Background & aim: Lately, it has been demonstrated that the signaling by the α7 nicotinic receptors produces the anti-inflammatory condition in both macrophages and T cells. Moreover, activation of macrophages and T cells play an important role in multiple sclerosis (MS).  In the present study, the therapeutic effect of nicotine on experimental autoimmune encephalomyelitis (EAE), an animal model of MS, and its effects on T-helper cells responses was evaluated.

Methods: In the present experimental study, EAE was induced by homogenised guinea pig spinal cord and complete Freund’s adjuvant in wistar rats. Animals were allocated in two therapeutic groups (n=7 per group). Treatment with nicotine (2.5 mg/kg-daily) was started in treatment group when the treatment group developed a disability score (at day 12). At the same time, the control group received only the solvent with the same program. Signs of disease were recorded daily until the day 36 when animals were sacrificed. The Splenocytes were checked for proliferation by MTT test and cytokine production by ELISA. The level of nitric oxide in serum was checked by griess test. The data was analyzed using the Student t test and Mann-Whitney U.

Results: Nicotine administration in the treatment group significantly reduced the clinical symptoms after the onset of symptoms. Simultaneously with the decrease of the level of serum nitric oxide, nicotine significantly decreased the pro-inflammatory cytokine IL-17 and IFN-γ. The levels of anti-inflammatory IL-10 were not changed significantly. Lymphocyte proliferation was significantly decreased in treatment group compared to control group

Conclusion: The results of this study indicated that nicotine had immune modulatory effects and could be used to control MS disease.