[Quantification of some qualitative changes of the rabbit sciatic nerve after the application of lidocaine into the mesoneurium].
Seven days after the application of 2% lidocaine (4 ml doze, the speed of application 3 ml/min, mean application pressure 15 +/- 2.47 kPa) into mesoneurium of adult rabbit sciatic nerve, a nerve segment was intravitally excided from the injection site with a length of 1 cm and qualitatively and quantitatively analyzed. Histological changes at the level of total nerve structures were found, especially of its sheaths. Epi- and interfascicular epineurium were thickened with a hipercellularity of a mononuclear inflammatory process type. On the side of application, occasional delamination of perineurium was registered. Myelinated fibers were sporadically demyelinated, followed by axon degeneration which, in thick fibers, reached a full disintegration. In general, the damages were more severe at the side of application although some zonal differences in the degree of damage (above, below and at the site of application) within individual fasciculi were expressed. A significantly higher volume density of epifascicular and interfascicular connective tissue in comparison to the control, untreted nerves, observed by the stereological analysis, may be considered as an inflammatory-repairing reaction which we identified microscopically. At the same time, we found a significantly higher volume density of endoneurium in lidocaine treated nerves.