Differential Protein Expression between the Motor and Sensory Fascicles in Rat Femoral Nerve Injury.

BACKGROUND AND AIMS: It is important to distinguish between motor and sensory fascicles of the peripheral nerves for nerve alignment in surgery. However, there are no biomarkers currently available for effective identification of motor or sensory fascicles. The objective of this study was to identify differentially expressed proteins between motor and sensory fascicles of rats in response to injury. SETTINGS AND DESIGN: The study was carried out using a rat femoral nerve injury model. MATERIALS: A proteomic analysis was performed to detect differential protein expression using samples of bilateral motor and sensory branches of intact and injured rat femoral nerves through fluorescent two-dimensional difference gel electrophoresis and matrix-assisted laser desorption ionization-time of flight mass spectrometry. STATISTICAL ANALYSIS: Chi-square tests and t-tests were performed for comparison between motor or sensory nerve groups. RESULTS: The data identified six proteins that were differentially expressed between motor and sensory fascicles (>1.5-fold, P < 0.05), including apolipoprotein E, neurofilament light polypepticle, TEC kinase, serine protease inhibitor A3N, peroxiredoxin-2, and TPM1. The proteomic results were consistent with the mRNA expression levels of these genes as determined by quantitative reverse transcription polymerase chain reaction. CONCLUSIONS: Our study suggests that these proteins may play roles in nerve regeneration and repair. Importantly, apolipoprotein E and Serpina3n may serve as specific biomarkers for distinguishing motor and sensory fascicles of the peripheral nerves for nerve alignment in surgery.

Identification of the sensory and motor fascicles in the peripheral nerve: A historical review and recent progress.

The aim of the study was to critically review the clinical approach to distinguish the sensory and motor nerve fascicles of the peripheral nerve system and to explore potential novel techniques to meet the clinical needs. The principles and shortcomings of the currently used methods for identification of sensory and motor nerve fascicles, including nerve morphology, electrical stimulation, spectroscopy, enzymohistochemistry staining (acetylcholinesterase [AchE], carbonic anhydrase [CA] and choline acetyltransferase [ChAC] histochemistry staining methods), and immunochemical staining were systematically reviewed. The progress in diffusion tensor imaging, proteomic approaches, and quantum dots (QDs) assessment in clinical applications to identify sensory or motor fascicles has been discussed. Traditional methods such as physical and enzymohistochemical methods are not suitable for the precise differentiation of sensory and motor nerve fascicles. Immunohistochemical staining using AchE, CA, and ChAC is promising in differentiation of sensory and motor nerve fascicles. Diffusion tensor imaging can reflect morphological details of nerve fibers. Proteomics can reveal the dynamics of specific proteins discriminating sensory and motor fascicles. QDs, with their size-dependent optical properties, make them the ideal protein markers for identification of the sensory or motor nerves. Diffusion tensor imaging, proteomics and QDs-imaging will facilitate the clinical identification of motor and sensory nerve fascicles, help in improving surgical success rates and assist in postoperative functional recovery.