Neuroprotective effects of bornyl acetate on experimental autoimmune encephalomyelitis via anti-inflammatory effects and maintaining blood-brain-barrier integrity

Bornyl acetate (BA), a chemical component of essential oil in the Pinus family, has yet to be actively studies in terms of its therapeutic effect on numerous diseases, including autoimmune diseases.This study aimed to investigate the pharmacological effects and molecular mechanisms of BA on myelin oligodendrocyte glycoprotein (MOG35-55)-induced experimental autoimmune encephalomyelitis (EAE) mice in an animal model of multiple sclerosis (MS), a representative autoimmune disease in central nervous system.BA (100, 200, or 400 mg/kg) was orally treated to EAE mice once daily for 30 days after immunization for the behavioral test and for the 16th-18th days for the histopathological and molecular analyses, from the onset stage (8th day) of EAE symptoms.BA mitigated behavioral dysfunction (motor disability) and demyelination in the spinal cord that were associated with the down-regulation of representative pro-inflammatory cytokines (interleukin (IL)-1 beta, IL-6, and tumor necrosis factor-alpha), enzymes (cyclooxygenase-2 and inducible nitric oxide synthase), and chemokines (monocyte chemotactic protein-1, macrophage inflammatory protein-1 alpha, and regulated on activation), and decreased infiltration of microglia (CD11b+/CD45+(low)) and macrophages (CD11b+/CD45+(high)). The anti-inflammatory effect of BA was related to the inhibition of mitogen-activated protein kinases and nuclear factor-kappa B pathways. BA also reduced the recruitment/infiltration rates of CD4+ T, Th1, and Th17 cells into the spinal cords of EAE mice, which was related to reduced blood-spinal cord barrier (BSCB) disruption.These findings strongly suggest that BA may alleviate EAE due to its anti-inflammatory and BSCB protective activities. This indicates that BA is a potential therapeutic agent for treating autoimmune demyelinating diseases including MS.