AIM: To compare and identify the differences in expression of retinal proteins between normal and diabetic rats, and to analyze the molecular pathogenetic mechanisms of retinal diseases caused by diabetes. METHODS: Changes in protein expression of retinal tissues from diabetic and normal rats were observed using 2-dimensional polyacrylamide gel electrophoresis (2-DE). Some protein spots exhibiting statistically significant variations (P < 0.05) were selected randomly and identified by tandem mass spectrometry and analyzed by bioinformatics. RESULTS: 2-DE showed that the expression was up-regulated in 5 retinal proteins, down-regulated in 23 retinal proteins, and disappeared in 8 retinal proteins. Eight spots were identified from the 36 spots by tandem mass spectrometry (MS/MS) and analyzed by bioinformatics. Guanylate kinase 1, triosephosphate isomerase 1, ATP synthase subunit d, albumin and dimethylarginine dimethylaminohydrolase 2 played an important role in signal transduction. Triosephosphate isomerase 1, crystallin alpha B, ATP synthase subunit d and peroxiredoxin 6 were involved in energy metabolism of retinal tissues. Guanylate kinase 1 played an important role in photoexcitation of retinal rod photoreceptor cells. Whether crystallin beta Al plays a role in diabetic retinas is unknown so far. CONCLUSION: There are differences in expression of retinal proteins between diabetic and normal rats. These proteins may be involved in the mechanisms and prognosis of retinal diseases caused by diabetes. AIM: To compare and identify the differences in expression of retinal proteins between normal and diabetic rats, and to analyze the molecular pathogenetic mechanisms of retinal diseases caused by diabetes. METHODS: Changes in protein expression of retinal tissues from diabetic and normal rats were observed using RESULTS: 2-dimensional polyacrylamide gel electrophoresis (2-DE). Some protein spots exhibiting statistically significant variations (P <0.05) were selected randomly and identified by tandem mass spectrometry and analyzed by bioinformatics. Eight spots were identified from the 36 retinal proteins by tandem mass spectrometry (MS / MS) and analyzed by bioinformatics. Guanylate kinase 1, triosephosphate isomerase 1 , ATP synthase subunit d, albumin and dimethylarginine dimethylaminohydrolase 2 played an important role in signal transduction. Trio sepharose isomerase 1, crystallin alpha B, ATP synthase subunit d and peroxiredoxin 6 are involved in energy metabolism of retinal tissues. Whether Guanylate kinase 1 plays an important role in photoexcitation of retinal rod photoreceptor cells. Whether crystallin beta Al plays a role in diabetic retinas is unknown so far. CONCLUSION: There are differences in expression of retinal proteins between diabetic and normal rats. These proteins may be involved in the mechanisms and prognosis of retinal diseases caused by diabetes.