hybridization for C3 mRNA in the retina following 670-nm light and bright continuous white light (BCL) exposure. (A-E) Representative images from the superior mid-periphery show in situ hybridization for C3 mRNA in the retina. Retinas from dim-reared (A) and 670-nm light-treated dim-reared (B) animals showed no staining for C3 mRNA in the retina except for infrequent C3-expressing nuclei associated with the retina vasculature (data not shown). In BCL-exposed animals (C-D) C3-expressing nuclei were more numerous in the outer nuclear layer (ONL) and outer segments within the lesion area, while none were observed in those treated with 670-nm light prior to BCL exposure (E). (F,G) C3 expression (dark grey) in sections counterimmunolabelled with anti-IBA1 (green), showing immunoreactivity in C3-expressing nuclei within the degenerating ONL (arrows) following BCL. Histogram: Quantification of C3-expressing nuclei per retina showed a dramatic increase from near zero in dim-reared animals to 26.7 following BCL exposure (P <0.05). In contrast, the number of C3-expressing nuclei was reduced to near zero in animals pretreated with 670-nm light following BCL (P <0.05). Dim reared n = 3, dim reared + 670-nm light n = 3, light damage n = 3, light damage + 670-nm light n = 3; error bars represent SEM. *Significant change using analysis of variance (ANOVA) with Tukey’s post test where P <0.05.