Intracerebral transplantation of erythropoietin‐producing fibroblasts facilitates neurogenesis and functional recovery in an ischemic stroke model

INTRODUCTION: Erythropoietin (EPO) can enhance neurogenesis and fibroblasts can secrete growth factors; together, they may benefit ischemic stroke. We transplanted EPO‐producing fibroblasts into the rodent infarcted brain to test their effect on neurogenesis and functional recovery. METHODS: A total of 10(6) cells of EPO‐producing NIH/3T3 fibroblasts (EPO/EGFP/3T3) or enhanced green fluorescence protein (EGFP)‐expressing fibroblasts (EGFP/3T3) were stereotaxically injected into the infarcted striatum of adult rats that received transient middle cerebral artery occlusion (MCAO) surgery 1 day poststroke. On day 14 after MCAO, the animals were euthanized for the evaluation of neurogenesis via immunohistochemistry and of the expression of growth factors using enzyme‐linked immunosorbent assay. The infarct volume was analyzed using magnetic resonance imaging and the neurological behavior was assessed using the neurological severity scoring performed within 14 days after MCAO. RESULTS: The MCAO rats with EPO/EGFP/3T3 treatment showed high EPO expression in the infarcted brain for at least 1 week. The concentration of brain‐derived neurotrophic factor was higher in both hemispheres of MCAO rats with either EGFP/3T3 or EPO/EGFP/3T3 treatment at 14 days poststroke compared with untreated MCAO rats. The number of Ki‐67‐, nestin‐, or doublecortin‐immunoreactive cells in bilateral subventricular zones was higher in EPO/EGFP/3T3‐treated MCAO rats than it was in untreated MCAO control animals, indicating the enhancement of neurogenesis after EPO/EGFP/3T3 treatment. Notably, post‐MCAO EPO/EGFP/3T3 treatment significantly reduced infarct size and improved functional recovery. CONCLUSION: The intracerebral transplantation of EPO‐producing fibroblasts benefited an ischemic stroke model probably via the enhancement of neurogenesis.