Objective To explore the possible mechanism of nitric oxide(NO) involved in iron-mediated cytotoxicity on renal tubular cells, meanwhile to estimate the effect of reactive oxygen sepcies scavenger on iron-mediated cytotoxicity and its relation to nitric oxide. Methods in this study, the relationship between NO production and lactate dehydrogenase(LDH) release were observed in primary subconfluent proximal tubular cells coincubated with different doses of NTA-Fe and lipopolysaccharide(LPS) alone or in combination. NO production was monitored by NO2 -- concentration in supernatant based on Griess reaction. Meanwhile, semi-quantitative RT-PCR was applied to detect the inducible nitric oxide synthase (iNOS) mRNA level induced by NTA-Fe and LPS together. In addition, experimental groups were exposed to reactive oxygen species (ROS) scavengers to determine the impact of the interaction between NO and ROS on iron-mediated cytotoxicity. Results After 12-hour coincubation, NTA-Fe could increase both LDH release and NO2 production in a dose-dependent manner (P 0. 05 ) although tubular injury was aggravated (P

Objective To investigate the effects of repeated low dose intravenous infusion of low molecular weight iron dextran and iron sucrose on oxidative stress in chronic renal failure (CRF) rats. Methods CRF model was established by 5/6 subtotal nephrectomy (5/6 Nx). Four weeks after removing the right kidney, successful rats were randomly divided into low molecular weight iron dextran group, sucrose iron group and CRF control group. The sham group was established simultaneously. The dose of iron administrated in each rat was similar in iron dextran group and sucrose iron group. There were 6 rats in each group. Animals were observed for 6weeks, then the blood, urine and renal tissue samples were collected, and indexes of renal function,anemia, iron status and oxidative stress were investigated. Results The hemoglobulin (Hb) level in iron groups was significantly higher as compared to control group (P＜0.05) but was not significantly different between two iron groups. The levels of serum iron, ferritin and saturation rate of transferring (TS) were obviously lower in control group as compared to sham group (P＜0.05).Levels of above 3 indexes were significantly higher in two iron groups as compared to control group (P＜0.05), but were not significantly different between two iron groups. Concentration of plasma advanced oxidation protein products (AOPP) was obviously higher in two iron groups than that in control group [(127.84±21.19) μmol/L, (134.21±29.38) μmol/L vs (81.83±19.93) μmol/L, P＜0.05]. Plasma malonaldehyde (MDA) was significantly higher in iron sucrose group than that in iron dextran group [(6.06±0.73) nmol/L vs (4.99i0.80) nmol/L, P＜0.05]. Serum levels of superoxide dismutase (SOD) and total anti-oxidant capacity (TAOC) had no significant differences among three CRF groups. Concentration of plasma glutathione peroxidase (GSH-Px) was significantly decreased in three CRF groups as compared to sham group (P＜0.05), while plasma GSH-Px was significantly lower in sucrose iron group than that in iron dextran group and control group [(2123.11±74.78)nmol ·ml-1 ·min-1 vs (2352.84±163.90) nmol· ml-1 ·min-1, (2310.23±125.99) nmol ·ml-1 ·min-1, P＜0.05]. Conclusions Injection of intravenous iron can partially improve the anemia and the iron status indexes in 5/6 Nx CRF rats. Repeated low dose intravenous infusion of iron dextran and iron sucrose can aggravate the oxidative stress state in CRF rats, and the iron sucrose is worst.

ObjectiveTo clarify the clinicopathological features of renal amyloidosis in order to achieve early diagnosis and treatment.MethodsClinicopathological data of 26 biopsyproven renal amyloidosis cases in Department of Nephrology,Zhongshan Hospital,Fudan University between2006and2010wereanalyzedretrospectively.Immunohistochemistryand immunofluorescence of amyloid A protein,immunoglobulin light chains such as K、λ were performed on renal specimens for further classification.ResultsAge of 26 patients ranged from 40 to 77 years old,average(58.54±10.07) years.Twenty-two out of 26 patients(84.62％) were treated in local hospital before admitted to our department,and 21 patients(95.45％) were misdiagnosed as chronic primary glomerulonephritis.The prominent clinical manifestations of renal amyloidosis were nephrotic syndrome(17 cases,65.38％),decreased blood pressure(16 cases,61.53％),organ enlargement (8 cases,30.77％) and bodyweight loss (6 cases,23.08％).Fourteen out of 25 patients (56.00％) were found to have monoclonal light chains in serum by immunofixation electrophoresis.Three patients with mild pathological changes who had no confirmable Congo red stain were conffimed by electron microscopy. Twenty-three(88.46％) patients werediagnosed as AL amyloidosis,one(3.85％) as AA amyloidosis,one was strongly suspected of hereditary amyloidosis,and one was undetermined.ConclusionsRenal amyloidosis is frequently misdiagnosed.Middleaged and old nephrotic patients with decreased blood presure,organ enlargement and bodyweight loss may be the most helpful clues of the disease.Most patients have monoclonal light chains in serum or urine.Renal biopsy,especially electronic microscopy plays a crucial role in the early diagnosis of renal amyloidosis.Immunohistochemistry is important for patients with renal amyloidosis in pathological classification and treatment.

