Unilateral ureteral obstruction evokes renal tubular apoptosis via the enhanced oxidative stress and endoplasmic reticulum stress in the rat

Purpose: Oxidative stress and endoplasmic reticulum (ER) stress may induce renal apoptosis and contribute to the pathogenesis of the kidney with unilateral ureteral obstruction (UUO). Materials and Methods: We induced UUO the female Wistar rats by ligation of the left ureter at the ureteropelvic junction. The UUO kidney was performed from 4 hr to 7 days course. At the indicated time, we measured the arterial blood pressure and renal blood flow in each rat, renal ROS measurement in vivo by a chemiluminescence analyzer. We performed immunohistochemistry of monocyte/macrophage (ED-1) stain for leukocyte infiltration, 4-hydroxynoneal (4-HNE) stain for ROS products, and apoptosis by terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL) and Western blot to analyze ER stress-associated andapoptosis-related proteins expression in the UUO kidney. Results: We found that UUO decreased renal blood flow and increased renal vascular resistance and renal ROS. UUO decreased renal manganese superoxide dismutase (MnSOD) and catalase protein expression in a time-dependent manner. Increased 4-HNE stain in the renal tubules and ED-1 stain in the renal tubulointerstitial compartment occurred after 4 hr of UUO in the kidney. UUO significantly enhanced ER stress markers like ER stress-response protein 25 and glucose-regulated protein 78 and ER-associated apoptosis proteins, c-JUN NH2-terminal kinase, and caspase 12, in the kidney. Subsequently, UUO enhanced renal pro-apoptotic Bax and caspase 3 expression and decreased anti-apoptotic Bcl-2 expression, leading to renal tubular apoptosis. Conclusions: Our data suggest that renal tubular apoptosis induced by oxidative stress and ER stress occurred in the UUO kidney. 2011.