Abstract
Purpose: :
Previously we have found that bovine lactoferrin (BLF) promoted the closure of alkali-induced-human corneal epithelial wounds in vitro and it also promoted up-regulation of IL-6 and PDGF BB during wound healing. This study was to investigate whether wound healing was primarily due to up-regulation of IL-6 or PDGF BB.
Methods: :
Confluent human corneal limbal epithelial (HCLE) cells were wounded using 0.5µl of 0.1N sodium hydroxide and extensively washed with serum-free culture medium, 1:1 K-SFM: DMEM/F12. The wounded cells were subsequently treated with BLF (0, 0.1, 1, 2.5 and 5mg/ml) and BLF in the presence of monoclonal antibody against BLF (50 and 10µg/ml in the presence of BLF). To inhibit the effect of IL-6 or PDGF, anti-human IL-6 receptor neutralizing antibody (rhIL-6 sR, 1, 10 and 50µg/ml) and the inhibitor of PDGF (Tyrphostin AG1295 at 1, 10 and 100µM) with or without BLF (5mg/ml) were used to treat the wounded cells. HCLE cells were treated with either IL-6 (4ng/ml) or PDGF-BB (8ng/ml) as positive controls. Twenty four hours after the treatment the cells were stained with Diff Quick and photographed. The wound area was measured and the percentage reduction of the wound area in response to each treatment was calculated and compared.
Results: :
At 2.5 and 5.0 mg/ml, BLF significantly promoted wound healing (46 ± 8% and 56 ± 2% respectively) as compared to the absence of BLF (25 ± 5%) whereas BLF antibody at 50µg/ml in the presence of BLF (5mg/ml) did not promote wound closure. When the selective inhibitors rHIL-6 sR or Tyrphostin AG1295 was used, the effect of BLF in promoting wound closure was eliminated.
Conclusions: :
BLF stimulates alkali-induced HCLE wound healing and the stimulation is mediated through its up-regulation of PDGF or IL-6.
Keywords: wound healing • cornea: epithelium • cytokines/chemokines