Research Article Comparative Effects of Bone Marrow Mesenchymal Stem Cells on Lipopolysaccharide-Induced Microglial Activation Fan-Wei Tseng,1,2 May-Jywan Tsai,2,3 Li-Yu Yu,2,4 Yu-Show Fu,4,5

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. After injury to the CNS, microglia are rapidly activated and concentrated and trigger inflammatory reaction at the sites of injury. Bone marrow mesenchymal stem cells (BMMSC) represent attractive cell sources for treating CNS injury. Although anti-inflammatory and paracrine effects of grafted BMMSChave been shown, directmodulation of BMMSConmicroglia in situ remains unclear. The present work employs in vitro transwell assay to characterize the effects of BMMSC on LPS-stimulated microglia. BMMSC are cultivated in serum and serum-free (sf) conditions, namely, BMMSC and BMMSC-sf. Both cultures express major surfacemarkers specific formesenchymal stem cells. However, the BMMSC-sf exhibit sphere-like structurewith reduced expression of two adherent cell markers, CD29 and CD90. Compared to BMMSC-sf, BMMSC are fibroblast like and have faster differentiatio