Background and purpose: Disability is common after severe stroke resulting from major cerebral artery occlusion despite adoption of prophylactic decompressive craniectomy. Experimental mesenchymal stem cell treatments are commonly administrated through systemic infusion, with limitations in dosage. In this study, the neuro-modulation effect of topical mesenchymal stem cells (MSCs) was tested in a rodent middle carotid artery occlusion (MCAO) model.
Methods: Twenty-four hours after MCAO, craniotomy was made and 0.8 x 106 GFP-MSCs were topically applied to the ipsilateral parietal cortex (N=30). In the control group, saline were topically applied to the ipsilateral parietal cortex (N=30).
Results: After topical MSC treatment, neurological assessments with Rotarod test (at days 3, 7, and 10) and Morris Water Maze test (at days 3, 7, and 14) were significantly better, as compared to the control group; the infarct volume was also smaller. MSCs were found in the penumbra of the infarct 3 days after topical application. In the PCR array analysis of the RNA extracted from penumbra cortex, topical application of MSCs changed 10 gene expressions in the penumbra at day 3 (fold change >1.25, p<0.05 after Bonferroni corrections for multiple comparisons). The seven up-regulated genes (Apoe, Ascl1, Efnb1, Mef2c,Nog,S100a6, B2m) involve neuronal migration, neuronal differentiation, neuronal cell fate determination, regulation of synaptic plasticity, axonogensis;, growth factors, and cell adhesion. Pax2, Pax3 and Th were downregulated. Pax2 and Pax3 are related to apoptosis. Both Apoe and Thl involve synaptic transmission.
Conclusions: Topically applied MSCs reduced cerebral infarction volume and improved the neurological function from cerebral ischemia resulting from a major cerebral artery occlusion in a rodent experimental model.