Introduction 1 2 3 5 6 7 6 Col4a3 Lamb1 7 8 9 10 9 11 18 Ctgf +/− Ctgf 19 20 22 Materials and methods Animals Streptozotocin-induced diabetic rat model n n n N ɛ 23 In vivo administration of exogenous AGE Preparation of AGE-modified albumin 24 25 RNA isolation and mRNA quantification 1 http://www.ncbi.nlm.nih.gov/blast/index.shtml 2 R E Ct E Ct 32 32 Western blotting 26 g 3 2 Immunohistochemistry 27 2 Statistics 10 p Results Glucose and CML levels in control and diabetic rats 1 Fig. 1 a b White bars black bars cross-hatched bars p p † p error bars  1 CCN family gene expression in control and diabetic rats Cyr61 Cyr61 2 3 Fig. 2 white bars cross-hatched bars black bars grey bars *p † p  Fig. 3 a b c INL OPL ONL RCL RPE  Ctgf 2 4 3 Fig. 4 a n n n n n n b  Wisp1 Wisp3 2 Nov Wisp2 Expression of transforming growth factor beta 1 and 2 in control and diabetic rats Tgfb1 Tgfb2 Tgfb1 5 Tgfb1 Tgfb2 5 6 Fig. 5 Tgfb1 Tgfb2 white bars cross-hatched bars black bars grey bars Tgfb1 *p Tgfb2  Fig. 6 a c d f  Expression of extracellular matrix molecules in control and diabetic rats Col4a3 Col4a3 7 Lamb1 Timp2 Timp1 7 6 3 Fig. 7 white bars cross-hatched bars black bars grey bars *p † p  CCN family mRNA expression in control and AGE-treated mice Cyr61 Ctgf 8 Wisp1 Wisp3 Fig. 8 Cyr61 Ctgf white bars black bars p Cyr61 Ctgf  Summary of results Cyr61 Ctgf Cyr61 Ctgf Discussion Cyr61 Ctgf 28 29 30 31 Ctgf 28 28 29 Cyr61 Nov Wisp2 Wisp2 32 Wisp1 33 Wisp3 34 35 36 37 38 Col4a3 Cyr61 Timp1 Lamb1 Ctgf Lamb1 Lamb1 39 40 41 Ctgf 10 10 42 44 45 46 47 Ctgf Cyr61 48 49 Ctgf 28 Ctgf 28 50 In summary, this study provides the first evidence that, in addition to CTGF, the CCN family molecules CYR61, WISP1 and WISP3 play possible roles in the development of early stages of experimental diabetic retinopathy. At the very least, these results warrant further study into the functional aspects of these molecules in the eye, and of how these aspects pertain to the development of diabetic retinopathy. Additionally, we demonstrate for the first time that AGEs directly upregulate both CTGF and CYR61 levels in the retina in vivo and that aminoguanidine inhibits these diabetes-induced increases. This provides the first evidence that CTGF and CYR61 are downstream effectors of AGEs in the diabetic retina and implicates them as possible targets for future intervention strategies. Electronic supplementary material Below is the link to the electronic supplementary material.