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PubMed1987

Production of cartilage degrading activity by human synovial tissues.

Human synovial tissues have been assayed for the production of cartilage degrading activity (CDA). This activity is thought to be homologous with catabolin/interleukin 1 (IL1) produced by porcine synovium and leucocytes and by human leucocytes. The CDA of 26 rheumatoid (RA) and 41 non-rheumatoid synovia was measured on a dry weight basis. The rheumatoid synovia showed a threefold increase in activity over the non-rheumatoid, but there was no significant overall difference on a deoxyribonucleic acid (DNA) basis. The rheumatoid synovia appeared to consist of two populations; in over half the samples CDA was not related to cellularity, but eight patients had a high CDA and a high cellularity.

Arthritis, Rheumatoid↗

PubMed1987

In vivo studies of articular tissue damage mediated by catabolin/interleukin 1.

A partially purified porcine synovial catabolin interleukin 1 (CF) preparation was injected intra-articularly into rabbit stifle (knee) joints. Radiolabelled CF was rapidly cleared from the joint (0.4 h). Repeated injections of CF caused a marked loss of articular cartilage glycosaminoglycan (GAG) and a great increase in synovial fluid GAG. 35SO4 uptake was inhibited. Time course experiments after a single injection produced similar loss of GAG from knee cartilages, which was maximal three days after injection. The above changes were significantly less with heat inactivated preparations. Loss of articular cartilage metachromasia was found histologically, and an acute synovitis occurred together with lymphocytic foci and plasma cell infiltration.

Animals↗

PubMed1991

In vivo studies of cartilage regeneration after damage induced by catabolin/interleukin-1.

The response of the rabbit knee joint to a brief episode of cytokine induced damage is described. After three intra-articular injections of catabolin/interleukin-1 all joint cartilages showed an immediate extensive loss of proteoglycan (glycosaminoglycan), which was gradually replaced over three to four weeks. Glycosaminoglycan biosynthesis (measured by 35SO4 uptake) was initially depressed, but at one week had almost doubled its rate as compared with the normal side. This increased synthetic activity was further maintained throughout the duration of the experiment (28 days), though the rate gradually fell. Histological cartilage metachromasia to toluidine blue mirrored the glycosaminoglycan changes. No disturbance of the articular cartilage collagen network was found. It is considered, therefore, that during treatment for arthritis the indigenous chondrocyte must continue to be capable of carrying out regenerative matrix repair and that antiarthritic agents should first be screened for interference with that process.

Animals↗

PubMed1986

Porcine heart valves produce a protein that induces cell-mediated connective tissue degradation: I. Biological properties.

Cultured porcine heart valves secrete a factor that induces cells to degrade their extracellular matrix. This activity was routinely monitored by measuring the release of glycosaminoglycans from proteoglycan in cultured bovine nasal cartilage. It was observed that factor-mediated matrix degradation was dose dependent and required live target cells, while factor production by valves was inhibited by cycloheximide and declined with reduced cell viability. The effect of various steroidal and nonsteroidal anti-inflammatory drugs on the production and activity of the factor is discussed with reference to similar cytokines. It is concluded that there is a close similarity between the cardiac catabolic factor described here and catabolin, a protein isolated from porcine synovia and leukocytes, as shown by the neutralization of biological activity with antisera raised to porcine catabolin (interleukin-1).

Animals↗

PubMed1986

Porcine heart valves produce a protein that induces cell-mediated connective tissue degradation: II. Biochemical properties of the partially purified protein.

A cardiac catabolic factor (CCF) has been partially purified from serum-free medium conditioned by minced porcine heart valves. CCF was prepared by a series of chromatographic techniques and compared directly with porcine synovial catabolin purified by the same protocol. CCF displayed a somewhat higher molecular weight (Mr 21,000) and isoelectric point (pI 5.2) than did synovial catabolin (Mr 18,000 and pI 4.8), but the two factors clearly resemble one another closely. CCF stimulated the release of glycosaminoglycans from cultured cartilage and mitral valve and provoked porcine valves to degrade their own collagen extracellular matrix. The release of hydroxyproline was inhibited by corticosteroids, whereas proteoglycan breakdown was not. Partially pure preparations of CCF and synovial catabolin stimulated murine thymocyte proliferation; moreover, that activity was almost totally abolished by an antibody raised against pure porcine interleukin-1. These observations suggest that CCF may represent a catabolic factor that belongs to the interleukin-1 family and that it could potentially regulate the composition of valvular connective tissue.

