Jobelyn® Ameliorates Anxiety-like Behaviour, Thermal Hyperalgesia and Neuroinflammation in Formaldehyde-Induced Arthritis in Mice

Arthritis describes a chronic inflammatory disease characterised by joint pain, stiffness, and swelling. Anxiety and depression are common comorbidities in rheumatoid arthritis, a major type of common arthritis in patients, which can worsen disease outcomes. Many medicinal herbs with various sites of action against inflammatory and oxidative processes that play important roles in arthritis pathogenesis are being studied as potential novel treatments. Jobelyn® (JB), a polyphenol-rich extract, has been shown to relieve arthritic pain and possess anti-inflammatory and antioxidant properties. This study investigated the effects of JB on anxiety-like behaviour, thermal hyperalgesia, and neuroinflammation in a mouse model of formaldehyde-induced arthritis. Thirty Swiss male mice were grouped into 5 (n=6) as follows: control (distilled water), formaldehyde-induced arthritis group (FIA only) (2.5%), FIA + JB 50mg/kg, FIA + JB 100mg/kg, FIA + JB 200mg/kg and FIA + celecoxib 20mg/kg for 7 days. Anxiety-like behaviour was assessed using an elevated plus maze (EPM) and an open field test (OFT). Thermal hyperalgesia was evaluated using the hot plate test. Oxidative stress and pro-inflammatory cytokines were assessed in brain and paw tissues. JB treatment significantly reduced anxiety-like behaviour in EPM and OFT, and thermal hyperalgesia on a hot plate in arthritic mice. JB decreased brain and paw tissue levels of malondialdehyde and nitrite and increased reduced glutathione, catalase, superoxide dismutase and glutathione-s-transferase. Furthermore, JB caused significant reduction in brain tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) as well as paw TNF-α. This study demonstrates the potential of JB to ameliorate anxiety-like behaviour, thermal hyperalgesia, and neuroinflammation.