A long-term observation of olfactory ensheathing cells transplantation to repair white matter and functional recovery in a focal ischemia model in rat.

Trials of neuroprotection in ischemic stroke mainly concern gray matter protection, with little information on white matter damage. Olfactory ensheathing cells (OECs) are capable of providing continuous neurotrophic factor and of promoting growth and remyelination of damaged axons. We evaluated OECs for the repair of white matter after transplantation in middle cerebral artery occlusion (MCAO) rat. OECs were cultured from the olfactory bulbs of adult green fluorescent protein (GFP)-expressing transgenic rats and transplanted into peri-infarct basal ganglia imminently after reperfusion. The mortality, neurological score, and function were record everyday until 56 days. At 24 h and 56 days, the infarction volume, the Luxol-fast blue (LFB) staining, and Neurofilament (NF) immunohistochemistry and Western blot were performed to assess the demyelination and remyelination in white matter. OECs transplantation reduced the infarct volume, decreased mortality, and improved neurological deficits in 56 days after MCAO. LFB marked myelin, NF-positive immunohistochemistry, and Western blot indicated that the remyelination and axon regeneration in OEC transplanted rat were significant. In conclusion, OECs can protect the white matter from ischemic injury, but the potential mechanisms of transplanted OEC-mediated recovery need further studies to identify.