Objective To investigate the effects and underlying mechanisms of human placental chorionic plate-derived mesenchymal stem cells (hpcMSCs) on cognitive dysfunction, neuroinflammation, neuronal damage and synaptic plasticity in a mouse model of stroke. Methods A mouse model of middle cerebral artery occlusion (MCAO) was adopted. The mice were randomly divided into three groups: sham operation group, MCAO group and hpcMSCs treatment group, with seven mice in each group. The hpcMSCs treatment group received hpcMSCs transplantation on the 1st, 3rd and 10th day after MCAO. One month after MCAO, the cognitive ability of the mice was evaluated by Morris water maze and Y maze behavioral tests; the morphological changes and synaptic functions of hippocampal neurons were analyzed by HE staining, Nissl staining, Golgi staining and immunofluorescence staining techniques; the density and activation status of microglia was analyzed by Fluorescent labeling method; the levels of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β) and IL-6 in brain tissue were analyzed by ELISA; the expressions of phosphorylated-mitogen-activated protein kinase kinase 1 (p-MEK1), phosphorylated-extracellular regulated protein kinase (p-ERK) and phosphorylated-cAMP-response element binding protein (p-CREB) and other proteins related to neuroprotection in the signal pathways were detected by Western blotting; and electrophysiological detection was performed using hippocampal slices in vitro. Results Compared with the MCAO group, mice in the hpcMSCs treatment group showed significant improvements, including improved cognitive ability, alleviated neuroinflammation (demonstrated by reduced microglial activation and decreased levels of inflammatory factors TNF-α, IL-1β and IL-6), and increased neuronal density with normalized morphology of neurons in the hippocampal CA1 region. The treatment group also demonstrated a significantly increased number of Nissl-positive cells and density of dendritic spines of hippocampal neurons, along with restored frequency of miniature excitatory postsynaptic potential (mEPSP). Moreover, hpcMSCs treatment significantly increased the expression levels of p-MEK1, p-ERK and p-CREB in the hippocampus. Conclusion Transplantation of hpcMSCs ameliorates cognitive dysfunction and hippocampal neuronal injury in stroke mice through the reduction of neuroinflammation, restoration of hippocampal neuronal function, promotion of synaptic plasticity and activation of the MEK/ERK/CREB signaling pathway. These findings suggest a new potential therapeutic approach for post-stroke neural repair.
Animals ; Hippocampus/physiopathology* ; Mice ; Cognitive Dysfunction/etiology* ; Mesenchymal Stem Cell Transplantation ; Male ; Neurons/metabolism* ; Stroke/metabolism* ; Humans ; Neuroinflammatory Diseases/therapy* ; Female ; Cyclic AMP Response Element-Binding Protein/metabolism* ; Disease Models, Animal ; Mesenchymal Stem Cells/cytology* ; Mice, Inbred C57BL