Bovine Lactoferrin Stimulates Human Corneal Epithelial Alkali Wound Healing In Vitro

Abstract

PURPOSE: The purpose of this study was to investigate the effect of bovine lactoferrin (BLF) on human corneal epithelial wound healing using an in vitro alkali-induced wound model and to understand its role in promoting wound healing. METHODS: Confluent human corneal limbal epithelial (HCLE) cells wounded using 0.5 microL of 0.1 M sodium hydroxide were treated with BLF (0, 0.1, 1, 2.5, and 5 mg/mL) or anti-human interleukin-6 (IL-6) receptor neutralizing antibody (anti-IL-6 antibody; 1, 10, and 50 microg/mL) or tyrphostin AG1295 (an inhibitor of platelet-derived growth factor [PDGF] receptor kinase; 1 and 10 microM), IL-6, or PDGF-BB. The conditioned medium collected for BLF treatment (0 and 5 mg/mL) was analyzed using a protein array for a number of cytokines/growth factors involved in corneal wound healing. A preliminary animal study using mice was carried out to determine the effect of BLF on alkali wounds. RESULTS: BLF at 2.5 and 5 mg/mL promoted wound healing (P<0.01). During wound closure, BLF upregulated PDGF-BB 180-fold and IL-6 10-fold compared with control. Treatment with tyrphostin AG1295 (10 microM; P<0.01) or anti-IL-6 antibody (50 microg/mL; P<0.01) in the presence of BLF inhibited wound closure, whereas the addition of exogenous IL-6 and PDGF-BB promoted wound closure. Preliminary animal studies have shown that BLF (5 mg/mL) promotes alkali wound healing in vivo. CONCLUSIONS: These results suggest that BLF at >or=2.5 mg/mL stimulates HCLE wound healing, and this stimulation is mediated through the upregulation of PDGF or IL-6.