Figure 6. Caspase 3 enzymatic activity in rat retinas. A: The level of protein expression of caspase 3 in the rat retina was evaluated by western blotting. Diabetes increased the cleaved form of caspase 3 (activated form), whereas treatment with etanercept reduced the diabetes-induced cleavage of caspase 3. B: The enzymatic activity of caspase 3 in the rat retina was evaluated by a colorimetric analysis. Diabetes increased the activity of caspase 3 as measured by the conversion of its specific substrate. Treatment with etanercept reduced the diabetes-induced caspase 3 activation and therefore the conversion of its substrate and correlates with the reduction in the cleaved form of the caspase as measured by the western blot shown.