Animals↗

PubMed2026

Gene expression profiling identifies potential biomarkers for vaso-occlusive episodes in sickle cell disease.

Vaso-occlusive episodes (VOEs) or acute pain events, involving complex interactions between sickle erythrocytes and other blood cells, are a hallmark of sickle cell disease (SCD). In this study, we analyzed changes in peripheral blood transcriptomes between steady state and VOEs in individuals with SCD. We followed a cohort of 174 individuals with SCD with or without chronic pain and collected peripheral blood at clinic visits (steady state) and during hospitalizations (VOEs). We performed RNA-Seq profiling of CD45+ leukocytes and CD71+ erythroid cells. Pathways linked to complement activation, coagulation, and IL-6/JAK/STAT3 signaling were enriched during VOEs in the CD45+ cells. Contrastingly, the CD71+ cells showed an enrichment of pathways related to the cell cycle, such as mTORC1 signaling and the G2M checkpoint during VOEs. We then analyzed the expression changes of genes in patients with longitudinal data to determine potential biomarkers for VOEs. Expression of 4 genes - FAM20A, IL1B, MS4A4A, and SERPINB2 - was elevated during VOEs compared with steady state in the majority of patients. Furthermore, our results indicate that patients experiencing chronic pain exhibited 44% increased enrichment of significant pathways during VOEs when compared with patients without chronic pain.

Humans↗

PubMed2026

Activating mutations in ESR1 contribute to an immunosuppressive breast tumor microenvironment by dampening cytokine secretion.

Patients with estrogen receptor+ (ER+, ESR1+) breast cancer are most at risk of relapse, where activating mutations in ESR1 promote metastasis and therapeutic resistance. These patients are also disadvantaged in responding to immunotherapies, the mechanisms of which remain to be elucidated. Here, we engineered a transgenic mouse model carrying either Y541S or D542G mutation in ESR1, mirroring the 2 most common mutations seen in patients. ESR1mut tumors do not differ in the total number of immune cells yet display downregulation in immune pathways and decreased immune-modulatory cytokines, including IL-17a and IL-1β. T cells and macrophages have lower IFN-γ and antigen presentation, respectively. Mechanistically, ESR1mut negatively regulates immune modulator expression and upregulates Stat5 to dampen cytokine expression. In concordance, validation on ESR1mut patient tumors shows decreased IL-17a and IL-1β. Collectively, our findings reveal that ESR1 mutations contribute to an immunosuppressive tumor microenvironment by dampening cytokine secretion and immune cell activity.

Animals↗

PubMed1989

Stimulation of glycosaminoglycan synthesis in cultured human dermal fibroblasts by interleukin 1. Induction of hyaluronic acid synthesis by natural and recombinant interleukin 1s and synthetic interleukin 1 beta peptide 163-171.

Hyaluronic acid (HA) is believed to play a critical role in wound healing and in morphogenesis. Factors controlling the production of HA by fibroblasts in normal and pathological states are not completely understood. In this report we have observed that natural human interleukin (IL-1)1 beta and human recombinant (hrIL)-1 alpha and beta are potent stimulators of HA production by fibroblasts in vitro. Hyaluronic acid is the major species of glycosaminoglycan (GAG) stimulated by IL-1 in fibroblasts. PGE2 does not appear to be involved directly in this IL-1 effect on fibroblasts, but stimulation of HA production by IL-1 is dependent on protein synthesis. The synthetic human IL-1 beta peptide 163-171 (Val-Gln-Gly-Glu-Glu-Ser-Asn-Asp-Lys), which has been previously shown to stimulate thymocyte proliferation but not fibroblast PGE2 production, is also able to stimulate fibroblast HA production. The synthesis and secretion of IL-1 by mononuclear phagocytes at sites of inflammation and immune reactions in vivo could potentially serve as a signal for fibroblasts to synthesize HA, which in turn could serve to facilitate and modulate reparative and immune processes by virtue of its ability to alter cell-cell, cell matrix, and cell-membrane receptor interactions.

Cells, Cultured↗

PubMed1990

Interleukin 1 suppresses inflammation in rabbit colitis. Mediation by endogenous prostaglandins.

