Fig. 2

MSC transplantation attenuates the JEV-induced inflammatory response in mouse brains. Mice in each group were euthanized at 6 dpi, and the histopathological alterations and inflammatory cytokines in the brain were investigated via H&E staining and qRT-PCR, respectively. a Severe meningitis in Japanese encephalitis virus (JEV)-infected mice as indicated by arrows; this disease state was significantly alleviated in the mesenchymal stem cell (MSC) treatment group. b Perivascular cuffing with increased inflammatory cell infiltration was more evident in JEV-infected mice compared with the MSC treatment group. c Phagocytosis of neurons by inflammatory cells was apparent in JEV-infected mice (phosphate-buffered saline (PBS) n= 3, JEV n= 6, JEV + MSC n= 6). d Total RNA from each brain was extracted, and the inflammatory cytokine levels were tested by qRT-PCR. There was decreased expression of the inflammatory cytokines tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and chemokine (C-C motif) ligand 2 (CCL-2) in the brains from the MSC treatment group compared to JEV-infected mice (PBS n= 2, JEV n= 5, JEV + MSC n= 5). e When co-cultured with JEV-infected Neuro2a cells via transwells, the expression of TSG-6 and transforming growth factor-β (TGF-β) in MSCs was increased, which might contribute to the alleviated inflammation. The data represent the mean ± SEM for three independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001. 1 MSCs, 2 MSCs co-cultured with JEV-infected Neuro2a cells