Muscle wasting in rheumatoid arthritis: The role of oxidative stress

Xanthorrhizol Ameliorates Oxidative Stress and Inflammation in Freund's Complete Adjuvant-Induced Rheumatoid Arthritis in Rats

Rheumatoid arthritis (RA) is an inflammatory disease and a common cause of disability. This study is aimed to ascertain the therapeutic potentials of the xanthorrhizol against Freund's complete adjuvant (FCA)-stimulated RA in rats. The RA was initiated in the rats via injecting FCA (0.1 ml) subcutaneously and then treated with xanthorrhizol (20 mg/kg) for 25 days. The hematological markers were investigated using the automated hematological analyzer. The organ index (spleen and thymus) and paw volume were inspected by standard methods. The ALP, SGOT, and SGPT activities were examined using kits. The levels of inflammatory biomarkers, i.e., IL-1β, IL-6, IL-10, and TNF-α, were inspected using assay kits. The status of MDA, SOD, CAT, GSH, COX-2, iNOS, and NF-κB was quantified using respective assay kits. The xanthorrhizol treatment appreciably improved the body weight and hematological parameters and reduced the arthritis score, organ index, and paw volume in the RA rats. The levels of RBCs and Hb were effectively improved, and activities of ALP, SGOT, and SGPT were decreased by the xanthorrhizol in the RA rats. The RA rats treated with 20 mg/kg of xanthorrhizol demonstrated the depleted IL-1β, IL-6, and TNF-α levels. The antioxidant markers SOD, CAT, and GSH were improved, and inflammatory biomarker levels such as COX-2, iNOS, and NF-κB were decreased by the xanthorrhizol in the RA rats. Overall, these outcomes witnessed that the xanthorrhizol effectively ameliorated the oxidative stress and inflammatory responses and attenuated the RA in rats. Hence, it could be a talented anti-arthritic medication to treat RA.

Activation of the Nrf2/HO-1 signaling pathway by dimethyl fumarate ameliorates complete Freund's adjuvant-induced arthritis in rats

The nuclear factor erythroid 2-related factor (Nrf2) signaling pathway has recently emerged as a novel therapeutic target in treating various diseases. Therefore, the present study aimed to assess the protective role of the Nrf2 activator, dimethyl fumarate (DMF) in the complete Freund's adjuvant (CFA)- induced arthritis model. DMF (25, 50, and 100 mg/kg) and dexamethasone (2 mg/kg) were orally administered for 14 days. Pain-related tests, paw volume, and arthritic scores were measured weekly. Serum TNF-α, IL-1β, cyclic citrullinated peptide (CCP), C-reactive protein (CRP), and rheumatoid factor (RF) levels were estimated. Nitrite, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione (GSH), catalase (CAT), and myeloperoxidase (MPO) levels were also evaluated. NF-κB, Nrf2, HO-1, and COX-2 levels were estimated in the joint tissue. DMF treatment exerted anti-arthritic activity by enhancing the nociceptive threshold, improving arthritis scores, and reducing paw edema. Also, DMF suppressed changes in oxidative stress markers and inflammatory mediators and enhanced Nrf2 and HO-1 levels in CFA-injected rats. These findings indicate that the anti-arthritic activity of DMF may be mediated by the activation of the Nrf2/HO-1 pathway, which reduced oxidative damage and inflammation.

Iron Supplementation Effects on Redox Status following Aseptic Skeletal Muscle Trauma in Adults and Children

Exercise-induced skeletal muscle microtrauma is characterized by loss of muscle cell integrity, marked aseptic inflammatory response, and oxidative stress. We examined if iron supplementation would alter redox status after eccentric exercise. In a randomized, double blind crossover study, that was conducted in two cycles, healthy adults (n = 14) and children (n = 11) received daily either 37 mg of elemental iron or placebo for 3 weeks prior to and up to 72 h after an acute eccentric exercise bout. Blood was drawn at baseline, before exercise, and 72 h after exercise for the assessment of iron status, creatine kinase activity (CK), and redox status. Iron supplementation at rest increased iron concentration and transferrin saturation (p < 0.01). In adults, CK activity increased at 72 h after exercise, while no changes occurred in children. Iron supplementation increased TBARS at 72 h after exercise in both adults and children; no changes occurred under placebo condition. Eccentric exercise decreased bilirubin concentration at 72 h in all groups. Iron supplementation can alter redox responses after muscle-damaging exercise in both adults and children. This could be of great importance not only for healthy exercising individuals, but also in clinical conditions which are characterized by skeletal muscle injury and inflammation, yet iron supplementation is crucial for maintaining iron homeostasis. This study was registered at Clinicaltrials.gov Identifier: NCT02374619.