Pretreatment with low-dose IL-1 has protective effects in animal models of inflammation or tissue injury, but the mechanisms of these protective effects are not established. To determine if prostaglandins are involved, we administered human recombinant IL-1 beta and measured rectal PGE2 production in rabbits with formalin-immune complex colitis. IL-1 beta (0.3 micrograms/kg) administered 24 h before induction of colitis increased PGE2 (231 +/- 36 to 1,299 +/- 572 pg/ml, P less than 0.01) and reduced subsequent inflammatory cell infiltration index (from 2.8 +/- 0.3 to 1.4 +/- 0.3, P less than 0.02) and edema (from 2.5 +/- 0.3 to 1.3 +/- 0.3, P less than 0.01) compared with vehicle-matched animals. Administration of ibuprofen (10 mg/kg i.v.) together with IL-1 beta prevented the stimulation of PGE2 and the reduction in inflammation. Colonic PGE2 production correlated inversely with subsequent severity of inflammation (P less than 0.02, r = -0.39) and edema (P less than 0.04, r = -0.35). IL-1-administration 30 min before induction of colitis did not affect the severity of inflammation. Similarly, pretreatment with a noninflammatory synthetic peptide (fragment 163-171) of human IL-1 beta, either 30 min or 24 h before colitis induction, did not reduce inflammation or increase prostaglandin synthesis. These data demonstrate that pretreatment with IL-1 beta 24 h before the induction of colitis reduces inflammation by a mechanism that requires prostaglandin synthesis.

Animals↗

PubMed2025

Cross-talk between NLRP3 and AIM2 inflammasomes in macrophage activation by LPS and titanium ions.

BACKGROUND: Periodontitis and peri-implantitis are chronic inflammatory diseases that contribute to tissue destruction and bone loss. Periodontitis is triggered by pathogenic bacteria, while peri-implantitis also involves metallic particles, which increase the inflammatory response. Both conditions are linked to the activation of inflammasomes, such as NLRP3 and AIM2, which facilitate the release of pro-inflammatory cytokines like IL-1β and IL-18 and induce pyroptosis. This study aims to investigate the activation of NLRP3 and AIM2 inflammasomes in macrophages exposed to bacterial and metallic components, as well as to explore the potential interplay between these two signaling pathways. METHODS: Human THP-1-derived macrophages were treated with bacterial lipopolysaccharide (LPS) and titanium ions to evaluate inflammasome activation. IL-1β secretion, ROS production, mitochondrial DNA release and pyroptosis were assessed. Additionally, macrophages deficient in NLRP3 and AIM2 were used to examine the roles of these inflammasomes in inflammatory responses. RESULTS: LPS and titanium ions synergistically activated NLRP3, resulting in increased IL-1β secretion, ROS production, and pyroptosis. Under these conditions, AIM2 was indirectly activated, as indicated by elevated mitochondrial DNA release. Notably, AIM2 expression was reduced in wild-type macrophages treated with LPS and titanium ions compared to LPS alone, however, in NLRP3-deficient cells, AIM2 expression was increased following LPS and titanium ions treatment. This upregulation of AIM2 in NLRP3-deficient cells was further reduced by ROS inhibition, which decreased mitochondrial DNA release. Additionally, NLRP3 knockout had a more pronounced effect on reducing IL-1β secretion and pyroptosis compared to AIM2 knockout, indicating a greater role of NLRP3 in these inflammatory responses. CONCLUSIONS: This study demonstrates that bacterial and metallic components drive the activation of both NLRP3 and AIM2 inflammasomes in macrophages, highlighting their roles in the inflammatory responses associated with periodontitis and peri-implantitis. The findings reveal a regulatory relationship between NLRP3 and AIM2, where the absence of one inflammasome can enhance the activity of the other. These results provide new insights into the mechanisms underlying inflammasome-mediated inflammation and suggest potential therapeutic targets for managing inflammatory diseases.

NLR Family, Pyrin Domain-Containing 3 Protein↗

PubMed2025

Expression of intron-containing HIV-1 RNA induces NLRP1 inflammasome activation in myeloid cells.

