Changes in expression of special AT-rich sequence binding protein 1 and phosphatase and tensin homologue in kidneys of diabetic rats during ageing

Abstract

Background. Diabetic nephropathy (DN) is a common complication of diabetes mellitus (DM). We studied the expression of special AT-rich sequence binding protein 1 (SATB1) and phosphatase and tensin homologue (PTEN) in the kidneys of diabetic rats during ageing. Methods. Male Sprague Dawley rats were injected with 55mg/kg streptozotocin (STZ) (DM group) or with citrate buffer (control group). Kidneys were collected after 2weeks, 6 months and 12months, and were analysed in three different kidney structures: glomeruli, proximal (PCT) and distal convoluted tubules (DCT). Sections were stained immunohistochemically, using SATB1 and PTEN. Results. Significant differences in marker expression were observed after 2 weeks, with higher SATB1 expression and lower PTEN expression in diabetic rats. PTEN was more highly expressed in controls after 6 and 12months. After 12months, there was higher SATB1 expression in diabetic rats. In the glomeruli, control rats had higher PTEN expression, whereas diabetic rats had higher SATB1 expression, after 12months. PTEN expression increased from 2 weeks to 12months in both the PCT and DCT of control rats. SATB1 was expressed exclusively in the PCT of diabetic rats after 2weeks, and its expression in the DCT was higher in controls. After 6months, both the PCT and DCT showed higher SATB1 expression in diabetic rats. Conclusions. The major changes in expression of SATB1 and PTEN occur after 2weeks of DM onset, particularly in the PCT, implying an early onset of pathophysiological changes in diabetic kidneys, which would normally occur with ageing. These findings help to contribute to our understanding of changes associated with DN and guide towards possible appropriate treatmentmodalities.