NEURODYNAMIC MOBILIZATION REDUCES INTRANEURAL FIBROSIS AFTER SCIATIC CRUSH LESION IN RATS

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), organization of collagen deposition (Kruskal-Wallis = 0.01, p<0.05 ). There was no influence of NM on the number of intraneural blood vessels (Kruskal-Wallis=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.

The Parameters of Transcutaneous Electrical Nerve Stimulation Are Critical to Its Regenerative Effects When Applied Just after a Sciatic Crush Lesion in Mice

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.