The role of proteasome in muscle wasting of experimental arthritis

Abstract Background Rheumatoid arthritis is an autoimmune inflammatory disease that often leads patients to muscle impairment and physical disability. This study aimed to evaluate changes in the activity of proteasome system in skeletal muscles of mice with collagen-induced arthritis (CIA) and treated with etanercept or methotrexate. Methods Male DBA1/J mice were divided into four groups (n = 8 each): CIA-Vehicle (treated with saline), CIA-ETN (treated with etanercept, 5.5 mg/kg), CIA-MTX (treated with methotrexate, 35 mg/kg) and CO (healthy control group). Mice were treated two times a week for 6 weeks. Clinical score and hind paw edema were measured. Muscles were weighted after euthanasia and used to quantify proteasome activity, gene (MuRF-1, PMSα4, PSMβ5, PMSβ6, PSMβ7, PSMβ8, PSMβ9, and PSMβ10), and protein (PSMβ1, PSMβ5, PSMβ1i, PSMβ5i) expression of proteasome subunits. Results Both treatments slowed disease development, but only CIA-ETN maintained muscle weight compared to CIA-MTX and CIA-Vehicle groups. Etanercept treatment showed caspase-like activity of 26S proteasome similar to CO group, while CIA-Vehicle and CIA-MTX had higher activity compared to CO group (p: 0.0057). MuRF-1 mRNA expression was decreased after etanercept administration compared to CIA-Vehicle and CO groups (p: 0.002, p: 0.007, respectively). PSMβ8 and PSMβ9 mRNA levels were increased in CIA-Vehicle and CIA-MTX compared to CO group, while CIA-ETN presented no difference from CO. PMSβ6 mRNA expression was higher in CIA-Vehicle and CIA-MTX groups than in CO group. Protein levels of the PSMβ5 subunit were increased in CO group compared to CIA-Vehicle; after both etanercept and methotrexate treatments, PSMβ5 expression was higher than in CIA-Vehicle group and did not differ from CO group expression (p: 0.0025, p: 0.001, respectively). The inflammation-induced subunit β1 (LMP2) was enhanced after methotrexate treatment compared to CO group (p: 0.043). Conclusions The results of CIA-Vehicle show that arthritis increases muscle proteasome activation by enhanced caspase-like activity of 26S proteasome and increased PSMβ8 and PSMβ9 mRNA levels. Etanercept treatment was able to maintain the muscle weight and to modulate proteasome so that its activity and gene expression were compared to CO after TNF inhibition. The protein expression of inflammation-induced proteasome subunit was increased in muscle of CIA-MTX group but not following etanercept treatment. Thus, anti-TNF treatment may be an interesting approach to attenuate the arthritis-related muscle wasting.

Repercussions of adjuvant-induced arthritis on body composition, soleus muscle, and heart muscle of rats

This study investigated the repercussions of adjuvant-induced arthritis (AIA) on body composition and the structural organization of the soleus and cardiac muscles, including their vascularization, at different times of disease manifestation. Male rats were submitted to AIA induction by intradermal administration of 100 μL of Mycobacterium tuberculosis (50 mg/mL), in the right hind paw. Animals submitted to AIA were studied 4 (AIA4), 15 (AIA15), and 40 (AIA40) days after AIA induction as well as a control group of animals not submitted to AIA. Unlike the control animals, AIA animals did not gain body mass throughout the evolution of the disease. AIA reduced food consumption, but only on the 40th day after induction. In the soleus muscle, AIA reduced the wet mass in a time-dependent manner but increased the capillary density by the 15th day and the fiber density by both 15 and 40 days after induction. The diameter of the soleus fiber decreased from the 4th day after AIA induction as well as the capillary/fiber ratio, which was most evident on the 40th day. Moreover, AIA induced slight histopathological changes in the cardiac muscle that were more evident on the 15th day after induction. In conclusion, AIA-induced changes in body composition as well as in the soleus muscle fibers and vasculature have early onset but are more evident by the 15th day after induction. Moreover, the heart may be a target organ of AIA, although less sensitive than skeletal muscles.

