Electrical stimulation and swimming in the acute phase of axonotmesis: their influence on nerve regeneration and functional recovery

Little attention has been given to the influence of low-frequency phasic electrical stimulation (LFPES) and physical exercise on the quality of peripheral nerve regeneration and functional recovery. AIM. To evaluate the influence of LFPES, swimming and the association between the two in terms of the morphology of the regenerated sciatic nerve following axonotmesis. Thirty Wistar mice (222.05 +/- 42.2 g) were distributed into groups: control (C), denervated (D), denervated + swimming (DS), denervated + electrostimulation (DE) and denervated + swimming + electrostimulation (DSE). After 24 hours of axonotmesis, the soleus muscle of the DE and DSE groups was stimulated electrically. The DS and DSE groups swam over a period of 22 days. The number of axons, morphometric data on the nerve and the functional index of the sciatic nerve (FIS) were evaluated. The number of axons in the denervated groups was higher than in the control group, and in the DE group the figure was higher than in the D group. The axonal diameter was smaller in the denervated groups, yet in the DS group it was higher than in the D group. The other morphometric parameters were quite similar to those of the C group. The FIS between days 7 and 14 of the post-operative period was different to the pre-operative index and that measured on day 21 of the post-operative period; the DSE group, however, differed from the pre-operative values. Swimming and LFPES, applied on an individual basis, do not affect the maturation of the regenerated fibres or functional recovery. LFPES favoured axonal regeneration and combining the treatments delayed functional recovery without having any influence on nerve regeneration.