Swimming exercise modulates pro-inflammatory cytokines in a mouse model of multiple sclerosis

Abstract Brain inflammation, particularly elevated cytokines such as TNF- α and IL-1 β , plays a key role in the onset and progression of multiple sclerosis (MS). Exercise is recognised as a safe, natural method to support brain health and reduce inflammation in MS. This study examined the effect of four weeks of moderate swimming exercise on inflammatory cytokines (TNF- α and IL-1 β ) and fatigue- and motivation-related behaviours in female C57BL/6 mice with experimental autoimmune encephalomyelitis (EAE), an established model of MS. Twenty-one female mice were assigned to three groups: Healthy Control (HC) (n = 7), EAE Control (EAE) (n = 7), and EAE + swimming exercise (EAE+EX) (n = 7). EAE was induced with the MOG35–55 peptide. The EAE+EX swam for 30 min/day, five days/week for four weeks. After training, brain tissue was collected to measure TNF- α and IL-1 β via Western blot. The open field test (OFT) and sucrose preference test (SPT) assessed locomotor and motivation-related behaviours. EAE significantly increased TNF- α and IL-1 β versus HC ( ). Swimming reduced both cytokines and improved movement and exploration in the OFT ( ), but not SPT performance. Four weeks of moderate swimming reduced brain inflammation and improved locomotor behaviour in EAE mice, suggesting swimming as a safe complementary strategy for managing MS-related inflammation and fatigue.