Fig. 8.

Genetic inhibition of ATF4 ameliorates retinal inflammation and vascular leakage in STZ-diabetic mice. Eight-week-old WT mice (white bars) and heterozygous Atf4 KO mice (black bars) were given five consecutive injections of STZ to induce diabetes mellitus (DM). Four weeks after the onset of hyperglycaemia, mRNA expression of Atf4 (a), Tnf (c) and Icam1 (d) in the retina was measured by real-time RT-PCR (mean±SD, n=6). **p<0.01 vs non-diabetic WT mice; ^††p<0.01 vs diabetic WT mice. (b,e) Immunostaining showing decreased levels of retinal ATF4 (b) and VEGF (e) in the diabetic Atf4 KO mice compared with the diabetic WT mice. ATF4 (green), VEGF (red) and DAPI (blue). (f) Immunofluorescence of albumin (green) showing markedly decreased extravasation of albumin in diabetic Atf4 KO mice. GCL: ganglion cell layer; INL: inner nuclear layer; ONL: outer nuclear layer. g BRB breakdown was quantified by FITC–dextran assay. Results show that diabetes induced a significant increase in retinal vascular permeability in WT mice (white bars), which was completely abolished in Atf4 KO mice (black bars) (mean±SD, n=5). **p<0.01 vs non-diabetic WT mice; †p<0.05 vs diabetic WT mice. (h) Immunostaining of phosphorylated STAT3 showing that phosphorylation of STAT3 in the retina induced by diabetes was markedly reduced in Atf4 KO mice