Despite the success of antiretroviral therapy in suppressing plasma viremia in people living with human immunodeficiency virus type-1 (HIV-1), persistent viral RNA expression in tissue reservoirs is observed and can contribute to HIV-1-induced immunopathology and comorbidities. Infection of long-lived innate immune cells, such as tissue-resident macrophages and microglia may contribute to persistent viral RNA production and chronic inflammation. We recently reported that de novo cytoplasmic expression of HIV-1 intron-containing RNA (icRNA) in macrophages and microglia leads to MDA5 and MAVS-dependent innate immune sensing and induction of type I IFN responses, demonstrating that HIV icRNA is a pathogen-associated molecular pattern (PAMP). In this report, we show that cytoplasmic expression of HIV-1 icRNA also induces NLRP1 inflammasome activation and IL-1β secretion in macrophages and microglia in an RLR- and endosomal TLR-independent manner. Infection of both macrophages and microglia with either replication-competent or single-cycle HIV-1 induced IL-1β secretion, which was attenuated when cytoplasmic expression of viral icRNA was prevented. While IL-1β secretion was blocked by treatment with caspase-1 inhibitors or knockdown of NLRP1 or caspase-1 expression in HIV-infected macrophages, overexpression of NLRP1 significantly enhanced IL-1β secretion in an HIV-icRNA-dependent manner. Immunoprecipitation analysis revealed interaction of HIV-1 icRNA, but not multiply-spliced HIV-1 RNA, with NLRP1, suggesting that HIV-1 icRNA sensing by NLRP1 is sufficient to trigger inflammasome activation. Together, these findings reveal a pathway of NLRP1 inflammasome activation induced by de novo expressed HIV icRNA in HIV-infected myeloid cells.

HIV-1↗

PubMed2025

NLRP3 and AIM2 inflammasomes exacerbate the pathogenic Th17 cell response to eggs of the helminth Schistosoma mansoni.

Infection with the helminth Schistosoma mansoni can cause exacerbated morbidity and mortality via a pathogenic host CD4 T cell-mediated immune response directed against parasite egg antigens, with T helper (Th) 17 cells playing a major role in the development of severe granulomatous hepatic immunopathology. The role of inflammasomes in intensifying disease has been reported; however, neither the types of caspases and inflammasomes involved, nor their impact on the Th17 response are known. Here we show that enhanced egg-induced IL-1β secretion and pyroptotic cell death required both caspase-1 and caspase-8 as well as NLRP3 and AIM2 inflammasome activation. Schistosome genomic DNA activated AIM2, whereas reactive oxygen species, potassium efflux and cathepsin B, were the major activators of NLRP3. NLRP3 and AIM2 deficiency led to a significant reduction in pathogenic Th17 responses, suggesting their crucial and non-redundant role in promoting inflammation. Additionally, we show that NLRP3- and AIM2-induced IL-1β suppressed IL-4 and protective Type I IFN (IFN-I) production, which further enhanced inflammation. IFN-I signaling also curbed inflammasome- mediated IL-1β production suggesting that these two antagonistic pathways shape the severity of disease. Lastly, Gasdermin D (Gsdmd) deficiency resulted in a marked decrease in egg-induced granulomatous inflammation. Our findings establish NLRP3/AIM2-Gsdmd axis as a central inducer of pathogenic Th17 responses which is counteracted by IFN-I pathway in schistosomiasis.

Animals↗

PubMed2026

Co-regulation of HIV control and cytomegalovirus pp65-specific IL-1β and TNF-α responses by genetic variants in the MHC region.

The spontaneous control of HIV infection in the absence of antiretroviral therapy, termed HIV control, is associated with genetic variation in the Major Histocompatibility Complex (MHC) locus. These variants are known to influence the immune response to HIV itself. However, people living with HIV are often co-infected with other pathogens that can also elicit immune responses, which might also be regulated by these variants. Here, we assessed whether genetic variants associated with HIV control influence cytokine responses to various co-pathogens. HIV-control-associated single nucleotide polymorphisms (SNPs) were enriched among variants regulating TNF-α and IL-1β production upon CMV pp65 peptide pool stimulation. The top enriched SNPs, rs1128175-A and rs2853971-A, were linked to lower odds of HIV control and increased cytokine responses to CMV. These SNPs were in linkage disequilibrium (LD) with classical HLA alleles HLA-B*07:02 and HLA-C*07:02. Intracellular cytokine staining showed CMV serostatus-dependent production of TNF-α by monocytes and CD8 T cells. The rs1128175-A/rs2853971-A/HLA-B*07:02/HLA-C*07:02 haplotype was associated with increased IFN-γ production by CD8 T cells upon CMV pp65 peptide pool stimulation, indicating an effect on memory responses. Quantitative trait locus (QTL) mapping showed that rs1128175 and rs2853971 influence HLA-B and HLA-C expression, DNA methylation levels and cell-type-specific cis-effects on chromatin accessibility, as well as CD8 T cell subset abundance. These QTL associations suggest that variants associated with poor HIV control are linked to heightened pro-inflammatory responses to CMV pp65 through effects on antigen presentation, epigenetic modifications, gene expression and immune cell repertoire, potentially negatively affecting HIV control status.

