Figure 3. DNA electrophoresis following 4 h of moderate intensity green light. Retinal DNA was extracted from dark-reared rats (n=3) 48 h after the onset of light to assess the early response to toxic light exposure. DNA from three separate retinas was combined and then electrophoresed on a neutral pH agarose gel (1 μg/lane). High molecular weight DNA fragments and a 200-bp apoptotic ladder are clearly present in the vehicle- and zinc oxide (0.65 mg/kg) -treated rat retinas (lanes 2 and 3). Rosemary pretreatment (8.5 mg/kg) significantly reduced the appearance of a 200 bp apoptotic DNA ladder (lane 4). Zinc combined with rosemary (R+Z) was even more effective (lane 5). Retinal DNA appeared as a high molecular weight band near the top of the gel, resembling the pattern found for rats unexposed to intense light (lane 1).