We investigated the effect of two frequencies of transcutaneous electrical nerve stimulation (TENS) applied immediately after lesion on peripheral nerve regeneration after a mouse sciatic crush injury. The animals were anesthetized and subjected to crushing of the right sciatic nerve and then separated into three groups: nontreated, Low-TENS (4 Hz), and High-TENS (100 Hz). The animals of Low- and High-TENS groups were stimulated for 2 h immediately after the surgical procedure, while the nontreated group was only positioned for the same period. After five weeks the animals were euthanized, and the nerves dissected bilaterally for histological and histomorphometric analysis. Histological assessment by light and electron microscopy showed that High-TENS and nontreated nerves had a similar profile, with extensive signs of degeneration. Conversely, Low-TENS led to increased regeneration, displaying histological aspects similar to control nerves. High-TENS also led to decreased density of fibers in the range of 6–12 μm diameter and decreased fiber diameter and myelin area in the range of 0–2 μm diameter. These findings suggest that High-TENS applied just after a peripheral nerve crush may be deleterious for regeneration, whereas Low-TENS may increase nerve regeneration capacity.

After a peripheral nerve injury, various aspects, including mechanical nerve properties, will influence regeneration. The reduction of nerve viscoelasticity, intraneural edema, mechanosensitivity, and adhesion of neural tissue to its interfaces may be a target to approaches that impose graded mechanical loads to the nerve. However, the effects of those treatments on peripheral nerve regeneration are not clear. Particularly neurodynamic mobilizations may be very useful. They consist of therapeutic maneuvers to assess nerve mechanical properties and restore their function through graded movements of the peripheral nerve attachments to bones and muscles. Here we discuss theoretical and experimental data regarding the effects of graded mechanical loads on peripheral nerve function and regeneration, and propose how neurodynamic mobilizations would interact with the peripheral nerve in order to promote regeneration. Those effects would influence the reduction of edema, normalization of axoplasmic flow, decrease nerve mechanosensitivity, and promotion of appropriate nerve mobility, increasing glial and neuronal activity.

| Peripheral nerve lesions may be associated with abnormal scarring that lead to regenerative failure and dysfunction. Neurodynamic mobilization (NM) imposes controlled mechanical loads on the peripheral nerve and may influence inflammation and collagen deposition after a lesion. However, there is lack of experimental data to support these claims. Objective: To evaluate the impact of NM in the intraneural number of mast cells, collagen deposition and number of blood vessels after an ischiatic crush lesion in rats. Methods: This is a laboratory animal study, where 20 rats (Rattus norvegicus) were randomly divided into two groups, NM (n=10) and control (n=10), submitted to a right ischiatic nerve lesion. A tensioning NM began 10 days after lesion, and was maintained once a day, six times a week, for three weeks. After this period, the animals were euthanized and the nerves assessed for the number of mast cells, collagen area and number of blood vessels. Results: NM led to a lower number of degranulated mast cells (Kruskal-Wallis = 0.29 p<0.05), higher organization of collagen deposition (KruskalWallis = 0.01, p<0.05 ). There was no influence of NM on the number of intraneural blood vessels (KruskalWallis = 0.46 p<0.05). Conclusion: NM started 10 days after a ischiatic nerve crush lesion modulates the inflammatory process and prevents random deposition of collagen at the lesion site, but has no influence on blood vessels formation.

Introdução: A mobilização neurodinâmicaé indicada em uma série de condições que afetam o nervo periférico, mas pouco se conhece sobre seus efeitos regenerativos.Objetivos: Descrever como a mobilização neurodinâmica pode interferir nas propriedades fisiológicas e mecânicas do nervo.Métodos: Esta revisão narrativa incluiu artigos registrados entre 1973 e 2012 no PubMed, escritos na língua Portuguesa e Inglesa e livros envolvendo estes tópicos. Discussão e Conclusão: Após uma lesão nervosa periférica uma série de eventos podem influenciar a regeneração, incluindo transporte axonal e movimento de fluidos, a carga mecânica aplicada no tecido neural e no tipo de lesão. Estes aspectos podem ser influenciados pela mobilização neurodinâmica. A dose, incluindo a magnitude da carga, velocidade e tempo são fatores que devem ser modulados para uma resposta ótima, enquanto a tensão, imobilidade ou hipomobilidade, podem ter efeitos negativos sobre a recuperação.