Humans↗

PubMed2026

Inflammasome activation dictates the efficacy of antimycobacterial activity of frontline TB drugs.

Recent developments in tuberculosis (TB) treatment have identified an enormous potential of host-directed therapies (HDT)) in achieving better and faster control of infection. We have previously demonstrated the synergistic effect of sertraline (SRT) with frontline TB drugs in clearing infection in murine tissues. Our attempts to uncover the mechanistic basis of this enhancement, using sertraline as a probe, help identify host signalling pathways critical for controlling Mycobacterium tuberculosis (Mtb). We identify a significant role for sertraline-mediated modulation of mitochondrial physiology and consequent reactive oxygen species (ROS) generation as a secondary signal, leading to greater IL-1β release and K+ efflux from macrophages via NLRP3 inflammasome activation. We thus highlight an important relationship between mitochondrial physiology and inflammasome activation, enabling infected macrophages to better control Mtb.

Animals↗

PubMed1990

The effect of N-terminal extension on the structure and function of human interleukin-1 beta.

Interleukin-1 beta (IL-1 beta) and N-terminally extended Met-Glu-Ala-Glu-IL-1 beta (MEAE-IL-1 beta) were cloned and expressed in E. coli. Extension of the chain results in a limited conformational change reflected by the CD spectrum in the far ultraviolet, while the aromatic side chains responsible for the CD in the near ultraviolet are not affected. No difference in immunoreactivity between IL-1 beta and MEAE-IL-1 beta is observed in the IL-1 beta ELISA. Like IL-1 beta, MEAE-IL-1 beta exhibits biological activity tested in the costimulatory mouse thymocyte (LAF) assay. The specific biological activity of IL-1 beta is 3 x 10(8) U/mg and that of MEAE-IL-1 beta 3 x 10(6) U/mg. Like IL-1 beta, MEAE-IL-1 beta displaces [125I]IL-1 beta from mouse thymocytes and the binding affinities of the two forms differ by a factor of 10(2). Finally the inhibitory effect of the two IL-1 beta forms on in vitro insulin secretion from isolated rat islets of Langerhans was measured. Again MEAE-IL-1 beta is 10(2) times less potent than IL-1 beta. The structure-activity relationship for IL-1 beta and MEAE-IL-1 beta is discussed.

Animals↗

PubMed2026

[Study on mechanism of Wendan Decoction in intervening in nonalcoholic fatty liver disease based on proteomics and network pharmacology].

