Comparison of Three Experimental Models for Rat Osteoarthritis Induction

Background: Osteoarthritis is a slowly progressive and debilitating disease with high prevalence in adult population. Knee is one of the joints most affected by this disorder. There are several models for animals’ osteoarthritis induction, however it is not identified any paper that compares these techniques. The present study was aimed to define the most appropriate model for rats osteoarthritis induction. Material and Methods: 40 Wistar rats were distributed into 4 groups of 10 animals each: normality group (NG);meniscectomy group (MG);quinolone group (QG) and iodoacetate group (IG). Radiographic images of the rat’s knees were analyzed as well as the amount of chondrocytes in the epiphyseal and articular cartilage. Results: In the radiographic analysis, there was a low correlation between the raters. Regarding the amount of chondrocytes in the epiphyseal cartilage, it was noticed that the IG and QG groups had fewer chondrocytes than NG, in contrast to MG that reported similar results to normality (p > 0.05). There was no significant difference between IG and QG groups (p > 0.05). Regarding the amount of chondrocytes in articular cartilage, it was noticed that the IG group showed fewer chondrocytes than NG (p 0.05). There was no significant difference between QG and MG groups (p > 0.05). Conclusion: Intraarticular injection of iodoacetate in rats is the model with greatest effect on reduction of chondrocytes amount.

Effect of Triptolide on Expression of Receptor Activator of Nuclear Factor-κB Ligand in Rat Adjuvant Induced Arthritis

The effect of triptolide （TP） on the expression of receptor activator of nuclear factor-κB ligand （RANKL） and osteoprotegerin （OPG） was explored in rat adjuvant induced arthritis （AA）. AA was induced in Wistar rats. Arthritis rats were treated with TP and methotrexate （MTX） at the onset （day 9） of arthritis. On the peak of arthritis （day 24）, the expression of RANKL and OPG protein in the joints and RANKL mRNA in peripheral blood mononuclear cells （PBMC） was detected. TNF-α and IL-1β levels in peripheral blood were determined. Bone erosion scores were also evaluated. The results showed that bone erosion scores in TP and MTX groups were lower than in AA group （.P〈0.01） ; The expression levels of RANKL in the synovium （P〈0.01） and bone （P〈0.05）, and OPG level in synovium （P〈0.05） were lower in TP group than in AA group （P〈0.05）. In TP group, the expression levels of RANKL mRNA and TNF-α, IL-1β in PBMC were lower than in AA group （all P〈0.01）. It was concluded that TP could inhibit rat adjuvant arthritis bone erosion by suppressing the expression of RANKL.

Effects of Huatan Tongluo decoction on vascular endothelial growth factor receptor 2 expression in synovial tissues of rats with collagen-induced arthritis

OBJECTIVE: To determine the therapeutic effect and potential mechanism of Huatan Tongluo decoction on rats with collagen-induced arthritis.METHODS: Forty specific pathogen-free Wistar rats were selected, and 10 were randomly selected as the control(group 1). The remaining rats were injected intradermally with emulsified type Ⅱ bovine collagen at the tail base and back, followed by a booster 7 d post first immunization. After establishing collagen-induced arthritis(CIA), rats were randomly divided into three groups(n = 10). The rats were treated orally for 30 d as follows: group 1, saline; group 2, model(saline); group 3, tripterygium polyglycoside(TP; 7.81 mg/kg, positive control);group 4, Huatan Tongluo decoction(HTTL; 7.5 g/kg). Body weight, ankle swelling and arthritis index were measured over the course of the study. The rats were sacrificed 30 d after treatment. Morphological changes in the synovium were observed by hematoxylin and eosin staining. Pannus formation and synovial thickness in the left ankle were observed by color Doppler ultrasoundVascular endothelial growth factor(VEGF) and VEGFR2 protein levels were measured by immunohistochemistry.VEGF/VEGFR2 mRNA levels were measured by real-time quantitative polymerase chain reaction.RESULTS: Compared with the model group, a significantly lower arthritis index was observed in the positive control group(P < 0.05) and HTTL group(P < 0.01), after treatment. Both positive control and HTTL reduced intra-articular pannus formation and synovial thickening. Furthermore, VEGF mRNA,and VEGFR2 protein and mRNA levels were significantly downregulated(P < 0.05) in the treatment groups.CONCLUSION: Inhibition of the expression of VEGF and VEGFR2 in synovial tissues and the formation of pannus and synovial hyperplasia may be part of the mechanism of HTTL for relieving the symptoms of rheumatoid arthritis in CIA rats.

Total glucosides of paeony improve complete freund’s adjuvant-induced rheumatoid arthritis in rats by inhibiting toll-like receptor 2-mediated tumor necrosis factor receptor-associated factor 6/nuclear factor-kappa B pathway activation

OBJECTIVE: To investigate the mechanism underlying anti-inflammatory and immunoregulatory effect of total glucosides of paeony(TGP) based on toll-like receptor 2(TLR2) mediated tumor necrosis factor(TNF) receptor-associated factor 6(TRAF6)/nuclear factor-kappa B(NF-κB) pathway activation in rats with rheumatoid arthritis.METHODS: Adjuvant arthritis(AA) model was developed by complete freund’s adjuvant(CFA) immunization. TGP(100, 50, 25 mg/kg) and celecoxib(2.8 mg/kg) were administered by intragastric administration for 21 d. Right hind paw swelling was assessed every 2 d. After 21 d, synovial changes of the ankle were detected by histopathology. CD4+and CD8+ T cell amounts in peripheral blood were measured by flow-cytometrically. Gene and protein levels of toll-like receptor(TLR)2, TRAF6, tumor necrosis factor ligand superfamily member 6(FASLG)in the spleen were assessed by RT-qPCR and Western Bolt, respectively. Nuclear expression of NF-κB p65 was detected by NF-κB p65 Assay Kit.RESULTS: Paw swelling and synovium lesions were obviously aggravated in AA rats. These symptoms were significantly relieved by TGP.The ratio of CD4+/CD8+ T cell was increased in AA rats, while TGP reduced this increased ratio.Gene and protein levels of splenic TLR2, TFAR6 and FASLG, and nuclear NF-κB p65 in AA rats were significantly increased, but overtly inhibited by TGP.CONCLUSION: These findings suggest that TGP’s anti-inflammatory effect onRA in rats with CFA may be related to the downregulation of TLR2/TRAF6/NF-κB pathway and the regulation of T cell subsets.