pathologic model for chronic inflammatory disease to evaluate the efficacy of therapeutic agents. 2. In the present work, attempts have been made to study the potency of a milk extract of Semecarpus anacardium (Serankottai Nei), a Siddha preparation from Semecarpus anacardium nut, which has been shown to have antiarthritic effects. 3. Experimental arthritis induces a significant modification in lysosomal enzyme release and total carbohydrate components of glycoprotein. 4. Milk extract was administered at the dose level of 50, 100, 150, 200, and 250 mg/kg body weight in olive oil orally (volume 0.5 ml) after 14 days from the day of adjuvant injection. 5. After administration of the extract the lysosomal enzyme activity and protein-bound carbohydrate component levels were significantly normalized. 6. The data obtained clearly indicate that the Semecarpus anacardium is effective at the dose level of 150 mg/kg body weight in adjuvant-induced arthritis in albino Wistar rats.

Metabolic studies on connective tissue collagens in bone and tendon of adjuvant arthritic rat

The metabolic alterations in the matrix of connective tissue collagen were investigated in bone and tendon of rats with adjuvant-induced arthritis. Adjuvant arthritis was induced in rats with the immunization of Freund's adjuvant containing heat-killed Mycobacterium tuberculosis. The changes in the metabolism of collagen were studied using radioactive isotopic measurements with (3H)-proline. Tissue specimens were fractionated individually into soluble and insoluble collagens. The synthesis of collagen was examined by measuring the total collagen content and the radioactivity of (3H)-hydroxyproline in soluble collagen fraction within 24 hours after the administration of tritiated proline. The conversion of soluble to insoluble collagen was analyzed by measuring the radioactivity of (3H)-hydroxyproline in both soluble and insoluble collagens. The catabolism of soluble and insoluble collagens was studied by estimating the radioactivity of urinary (3H)-hydroxyproline 24 hours after the injection of tritiated proline. It was observed that the total collagen content and the total radioactivity of (3H)-hydroxyproline in bone and tendon were decreased significantly in adjuvant arthritic rats. The specific and total radioactivities of (3H)-hydroxyproline in soluble collagen were found to be reduced, indicating the decreased de novo synthesis of collagen during the diseased state. The conversion of soluble to insoluble collagen was impaired in tissues as evidenced by the increased content of soluble collagen in arthritic disease. In addition, an enhanced excretion of hydroxyproline was found in urine of arthritic rats, indicating the increased degradation of collagen in arthritic disease. These observations could, therefore, explain in part the changes in synthesis and degradation of collagen in bone and tendon during the development of experimentally induced adjuvant arthritis in rats.

Connective tissue metabolism in bone and cartilage of adjuvant arthritic rat

The metabolism of connective tissue matrix components such as glycosaminoglycans and glycoproteins was investigated in normal as well as pathological tissues of bone and cartilage associated with adjuvant arthritis using rat as animal model of the disease. The inflammatory process of adjuvant arthritis was induced in rats with the inoculation of Freund's adjuvant containing heat killed Mycobacterium tuberculosis suspended in paraffin oil. The changes in the metabolism of matrix components in bone and cartilage were examined using radioactive isotopic labeling measurements during the acute as well as chronic phases of arthritic disease. The glycosaminoglycans were fractionated into sulfated and non-sulfated glycosaminoglycans by chemical and enzymic modifications. The biosynthesis of sulfated glycosaminoglycans was evaluated using radioactive labeled (35S)-sulfate. Alterations were demonstrated in the metabolism of connective tissue in the bone and cartilage tissues of arthritic rat. The results obtained showed an increased incorporation of radioactive sulfate in specimens of bone and cartilage during the process of adjuvant arthritis. The contents of sulfated as well as non-sulfated glycosaminoglycans were found to be increased in both the tissues of arthritic rat. Similarly, the amount of total glycosaminoglycans was also found to be increased significantly in the diseased tissues. In addition, various components of tissue glycoproteins such as fucose, sialic acid and total hexose were found to be elevated in insoluble fractions of bone and cartilage during the diseased state. The effects of experimentally induced adjuvant arthritis on the connective tissue were discussed in the light of changes taking place in the metabolism of glycosaminoglycans and glycoproteins in bone and cartilage of arthritic rat.

Metabolism of collagen in bone of adjuvant induced arthritic rat

The metabolism of collagen was examined in bones of rats rendered adjuvant arthritis and matched controls using radioactive isotopic tracer techniques. The rate of the synthesis was studied after the incorporation of tritiated labeled proline into the total bone collagen and determining the content of total hydroxyproline and estimating the specific and total activities of radioactive labeled hydroxyproline. The rate of the catabolism was examined by measuring the activities of various collagen degrading proteolytic enzymes in the bone extract and by estimating the total content of hydroxyproline excreted in the urine. The degradation of collagen was also followed by measuring the specific and total radioactivities of (3H)-hydroxyproline in the urine. When (3H)-proline was injected into the adjuvant arthritic rat, the specific and total radioactivities of (3H)-hydroxyproline in bone collagen were reduced significantly in diseased bone. The activities of various enzymes involved in the catabolism of collagen and other extracellular matrix components were appreciably elevated (about 2-3 fold) in the bone extract of arthritic rat. Similarly, the specific and total activities of (3H)-hydroxyproline in urine samples were also greatly increased in arthritic rats. In addition, the decreased content of hydroxyproline in total bone collagen was accompanied by the increased excretion of urinary hydroxyproline in adjuvant arthritic rats. The results clearly suggest that the arthritic disease induces the qualitative and quantitative changes in bone composition and causes the alteration in the metabolism of collagen in diseased tissue. These observations could therefore, explain in part, the altered response of connective tissue of bone to inflammation and arthritis.