Repair of ulcer with rhEGF sustained-release microspheres in diabetic rats / 中华创伤杂志

ABSTRACT

Objective To prepare recombinant human epidermal growth factor (rhEGF) sustained-release microspheres and evaluate their morphology, rhEGF releasing activities and cell proliferation activity in vitro and compare difference of rhEGF sustained-release microspheres and rhEGF in facilitaring ulcer healing in diabetic rats. Methods (1) rhEGF sustained-release microspheres were prepared by the modified double emulsion method. Morphology of the microspheres was detected by transmission electron microscope and size distribution measured by laser granularity meter/Zeta electric potential meter. ELISA assays were applied to determine rhEGF releasing. (2)Proliferation of mouse fibroblasts was analyzed by MTr method. (3) Diabetic rat models were prepared and divided into four groups, ie, rhEGF sustained-release mierospheres group (Group A), rhEGF stock solution group (Group B), blank sustainedrelease mierospheres group (Group C) and PBS meustruum control group (Group D), which were given drug once a day. The wound healing rate was calculated by taking photographs at days 3,7,14 and 21. Skin specimens from the wound edge were harvested partially for observation of hydroxyproline (HYP) contents. Immunohistochemistry was employed to detect integrin 131 and keratin-19 and measure their positive staining area ratio. Results (1) The particle diameter of rhEGF sustained-release microspheres was 193.5 nm, with relative uniform particle diameter distribution. There showed no conglutination among rhEGF susrained-release microspheres, with good dispersibility. Releasing drug lasted for 24 hours and accorded with Higuchi release kinetic model. (2) Different concentrations of rhEGF sustained-release microspheres could promote the proliferation of mouse fibroblast, especially the concentration of 10 μg/L (P <0.05, compared with the control). (3) From the 7th day after treatment, Group A had the fastest wound healing rate, with statistical difference compared with other three groups (P < 0.05). Group A had higher HYP contents and positive area ratio of integrin β1 and keratin-19 than Group B. Conclusions rhEGF sustained-release microspheres prepared by the modified double emulsion method have uniform particle size and can last release for 24 hours. Compared with rhEGF stock solution, rhEGF sustained-release microspheres have faster and better ulcer healing and higher healing quality in diabetic rats.