Figure 5: GHK and GHK-PEG induce apoptosis in SH-SY5Y cells. The effect of GHK and GHK-PEG on apoptosis was assessed in SH-SY5Y cells which were plated in 96 well plates at 5000 cells per well and incubated for 24 hrs. Cells were either not treated or treated with GHK or GHK-PEG at 1 or 10 nM for 24 hrs. Apoptosis was assessed by measuring caspase 3 and 7 activities on the tetrapeptide substrate DEVD using the ApoTox-Glo Triplex Assay. The result for each treatment was expressed as fold control and the effect of each treatment was determined by comparing treated and nontreated cells using analysis of variance (ANOVA). n=3; *p≤0.05.