Rosiglitazone Prevents High Glucose-Induced Vascular Endothelial Growth Factor and Collagen IV Expression in Cultured Mesangial Cells
Effect of high glucose on PPAR expression. Rat glomerular mesangial cells were cultured in 5.6 mM (NG) or 25 mM D-glucose (HG), or 5.6 mM D-glucose 24.4 mM L-glucose (LG) for up to 48 hours. (a) PPAR was detected by immunobloting in total cell lysates, using -actin as the loading controls. The graphs represent PPAR protein levels relative to NG. (b) PPAR mRNA levels were determined by real-time RT-PCR. (, versus NG; versus NG). (c) Preincubated with 10 M rosiglitazone (RSG) or/and 10 M GW9662, the protein expression of PPAR was not affected by RSG or GW6992 in HG ( versus NG). Mesangial cells were transiently transfected with a luciferase reporter gene containing three PPAR response elements and then cultured in the above conditions. (d) Luciferase reporter activity was reduced in HG ( versus NG, versus NG). (e) In NG, PPARpromoter activity increased in dose response to RSG (, versus NG). (f) GW6992 blocked the effect of RSG (, versus NG alone, versus NG or HG alone, versus NG or HG with RSG).