Detection of endothelial nitric oxide synthase and NADPH-diaphorase in experimentally induced hyperoxaluric animals

Abstract

Nitrosative stress plays a role in calcium oxalate stone formation, as nitrosated proteins have been identified in stone formers. Nitric oxide (NO(*)), the common precursor for reactive nitrogen species, is synthesized in the juxtaglomerular apparatus of the kidneys. The present study is aimed to determine the role of nitric oxide synthase (NOS) in an experimental hyperoxaluric condition by histological and biochemical techniques. Hyperoxaluria was induced by 0.75% ethylene glycol in drinking water. L-arginine (L-arg) was supplemented at a dose of 1.25 g/kg body weight orally for 28 days. Nitric oxide metabolites (NOx), protein content in the urine and lipid peroxidation in the kidney were determined at the end of the experimental period. Histopathological examination of the rat kidneys was then carried out. NADPH-diaphorase and eNOS expression studies were carried out in control and hyperoxaluric rat kidneys using histochemical and immunohistochemical techniques. Significant amounts of NOx were present in the urine of hyperoxaluric animals when compared to control rats. Histopathological examinations revealed membrane injury, tubular dilatation and edema in the hyperoxaluric rats, whereas co-supplementation of L-arg to the hyperoxaluric rats significantly reduced these changes. The results of histochemical analysis for NADPH-diaphorase staining demonstrate the role of NOS in hyperoxaluric rats. Hyperoxaluric rats showed intense staining for NADPH-diaphorase when compared to control and L-arg co-supplemented hyperoxaluric rats. Immunohistochemical demonstration confirmed that eNOS expression was markedly increased in L-arg supplemented rats, when compared to EG treated rat kidney sections. Thus, from the present study, we conclude that supplementation of L-arg to the hyperoxaluric animals minimizes the cellular injury mediated by ethylene glycol, prevents oxidative/nitrosative damage to the membranes and reduces the incidence of calcium oxalate stone formation.

MiR-21 promotes calcium oxalate-induced renal tubular cell injury by targeting PPARA

“…Paraffin-embedded tissues were analyzed using immunohistochemical staining as previously described with the following primary antibodies: anti-PPAR-␣ antibody (Santa Cruz Biotechnology, Dallas, TX) and anti-kidney injury molecule (KIM)-1 antibody (Sino Biological, Beijing, China) (35). Renal calcium oxalate deposition in the mouse model was detected by Alizarin red staining according to the method of Bancroft and Cook (29). Frozen sections (5 m) were used for ORO staining to determine lipid accumulation as previously described (30).…”

High perirenal fat thickness predicts a greater risk of recurrence in Chinese patients with unilateral nephrolithiasis

“…Patients in the high-PFT group had a significantly higher risk of HLD than those in the low-PFT group. Moreover, recent experimental studies had described a link between perirenal fat and renal endothelial dysfunction, which has been reported to be a common etiology of chronic kidney disease, as well as a potential cause of urolithiasis [ 24 , 25 ]. In addition, CKD leads to the dysregulation of fibroblast growth factor 23 (FGF23)-Vitamin D (Vit.…”

Three-dimensional evaluation of perirenal fat volume in patients with nephrolithiasis

“…19 Endothelial injury is common etiology of chronic kidney disease, and has also been suggested as a potential cause of urolithiasis. 20,21 The potential for similar pathologic hormonal signaling in human renal units has yet to be studied.…”