Restoration of a nerve defect using a nerve stem implant containing silk fibroin in an experiment.

INTRODUCTION. The relevance of the study is due to the constant conduct of military conflicts and high-tech local wars around the world using modern cluster munitions and various missiles. At the same time, the number of injuries to large nerves of the extremities has increased, often with the formation of large defects in the nerve trunks. One of the ways to restore the anatomical integrity of damaged nerves is to connect the proximal and distal ends of the nerve using conduits of various sizes made of biodegradable materials of biological and synthetic origin.

AIM. To evaluate the possibility and effectiveness of restoring tissue innervation lost in trauma after replacing extensive nerve defects with polycaprolactone–based conduits with collagen gel and silk fibroin filaments in an experiment on laboratory animals.

MATERIALS AND METHODS. In an experiment on 10 laboratory animals (rats), a simulation of an extensive sciatic nerve defect was performed, followed by its replacement using polycaprolactone with collagen gel and silk fibroin filaments. The results of the functional state of the restored nerves in the postoperative period were evaluated experimentally by clinical, electrophysiological and morphological methods.

RESULTS. When analyzing the behavior of laboratory animals in the postoperative period, it was found that after 1.5 months after surgery, the animals almost fully used the limb, where the sciatic nerve conduit was performed. Based on the results of stimulation electroneuromyography in animals of the experimental group, the restoration of M responses was noted, the amplitude of which increased. After euthanasia of animals during conduit sampling in the area of experimental surgery, there were no pronounced scar-adhesive changes around it, in addition, signs of implant biodegradation were noted. Morphological examination revealed the complete germination of axons from the proximal end of the sciatic nerve to the distal one.

CONCLUSION. When replacing the defect of the ends of the experimentally damaged nerve with a conduit consisting of polycaprolactone with collagen gel and silk fibroin filaments, we established the germination of axons from the proximal end of the sciatic nerve into the proximal one. Reactions of the surrounding tissues at the site of conduit implantation in the form of signs of inflammation and the formation of rough scars were not revealed, signs of implant biodegradation were noted. A conduit made of polycaprolactone with collagen gel and silk fibroin filaments can be used to replace defects in nerve trunks. 

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