Background: Diabetic nephropathy (DN) is a leading cause of end-stage renal disease. To search for glomerular proteins associated with early-stage DN, glomeruli of spontaneous type 2 diabetic KKAy mice were analyzed by 2-dimensional differential gel electrophoresis (2D-DIGE).
Material and Methods: Glomeruli of 20-week spontaneous type 2 diabetic KKAy mice and age-matched C57BL/6 mice were isolated by kidney perfusion with magnetic beads. Proteomic profiles of glomeruli were investigated by using 2D-DIGE and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Western blot analysis was used to confirm the results of proteomics. Immunohistochemical and semi-quantitative analysis were used to confirm the differential expression of prohibitin and annexin A2 in glomeruli.
Results: We identified 19 differentially expressed proteins – 17 proteins were significantly up-regulated and 2 proteins were significantly down-regulated in glomeruli of diabetic KKAy mice. Among them, prohibitin and annexin A2 were up-regulated and Western blot analysis validated the same result in proteomics. Immunohistochemical analysis also revealed up-regulation of prohibitin and annexin A2 in glomeruli of KKAy mice.
Conclusions: Our findings suggest that prohibitin and annexin A2 may be associated with early-stage DN. Further functional research might help to reveal the pathogenesis of DN.

Keywords: Annexin A2 - metabolism, Animals, Blotting, Western, Diabetic Nephropathies - pathology, Down-Regulation, Electrophoresis, Gel, Two-Dimensional, Immunohistochemistry, Kidney Glomerulus - pathology, Male, Mice, Inbred C57BL, Phenotype, Proteomics - methods, Repressor Proteins - metabolism, Up-Regulation