Cell activity during peripheral nerve defect repair process using a nerve scaffold

Area of Science:

• Regenerative Medicine
• Biomaterials Science
• Neuroscience

Background:

• Peripheral nerve defects require effective repair strategies.
• Endogenous cells play a crucial role in natural nerve regeneration.
• Artificial nerve conduits aim to mimic biological environments for repair.

Purpose of the Study:

• To investigate cellular activity during peripheral nerve repair using autologous nerves and artificial nerve scaffolds.
• To guide the future fabrication of artificial nerves by understanding repair mechanisms.
• To correlate cellular responses with functional recovery after nerve grafting.

Main Methods:

• Implantation of PLGA tubes, nerve scaffolds (PLGA + fibroin fibers), or autologous nerves into 10 mm rat sciatic nerve defects (n=60 per group).
• Histological analysis of nerve sections from 1-20 weeks post-grafting to identify cell types.
• Quantification of motor and sensory function recovery using hot water withdrawal and static sciatic index (SSI).

Main Results:

• Inflammatory cell and fibroblast counts decreased over time, with higher counts in PLGA tubes compared to nerve scaffolds, autologous nerves, and sham groups.
• Schwann cell counts showed an opposite trend, increasing over time and correlating with better functional outcomes.
• Functional recovery (sensory and motor) was highest in the sham group, followed by autologous nerve, nerve scaffold, and PLGA groups.

Conclusions:

• Peripheral nerve repair involves an initial inflammatory phase followed by fibroblast and Schwann cell proliferation, guiding axon regeneration.
• A weaker inflammatory response during nerve grafting correlated with superior sensorimotor functional recovery.
• Nerve scaffolds incorporating fibroin fibers show potential for enhanced peripheral nerve repair compared to simple PLGA tubes.