To investigate the effect and mechanism of epidermal growth factor(EGF) nanoparticles on the wounds of diabetic rats.

(1) EGF nanoparticles were prepared by the modified multiple emulsion way with poly lactic-co-glycolic acid(PLGA) as carrier. Drug-loaded rate, encapsulation ratio and release of EGF nanoparticles were measured. (2) Diabetic rats model were made with streptozocin(STZ) through vena caudalis. Skin wound model of diabetic rats were prepared by hole puncher and were divided into 4 groups: EGF nanoparticles group(containing 1 μg/d EGF nanoparticles), EGF group(1 μg/d EGF), empty nanometer particle group(without EGF but the quality was equivalent to the EGF nanoparticles/d) and PBS control group. (3) Photographs and sampling at 3, 7, 14, 21 days were taken and wound healing rate were calculated. The positive cells area of epidermal growth factor receptor were compared by immunohistochemistry.

(1)The average particle diameter of EGF nanoparticles was 193.5 nm. The drug loading ratio was 0.02% and the encapsulation ratio was 85%. The group of EGF nanoparticles released up to 24 h. (2) Healing of wound of EGF nanoparticles group was fast than that of EGF [14 d: (93.8±1.8)% vs(89.3±2.3)%, P<0.05; 21 d: (96.6±1.6)% vs(92.1±4.3)%, P<0.05]. EGF receptor positive cells area of EGF nanoparticles group was more than that of EGF group[7 d: (49.4±6.5)% vs(35.1±2.8)%, P<0.05; 14 d: (80.2±3.8)% vs(73.4±1.7)%, P<0.05].

EGF nanoparticles can upregulate the expression of EGF receptor of cells in wound and accelerate wound healing. The effects are better than that of EGF.

Diabetes mellitus; Epidermal growth factor; Nanoparticle; Epidermal growth factor receptor; Wound healing