Enhanced Neuroprotective Effects of Combination Therapy with Bone Marrow-Derived Mesenchymal Stem Cells and Ginkgo biloba Extract (EGb761) in a Rat Model of Experimental Autoimmune Encephalomyelitis.

OBJECTIVES: We investigated whether Ginkgo biloba extract (EGb761) can provide neuroprotective effects and enhance the efficacy of bone marrow-derived mesenchymal stem cells (BMSCs) in a rat model of experimental autoimmune encephalomyelitis (EAE).

METHODS: We examined the synergistic action of BMSCs combined with EGb761 treatment in EAE rats. The immunized rats received an intravenous injection of BMSCs or intraperitoneal administration of EGb761 or both on the day of the onset of clinical symptoms and for the following 21 days. Clinical severity scores were recorded daily and histopathological examination of the spinal cord and cytokine concentrations in the serum were studied on days 14 and 31 postimmunization.

RESULTS: Our results showed that combined treatment with BMSCs and EGb761 further decreased the disease severity, maximal clinical score and number of infiltrated mononuclear cells, especially CD3-positive T cells. We observed that the demyelination score and the density of axonal loss in the spinal cord were significantly reduced in mice receiving the combination therapy. The serum concentrations of the phosphorylated neurofilament heavy chain, tumor necrosis factor-α and interferon-γ were reduced in the combination-treatment group.

CONCLUSION: Our results suggest that combined treatment with BMSCs and EGb761 have a synergistic effect in rats with EAE by inhibiting the secretion of proinflammatory cytokines, demyelination and protecting axons and neurons.