Mechanism of Fibroblast‐Like Synoviocyte Apoptosis Induced by Recombinant Human Endostatin in Rats with Adjuvant Arthritis

Abstract

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by pronounced synovial hyperplasia, in which there may be an imbalance between the growth and death of fibroblast-like synoviocytes (FLS). The present study was undertaken to examine the effect of recombinant human endostatin (rhEndostatin) on FLS apoptosis in experimental RA. Adjuvant arthritis (AA) was induced in male Sprague Dawley (SD) rats. Using cultured AA FLS obtained from these rats, the apoptosis process was measured by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) as well as Annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) labeling methods. In addition, the expression levels of the Fas, c-jun, NFjB, and caspase-3 gene products in synovial tissues were quantified by quantitative real-time polymerase chain reaction (qPCR) and/or Western blotting assays. Our data revealed that rhEndostatin induced apoptosis in AA FLS. The number and signal density of TUNEL-positive cells were significantly increased in rats treated with rhEndostatin (2.5 mg/kg). The percentage of Annexin V-FITC-positive cells was 6.67% after treatment with rhEndostatin at 25 mg/mL for 48 hr, compared with only 3.32% among untreated control cells. There were significant increases in Fas mRNA, c-jun mRNA, c-Jun protein, and caspase-3 (p20) protein in AA synovial tissues treated with rhEndostatin (2.5 mg/kg), whereas no significant difference in NFjB expression was detected between treated and untreated tissues. These findings indicate that rhEndostatin has a therapeutic effect on RA by inducing FLS apoptosis, which is strongly associated with increased expression of Fas, c-jun, and caspase-3, but not NFjB.

Anti-inflammatory Effects of a Small Molecule Gastrin-Releasing Peptide Receptor Antagonist on Adjuvant-Induced Rheumatoid Arthritis in Rats

“…24 Adjuvant-Induced Arthritis (AIA) was used as model for evaluation, because it is a well established model for experimental rheumatoid arthritis, which has many similar features with RA of human, like genetic linkage, synovial CD4+ cells and T cell dependence. [25][26] In present study, the significant difference in arthritis score between treated groups and negative control can only be seen within the administration period (day [14][15][16][17][18][19][20]. After administration period (day 21-28) arthritis score of middle and high dosage of RH-1402 are generally lower than that of negative control.…”

“…15 Arthritis was characterized by the first signs of redness or swelling of the ankle joints, which was observed at 10-12 days after the immunization.…”

Recombinant human endostatin inhibits adjuvant arthritis by down-regulating VEGF expression and suppression of TNF-α, IL-1β production

“…VEGF is a endothelial-cell-specific angiogenic factor and the best characterized system in the regulation of RA by angiogenesis. In addition, VEGF can act as a direct proinflammatory mediator during the pathogenesis of RA, and inhibition of rheumatoid synoviocytes apoptosis, which contributes to synovial hyperplasia [7,20]. In this study, we first identified a novel mechanism for antiangiogenesis in AA involving rhEndostatin.…”

“…Interestingly, the functionality of endostatin has been demonstrated in vivo by its ability to induce regression of synovial proliferation of severe combined immunodeficiency (SCID) mice grafted from human rheumatoid arthritis [6]. Previous studies have indicated that administration of endostatin had an arthritis inhibiting effect in RA animal models [7]. These reports suggest that rhEndostatin can be considered as a potential therapeutic agent for RA.…”

7,3′‐dimethoxy hesperetin induces apoptosis of fibroblast‐like synoviocytes in rats with adjuvant arthritis through caspase 3 activation

“…FLS was prepared by the method of tissue explant cultivation as described (Huang et al, 2008). Fresh synovial membranes obtained from the knee joints of rats were minced, incubated in a fl atbottomed culture bottle and maintained in RPMI 1640 containing 15% fetal bovine serum (FBS) at 37°C, 5% CO 2 for 7 days.…”