Abstract: BACKGROUND: Plant-derived exosome-like nanoparticles have become a research hotspot in tissue repair due to their natural biocompatibility, low immunogenicity, and rich bioactive components. Among them, ginger-derived exosome-like nanoparticles have shown potential in anti-inflammatory and tissue repair promotion, but their role and mechanism in peripheral nerve regeneration remain unclear.
OBJECTIVE: To investigate the role and potential mechanism of ginger-derived exosome-like nanoparticles in the repair of sciatic nerve injury.
METHODS: (1) Ginger-derived exosome-like nanoparticles were isolated from fresh ginger using differential centrifugation combined with sucrose density gradient centrifugation and characterized by transmission electron microscopy, nanoparticle tracking analysis, BCA protein quantification, Coomassie Brilliant Blue staining, and western blot analysis for plant vesicle markers. (2) Ginger-derived exosome-like nanoparticles suspensions of different mass concentrations (0, 5, 10, and 15 μg/mL) were co-cultured with dorsal root ganglion neurons of newborn mice. β-III tubulin immunofluorescence staining was used to observe neuronal axonal growth and the uptake of ginger-derived exosome-like nanoparticles by neurons. (3) A sciatic nerve crush injury model was established in mice. Ninety-six mice were randomly divided into a model control group and low-, moderate-, and high-dose ginger-derived exosome-like nanoparticle groups (n=24 per group). Assuming the dosage volume was 5 mL/kg, each group was administered ginger-derived exosome-like nanoparticle suspension by gavage at doses of 0, 5, 10, and 15 μg/kg, respectively, once daily for 28 days. Body weight and limb motor function were assessed on days 7, 14, 21, and 28 post-administration. After the last administration, histopathological changes in major organs and relative wet weight of the gastrocnemius muscle were examined. Fluoro-gold retrograde labeling was used to measure dorsal root ganglion axonal regeneration. Transmission electron microscopy was utilized to detect sciatic nerve myelin regeneration. Within 48 hours post-administration, the biodistribution of DiR-labeled ginger-derived exosome-like nanoparticles in mice was dynamically observed using in vivo imaging. Western blot analysis was used to detect the protein expression of growth-associated protein 43 (day 7 post-administration) and neurofilament protein 200 (day 28 post-administration) in the dorsal root ganglion.
RESULTS AND CONCLUSION: (1) Ginger-derived exosome-like nanoparticles exhibited a particle size distribution peaking at (113.4±35.8) nm and a typical cup-shaped vesicular morphology consistent with exosome characteristics. Western blot analysis confirmed the high purity of ginger-derived exosome-like nanoparticles. (2) Compared with the other three groups, 15 μg/mL ginger-derived exosome-like nanoparticles suspension significantly promoted neurite growth. Ginger-derived exosome-like nanoparticles could be effectively taken up by neurons. (3) Body weight monitoring results showed that different doses of ginger-derived exosome-like nanoparticles did not affect the growth and development of mice. Hematoxylin-eosin staining showed that different doses of ginger-derived exosome-like nanoparticles did not cause significant organ damage in mice, demonstrating good systemic safety. In vivo imaging dynamic observation showed that ginger-derived exosome-like nanoparticles specifically accumulated in the gastrointestinal tract, reaching a peak at 12 hours after administration. The high-dose ginger-derived exosome-like nanoparticle group showed better dorsal root ganglion axon regeneration, sciatic nerve myelin regeneration, and limb motor function than the other three groups. The relative wet weight of the gastrocnemius muscle and the protein expression of growth-related protein 43 and neurofilament protein 200 were also higher than the other three groups. The results confirm that oral administration of ginger-derived exosome-like nanoparticles promoted the regeneration of neural structures and the recovery of function after sciatic nerve injury, demonstrating clear neurorepair activity. This mechanism was closely related to the upregulation of neurofilament protein 200 and growth-associated protein 43 expression.

Key words: ginger-derived exosome-like nanoparticle, sciatic nerve injury, nerve regeneration, dose-dependency, motor function recovery, axonal regeneration, dorsal root ganglion neuron, neurofilament protein 200, growth-associated protein 43