Figure 2

Apoptosis based on terminal deoxynucleotidyltransferase dUTP nick-end labeling (TUNEL) staining of male C57BL/6 flight (FLT), ground control (GC) mouse retinal tissue. (A) TUNEL-positive cells were identified with green fluorescence, endothelium was stained with lectin (red). TUNEL-positive cells that were laid within red lectin-labeled endothelium were identified as TUNEL-positive endothelial cells. The nuclei of photoreceptors were counterstained with DAPI (blue). In the control retinal tissue, only sparse TUNEL-positive cells were found. In the retina from flight mice, TUNEL-positive labeling was apparent in the retinal endothelial cells, nuclear layers and ganglion cell layers. Arrow: TUNEL-positive endothelial cell. Outer nuclear layer (ONL); inner nuclear layer (INL); ganglion cell layer (GCL). Scale bar = 50 μm. (B) Apoptotic cell density in the retinal ONL, INL and GCL of ground vivarium (GV), Ground control (GC), flight vivarium (FV) and Flight (FLT) mice; (C) Apoptotic cell density in the retinal endothelium of GV, GC, FV and FLT mice. Values are represented as mean density ± SEM for 6 mice/group, and the density profiles were expressed as mean number of apoptotic positive cells/mm². The mean of the density profile measurements across 5 retina sections per eye was used as a single experimental value. Values are represented as mean density ± SEM for 6 mice/group. ^*Significantly higher than all other groups (p < 0.05).