This study systematically explored the molecular mechanism of Wendan Decoction(WDD) in treating nonalcoholic fatty liver disease(NAFLD) by integrating network pharmacology, proteomics, and experimental validation. A mouse NAFLD model was established using a high-fat diet, and the mice were randomly divided into a blank control group, a model group, a positive drug group(simvastatin, 3.03 mg·kg~(-1)), and low-(3.035 g·kg~(-1)), medium-(6.07 g·kg~(-1)), and high-dose(12.14 g·kg~(-1)) WDD groups, with intervention lasting for 6 weeks. After the intervention, the serum levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), triglycerides(TG), total cholesterol(TC), low-density lipoprotein cholesterol(LDL-C), and high-density lipoprotein cholesterol(HDL-C) were measured using an automatic biochemical analyzer. The serum levels of interleukin-1β(IL-1β), interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α) were detected by ELISA. Liver histopathology was observed via hematoxylin-eosin(HE) staining and oil red O staining. Network pharmacology was used to predict potential targets and pathways, and proteomics was applied to identify differentially expressed proteins and related pathways. RT-qPCR and Western blot were performed to detect mRNA and protein expression of relevant genes. Animal experiments demonstrated that WDD dose-dependently ameliorated hepatic steatosis, inflammation, and lipid deposition, significantly reducing serum levels of ALT, AST, TG, TC, LDL-C, and pro-inflammatory cytokines(IL-1β, IL-6, and TNF-α), while significantly increasing serum HDL-C levels. Network pharmacology screening identified naringenin, baicalein, and other key active components, which were involved in pathways such as the peroxisome proliferator-activated receptor(PPAR), lipid, and atherosclerosis pathways. Proteomics further revealed differentially expressed pathways including the PPAR and advanced glycation end product-receptor(AGE-RAGE) signaling pathways. Integrated analysis highlighted the PPAR signaling pathway as the core mechanism. Molecular biology validation showed that WDD significantly regulated the mRNA expression of sterol regulatory element-binding protein-1c(SREBP-1c), fatty acid synthase(FASN), carnitine palmitoyl transferase 1A(CPT1A), acyl-CoA oxidase 1(ACOX1), and PPARα, as well as protein expression of PPARα, CPT1A, and PPARγ in mouse liver tissue. These results suggested that WDD might exert a multi-component, multi-target, and multi-pathway synergistic effect to improve lipid metabolism disorders and inflammatory responses with the PPAR signaling pathway as the central hub, thereby alleviating NAFLD progression.

Animals↗

PubMed2025

Effect of acupuncture on brain microenvironment in rats with post-stroke limb spasticity based on single-cell transcriptome sequencing technology.

OBJECTIVE: To investigate the possible mechanisms by which acupuncture improves post-stroke limb spasticity using single-cell sequencing technology. METHODS: Thirty-two rats were randomly assigned to four groups: Control, Sham, Model, and Acupuncture. The middle cerebral artery occlusion (MCAO) model was established, and the acupuncture groups received acupuncture treatment. After treatment, brain morphological changes and the degree of neurological impairment were assessed. The effect of acupuncture on the proportion of brain cell types in the ischemic penumbra of MCAO rats was analyzed using single-cell transcriptomics, and the expression and enrichment of differentially expressed genes were examined. Finally, selected differential genes were validated by Western blot and quantitative real-time polymerase chain reaction. RESULTS: Triphenyltetrazolium chloride staining showed that the infarct area in MCAO rats was significantly reduced after acupuncture. Garcia scoring, hematoxylin-eosin staining, Nissl staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling demonstrated that acupuncture reduced brain damage. Enzyme-linked immunosorbent assay results showed that acupuncture significantly decreased serum inflammatory factors, including interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Single-cell transcriptome analysis revealed marked changes in cell type proportions between the Acupuncture and Model groups. A total of 207 differential genes were identified, including 157 upregulated and 50 downregulated genes. Analysis of macrophage-specific differential genes in the ischemic penumbra showed enrichment in Gene Ontology terms such as Ras protein signal transduction and regulation of GTPase activity, and Kyoto Encyclopedia of Genes and Genomes pathways including lysosome, axon guidance, and mitogen-activated protein kinase signaling. S100a8 and leukocyte specific transcript 1 (LST1) were identified as key differential genes. CONCLUSION: These findings suggest that the key differential genes S100a8 and LST1 may alleviate post-stroke limb spasticity by regulating the inflammatory response in the ischemic penumbra.

Animals↗

PubMed1984

The effect of synovial catabolin on cartilage synthetic activity.

The effect of porcine synovial catabolin on the incorporation of [3H]amino acids and [35S]sulfate into bovine nasal cartilage was investigated. The rapid breakdown of matrix caused by partially purified catabolin had little affect on the incorporation of [3H]amino acids but there was inhibition of [35S]sulfate uptake. While the 35S-labelled material released into the medium was largely incapable of aggregation with hyaluronate, this was only a small part (less than 10%) of the total incorporated. The principal inhibitory action was in the formation of large molecular size material (guanidinium chloride extractable). The amount of newly synthesized glycosaminoglycans (GAG) during the 8 day culture period was too low (less than 0.8%) to influence the very rapid breakdown of the matrix under catabolin stimulation. Cartilage organ cultures recovered from inhibition of [35S]sulfate incorporation and from the catabolic stimulation after removal of catabolin. It is suggested that the two properties of the catabolin preparation demonstrated in this study may work synergistically both in causing and prolonging cartilage damage in vivo.

Animals↗