Figure 4. Apoptosis at P19, P24, P32, and P47 in RA and OIR mice.A: TUNEL staining for apoptosis shows increased apoptosis in the OIR mice compared to the RA mice. B: Quantification of TUNEL staining in RA and OIR mice with increasing developmental age. RA = room air; OIR = oxygen-induced
ischemic retinopathy; P = postnatal day; TUNEL = terminal deoxynucleotidyl transferase dUTP nicked-end labeling. Three RA
mice and three OIR mice were examined for each developmental age studied. Stars denote level of significance: *p< 0.05, **p<
0.01, ***p< 0.001, and ****p< 0.0001. Sampling size: n=3 for each group. Error bars represent SEM.