Figure 2. Norgestrel increases LIF in retinal explant cultures. A: Retinal explants from C57BL/6 were screened for changes in relative mRNA expression of the neurotrophic factors leukemia inhibitory factor (Lif), epidermal growth factor (Egf), hepatocyte growth factor (Hgf), and nerve growth factor (Ngf), and basic fibroblast growth factor (bFGF) in response to treatment with 20 µM norgestrel for the times indicated, or vehicle control (ctrl) for 24 h. B: Relative expression of Lif in C57BL/6 retinal explants treated with 20 µM norgestrel or vehicle control for the times indicated. For A and B, relative expression was analyzed with real-time (RT) PCR, with the fold change compared to the geometric mean of three endogenous reference genes. C: Immunofluorescent staining detects an increase in LIF (green) at the protein level in explants treated with norgestrel for 6 h compared to vehicle control. Sections were counter-stained with Hoechst dye for orientation of the retinal layers. Outer segment layer = OSL; outer nuclear layer = ONL; outer plexiform layer = OPL; inner nuclear layer = INL; inner plexiform layer = OPL. Scale bar represents 50 µm. Error bars denote ±   standard error of the mean (SEM) from three independent experiments. *p<0.05, **p<0.01, ***p<0.001 (ANOVA).