Figure 1. Lack of LIF increases light-induced photoreceptor degeneration. A: Retinal morphology of Lif^+/– and Lif^–/– mice was analyzed before (upper panels) or at 9 days after exposure to 15,000 lx of white light for 2 h (lower panels). Fewer photoreceptors survived light exposure in the lower central retina (the most affected region) in the absence of LIF in Lif^–/– mice. Shown are representative sections of at least three animals. B: Rhodopsin levels were determined spectrophotometrically at 9 days after light exposure as a quantitative assessment of surviving rod photoreceptors in the whole retina. Rhodopsin levels after light exposure were expressed relatively to the respective dark controls, which were set to 100%. Note that values represent the average rhodopsin content of the whole retina, whereas the morphological pictures (A) show only the most affected areas. Abbreviations: retinal pigment epithelium (RPE); rod outer segments (ROS); rod inner segments (RIS); outer nuclear layer (ONL); inner nuclear layer (INL). Number of animals (N) is indicated for each group. The asterisk (*) indicates a p value of 0.0164 as calculated by a two-tailed t-test.