Lactoferrin (LF) is a multifunctional protein which have the antibacterial and immunomodulatory action in the milk of mammals. Recent studies have been investigated the effect of improvement of cognitive impairment in the central nerve system. However, the mechanisms underlying the effects of LF on neuron have not yet been elucidated. The aim of present study investigated the efficacy of LF on the cell outgrowth effect using by PC12 cells, and demonstrated to mechanisms of LF.
PC12 cells were treated with different concentration of LF (100 to 1000 µg/mL) for maximum of 72 h, and were treated with 50 ng/mL of nerve growth factor (NGF) as a positive control. Digital images of cells were taken with a phase-contrast inverted microscope with a camera at 24 and 72 hours after treatment of either LF or NGF. Total ERK and phosphorylated ERK expression levels were analyzed by western blotting, and the inhibitors were used AG879 and PD98059.
The cell outgrowth was significantly increased at 72 hours after NGF treatment. Treatment of 250 µg/mL LF was significantly increased all of the neurite length, neurite joint, and neurite branching (pass) compared to the non-treated group. The ratio of total ERK and phosphorylated ERK expression levels was maximized at 5 minutes after treatment of LF, and was persisted up to 10 minutes. These observed activities were inhibited by AG879 and PD98059.
This present study clarified that the role of LF may enhance the cell outgrowth via activation of phosphorylated ERK after 5 minutes, and it suggested to undergo nerve outgrowth via the same pathway of NGF.