Abstract
Purpose: :
The wound healing properties of hEGF in the corneal epithelium are well known. The aim of the present study was to construct an eukaryotic expression vector for hEGF and to examine the efficacy of corneal delivery of rhEGF in the rabbit corneal alkali injury model.
Methods: :
hEGF cDNA was amplified by RT–PCR and inserted in to a pcDNA3.1 vector. After liposomal encapsulation, right eyes of alkali–injured rabbits either received pcDNA3.1–liposome or rhEGF–pcDNA3.1–liposome as eye drops while the left eyes served as untreated controls. The mRNA, DNA levels of rhEGF in 24 h to 28 days corneal tissue samples were determined by RT–PCR and PCR. Protein expression was monitored by immunohistochemistry and ELISA assay.
Results: :
The rhEGF level in the injured cornea in the group that received EGF vector–containing liposome was significantly higher as compared to empty vector control and uninjected groups in 24h. The peak expression of rhEGF protein (224.3 ng/g corneal wet weight) was achieved on days 5–7 after injury. The EGF expression decreased thereafter but was measurable for over 20 days. Immunohistochemistry revealed rhEGF expression in the entire corneal layers with a markedly high transfection efficiency observed on day 7 after which it declined.
Conclusions: :
Our data describe construction of an eukaryotic expression vector for hEGF and its efficient delivery as eye drops with predominant accumulation in alkali–injured corneal tissue. This gene therapy approach of prolonged rhEGF delivery may find application in treating corneal diseases.
Keywords: wound healing • cornea: epithelium • protective mechanisms