Morphological and functional aspects of sciatic nerve regeneration after crush injury.

Experimental models for the investigation of nerve regeneration are critical in studying new strategies able to promote the repair process. The aim of the present work was to characterize morphological and functional aspects of sciatic nerve regeneration after mechanical crush injury in rodents. Morphological changes were assessed after a four minutes sciatic nerve injury induced by means of a standardized compression clip. Rat nerve samples were collected before injury and after 24 hours, four days, two weeks, and four weeks after injury, respectively. In an additional group with unilateral sciatic nerve injury, animals were evaluated for four weeks using walking track analysis and the sciatic static index (SSI) measured in both rearing and normal standing position. Histological study showed important axonal degeneration at four days and axonal regeneration at four weeks after injury. We observed no significant differences between SSI in rearing and normal standing stance and a strong correlation between SSI values measured in the two positions during the evaluation period. Positive correlations were also found for the footprint parameters. Our data provide a baseline characterization of the sciatic nerve crush injury that will further allow the investigation of peripheral nerve regeneration in the presence of potential neuroprotective agents in post-traumatic nerve repair.