Abstract
Purpose: :
It was demonstrated that cationized gelatin hydrogels could achieve the controlled release of biologically active epidermal growth factor (EGF) on the ocular surface (2005 ARVO #2153). EGF is incorporated in the hydrogel through the physicochemical interaction with the cationized gelatin and released as a result of hydrogel biodegradation. The object of this study is to investigate the healing effect of EGF released on the corneal epithelial wound with a rabbit model of corneal epithelial defect.
Methods: :
The hydrogel incorporating 5 µg of EGF was placed on a circular corneal defect of 177 mm2, and the healing process was evaluated by image analysis software (n=6). Epithelial proliferation was immunohistochemically assessed by counting the number of Ki67–positive cells at the area of limbus (Li), peripheral unwounded cornea (P), and leading edge (Le). The data were compared with that of 5 µg EGF topically applied in the solution form.
Results: :
After the hydrogel incorporating EGF (Ec) was applied to the corneal epithelial defect, the defect area decreased to 68.0±22.2 and 15.3±18.2 mm2, 48 and 96 hr after wounding, respectively. The values were significantly smaller than those of EGF applied topically (Es) (102.4±13.8 and 42.0±23.0 mm2 ) (p=0.002 and 0.01). The number of Ki67–positive cells (Li, P, Le) was 26.7±3.7, 14.75±9.0, and 11.8±4.0 for Ec and 20.8±1.39, 4.5±2.1, and 8.8±2.7 cells/mm for Es.
Conclusions: :
The controlled release facilitated by the hydrogel enabled EGF to promote the wound healing of corneal epithelium. This effect was greater than that caused by the EGF topical solution. This growth factor release system can be applied to other growth factors and will be promising therapeutic option for ocular surface diseases.
Keywords: cornea: epithelium • wound healing • drug toxicity/drug effects