Peripheral Nerve Regeneration In Rats Research Articles

A comparison of electric and magnetic compound action signals as quantitative assays of peripheralo nerve regeneration

The evaluation of peripheral nerve regeneration is of great interest in clinical as well as in experimental situations. However, there are few techniques that give early and quantitative information on the status of the regeneration process. If quantitative assays would be available, different surgical techniques and medications could be evaluated more accurately in relation to axonal ingrowth and functional recovery. The purpose of this study was to investigate the merits of nerve compound action signals (NCASs) recorded electrically and signals recorded with a novel magnetic recording technique. We compared the two techniques in the rabbit peroneal nerve, 2, 4, 6, and 8 weeks after a nerve reconstruction. Our conclusions are that the signals recorded with the magnetic sensor are far more reproducible and less prone to stimulus artifact than the electrically recorded signals. Furthermore, the magnetic recording shows that the number of axons that have regenerated increases with time. Previously, this could only be determined with histological studies. Other ingrowth parameters that can be quantified are the average ingrowth distance, and the variation between axons in ingrowth velocity.

Electrophysiologic evaluation of peripheral nerve regeneration through grafts immunosuppressed with cyclosporin

Electrophysiologic evaluation of peripheral nerve regeneration through grafts immunosuppressed with cyclosporin

Morphological and Functional Evaluation of Peripheral Nerve Regeneration in the Rat Using an Expanded Polytetrafluoroethylene (PTFE) Microprosthesis

The aim of our study was to evaluate in the rat the ability of a polytetrafluoroethylene microprosthesis (PTFE), to guide the peripheral nerve regeneration between the two extremities of a transected sciatic nerve. In 15 adult male Wistar rats, weighing 200 g, a segment of the right sciatic nerve was resected, leaving a gap of about 1 cm, bridged with microprosthesis, using our original microsurgical technique. Neurophysiological evaluations were performed at 6 and 9 months post-operatively to study the distal motor latency either in the right sciatic nerve or in the unoperated control side. In all the rats myoelectrical responses with an increased latency of the operated side were produced from the interosseous muscle of the foot. The animals were sacrificed 9 months post surgery. Histological sections at the level of the graft were done in all the rats, and in 10 animals biopsies of the tibialis anterior muscle (TA) of each side were performed. An active process of axonal regeneration was documented inside the graft, with no infiltration of nerve fibers through the wall of the prosthesis. A connective fibrous reaction was present around the external wall of the graft. Muscle biopsies showed definite signs of muscle reinnervation, with residual features of variable degree of denervation. These findings stress and confirm the ability of the PTFE graft to allow effective regeneration in a peripheral nerve gap in the rat.

Electrophysiologic Evaluation of Peripheral Nerve Regeneration Through Allografts Immunosuppressed with Cyclosporin

A model was designed to evaluate the long-term in vivo electrophysiology of rat peripheral nerve transplants. The application of this model was demonstrated using cyclosporin (CSA) immunosuppression of recipient animals to facilitate peripheral nerve regeneration through nerve allografts. Isogenic Brown Norway (BN) rats [RT1n] were divided into three groups: two received Lewis (LE) rat [RT1l] allografts and one received BN isografts. One allograft recipient group received CSA immunosuppression for the duration of the investigation (150 days). Successful nerve regeneration in the isograft and the immunosuppressed allograft recipient groups was determined by immunohistochemical methods and serial in vivo electrophysiologic techniques to measure nerve conduction velocity and evoked compound muscle action potential amplitude. Statistical analysis of these results indicate that: (a) CSA immunosuppression of peripheral nerve allograft recipients facilitates peripheral nerve regeneration which is indistinguishable from isograft recipient controls at the functioning axon level; and (b) in vivo electrophysiologic monitoring in this model is particularly useful for long term peripheral nerve transplantation studies permitting serial assessment of regeneration with little morbidity.

Influence of isaxonine on the target phenomenon, muscle fibre size and neuromuscular junction in the tenotomized and denervated gastrocnemius muscle of the rat.

Isaxonine is reported to accelerate the rate of peripheral nerve regeneration, stimulate axonal sprouting and promote motor and sensory function recovery. The target phenomenon in muscle fibers is the morphological expression of increased stretch activity in a diseased muscle. It can be produced in the gastrocnemius muscle of the rat by tenotomy and is inhibited by simultaneous denervation. The influence of isaxonine on this experimental model was studied. Twenty Wistar rats were submitted to bilateral section of the Achilles tendon and section of the left sciatic nerve. In ten rats, treated with isaxonine, the qualitative and quantitative changes in the gastrocnemius muscle were compared with the control group over a period of 3 weeks. No statistical differences were observed in the occurrence and inhibition of the target phenomenon, the muscle fibre size and the neuromuscular junction. Isaxonine has no direct effect on a diseased muscle with an intact nerve supply, nor in the early stages after complete denervation.

Increased rate of peripheral nerve regeneration using bioresorbable nerve guides and a laminin-containing gel

The sciatic nerve of adult mice was transected and proximal and distal nerve stumps were sutured into a nontoxic bioresorbable nerve guide. Nerve guide lumens were either empty or filled with a gel containing 80% laminin and additional extracellular matrix components. Two weeks later cells in the L3 through L5 dorsal root ganglia and the ventral horn of the spinal cord were retrogradely filled with horseradish peroxidase. All animals with the laminin-containing gel but none with empty nerve guides displayed labeled cells. This suggests that the laminin-containing gel significantly hastened axonal regeneration in vivo.

Evaluation of peripheral nerve regeneration following crushing or transection injuries

Infraorbital nerves were subjected to experimental transection or crushing injury. Repair was evaluated using horseradish peroxidase as a tracer. Labeled neurons in the trigeminal ganglion were compared in both types of injury. Results showed that regeneration of the infraorbital nerve after crushing injury was better than when there was nerve transection with passive reapproximation.

Electrophysiological evaluation of peripheral nerve regeneration after nerve repair : T. Minejima, K. Sato, H. Matsuzaki and J. Kawashima (Tokyo, Japan)

Electrophysiological evaluation of peripheral nerve regeneration after nerve repair : T. Minejima, K. Sato, H. Matsuzaki and J. Kawashima (Tokyo, Japan)