Royal jelly attenuated cognitive and non-cognitive deficits and blood-brain barrier disruption inducedby ethidium bromide

Introduction: Multiple sclerosis (MS) is an autoimmune disease. The main aims of the present investigation were to evaluate the effect of royal jelly (RJ) on cognitive and noncognitive behavior, demyelination and the level of blood-brain barrier (BBB) disruption induced by ethidium bromide (EB). Methods: Twenty-five adult male Sprague Dawley in five groups were used. Control (intact rat); Sham (surgery without EB injection); treatment control (EB injection without treatment); treatment1 and treatment2 (orally administered of RJ 100 and 200 mg/kg/day after EB injection). EB (3µl of 0.01%) injection in the dentate gyrus (DG) was used for demyelination. Demyelination induction was proved by histological examination. For the estimation of BBB integrity, Evans blue extravasation was done using an ELISA reader. Cognitive and non-cognitive behavior was evaluated by Morris water maze. Results: Data showed that RJ corrected the deficit of demyelination. Cognitive and noncognitive behavior improved in treatment groups relative to treatment control by RJ. The extent of BBB disruption significantly improved in treatment groups compared to the treatment control group, in the whole brain and hippocampus. Conclusion: Results indicate that RJ after EB injection in DG can improve cognitive and non-cognitive behavior, demyelination and BBB disruption in rat after EB injection. Therefore, it seems that RJ can be a supplementary drug for MS.