Astrocyte-protective effect of human arginine decarboxylase (hADC) transduction against oxygen-glucose deprivation (OGD). Cytotoxicity was assessed by Hoechst 33258 and propidium iodide (PI) nuclear staining; (A) No treatment control astrocytes, (B) astrocytes after 4 hrs OGD, (C) hADC-overexpressing astrocytes (hADC-astrocytes), (D) hADC-astrocytes after 4 hrs OGD. Scale bars = 100 μm. (E) Proportion of PI-labeled damaged cells with red fluorescence. Asterisks indicate a p < 0.05 when the samples were compared to no treatment control. Double asterisk indicate a p < 0.05 that that the two samples were significantly different which was confirmed by a post-hoc analysis.