(A) Schema depicting the time course of experiments described in this study (B) QRT-PCR analysis of GDNF mRNA at 14 days post injection of eyes with PEGPOD pcpg-GDNF NPs shows an 11,200 fold increase in GDNF signal relative to eyes injected with PBS. n=4 (C) Average ONL thickness of the superior hemisphere within 500μm of the optic nerve head 7 days following exposure to blue light. ONL thickness, measured at 21 days post injection, shows a significant increase in ONL thickness of retinas injected with PEGPOD pcpg-GDNF NPs relative to PBS and PEGPOD pcpg-Luc NP injected (p<0.01, p<0.0005, respectively). Unexposed eyes were injected with PBS 21 days prior to analysis and unexposed to blue light. PBS, n=5; PEGPOD pcpg-GDNF, n=13; PEGPOD pcpg-Luc, n=10. Data is shown as mean+SEM. (D) Average Erg tracings of eyes injected with PEGPOD pcpg-GDNF NPs, PEGPOD pcpg-Luc NPS, or PBS 14 days prior to light exposure were recorded at 7 days following exposure to blue light (21 days post injection). An amplified image of the boxed region of the ERG (A-wave) is also shown. Unexposed eyes were injected 21 days prior to analysis but unexposed to blue light. (E) Average A- and B-wave amplitudes of eyes injected with PEGPOD pcpg-GDNF NPs, PEGPOD pcpg-Luc NPs, or PBS 14 days prior to light exposure. PEGPOD pcpg-GDNF NP injected eyes show significantly increased A- and B-wave amplitudes relative to both PEGPOD pcpg-Luc NP injected (p<0.05, p<0.01 for A-wave and B-wave amplitudes, respectively) and PBS injected (p<0.05 for both A- and B-wave amplitudes) eyes. Data is shown as mean+SEM. ONL, outer nuclear layer; n.s., not significant.