Nicotine Augments the Beneficial Effects of Mesenchymal Stem Cell-based Therapy in Rat Model of Multiple Sclerosis.

Experimental autoimmune encephalomyelitis (EAE) in rats through immunization with guinea pig spinal cord homogenate (GPSCH) produces a chronic disease with a relapsing pattern such as multiple sclerosis (MS) in humans. In previous studies, the immunomodulatory benefits of mesenchymal stem cells (MSCs) and nicotine have already been determined. Thus, this research was conducted to assess the additional benefits of the combination therapy of MSCs and nicotine in a rat model of MS. EAE was induced by GPSCH and complete Freund's adjuvant (CFA) in female Wistar rats. The therapies were initiated at day 12 post-immunization (p.i.), when the rats developed a neurological disability score. The symptoms were recorded daily until day 33, when the rats were sacrificed. Finally, the splenocytes were evaluated by Enzyme-linked immunosorbent assay (ELISA) for cytokine production. The therapeutic treatment in the EAE rats with a combination of MSCs and nicotine exhibited a more desirable outcome, causing the regression of the average mean clinical score and neuropathological features to be more favorable than the treatment with either therapy alone. The combination therapy led to a significant reduction in the cumulative disease disability from day 21. For the EAE rats treated with nicotine and MSCs, this period was started from day 22 and 28 p.i., respectively. Besides the increase in the levels of IL-10, the combined therapy significantly reduced the splenocytes production of pro-inflammatory IL-17 as well as TNF-α more profoundly than either of the medications alone. In conclusion, the combination of MSCs and nicotine can be suggested as a promising strategy for further MS therapeutics improvement.