Effect of combined administration of insulin-like growth factor and platelet-derived growth factor on the regeneration of transected and anastomosed sciatic nerve in rats.

Objective: To evaluate the efficacy of combined administration of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF-I) on the regeneration of transected and anastomosed sciatic nerves.
Animals: 25 male Lewis rats.
Procedure: Transection and anastomosis was performed of the left sciatic nerve of all rats. At the time of surgery, treatment group rats received a combination of PDGF (0.75 microgram) and IGF-I (1.5 micrograms) along with vehicle (2% methyl cellulose gel) at the anastomosis site. Control rats received vehicle alone. Evaluation consisted of motor evoked potentials and nerve conduction velocity, quantitative histologic examination, sciatic functional index, and visual assessment of repair organization (lesion scores).
Results: Significant differences in motor evoked potential latency, nerve conduction velocity, axon number, sciatic functional index, or lesion scores were not found between groups.
Conclusions: Combined administration of PDGF and IGF-I did not enhance peripheral nerve regeneration in a transection and anastomosis model as determined 6 weeks after surgery.
Clinical Relevance: These findings support the assumption that mechanical, versus trophic, effects predominate when nerve ends are closely apposed.