Magnetization Transfer Ratio (MTR) as a Non-Invasive Biomarker in Small Rodent Peripheral Nerve Injury Models

The study of myelin density in peripheral nerve injuries and pathologies is largely limited to post-mortem analysis due to the difficulty in obtaining biopsies without affecting nerve function, as well as because of the small size of the tissue and its location. In this study, we used magnetization transfer ratio (MTR) MRI to longitudinally and non-invasively analyze two models of peripheral nerve injury in small rodents, obtained by sciatic nerve crush or lysolecithin injection. Multiple techniques (electrophysiology, gene expression and histology) have been used to validate the extensive MRI analysis and young and old animals have been included for comparison. This study underlines the power of MTR for the study of myelin density in small tissues such as the sciatic nerve of rodents and describes how age significantly affects recovery after injury.