Extract of the aerial parts of Aster koraiensis reduced development of diabetic nephropathy via anti-apoptosis of podocytes in streptozotocin-induced diabetic rats.

Advanced glycation end products (AGEs) is produced from glycolysis in vivo, which may result in diabetic nephropathy. Podocyte loss has been implicated in the development of diabetic nephropathy. The aim of this study was to investigate the protective effects of Aster koraiensis extract (AKE), on the damage of renal podocytes in streptozotocin (STZ)-induced diabetic rats. AKE (100, 200mg/kg per day) was given to diabetic rats for 13weeks. Blood glucose, glycated haemoglobin (HbA1c), proteinuria and albuminuria were examined. Kidney histopathology, AGEs accumulation, apoptosis, and expression of Bax and Bcl-2 also were examined. In 20-week-old STZ-induced diabetic rats, severe hyperglycemia was developed, and proteinuria and albuminuria were markedly increased. TUNEL-positive signals were highly detected in glomeruli of STZ-induced diabetic rats. However, AKE reduced proteinuria and albuminuria in diabetic rats. AKE prevented AGEs deposition and podocyte apoptosis. Expression of Bax and Bcl-2 protein were restored by AKE treatment in the renal cortex. These results suggested that AKE has an inhibitory effect of AGE accumulation and anti-apoptotic effect in the glomeruli of diabetic rat. AKE could be beneficial in preventing the progression of diabetic nephropathy.

Sohn E ，Kim J ，Kim CS ，Kim YS ，Jang DS ，Kim JS ... -  《-》

Schisandra chinensis fruit extract attenuates albuminuria and protects podocyte integrity in a mouse model of streptozotocin-induced diabetic nephropathy.

Schisandra chinensis fruit is widely used in Chinese medicine for the treatment of hepatic, renal, heart, cerebrovascular and infectious diseases. To investigate the effects of Schisandra chinensis fruit extract (SE) on albuminuria and podocyte injury as well as the underlying mechanism in the mouse model of streptozotocin (STZ)-induced diabetic nephropathy and in cultured mouse podocyte cells. SE was orally administrated in STZ-induced diabetic nephropathy mice for 7 weeks, at a daily dose of 5g/kg body weight. The urinary albumin/creatinine ratio and urine albumin excretion rate were measured at the 6th and 9th week of the experiment. The extent of glomerulosclerosis and extracellular matrix deposition were determined by periodic acid-silver methenamine and Masson's trichrome staining. The amount of podocytes and the integrity of the slit diaphragm were detected by immunohistological staining of podocyte markers, Wilms' tumor 1 and nephrin. Alpha-smooth muscle actin, E-cadherin and plasminogen activator inhibitor-1 were measured by western blot and immunohistological staining to evaluate the level of epithelial-to-mesenchymal transition (EMT). Real-time reverse transcription PCR was used to detect the mRNA level of E-cadherin, alpha-SMA and snail in cultured podocyte cells. Treatment with SE significantly decreased the urine albumin excretion rate and urinary albumin/creatinine ratio. In addition, SE attenuated glomerulosclerosis and protected against podocyte loss and integrity of the slit diaphragm. Furthermore, SE effectively prevented the EMT of podocytes caused by diabetic nephropathy. Our studies suggest that SE might be beneficial for diabetic nephropathy. The effects of SE on attenuating albuminuria and glomerulosclerosis are possibly mediated by preserving podocyte integrity through suppressing EMT.

Zhang M ，Liu M ，Xiong M ，Gong J ，Tan X ... -  《-》

Mesenchymal stem cells ameliorate podocyte injury and proteinuria in a type 1 diabetic nephropathy rat model.

Mesenchymal stem cells (MSC) attenuate albuminuria and preserve normal renal histology in diabetic mice. However, the effects of MSC on glomerular podocyte injury remain uncertain. The aim of this study was to evaluate the effects of MSC on podocyte injury in streptozotocin (STZ)-induced diabetic rats. Thirty days after diabetes induction by STZ injection (65 mg/kg, intraperitoneally) in Sprague-Dawley rats, the diabetic rats received medium or 2 × 10(6) enhanced green fluorescent protein-labeled MSC via the renal artery. In vivo tracking of MSC was followed by immunofluorescence analysis. Diabetes-related physical and biochemical parameters were measured on day 60 after the MSC infusion. The expression of podocyte markers (nephrin and podocin), podocyte survival factors (VEGF and BMP-7), and the ultrastructural pathology of podocytes were also assessed. MSC were only detected in the glomeruli from the left kidney receiving MSC infusion. Compared with medium-treated diabetic rats, rats treated with MSC showed a suppressed increase in kidney weight, kidney to body weight index, creatinine clearance rate, and urinary albumin to creatinine ratio; however, the treatment had no effect on blood glucose or body weight levels. Furthermore, the MSC treatment reduced the loss of podocytes, effacement of foot processes, widening of foot processes, thickening of glomerular basal membrane (GBM), and loss of glomerular nephrin and podocin. Most important, MSC-injected kidneys expressed higher levels of BMP-7 but not of VEGF. Our results clearly demonstrated that intra-arterial administration of MSC prevented the development of albuminuria as well as any damage to or loss of podocytes, though there was no improvement in blood sugar levels. The protective effects of MSC may be mediated in part by increasing BMP-7 secretion.

Wang S ，Li Y ，Zhao J ，Zhang J ，Huang Y ... -  《-》

Extract of Rhizoma Polygonum cuspidatum reduces early renal podocyte injury in streptozotocin‑induced diabetic rats and its active compound emodin inhibits methylglyoxal‑mediated glycation of proteins.

Sohn E ，Kim J ，Kim CS ，Jo K ，Kim JS ... -  《-》

Renal podocyte apoptosis in Zucker diabetic fatty rats: involvement of methylglyoxal-induced oxidative DNA damage.

Methylglyoxal (MGO) is a cytotoxic metabolite produced by in-vivo glycolysis that may result in diabetic complications. The aim of this study was to determine whether MGO and oxidative stress caused apoptosis of renal podocytes in the Zucker diabetic fatty (ZDF) rat, an animal model of type 2 diabetes mellitus. Male ZDF rats aged 21 weeks developed marked hyperglycaemia with proteinuria and albuminuria. Immunohistochemical evaluation of sections of kidney demonstrated expression of MGO and 8-hydroxydeoxyguanosine (8-OHdG) in the podocytes of both normoglycaemic and diabetic rats. Podocyte apoptosis was shown through application of the TUNEL method. These findings suggest that expression of MGO and 8-OHdG is caused by hyperglycaemia, and that this expression is associated with the observed apoptosis of podocytes and is related to diabetic nephropathy.

Kim J ，Sohn E ，Kim CS ，Kim JS ... -  《-》