Effects of degeneration-regeneration induced by nerve crush in rat flexor digitorum sublimis

Peripheral nerve lesions occur as a consequence of a variety of traumas and diseases inducing a dramatic muscle atrophy. Although transected peripheral nerves can spontaneously regenerate leading to functional recovery, axon regeneration requires a longer time during which the denervated muscles undergo atrophy. The required time hinder the functional muscle recovery after reinnervation. To monitor these events, 2-D DIGE and mass spectrometry were applied to profile the qualitative and quantitative differences in the proteome of rat flexor digitorum sublimis muscle during the process of denervation-reinnervation after median nerve crush. The changes in protein expression levels were analysed at days: 1, 3, 7, 15, 30 after nerve crush, respectively, using non-crushed samples as controls. Results revealed 240 differentially expressed spots matched among the 6 groups. Statistical multivariate analysis highlighted 9 main spot clusters with a time-course expression pattern compatible with the degenerative-regenerative process. The major alterations were shown at time point 3 and 7, after which protein levels were progressively renormalized. After mass spectrometry identification, proteins were grouped in 11 functional classes, the majority of them were involved in energy transduction (8 spots), glycolysis (20 spots), transport (19 spots), stress response (13 spots). Furthermore, 19 spots were identified as structural components of the muscle cell. Next goal will be to define the contribution of these quantitative protein variations after merging data from mRNA arrays on the same samples defining targets for the degeneration-reinnervation process.