Effect of local administration of insulin-like growth factor I combined with inside-out artery graft on peripheral nerve regeneration

The objective was to assess the effect of topically administered insulin-like growth factor (IGF I) on peripheral nerve regeneration and functional recovery. Eighty male healthy white Wistar rats were divided into four experimental groups (n = 20), randomly: in transected group (TC), the left sciatic nerve was transected and stumps were fixed in the adjacent muscle. In treatment group, defect was bridged using an inside-out artery graft (IOAG/IGF) filled with 10 μL IGF I (100 ng/kg). In artery graft group (IOAG), the graft was filled with phosphate-buffered saline alone. In sham-operated group (SHAM), sciatic nerve was exposed and manipulated. Each group was subdivided into five subgroups of five animals each and regenerated nerve fibres were studied 4, 8, 12 and 16 weeks after surgery. Behavioural testing, sciatic nerve functional study, gastrocnemius muscle mass and morphometric indices confirmed faster recovery of regenerated axons in IOAG/IGF than IOAG group (P < 0.05). In immunohistochemistry, location of reactions to S-100 in IOAG/IGF was clearly more positive than that in IOAG group. When loaded in an artery graft, IGF I accelerated and improved functional recovery and morphometric indices of sciatic nerve.