J Vet Sci.  2001 Aug;2(2):85-89.

Melatonin ameliorates autoimmune encephalomyelitis through suppression of intercellular adhesion molecule-1

• Kang JC
• Ahn M
• Kim YS
• Moon C
• Lee Y
• Wie MB
• Lee YJ
• Shin T

Abstract

Melatonin (N-acetyl-5-methoxytryptamine), a pineal neurohormone, is a hydroxyl radical scavenger and antioxidant, and plays an important role in the immune system. We studied the effect of exogenous melatonin on the pathogenesis of experimental autoimmune encephalomyelitis (EAE). EAE was induced in Lewis rats by immunization with rat spinal cord homogenates. Subsequent oral administration of melatonin at 5 mg/kg significantly reduced the clinical severity of EAE paralysis compared with administration of the vehicle alone (p<0.01). Infiltration of ED1 macrophages and CD4 T cells into spinal cords occurred both in the absence and presence of melatonin treatment, but melatonin-treated rats had less spinal cord infiltration of inflammatory cells than did the control group. ICAM-1 immunoreactivity in the blood vessels of EAE lesions was decreased in melatonin-treated rats compared to vehicle-treated rats. These findings suggest that exogenous melatonin ameliorates EAE via a mechanism involving reduced expression of ICAM-1 and lymphocyte function associated antigen-1a in autoimmune target organs.

Keyword

Melatonin; experimental autoimmune encepha-lomyelitis; intercellular adhesion molecule-1

MeSH Terms

Animals
Encephalomyelitis, Autoimmune, Experimental/*immunology/prevention & control
Female
Immunohistochemistry
Intercellular Adhesion Molecule-1/analysis/*immunology
Male
Melatonin/administration & dosage/*physiology
Rats
Rats, Inbred Lew
Spinal Cord/chemistry/pathology