In Vitro Effects of Epidermal Growth Factor or Insulin-Like Growth Factor on Tenoblast Migration on Absorbable Suture Material

OBJECTIVE: To determine the effects of epidermal growth factor (EGF) or insulin-like growth factor (IGF) on tenoblast migration on absorbable suture material using an in vitro model. STUDY DESIGN: An in vitro evaluation of tenoblast migration. ANIMAL OR SAMPLE POPULATION: Segments of the long digital flexor tendon were obtained from Cobb chickens (9-11 weeks old) immediately after the birds were euthanatized. METHODS: Tissue culture explants of tendons containing absorbable suture material were treated with either EGF or IGF. Tenoblast migration was assessed daily using an inverted microscope equipped with bright field and phase optics. Tenoblast migration was assessed according to the following criteria: time of first cell appearance, percent of explant interfaces producing cells, migration distance, and terminal migration index at 120 and 168 hours. RESULTS: EGF had a stimulatory effect on tenoblast migration for cells originating from the endotenon interfaces. No significant effect was noted on migration distance for cells originating from epitenon interfaces. A stimulatory effect on the percentage of interfaces producing cells and a significant decrease in time of first cell appearance were also observed after EGF treatment. IGF-stimulated cell migration distance for epitenon interfaces but this stimulatory effect did not occur at a higher concentration. IGF was inhibitory to percent of epitenon and endotenon interfaces producing cells but decreased time of first cell appearance at low concentration. CONCLUSIONS: Using an in vitro model, EGF had a stimulatory effect on tenoblast migration. IGF was stimulatory at low concentration levels but inhibitory at a higher concentration. Increased migration distance was observed for endotenon interfaces after EGF treatment and for epitenon interfaces after IGF treatment. CLINICAL RELEVANCE: EGF or IGF might enhance tendon repair if they could be delivered to the repair site. Incorporation of EGF or IGF into suture material would allow slow release and prolonged exposure of migrating tenoblasts to growth factors.