Objective To explore the role of brief ischemia pretreatment in the induction of renal ischemic tolerance,and investigate its effects on tubular cell necrosis,apoptosis and proliferation. Methods Male Sprague-Dawley rats were randomly divided into three groups,including sham-operated group (Sham),ischemia/reperfusion injured group subjected to theocclusion of both renal pedicles for 40 min followed by reperfusion(I/R),and preconditioned group with 20-min ischemia pretreatment induced 4 days before I/R(IPC).Histological changes were evaluated by PAS staining.The ultra-structure of tubular cells was observed by transmission electron microscopy(TEM).Apoptosis was confirmed by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL).The proliferation of tubular cells was evaluated with proliferating cell nuclear antigen(PCNA). Results Twenty-minites ischemia pretreatment offered both promising functional and histological protection against 40-min ischemia/reperfusion injury (P<0.01).The mortality rate wag reduced from 33%in I/R group to 0 in IPC group.The renopmtection offered by 20-min ischemia pretreatment was accompanied with reduced postischemic tubular cell apoptosis and necrosis (P<0.05), and increased cell proliferation (PCNA positive) (P< 0.01). Conclusions Brief and sublethal prior ischemia can render the kidney more tolerant to subsequent prolonged I/R injury. Its ability to tilt the balance of tubular cell fate toward survival, reducing postischemic cell death and enhancing cell proliferation, may play an important role in renal protection of ischemic preconditioning.

Objective To investigate the location and expression of hypoxia inducible factor (HIF) subunits in the remnant kidney of 5/6 nephrectomy rats. Methods Remnant kidneys were produced in adult male SD rats by 5/6 nephrectomy. The renal function and histopathological changes were evaluated at week 1, 2, 4, 6, 8 and 12 after operation. Tissues of remnant kidneys were collected to detect the location and expression of HIF-1α and HIF-2α by immunohistochemistry staining and Western blotting. The mRNA levels of HIF targeted genes vascular endothelial growth factor (VEGF) and heme oxygenase-1 (HO-1) were determined by RTPCR. Results (1) 5/6 nephrectomy rats underwent one week of acute renal failure at first[Scr (122.8±22.1) μmol/L] and then developed compensative chronic renal failure [(66.0±3.7)-(66.4±8.4) μmol/L], but the level of Scr increased quickly after week 6 [(66.4±8.4)-(127.8±22.7) μmol/L],concomitantly with progressive tubulointerstitial fibrosis in remnant kidney cortex. (2) In cortex, HIF-1α was expressed only in the atrophic and dilated tubular cells while HIF-2α was located in endothelial, interstitial fibroblasts, and vascular smooth muscle cells. The semiquantitative results of imunohistochemistry and Western blotting revealed that HIF-1α and HIF-2α were both gradually up-regulated during the early stage of remnant kidney, peaked at week 4 and 6, and then gradually down-regulated. (3) The mRNA levels of HIF targeted genes VEGF and HO-1 transiently peeked at week 4 and 6, and then decreased gradually. Conclusions The increased stabilization of HIF-αprotein and transcription of HIF targeted genes at the early stage of this model is a compensation reaction towards hypoxia. The mechanism of decreased expression of HIF-α at the end stage of chronic kidney disease deserves further investigation.

Objective To explore the effects of Dimethyloxalyl Glycine(DMOG)on isehemic acute renal failure(iARF)in mice and its relationship with activation of hypoxia inducible factor 1α(HIF-1α).Method Twenty five C57/BL male mice were divided into 5 groups randomly:control group,DMOG group,sham operation group,ischemia/reperfusion(I/R)group and DMOG pretreated group(DMOG+I/R).Ischemia/reperfusion injury was induced in mice by clamping both renal pedicles for 30 minutes.The expression of HIF-1α was determined by Western blot.Renal function was reflected by blood urea nitrogen(BUN)and serum creatinine(Scr).Morphologic changes were evaluated under light microscopy.Apoptosis in the kidney was detected by TUNEL staining.Expression of Vimentin,a marker of tubulointerstitial damage was detected by immunohistochemistry.Results The elvated levels of of BUN((65.8±2.6) vs (13.6±0.7),P＜0.01],and Scr[(229.5±11.2) vs (6.5±0.8),P＜0.01]andwere found morphological injury were induced by the ischemic insult in I/R group.Administration of DMOG dramatically improved renal function[BUN,(26.3±6.5)vs(65.8±2.6);Scr,(27.0±14.1)vs(229.5±11.2),P＜0.01]associated with amelioration of tubulointerstital damage.In the DMOG treated group,the protein level of HIF-1α in the kidney of mile was also up-regulated significantly.Conclusions The protection against iARF in mice by DMOG administration is mediated by activation of HIF-1α.