Effect of FK1706 on nerve regeneration after end-to-side neurorrhaphy of autonomic nerve and somatic nerve in rats

Abstract

Objective To evaluate the effect of FK1706 on nerve regeneration after end-to-side (ETS) neurorrhaphy of autonomic nerve and somatic nerve in rats through morphological observation. Methods Thirty rats were randomly divided into three groups in terms of different treatments (n=10 in each group). In FK1706 group, the left L6 ventral root (L6VR) and L4 ventral root (L4VR) of rats were sutured in an ETS fashion and FK1706 (0.3 mg/kg) was administrated subcutaneously for 5 consecutive days per week for a total of 8 weeks after ETS neurorrhaphy. In ETS group, the same operation as FK1706 group was performed but without FK1706 applied after surgery. In control group, left L6 dorsal root (L6DR), S1 ventral root (S1VR) and S1 dorsal root (S1DR) were transected but the left L6VR was preserved as normal control. After 4 months, the left pelvic parasympathetic nerve (PPN) to which L6VR extended was harvested for semithin and ultrathin sections in FK1706 and ETS groups to count the number of myelinated axons. The number and morphology of myelinated axons and thickness of myelin sheath were compared between the two groups. Results After 4 months, the morphology of the regenerated L6VR distal to the neurorrhaphy site in FK1706 and ETS groups was normal. The number of regenerated myelinated axons of PPN was 515.6±43.3 and 328.4±46.4 in FK1706 and ETS groups, respectively (P=0.000). The thickness of myelin sheath of regenerated PPN was (0.672 4±0.110 1) μm and (0.466 8±0.076 3) μm in FK1706 and ETS groups, respectively (P=0.000). Conclusion The effect of autonomic nerve regeneration could be enhanced after ETS neurorrhaphy of autonomic nerve and somatic nerve through FK1706, which could improve rehabilitation of nerve injury. Key words: FK1706; Nerve regeneration; Autonomic nerve; Somatic nerve; End-to-side neurorrhaphy