The Therapeutic Effect of Sauchinone on Inflammatory Arthritis in Mice

OBJECTIVE: Rheumatoid arthritis (RA) is a chronic inflammatory disease, mainly involving joints and bones. Sauchinone is an anti-inflammatory agent isolated from Saururus chinensis, which was used in oriental medicine. The aim of this study was to evaluate the therapeutic effect of sauchinone on inflammatory arthritis and underlying mechanism of anti-arthritic effect. METHODS: Mice with collagen induced arthritis (CIA) was intraperitoneally injected with sauchinone (20 mg/kg) or vehicle. The clinical and histological evaluations were performed with arthritis scoring and hematoxylin-eosin staining, respectively. CD4+ interleukin (IL) 17+ T cells were determined under Th17 skewing condition treated with sauchinone. To evaluate the effect of sauchinone on osteoclastogenesis, mice bone marrow macrophages (BMMs) and human peripheral blood mononuclear cells (PBMCs) were cultured with macrophage-colony stimulating factor and receptor activator of nuclear factor-κB ligand in the absence or presence of sauchinone. RESULTS: Sauchinone significantly attenuated the inflammatory arthritis in CIA mice both clinically and histologically. The proportion of Th17 cells were decreased with treatment with sauchinone in vivo and in vitro. The expressions of Th17 cell markers (IL-17 and retinoic acid receptor-related orphan receptor gamma t) and B cell markers (activation-induced cytidine deaminase) were downregulated in the presence of sauchinone. Sauchinone also suppressed the formation of tartrate-resistant acid phosphatase positive cells from mice BMMs and human PBMCs, and the expression of osteoclastogenic markers. CONCLUSION: Sauchinone alleviates inflammatory arthritis in mice through inhibition of Th17 differentiation and osteoclastogenesis. Sauchinone, one of traditional herbal medicine, could be a therapeutic candidate for the treatment of RA.

Compound K, a Metabolite of Ginsenosides, Attenuates Collagen-induced Arthritis in Mice

OBJECTIVE: Although several ginsenosides have been reported to have anti-arthritic activity, few in vivo studies of the anti-arthritic effects of compound K (CK), a major metabolite of ginsenosides, have been conducted. Therefore, we investigated the preventative and therapeutic effects of CK on collagen-induced arthritis (CIA). METHODS: CK was administered to CIA mice preventively and therapeutically and post-treatment bone microarchitectural characteristics, histopathological changes, and serum levels of anti-collagen antibodies, tumor necrosis factor-alpha, and interleukin (IL)-17 were investigated. We also examined cytokine production by type II collagen (CII)-stimulated splenocytes and mRNA expression of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinase (TIMP)-1, receptor activator of nuclear factor-kappaB ligand (RANKL), and osteoprotegerin (OPG) in the joint tissues. RESULTS: CK reduced the severity of CIA preventively and therapeutically (all p<0.05). Additionally, CK dose-dependently decreased histopathological signs of arthritis and improved microarchitectural characteristics (all p<0.05) at 10 to 20 mg/kg/d in CIA mice. CK treatment significantly decreased the serum levels of anti-CII immunoglobulin G (p<0.01) and the secretion of interferon-gamma and IL-2 from stimulated splenocytes (all p<0.05). Furthermore, MMP-3/TIMP-1 and RANKL/OPG ratios were suppressed in CK treated mice (all p<0.01). CONCLUSION: CK attenuated CIA via suppression of the humoral immune response and modulation of joint-destructive mediators. These results suggest that CK has therapeutic potential in rheumatoid arthritis.

Avaliação da eficácia do extrato de óleo insaponificavel de abacate e soja (Piascledine) no tratamento de doença periodontal induzida em ratos com artrite / Evaluation of the effect of the avocado soybean unsaponifiables (Piascledine®) on the treatment of the induced periodontitis in rats with experimental arthritis

Atualmente no mercado se encontra o extrato de óleo insaponificável de abacate e soja, considerado potente anti-inflamatório, agente antioxidante e analgésico, eficaz no tratamento de distúrbios que afetam os tecidos conjuntivos. O objetivo desse estudo foi avaliar a eficácia deste medicamento no tratamento da doença periodontal induzida em ratos com artrite. Foram utilizados 60 ratos (Rattus Norvegicus) submetidos à indução de artrite por antígeno (AIA) e a indução da doença periodontal (DP) através da inserção de ligadura no segundo molar superior. Após a remoção das ligaduras, em todos os dentes foi realizada raspagem radicular (R). Os animais foram distribuídos randomicamente em 4 grupos, avaliados em três períodos experimentais (7, 15 e 30 dias). Grupo Controle (CTR); Grupo ASU; Grupo ASU e artrite (ASU/AR); Grupo AR. Após os períodos experimentais pós-tratamento, suas maxilas e articulação da pata dianteira foram removidos para processamento laboratorial. A porcentagem de volume ósseo nas regiões proximais foi analisada por microtomografia (MicroCT). Não houve diferenças entre os grupos, entretanto foi verificado na análise intragrupos que no grupo ASU/AR houve um aumento estatisticamente significativo na porcentagem óssea no período de 30 dias em relação ao período de 7 dias e no grupo AR um aumento na porcentagem óssea no período de 30 dias em comparação ao período de 15 dias. Os períodos avaliados apresentaram leve infiltrado inflamatório, desorganização das fibras colágenas e integridade do cemento radicular. Dessa forma conclui-se que o ASU não adicionou efeito ao reparo periodontal após tratamento da periodontite induzida associada ou não a indução de artrite experimental em ratos.

