Effect of bone marrow-derived mesenchymal stem cells (BM-MSCs) on animal model of multiple sclerosis through immunomodulatory mechanism

Abstract

Multiple sclerosis (MS) is an autoimmune disease characterized by demyelination in the central nervous system (CNS). An animal model of multiple sclerosis is experimental autoimmune encephalomyelitis (EAE). Like MS, the CNS of EAE shows infiltration of peripheral immune cells and demyelination. Using this model, we determined to investigate effect of mesenchymal stem cell (MSC) as therapeutics for MS. As a first step, EAE model was established by myelin oligodendrocyte glyciprotein33-55 (MOG) peptide injection in C57BL/6 mice. We identified the onset of symptoms 7 day after immunization (DAI) and the EAE severity was maximized at 30 DAI. To investigate the effect of MSC in EAE model, we injected MSC intravenously at 7 DAI and performed an immunohistochemical study at 30 DAI. We analyzed the peripheral cell infiltration with hematoxylin and eosin stain (H&E stain) and demyelination with luxol fast blue stain (LFB stain). T cell infiltration and demyelination were confirmed by DAB stain using T cell marker CD3 and myeline basic protein (MBP), respectively. In quantitative Real Time-PCR (qRT-PCR), we analyzed the level of pro-inflammatory cytokines (IFN-γ, TNF-α, IL-1β) and anti-inflammatory cytokines (TGF-β and IL-10). FOXP3 and CX3CR1 were used for Treg and M2 microglia marker, respectively. In this study, we have established EAE models and investigated the effect of bone marrow derived-MSCs (BM-MSCs) administered intravenously in EAE model. We identified that intravenous BM-MSC injection in EAE models alleviated neurological symptom and demyelination in MS. In the mRNA analysis of spinal cord that was dissected after behavior assay, BM-MSC reduced pro-inflammatory cytokines such as TNF-α, IFN-γ and IL-1β with Th1 transcription factors (tbx21). In the histological analysis, BM-MSC reduced CD3 positive cell infiltration and demyelination, and restored myelin basic protein (MBP) immunoreactivities (IR) in spinal cord of EAE animal. Taken together, we suggest that intravenous BM-MSC injection may attribute to maintain stable clinical score and symptom via immunomodulatory function in MS.