Figure 2.

Protection of RGCs by caspase substrate-binding peptide IQACRG and canonical caspase inhibitor z-VAD. RGC cultures were pretreated for 3 hours with control (scrambled) peptide, P-IQACRG (200 nM) or the broad-spectrum caspase inhibitor zVAD-fmk (50 μM) before 20-minute exposure to NMDA (200 μM) plus glycine (5 μM). Control cultures did not receive these pretreatments. Eighteen hours later, RGC cultures were fixed and stained with propidium iodide to count total and pyknotic nuclei. The basal level of pyknosis was determined in cultures exposed to vehicle (glycine) alone. Data are mean ± SEM (n = 5 each group). *P < 0.05 by ANOVA.