1063 Protective Mechanism of Stem Cells From Human Exfoliated Deciduous Teeth in Treating Spinal Cord Injury

INTRODUCTION: Spinal cord injury (SCI) precipitates profound enduring deficits. Recently, cell transplantation therapy has emerged as a noteworthy intervention for SCI. Although stem cells derived from human exfoliated deciduous teeth (SHED) present an enticing therapeutic prospect, their precise mode of action remains elusive. METHODS: Employing a rat clip compression SCI model, we partitioned the animals randomly into three cohorts: SCI, SCI + PBS, and SCI + SHED. Subsequent to SCI induction, we assessed the impact of SHED on motor function via the Basso, Beattie, and Bresnahan score, along with the inclined plane method. We scrutinized the signal transduction pathway, particularly the JAK and STAT3 pathway, the apoptotic pathway, and the expression of neurocan, a member of the chondroitin sulfate proteoglycans. RESULTS: SHED treatment notably ameliorated functional recovery beginning on day 14 compared to the controls. Western blot analysis revealed that SHED significantly attenuated the expression of GFAP and phosphorylated (p-) STAT3 at Tyr705 on day 10, albeit not on day 5. Immunohistochemistry unveiled that p-STAT3 at Tyr705 was chiefly expressed in GFAP-positive astrocytes on day 10 post-SCI, with its expression curtailed by SHED administration. Furthermore, SHED treatment substantially triggered the expression of cleaved caspase 3 in GFAP-positive astrocytes on day 10 post-SCI, without such effects observed on day 5. Neurocan expression was also markedly diminished following SHED injection on day 10 post-SCI. CONCLUSIONS: Our findings elucidate the pivotal role of SHED in mitigating astrogliosis and glial scar formation between days 5 and 10 post-SCI, plausibly through astrocyte apoptosis, ultimately culminating in neurological functional enhancements thereafter. Thus, our data unveil one of the neuroprotective mechanisms of SHED during the subacute phase following SCI, contributing to enhanced functional recovery post-SCI.