Sleeve bridging of the rhesus monkey ulnar nerve with muscular branches of the pronator teres：multiple ampliifcation of axonal regeneration

摘要

Multiple-bud regeneration,i.e., multiple amplification, has been shown to exist in peripheral nerve regeneration. Multiple buds grow towards the distal nerve stump during proximal nerve ifber regeneration. Our previous studies have veriifed the limit and validity of multiple ampli-ifcation of peripheral nerve regeneration using small gap sleeve bridging of small donor nerves to repair large receptor nerves in rodents. The present study sought to observe multiple ampli-ifcation of myelinated nerve ifber regeneration in the primate peripheral nerve. Rhesus monkey models of distal ulnar nerve defects were established and repaired using muscular branches of the right forearm pronator teres. Proximal muscular branches of the pronator teres were su-tured into the distal ulnar nerve using the small gap sleeve bridging method. At 6 months after suture, two-ifnger lfexion and mild wrist lfexion were restored in the ulnar-sided injured limbs of rhesus monkey. Neurophysiological examination showed that motor nerve conduction veloc-ity reached 22.63 ± 6.34 m/s on the affected side of rhesus monkey. Osmium tetroxide staining demonstrated that the number of myelinated nerve fibers was 1,657 ± 652 in the branches of pronator teres of donor, and 2,661 ± 843 in the repaired ulnar nerve. The rate of multiple ampliifcation of regenerating myelinated nerve ifbers was 1.61. These data showed that when muscular branches of the pronator teres were used to repair ulnar nerve in primates, effective regeneration was observed in regenerating nerve ifbers, and functions of the injured ulnar nerve were restored to a certain extent. Moreover, multiple ampliifcation was subsequently detected in ulnar nerve axons.