Systemic Infusion of Bone Marrow-Derived Mesenchymal Stem Cells for Treatment of Experimental Colitis in Mice

The anti-inflammatory and reparative properties of mesenchymal stem cells (MSCs) make them a promising tool for treating immune-mediated and inflammatory disorders. However, whether MSCs can be used for treatment of inflammatory bowel disease (IBD) still remains unclear. In this study, a dextran sulfate sodium (DSS)-induced mouse colitis model was used to test the hypothesis that infused bone marrow-derived MSCs could exert anti-inflammatory effects against experimental colitis. DSS-induced colitis mice were injected with 1 x 10(6) MSCs [in phosphate-buffered saline (PBS)] via the tail vein. Control colitis mice received PBS alone. To trace the injected cells in vivo, MSCs were labeled with chloromethyl-benzamidodialkylcarbocyanine (CM-DiI). On day 15 of the experiment, the colon was sectioned and examined for histopathological changes. Pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta] in the inflamed colon were analyzed by real-time reverse-transcription polymerase chain reaction (RT-PCR). Serum values of TNF-alpha in mice were evaluated quantitatively by enzyme-linked immunosorbent assay (ELISA) analysis. DSS-induced colitis showed symptoms similar to ulcerative colitis in humans, including body weight loss, bloody diarrhea, mucosal ulceration, and shortening of the colon. Bone marrow-derived MSCs significantly ameliorated the clinical and histopathologic severity of DSS colitis compared with non-MSC control. Pro-inflammatory cytokines in both the inflamed colon (TNF-alpha, IL-1 beta) and serum (TNF-alpha) were downregulated in MSC-treated mice in contrast to control. CM-DiI-labeled MSCs accumulated in inflamed regions of the colon, mainly in the submucosa. Systemic infusion of bone marrow-derived MSCs may exert therapeutic efficacy on acute DSS-induced colitis in mice through their anti-inflammatory effects, which demonstrates the feasibility of using bone marrow-derived MSCs to treat IBD.