Carvacrol ameliorates experimental autoimmune encephalomyelitis through modulating pro- and anti-inflammatory cytokines.

Objective: The inflammatory process is a key step in multiple sclerosis (MS) development. Carvacrol exhibits various anti-inflammatory properties. We aimed to assess the Carvacrol effects on clinical manifestations and production of pro-inflammatory (IFN-γ, IL-6 and IL-17) and anti-inflammatory (TGF-β, IL-4, and IL-10) cytokines in experimental autoimmune encephalomyelitis (EAE) as MS animal model.

Methods: EAE mice were treated with 5, 10 mg/kg dose of Carvacrol or vehicle, as the control EAE group, every other day until day-21 post EAE induction. On day22, the leukocyte infiltration within the CNS was estimated using hematoxylin-eosin staining. The cytokine production by splenocytes was determined after in vitro stimulating with myelin oligodendrocyte protein (MOG).

Results: The EAE clinical scores in 5 and 10 mg/kg Carvacrol-treated mice were lower than untreated group (P < 0.001 and P < 0.01, respectively). The amounts of IFN-γ and IL-6 production by splenocytes of 5 and 10 mg/kg Carvacrol-administered mice were lower than control group (P < 0.001, and P < 0.01 for IFN-γ respectively; P ˂ 0.05 for IL-6). Splenocytes of 5 and 10 mg/kg Carvacrol-treated mice produced higher levels of TGF-β than untreated mice (P < 0.001). in splenocytes of 5 mg/kg Carvacrol-treated group the IL-10 production was higher while IL-17 secretion was lower than control group (both with P < 0.01).

Conclusions: Carvacrol exhibits modulatory effects on expression of pro- and anti-inflammatory cytokines. It ameliorates EAE clinical and pathological consequences and therefore its potentials may be considered in treating MS patients.