Figure 2. VEGF expression in the developing retina

Expression of VEGF mRNA was assayed by in situ hybridization using a ³⁵S-labeled probe. At P1, levels of VEGF transcripts were highest in the RPE. Low levels of VEGF transcripts were seen in the ganglion cell layer and in the periocular mesenchyme (A). A bright-field image of the P1 eye section at higher magnification shows that RPE cells were densely labeled with silver grains (B). At P7, VEGF mRNA remained expressed in the RPE (C). In addition, high levels of VEGF transcripts were detected in astrocytes at the vitreous surface and in the inner nuclear layer of the neural retina (C). The bright-field image of the P7 eye shows heavy labeling of silver grains in RPE cells and cells in the inner nuclear layer (D). Abbreviations: GCL, ganglion cell layer; INL, inner nuclear layer; ONL, outer nuclear layer; RBL, retinoblast layer. Scale bars: 100 mm (A, C) and 50 mm (B, D).