Figure 2: GHK and GHK-PEG induce fibroblast cell proliferation. In order to test if the GHK and GHK-PEG that were synthesized were active in promoting fibroblast proliferation, NIH3T3 cells were cultured in 24 well plates and treated with GHK or GHK-PEG at 1, 5 and 10 nM for 24 h, 48 or 72 h. Following treatment with GHK or GHK-PEG, cell proliferation was assessed using a hemocytometer. The rate of cell proliferation was expressed as fold control and compared between treated and non-treated cells using analysis of variance (ANOVA). n=3; *p≤0.05