MRI Tracking of MPIO-Labeled Amniotic Fluid-Derived Stem Cells on an Acellular Nerve Graft in a Rat Model

Stem cell therapies show promise for peripheral nerve repair, but optimal delivery requires understanding of cell fate and survival at the repair site. This protocol describes a method for longitudinally tracking amniotic fluid stem (AFS) cells using magnetic resonance imaging (MRI) in a rat sciatic nerve injury model. AFS cells are labeled with micrometer-sized paramagnetic iron oxide (MPIO) particles and assessed for viability. The MPIO AFS cells are then seeded onto acellular nerve allografts (ANAs) by injection beneath the epineurium and implanted to repair sciatic nerve defects in rats. At multiple timepoints post-implantation, up to 4 weeks, cell location is monitored using a 7-Tesla MRI, with histological confirmation via Prussian blue staining for MPIO. This protocol details methodology involving non-invasive longitudinal tracking of stem cells following transplantation, providing evidence on AFS cell survival and integration within nerve grafts. This method can be adapted for other stem cell delivery approaches in peripheral nerve regeneration research.