Epidermal Growth Factor Stimulates Rabbit Achilles Tendon Histologically and Biomechanically Healing

Background. Epidermal Growth Factor (EGF) stimulates epidermis cell growth, proliferation and differentiation in skin regeneration. The aim of this study was to pre-clinically investigation of the role of EGF in tendon healing. Methods. One cm defects were created at the right Achilles tendons of 30 New Zealand White rabbits. Ten rabbits were allocated to one of three groups: Group-1-(Sham) tendon defect with a gap that was splinted with a non-absorbable suture; Group-2-(EGF +) tendon defect with a gap that was splinted with a non-absorbable suture and a 25 mu g/kg EGF injection into the defect; Group-3-(Scaffold + EGF) tendon defect was grafted with a biodegradable, porous Polycaprolactone (PCL) scaffold loaded with 25 mu g/kg EGF and stabilized with a non-absorbable suture. Animals were sacrificed at 8 weeks post-surgery and Achilles tendon repair and healing status was investigated using histopathologic and biomechanical analysis methods. Results. Group-2-(EGF +) had greater adipocyte development (moderate) than Group1-(Sham) and Group-3-(Scaffold + EGF). Group-2-(EGF +) and Group-3-(Scaffold + EGF) had greater peripheral nerve development (weak) than Group-1-(Sham). Group-2(EGF +) had greater vascularization (moderate) than Group-1-(Sham) and Group-3-(Scaffold + EGF). Group-2-(EGF +) had greater collagen Type-III development (moderate) than Group-1-(Sham) and Group-3-(Scaffold + EGF). Group-3-(Scaffold + EGF) had greater collagen Type-I development (moderate) than Group-1-(Sham) and Group2-(EGF +). Groups did not display statistically significant differences for load to failure or elongation at failure. Group-2-(EGF +) and Group-3-(Scaffold + EGF) displayed less stiffness that the control (healthy contralateral Achilles tendon) (p < 0.05), however, experimental groups did not differ (p > 0.05). Conclusions. The application of EGF and scaffold displayed superior histological tendon healing evidence, but there was no significant difference in terms of biomechanics.