Lactoferrin with Zn-ion protects and recovers fibroblast from H₂O₂-induced oxidative damage

Lactoferrin (LF) has attracted great attention due to its various bioactivities, which depend on the degree of saturation with different cations. This study focused on the synergistic effect of LF and Zn²⁺ on human gingival fibroblasts (hGFs), considering antioxidant activities, cell proliferation, and collagen gene expression levels in these cells to improve the wound healing. The hGFs were cultured in an experimental medium, containing 1000 μg/mL of LF and various concentrations of ZnCl₂. The cells were subjected to oxidative damage by exposure to 600 μM H₂O₂ for 30 min before incubation in the experimental medium. The cell proliferation rate and the relative gene expression levels of genes associated with apoptosis, antioxidant enzymes, and collagen were compared. H₂O₂ decomposition by LF was also measured using a colorimetric assay. LF enhanced hGF proliferation and the expression of collagen. Furthermore, LF directly scavenged H₂O₂ and prevented lipid peroxidation by enhancing the expression of glutathione peroxidase 4 gene expression, resulting in the prevention of apoptosis and recovery of the cells from H₂O₂-induced oxidative damage. The addition of ZnCl₂ enhanced these results. The results indicated that LF with Zn-ion could play an important role in modulating the functions related to wound healing.