Figure 3. Histological indicators of cellular stress in the retina 24 h post-injection. A–D: IBA1 positive microglia (labeled in red) displayed a normal profile with ramified shape and distributed within the inner layers of the retina. This was true for the non-injected PBS and needle-stick controls as well as the Invivofectamine 3.0-injected animals. E–H: The GFAP profile between the control group and the Invivofectamine 3.0 group had the same profile with labeling only in the inner limiting membrane (ILM) and beneath the inner nuclear layer (INL). Labeled Müller cell processes were not evident. I–L: TdT-mediated dUTP nick-end labeling (TUNEL) positive labeling was little to absent in all samples. M: Quantification of IBA1 positive cells revealed no differences between all samples. N: Quantification of TUNEL cells revealed no differences between all samples. O: Quantitative real-time PCR (qRT-PCR) showed no statistically significant changes in a suite of inflammatory and retinal stress genes in Invivofectamine 3.0-injected animals compared to the PBS controls. Ccl2, Il-10, and Il-6 expression was undetermined (UD, expression levels were too low for the software to detect; n=4, scale bars represent 100 μm).