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Fig. 3 Cytokine IL-1β is necessary for Müller glia proliferation in light-damaged retinas. (A–D) Confocal images from albino;Tg(gfap:EGFP)nt11 retinas that were intravitreally injected with a caspase-1 inhibitor Ac-YVAD-cmk (YVAD) 24 h prior to the start of light treatment and continued to inject every 24 h until 36 h LT. At 0 h LT, retinas were intravitreally injected with either DMSO vehicle control: (A,C) or YVAD (B,D). Retinal sections were immunostained to detect GFP Müller glia, green: (A,B) ande PCNA proliferating cells, magenta in (A,B), grayscale in (C,D), with DAPI counterstain (nuclei, blue: (A,B). (E) The numbers of PCNA+ INL cells in the YVAD group (red circles) relative to the DMSO control group (blue circles). (F–I) Confocal images of retinas from albino;Tg(gfap:EGFP)nt11 zebrafish electroporated with either Standard Control (S.C.; (F,H) or il-1β morpholino (MO; (G,I) to knockdown IL-1β protein expression and immediately placed in constant light treatment. Retinas were collected at 36 h LT and immunostained to detect GFP Müller glia, green: (F,G) and PCNA proliferating cells, magenta in (F,G), grayscale in (H,I), with DAPI counterstain (nuclei, blue: (F,G). (J) Quantification of the numbers of PNCA+ INL cells in the il-1β morphant (red circles) and the S.C. MO (blue circles). Quantifications were normalized to 300 μm along the length of the central-dorsal retina. Statistical analyses were performed using Student’s t-test. Graphs represent the Mean ± SEM and n ≥ 7. ****, p < 0.0001. ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer. Scale bars in (A,F) are 20 μm and are the same for (B–D) and (G–I), respectively.