Mechanical hypernociception in experimental autoimmune encephalomyelitis

Abstract

Background: Pain is an important clinical manifestation in multiple sclerosis (MS) patients, though it has been neglected in clinical and experimental researches. Objective: To investigate the nociceptive response in MOG35-55 experimental autoimmune encephalomyelitis (EAE)-induced mice. Method: EAE was induced in 8 to 10 week old C57BL/6 female mice with an emulsion of MOG35-55, Complete Freund Adjuvant, Mycobacterium tuberculosis H37 RA and pertussis toxin. Nociception was evaluated by the von Frey filaments method. A clinical scale ranging from 0 to 15 was used to assess motor impairment. Results: Clinical evidence of disease started at day 10 and peaked at day 14 after immunization. Thereafter, there was no worsening of symptoms until day 26. The EAE-induced mice presented reduced pressure threshold at days 7th and 10th after immunization and before the onset of clinical motor signs. Conclusion: The hypemociception found validates MOG35-55 EAE as a model for the study of pain in multiple sclerosis.