Electroacupuncture enhances mesenchymal stem cell therapy via improved perfusion and inflammation modulation in peripheral nerve injury: an IVIM-MRI study in rats.

BACKGROUND: Stem cells are widely applied in peripheral nerve repair; however, their therapeutic potential is constrained by immune rejection, inflammatory responses, and a poor regenerative microenvironment. Therefore, reducing the inflammatory response, improving the regenerative environment and dynamically monitoring these processes by imaging techniques are critical. This study examined the effectiveness of electroacupuncture (EA) and bone mesenchymal stem cells (BMSCs) on acute sciatic nerve injury in rats. By employing intravoxel incoherent motion (IVIM) MRI, the study monitored perfusion and explored how EA improves the regenerative environment to optimize stem cell transplantation outcomes. METHODS: Seventy-two rats were randomly assigned to four groups: EA, EA + BMSCs, BMSCs, and PBS. EA was applied at GB30 and ST36. IVIM-MRI (perfusion fraction f), T2WI, histological staining, immunostaining (CD31, IL-1α, IL-10, PPARγ), and SFI were used to evaluate treatment effects. RESULTS: At 2-4 weeks, the nerve perfusion fraction f in the EA group recovered faster than in the BMSCs group (p < 0.05). By week 4, the EA group showed the greatest myelin regeneration and nerve fiber restoration (p < 0.05). The expression of vascular marker CD31 and anti-inflammatory markers IL-10 and PPARγ increased (p < 0.05), while pro-inflammatory marker IL-1α decreased in the EA and EA + BMSCs groups (p < 0.05). Furthermore, f values were strongly correlated with histological and functional outcomes (p < 0.05). CONCLUSION: EA is more effective than BMSCs alone in promoting nerve repair, enhancing blood flow, and reducing inflammation. Moreover, EA enhances the anti-inflammatory effects of BMSCs. The perfusion fraction (f) is a sensitive biomarker for evaluating nerve repair and perfusion restoration.