Anti-inflammatory effects of a synthetic peptide derived from pigment epithelium-derived factor on H₂O₂-induced corneal injury in vitro.

BACKGROUND

The common pathological characteristics of corneal injury include inflammatory factors activation, vascular endothelial cells or inflammatory cells infiltration into lesions, corneal edema, corneal neovascularization (CNV), and scar formation. PEDF-34 is the functional fragment of pigment epithelium-derived factor (PEDF) that has anti-angiogenic and anti-inflammatory properties and contains an N-terminal 34-amino acid peptide. This study was to investigate the anti-inflammatory effects of PEDF-34 on H2O2-induced corneal injury in vitro.

METHODS

After cultured in H2O2 (0.1 mmol/L) for 2 hours, human corneal fibroblasts (HCFs) and human umbilical vein endothelial cells (HUVECs) were treated with PEDF-34-nanoparticles (NPs) at different concentrations (0.1, 0.5, 1.0, 2.0 µg/ml) or 2.0 µg/ml control-NPs for 24 hours. The viable cells were quantified using the MTT assay. Western blotting or ELISA analysis was performed for measuring the human vascular endothelial growth factor (VEGF) and intercellular adhesion molecule-1 (ICAM-1) expression of both HCFs and HUVECs. VEGF and nuclear factor κB (NF-κB) mRNA levels of HCFs were semi-quantified by RT-PCR.

RESULTS

The survival rates of HCFs or HUVECs stimulated by H2O2 did not decrease significantly (P > 0.05) compared to those in the normal conditions. As compared to control-NP group, PEDF-34-NPs had dose-dependent inhibitive effect on HUVECs with the MTT assay, but not HCFs. Western blotting analysis showed that the VEGF and ICAM-1 levels in the HCFs and HUVECs stimulated by H2O2 were significantly higher than those in the normal conditions, which were decreased dramatically in those treated with PEDF-34-NPs. RT-PCR analysis revealed that the VEGF mRNA and NF-κB mRNA levels increased in H2O2-stimulated HCFs, while both of them decreased in PEDF-34-NP groups dose dependently.

CONCLUSIONS

PEDF-34-NPs may play an important role in regulating the NF-κB pathway, inhibiting inflammatory activity. PEDF-34-NPs may be a potential new drug for treating corneal injury in the future.