The avocado/soybean unsaponifiables(ASU) is a drug that has been used for the treatment of rheumatoid arthritis(AR) and other connective tissue disorders due to their potent anti-inflammatory and analgesic effect and antioxidant. Thus, the aim of this study was to evaluate the effect of this drug on the treatment of the ligatureinduced periodontitis in rats with experimental arthritis. Sixty rats were used in this experiment. The arthritis was induced in thirty rats by injection of specific antigen (AIA) and the periodontitis was induced in all the rats by a insertion of a cotton ligature in the periodontal sulcus of the second upper molar. The ligatures removal and the scaling was performed 7 days after the ligatures placement. The animals were randomly divided in four groups: Control (CTR), ASU, ASU/AR and AR. The animals were euthanized 7, 15 and 30 days after the treatments. The maxilla's and the joint of the front paw was removed to perform the analysis. The percentage of bone tissue in the proximal were analyzed by the micro CT. No statistical differences were detected between the groups. Regarding the intragroup analysis it was showed an enhance on the bone volume in the ASU/AR at 30 days compared with the period of 7 days, and an improve in bone volume the AR at 30 days compared with the period of 15 days. The descriptive histology showed that all the groups presented a mild inflammatory infiltrate, disorganization of collagen fibers and cementum integrity. In conclusion, the consumption of the ASU did not add any additional effect on the periodontal healing after the treatment of the ligature-induced periodontitis in rats with/without experimental arthritis

Protective effect of synthetic fibers with tourmaline on collagen-induced arthritis in rats / 第二军医大学学报

Objective To investigate the protective effect of synthetic fibers with tourmaline on collagen-induced arthritis in rats. Methods Wistar rats were randomly divided into three groups, namely, the control (n = 5), model (n = 12), and protected (n = 13) groups. Rheumatoid arthritis (RA) was induced by immunization with type II collagen in Freund' s incomplete adjuvant in model group and protected group. Animals in model group were protected by conventional synthetic fibers and those in protected group were protected by the synthetic fibers with tourmaline. The protective effects were evaluated by comparing the appearance, volume (water drainage method), and pathological changes of rat paws in different groups. Results Rats in model group exhibited more severe arthrocele than those in the protected group, and there was even arthrentasis. Histological analysis showed that the model group had more severe pathological changes in both left and right hindpaws than the protected group. Since the second week, the mean volumes of left hindpaws of protected group were smaller than those of model group, with the differences at week 2, 6, 8, 10, and 12 being significantly different (P<0. 05). The protected group also had a lower incidence of RA than the model group. Conclusion Synthetic fibers with tourmaline have protective effect against collagen II -induced arthritis in rats.

Mechanisms of Stimulating Vagus Nerve on CD4~+ T Lymphocytes Activation in Experimental Arthritis Rats / 实用儿科临床杂志

Objective To explore the effects of stimulating vagus nerve with pulse current on peripheral blood CD4+T lymphocyte of rats with collagen induced arthritis and its mechanism.Methods To duplicate model rats of experimental arthritis(EA)by intradermal injection of Ⅱtype collagen,divide the rats into 2 groups:vagus nerve stimulation(VNS)group and sham operated group.Rats in VNS group were stimulated at the left cervical vagus nerves for 30 minutes a day with constant square wave,pulse current with intra train of 16 Hz,pulse duration of 1.0 ms,train duration of 10 s,interstimulus interval of 1.5 min and intensities of 3.0 mA.Then flow cytometry and immunofluorescence methods were used to detect the activation of CD4+T lymphocytes(expressing CD71)and the expression of nicotinic acetylcholine receptors alpha 7(nAChR?7)and choline acetyltransferase(ChAT)in peripheral blood CD4+T lymphocytes.Results In VNS group,the expression of nAChR?7 and ChAT were significantly raised in CD4+ T cells at 1st weekend(Pa

Dose-Related Effects of Steroid on the Experimental Arthritis in Rabbits

OBJECTIVE: To investigate dose-related effects of repeated intraarticular steroid injection on the experimental arthritis. METHOD: Twenty-four adult male rabbits received Zymosan A into their right knee joint for experimental arthritis. After a week, they were injected with 2 mg (group I; n=9), 10 mg (group II; n=7) or 20 mg (group III; n=8) triamcinolone acetonide into their right knee weekly interval for 4 weeks. We measured weekly changes of the weight and the mediolateral diameter of both knees for the calculation of edema index. 99mTechnetium pertechnate (99mTc) uptake measurement were performed before the first steroid injection and a week after the final steroid injection. All rabbits were sacrificed and histologic examinations of their proximal tibia were performed. RESULTS: A progressive weight loss and changes of edema index were evident for all rabbits (p0.05). In the histological findings, fibrillation-frayings and fissures of the surface were similar in all rabbits, but loss of nuclear stains and cyst formations were increased prominently in group III than group I (p<0.05). CONCLUSION: Low-dose repeated steroid intraarticular injections are safe and effective treatment in arthritis though no definite evidence of chondroprotection, and high-dose steroid injections accelerate degeneration of the arthritic cartilage.