ABSTRACT
Objective To investigate the mechanisms of calculus crystal transport by macro-phage in kidney. Methods Hyperoxaluria rat model was established by administration of 1% ethyl-ene glycol and 1% ammonium chloride in drinking water. 24 h rat urine was collected, urinary oxalate were analyzed by ion chromatography. The expression and location of osteopontin and macrophage in kidney were observed by immunohistochemistry. Macrophage and calculus crystal at the basement membrane of renal tubular epithelial cells and interstitium were observed. Results The urinary ox-slate concentration were (0.22±0.13), (0.29±0.08), (0. 50±0.26), (0. 41±0. 22), (0.25±0. 12) ng/ml among these 5 groups. The osteoponitin expression was 0.16±0.04, 0.25±0.09, 0.37±0.10, 0.23±0.08, 0.19±0.02 respectively. The expression of osteopontin was positively correlated with urinary oxlate concentration(r=0.887, P<0.05). The macrophage at the basement membrane of renal tubular epithelial cells was 0.12±0.08, 0.19±0.06, 0.27±0.04, 0.16±0.03, 0.18±0.03 respectively. The macrophage distribution was positively correlated with the expression of osteopontin (r= 0.596, P<0.05). The macrophage moved from vessel to the basement membrane of loops of Henle, then disrupted and released the calculus crystal. Conclusions The macrophage might take part in the calculus crystal transport in kidney at the basement membrane of loops of Henle, which may be the source of Randall plaque. This process may be mediated by osteopontin.
ABSTRACT
AIM: To investigate the roles of angiotensin Ⅱ and NADPH oxidase in the development of renal oxidative stress (OS) in a rat model of hyperoxaluria. METHODS:Animal model of hyperoxaluria was established in a-dult male Sprague - Dawley rats by administration of 0.8% ethylene glycol (EC) in drinking water for 4 weeks. Simultaneous treatment with apocynin (0.2g·kg~(-1)·d~(-1))or losartan (30 mg·kg~(-1)·d~(-1) ) by intragastric administration were performed in rats, respectively. At the end of the study, markers for the state of oxidative stress (OS) , urinary 8 - IP and the enzymatic activity of superoxide dismutase ( SOD) in kidney homogenates were assessed. The concentration of angiotensin H in kidney homogenates was determined using radioimmunoassay method. Expression of NADPH oxidase subunit p47phox in kidney was localized and evaluated by immunohistochemistry and real time - PCR, respectively. RESULTS: p47phox expressed widely in the kidneys of this rat model, including renal cortex, inner medulla and outer medulla. Compared with the control, OS developed significantly in rats received EG, with increased expression of p47phox mRNA in kidneys. Renal angiotensin Ⅱ also increased significantly. Treatment with apocynin or losartan significantly reduced the excretion of urinary 8 - IP, restored the SOD activity, with decrease in the expression of p47phox mRNA in kidney, but the levels of those OS markers in apocynin or losartan treated rats were still higher than those in normal controls. CONCLUSION: Results suggest that renal Ang Ⅱ and its stimulation of NADPH oxidase may partially account for the development of OS in kidney in this rat model of hyperoxaluria.
ABSTRACT
Objective To investigate the protective effect of apocynin against renal oxidative injury in a rat model of hyperoxaluria. Methods Animal model of hyperoxaluria was established by administration of 0.8% ethylene glycol (EG) to adult male Sprague-Dawley rats in administration were performed in the rats. Markers of oxidative stress(OS) state, urinary H2O2 and 8-(so-prostaglandin IP), and renal injury were assessed at the end of the study. Expression and localization of NADPH oxidase subunits (p47phox, gp91phox, Nox-1) in kidneys were examined by immunohistochemistry, real-time PCR and Western blot, respectively. Results p47phox expressed widely in kidneys of model rats, including renal cortex, inner medulla and outer medulla. Compared with the control, OS and renal injury occurred in rats receiving EG, in accordance with the up-regulated expression of NADPH oxidase subunits in kidneys. Treatment with apocynin significantly reduced the excretion of urinary H2O2 and 8-IP, improved the creatinine clearance and the kidney/body weight, with the down-reguLated expression of NADPH oxidase subunits (except gp91phox mRNA) in kidneys, but the levels of OS markers in apocynin-treated rats were still higher than thoset of normal controls. Conclusions The increased expression of NADPH oxidase subunits is suggested to be partially accounted for the development of renal OS in this rat model of hyperoxaluria. Apocynin treatment is effective for renal protection in this model.
ABSTRACT
AIM: To investigate the protective effect of taurine on kidney in a rat model of calcium oxalate nephrolithiasis.METHODS: Animal model of calcium oxalate nephrolithiasis was established by administration of 2.5% ethylene glycol+2.5% ammonium chloride 2 mL two doses daily to adult male Sprague-Dawley rats in company with restriction of drinking water intake for 4 weeks.Four groups of 8 rats each were studied: group A,untreated control animals;group B,nephrolithiasis without treatment;group C,nephrolithiasis with taurine(2.0% mixed with the chow);group D,only taurine(2.0% mixed with the chow).Intake of drinking water in each group for each rat was limited to 20 mL/d.Indexes of oxidative stress(OS) and renal injury in urine and kidney,and the enzymatic activities of superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) in mitochondria of homogenized kidney samples were assessed at the day when the rats were sacrificed.Crystals deposited in kidney were scored under light microscopy.Renal tubular ultrastruture changes were analyzed by transmission electron microscopy.Expression of macrophage cell marker CD68 in kidney was evaluated by immunohistochemistry.RESULTS: Compared to the control group,oxidative stress and renal injury were developed after induction of nephrolithiasis,in accordance with increase in expression of CD68 in kidney.The enzymatic activities of SOD and GSH-Px in mitochondria were decreased significantly.Administration of taurine significantly reduced OS and renal injury,as well as the crystals deposited in kidney.Expression of CD68 in kidney was also reduced,while the enzymatic activities of SOD and GSH-Px in mitochondria were improved significantly.CONCLUSION: Attributed to its antioxidant capacity,taurine showed renal protective action in this rat model of calcium oxalate nephrolithiasis.