Mouse wildtype (A) ERKOα (B) and ERKOβ (C) RPE cells were treated with 17β-estradiol (E2,1nM) for 24 hours prior to MPO/H2O2 treatment (I, injury). MMP-14 was determined with an activity kit as described in methods and data were normalized to the protein concentrations of each sample, *p<0.05 compared to vehicle (V), # p<0.05, ## p<0.001 injury compared to E2+injury, n=5 wildtype, n=3 ERKOα, n=4 ERKOβ. Data are expressed as percent of vehicle treatment.