Divulging the Intricacies of Crosstalk Between NF-kB and Nrf-2/Keap1 Pathway in the Treatment of Arthritis by Dimethyl Fumarate.

The aim of this study was to examine the hypothesis that use of dimethyl fumarate (DMF) may mitigate arthritic symptoms in collagen-induced arthritis (CIA) rats through activation of NF-E2-related factor 2(Nrf-2) and suppression of NF-kB pathway. Arthritis in rats was induced by subcutaneous injection of collagen type II (200 µl) at the base of the tail. After induction arthritic rats were treated with DMF (25 mg/kg b.wt.) for 20 days from the day 25th to 45th. At the end of the study, serum and joint homogenate was used to assess the oxidative stress and cytokines level. In addition, mRNA expression of various genes such as NF-kB, Keap-1 (Kelch-like ECH-associated protein 1) and Nrf-2 was assayed through qRT-PCR in joint tissue. Finally, all these biochemical and molecular results were confirmed by histological and in silico study. Our results showed that decrease in the clinical severity, inflammation, and cell necrosis in DMF-treated rats. This was related with decrease in NF-kB activity and increase in activity of Nrf-2. Treatment with DMF increases the levels of endogenous antioxidant biomarkers glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) and decreases inflammation. These biochemical and molecular results were further confirmed by performing in silico study that shows DMF strongly inhibits the activation of NF-kB, and conversely at the same time increases the activity of Nrf-2 that means a significantly lower amount of inflammatory mediators and oxidants was produced. Decrease in inflammation leads to preserving the joint architecture and alleviation from clinical symptoms of arthritis. Collectively, these results indicate that Nrf-2 activation protects against arthritic symptoms.