The kidney expression of matrix metalloproteinase-9 in the diabetic nephropathy of Kkay mice

BackgroundDisorder of the extracellular matrix has been suggested to play a role in the development of diabetic nephropathy. The aim of the present study was to examine the expression of matrix metalloproteinase-9 (MMP-9) in the kidney of Kkay mice, a type 2 diabetic model.MethodsEight Kkay control mice (KA) and eight Kkay diabetic mice (KB) were fed with the same diets for 4 months and sacrificed after glucose levels and weight were measured. The renal pathological changes were examined by periodic acid–Schiff and periodic acid–silver methenamine staining, and the glomerulosclerosis indexes (GIs) were calculated. The levels of MMP-9 protein in the kidney tissue were assessed by immunohistochemistry. The gene expression of MMP-9 was measured by reverse transcription polymerase chain reaction.ResultsThe diabetic group had morphological findings of diabetic nephropathy, and their GI (240.0±17.3) was much higher than that of the control group (118.4±15.1) (P<.01). The mean positive area of MMP-9 protein in the glomeruli of Kkay mice in the KB group was higher than that in the KA group. The expression of MMP-9 messenger RNA level in the diabetic KB group was up-regulated when compared with the KA group.ConclusionThe expression of MMP-9 in the kidney of mice with diabetic nephropathy was enhanced, and MMP-9 might be involved in the development of diabetic nephropathy.