Prevention of motor relapses and associated trigeminal pain in experimental autoimmune encephalomyelitis by reducing neuroinflammation with a purple corn extract enriched in anthocyanins

Abstract

Multiple sclerosis (MS) is the leading cause of disability in young adults, with about 2.5–3 million cases currently diagnosed. Pain is a common comorbid symptom of MS, and develops independently from motor impairments. Currently utilized drugs bear severe side effects; thus, new therapeutic strategies are needed, and nutraceutical supplements represent innovative and safe opportunities. We have selected a variety of anthocyanin-enriched purple corn, from which a water-soluble extract (Red extract) has been obtained and administered to male rats exposed to experimental autoimmune encephalomyelitis (EAE). Animals developed relapsing-remitting motor symptoms, accompanied by early onset trigeminal allodynia. The preventive administration of Red extract facilitated the remission of motor symptoms, prevented the development of relapses, and delayed and reduced the development of EAE-associated trigeminal pain. An overall inhibition of neuroinflammation, blunted microgliosis and astrogliosis, activation of autophagy and reduced immune cell infiltration in the brainstem, cervical and lumbar spinal cord were observed. Yellow corn extract, lacking anthocyanins, had no behavioral effects, despite a limited anti-inflammatory action. Therapeutic Red extract administration did not affect EAE motor symptoms, only partially reduced the development of trigeminal pain but maintained its ability to reduce neuroinflammation and glial cell activation and to promote autophagy. Overall, our data suggest that a nutraceutical supplement from anthocyanin-enriched purple corn represents an interesting option to limit the development of motor relapses and the chronicization of multiple sclerosis-associated pain, through the mitigation of neuroinflammation, of the infiltration of immune cells and the promotion of autophagy.