Figure 3. Caspase-3 analyses of rat retinas exposed to low-intensity light. A. A western blot showing caspase-3 in retinas after exposure to a regular LD cycle of 200 lx (LD Cycle; 12h L:12h D) or to 12 h or to one, two, five or ten days of constant light (LL), respectively. A positive control from embryonic chick retina is also included. Results are representative of five independent experiments. B: Caspase-3 activity by detection of DEVD-pNA cleavage was measured in rat retinas at the same time as that in A. The results are expressed as the enzyme activity in LL relative to that in retinas maintained in LD (%). Data are mean ± SD (n=2 animals/group) from four independent experiments. Non-parametric Kruskal-Wallis test showed no significant statistical differences (p=0.7631). The results are expressed as percentages.