ESWT Diminishes Axonal Regeneration following Repair of the Rat Median Nerve with Muscle-In-Vein Conduits but Not after Autologous Nerve Grafting.

Investigations reporting positive effects of extracorporeal shockwave therapy (ESWT) on nerve regeneration are limited to the rat sciatic nerve model. The effects of ESWT on muscle-in-vein conduits (MVCs) have also not been investigated yet. This study aimed to evaluate the effects of ESWT after repair of the rat median nerve with either autografts (ANGs) or MVCs. In male Lewis rats, a 7 mm segment of the right median nerve was reconstructed either with an ANG or an MVC. For each reconstructive technique, one group of animals received one application of ESWT while the other rats served as controls. The animals were observed for 12 weeks, and nerve regeneration was assessed using computerized gait analysis, the grasping test, electrophysiological evaluations and histological quantification of axons, blood vessels and lymphatic vasculature. Here, we provide for the first time a comprehensive analysis of ESWT effects on nerve regeneration in a rat model of median nerve injury. Furthermore, this study is among the first reporting the quantification of lymphatic vessels following peripheral nerve injury and reconstruction in vivo. While we found no significant direct positive effects of ESWT on peripheral nerve regeneration, results following nerve repair with MVCs were significantly inferior to those after ANG repair.

Use of the CatWalk gait analysis system to assess functional recovery in rodent models of peripheral nerve injury - a systematic review.

Injuries of the peripheral nervous system are common among the population affecting around 3% of all trauma patients. This high clinical need in the field of peripheral nerve injury and regeneration has been steadily driving experimental and epidemiological research. Thereby, it is crucial to determine the exact degree of recovery of end-organ function. Regeneration after nerve injuries is assessed by a wide variety of techniques and pre-clinical model systems, where rodent models are among the most widely used. However, results from rodents are difficult to translate to human patients in general, and reproducible and comparable assessment of functional recovery is of highest importance. Computerized gait analysis allows comprehensive acquisition of locomotor function. As the animals cross the recording device voluntarily, functional recovery is assessable with a minimum degree of human interference on their behavior. This article aims to give a detailed overview on the existing literature on CatWalk gait analysis in rodent models of peripheral nerve injuries of upper and lower extremities, e.g. axonotmesis, neurotmesis or fibrosis, with special emphasis on differences between models. Researchers interested in assessment of locomotor function in such models will especially benefit from this work as it will provide them with an overview of the various experimental setups and expected outcomes. This work also addresses potential pitfalls and hurdles in order to promote well designed, comparable studies allowing for accelerated development of therapeutic strategies in peripheral repair and regeneration.

Evaluation of Functional Recovery in Rats After Median Nerve Resection and Autograft Repair Using Computerized Gait Analysis.

Computerized gait analysis is a common evaluation method in rat models of hind limb nerve injuries, but its use remains unpublished in models of segmental nerve injury of the forelimb. It was the aim of this work to investigate if computerized gait analysis is a feasible evaluation method in a rat model of segmental median nerve injury and autograft repair. Ten male Lewis rats underwent 7-mm resection of the right median nerve with immediate autograft repair. The left median nerve was resected without repair and served as an internal control. Animals were assessed for 12 weeks after surgery via CatWalk (CW) gait analysis every 2 weeks. Evaluation of motor recovery by means of the grasping test was performed weekly while electrophysiological measurements were performed at the end of the observation period. CW data were correlated with grasping strength at each post-operative time point. CW data were also correlated with electrophysiology using linear regression analysis. Principal component analysis was performed to identify clusters of outcome metrics. Recovery of motor function was observable 4 weeks after surgery, but grasping strength was significantly reduced (p < 0.01) compared to baseline values until post-operative week 6. In terms of sensory recovery, the pain-related parameter Duty Cycle showed significant (p < 0.05) recovery starting from post-operative week 8. The Print Area of the right paw was significantly (p < 0.05) increased compared to the left side starting from post-operative week 10. Various parameters of gait correlated significantly (p < 0.05) with mean and maximum grasping strength. However, only Stand Index showed a significant correlation with compound muscle action potential (CMAP) amplitude (p < 0.05). With this work, we prove that computerized gait analysis is a valid and feasible method to evaluate functional recovery after autograft repair of the rat median nerve. We were able to identify parameters such as Print Area, Duty Cycle, and Stand Index, which allow assessment of nerve regeneration. The course of these parameters following nerve resection without repair was also assessed. Additionally, external paw rotation was identified as a valid parameter to evaluate motor reinnervation. In summary, computerized gait analysis is a valuable additional tool to study nerve regeneration in rats with median nerve injury.