Retina Cell Death Apoptosis Assay

We investigated cell death in the retina as previously described [30 (link)]. We performed Terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) assay for the detection of apoptosis in situ. The nucleotide-labeling mix was used in combination with the TUNEL enzyme to prepare a TUNEL reaction mixture (all from Sigma-Aldrich, city, State, USA) and the assay was performed according to the manufacturer’s instructions. The number of TUNEL-positive cells was counted in 3–5 cross-sections of the retina per animal. Results are expressed as the average number of TUNEL-positive cells per section ± SEM.