Reduction in muscular motility by selective focused cold therapy: a preclinical study

Application of freezing temperatures to the temporal branch of the facial nerve can temporarily inhibit motor nerve conduction, resulting in inhibition of voluntary contraction of the frontalis and glabella muscle groups. This feasibility study demonstrates the reduction in motility of muscle groups through application of low temperatures to nerves in a rat model. Twenty-seven adult female Sprague–Dawley rats received cryotreatment to the tibial nerve of the hind limb, and the contralateral limb was left untreated as a negative control. The use of a cold temperature application (−59 ± 8 °C for 60 s) onto the rat tibial nerve resulted in temporary reduction of physiological function of the hind limb. Histological observations of the nerve revealed demyelination and axonal degeneration by 2 weeks post-treatment followed by complete axonal regeneration and remyelination at 16 weeks. Application of low temperatures to peripheral motor nerves resulted in temporary denervation and loss of function of the treated hind limb. Low temperature treatment on motor nerves did not result in any permanent or long-term changes to function and structure of the nerves.