tailieunhanh - Failure of regeneration of sensory nerve fibers following neonatal denervation and crush lesion in rats

The effects of chronic neonatal denervation and a crush lesion on the regenerative capacity of sensory nerve fibers were studied in rats. After 50 weeks of postnatal denervation, the amplitudes of compound action potentials (CAPs) of Aαβ-, Aδ- and Cfibers were reduced to , and , respectively (P ). However, the means of the conduction velocities of the CAPs of Aδ-nerve fibers ranged from P > to P < compared to those after the sham operations. In contrast, the means of the conduction velocities of Cnerve fibers were significantly different from those after the sham operations (P < ). The thresholds and maximum strength of stimulation of all nerve fibers after chronic neonatal denervation and the crush lesion were normal, as shown in Tables 2 and 3, respectively. Neurogenic plasma extravasation Neurogenic plasma extravasation of Evans blue into the skin due to antidromic nerve stimulation was highly Table 1. Conduction velocities (m/s) of the CAPs of Aαβ, Aδ- and C-nerve fibers of the rat saphenous nerve after 12, 20 and 50 weeks of postnatal denervation, crush lesion and sham operations. Mean ± . Aαβ-fibers Denervation Crush Sham 218 Aδ-fibers C-fibers 12 weeks ± (11) ± (11) ± (11) 20 weeks ± (10) ± .