Regular Exercise Training Enhances Spatial Memory and Regulates Glucocorticoid System in Experimental Autoimmune Encephalomyelitis

Background & objective: Exercise has been shown to improve cognitive function in patients with multiple sclerosis (MS). Experimentally, glucocorticoids (GCs) treatment has been observed to improve cognitive deterioration in an autoimmune model for MS, experimental autoimmune encephalomyelitis (EAE). We aimed to determine the combined effect of exercise and ۴ mg/kg of dexamethasone (Dex) for ۴ weeks on spatial memory in EAE. Materials & Methods: Rats with EAE were subjected to the Morris water maze (MWM) for four days and a prop test for one day. The prop test was repeated on day ۴۰ post-induction (dpi). Rats were randomly assigned to one of four groups (۱۰ rats per group): control EAE without treatment; EAE + dexamethasone, (EAE + Dex); EAE + exercise (EAE + Ex); and EAE+Dex+Ex. Rats receiving dexamethasone were administered ۴ mg/kg injections daily for two weeks after EAE induction. Exercise training was initiated on a motorized treadmill ۲ weeks before EAE induction and continued until ۱۴ dpi. On day ۴۱, animals were dissected and CORT level was assessed by enzyme-linked immunosorbent assay corticosterone kit. Results: One-way analysis of variance (ANOVA) with repeated measures followed by a protected LSD post hoc test indicated that, EAE+Ex group increased body weight (P < ۰.۰۰۱) and it displayed a significantly lower CORT concentration (P <۰.۰۰۱) with delayed clinical score until day ۱۳ dpi. Further EAE+Ex improved memory by time spent (p > ۰.۰۰۱) and swimming speed (p>۰.۰۰۲). Conclusion: The protocol selected in this study was an effective treatment for the EAE model to improve spatial memory and regulate corticosterone concentrations.

کلیدواژه ها:

Regular Exercise ، Experimental Autoimmune Encephalomyelitis ، Dexamethasone ، Memory ، Corticosterone