The nerve regeneration after end-to-side nerve anastomosis of distal stump of autonomic nerve to somatic nerve in rats

Abstract

Objective To observe the nerve regeneration after end-to-side anastomosis of distal stump of autonomic nerve to somatic nerve in rats. Methods Twenty-four Sprague-Dawley rats were divided into two groups: experimental group (n = 12) and control group (n = 12). In experimental group, rats had the left lumbar 6 ventral root (L6VR) transected in dura and the distal stump was sutured to the lateral face of left lumbar 4 ventral root (L4VR). In control group, rats had not been done any surgery. After 6 months, in experimental group, the nerves were intercepted 10 mm in length, from the proximal and distal end-to-side nerve anastomosis, regarded as donor nerve (L4VR) and recipient nerve (L%VR), and 10 mm from the pelvic parasympathetic nerve (PPN) and pudendal nerve (PN) from L6VR was intercepted, respectively. In control group, the corresponding nerves were harvested. The cross-sectional nerve slices were stained with toluidine blue through the use of histochemical technique, and the number of myelinated nerve fibers was counted. By comparing L6VR with L4VR the nerve passing rate was calculated, and the number of the nerve fibers of L6VR, PPN and PN between experimental group and control group was compared. Results The new myelinated nerve fibers were observed in the cross-sectional slices of the experimental rats. The number of the nerve fibers located in the L4VR, L6VR, PPN and PN was 1602. 2 ± 75.7,1037.9 ± 123.6, 817. 0 ±52. 2 and 510. 4 ± 29. 1, respectively. The nerve passing rate of the distal and the proximal ends from the anastomosis was 64. 8%, the ratio of the number of nerve fibers in L6VR, PPN and PN was 70.2%, 68.9% and 62.2%, respectively, between the experimental group and control group. Conclusion The somatic nerve can grow into and replace the autonomic nerve after the reflex pathway established by end-to-side anastomosis of autonomic nerve and somatic nerve in rats. Key words: End-to-side coaptation; Nerve regeneration; Somatic nerve; Autonomic nerve