Protective effects of quercetin on cadmium-induced cytotoxicity in primary cultures of rat proximal tubular cells / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the protective effects of quercetin on cadmium-induced cytotoxicity in primary cultures of rat proximal tubular (rPT) cells.</p><p><b>METHODS</b>Primary cultures of rPT cells undergoing exponential growth were incubated with 1.0 μg/mL quercetin and/or cadmium (2.5, 5.0 μmol/L), in a serum-free medium at 37 °C at different time intervals. Commercial kits were used and flow cytometric analyses were performed on rPT cell cultures to assay apoptosis and oxidative stress.</p><p><b>RESULTS</b>Exposure of rPT cells to cadmium acetate (2.5, 5.0 µmol/L) induced a decrease in cell viability, caused an increase in apoptotic rate and apoptotic morphological changes. Simultaneously, elevation of intracellular reactive oxygen species, malondialdehyde and calcium levels, depletion of mitochondrial membrane potential and intracellular glutathione, and inhibition of Na+, K+-ATPase, Ca2+-ATPase, glutathione peroxidase (GSH-Px), catalase (CAT), and superoxide dismutase (SOD) activities were revealed during the cadmium exposure of rPT cells. However, simultaneous supplementation with 1 µg/mL quercetin protected rPT cells against cadmium-induced cytotoxicity through inhibiting apoptosis, attenuating lipid peroxidation, renewing mitochondrial function and elevating the intracellular antioxidants (non-enzymatic and enzymic) levels.</p><p><b>CONCLUSION</b>The present study has suggested that quercetin, as a widely distributed dietary antioxidant, contributes potentially to prevent cadmium-induced cytotoxicity in rPT cells.</p>

Effects of endoplasmic reticulum stress on albumin-induced apoptosis in renal proximal tubular cells / 中华肾脏病杂志

ObjectiveTo investigate the effects and molecular mechanism of endoplasmic reticalam stress (ERS) on albumin-induced apoptosis in renal proximal tubular cells (HKCs). MethodsWestern blot was performed to detect the relationship of the expression of glucose-regulated protein 78 (GRF78) and CCAAT/enhancer-binding protein-homologous protein (CHOP) with the action time and concentration of haman serum albumin (HSA). Expression levels of CHPO mRNA and protein in HKCs after CHOP siRNA transfection were examined by real-time fluorescence quantitative PCR and Western blot respectively. Annexin-V-FITC and PI doable staining cytometry was used to detect the apoptosis of HKCs induced by HSA and influenced by CHOP siRNA. Results(1)After HKCs were stimulatde by 0, 5, 10, 20 g/L albumin for 24 hours respectively, the expression of GRP78, CHOP and HKCs apoptosis were increased with the albumin concentration (P<0.01). After HKCs were stimulated by 20 g/L albumin for 0, 6, 12, 24, 36 hours respectively, the expression of GRP78 was up-regulated at 6-hour, while CHOP and HKCs apoptosis were increased at 12-hour, and significant differences were found among groups (P<0.01). (2) CHOP siRNA significantly inhibited albumin-induced HKC CHOP mRNA and protein expression, as well as HKC apoptosis (P<0.01). ConclusionsRenal tubular cells exposed to high protein load result in EBS. ERS may subsequently lead to tubular damage by activation of pro-apoptosis factor CHOP.

Ultrasound-mediated microbubble destruction enchances β-galactosidase gene transfection and expression in HKCs / 中南大学学报(医学版)

Objective To investigate the efficiency and safety of ultrasound-mediated microbubble destruction in enhancing β-galactosidase gene (β-gal gene) transfer into human proximal tubular cells(HKCs). Methods β-gal gene was transfected to HKCs as a mark gene with ultrasound-mediated microbubble destruction. Cultured HKCs were grouped to receive the following 7 treatments respectively: ultrasound alone; microbubble alone; naked plasmid; ultrasound and plasmid; microbubble and plasmid; ultrasound, microbubble, and plasmid; and VigoFect and plasmid. In Group 6, HKCs were exposed to ultrasound under different sound intensities and time. X-gal stainning, typan blue stainning, and Hochest stainning were used to detect the transfection efficiency, cell survival rate, and cell apoptosis rate, respectively.Results β-galactosidase expression could be observed in the ultrasound-mediated microbubble destruction groups. Along with the increasing of sound intensity and exposure time, the cell survival rate of HKCs decreased, and the cell apoptosis rate increased gradually. The transduction efficiency and survival rate in middle intensity (0.3 W/cm~2×60 s) of ultrasound exposure were higher than those of other groups, similar to those of Group 7.Conclusion Under optimum sound intensity and exposure time, ultrasound-mediated microbubble destruction can increase gene transfer into HKCs. This non-invasive gene transfer method may be a useful tool for clinical gene therapy.

Role of phospholipase A2 in oxidant-induced alteration in phosphate transport in primary cultured rabbit renal proximal tubule cells

The present study was undertaken to examine the role of phospholipase A2 (PLA2) in oxidant-induced inhibition of phosphate transport in primary cultured rabbit renal proximal tubule cells. Uptakes of phosphate and glucose were dose-dependently inhibited by an oxidant t-butylhydroperoxide (tBHP), and the significant inhibition appeared at 0.025 mM of tBHP, whereas tBHP-induced alterations in lipid peroxidation and cell viability were seen at 0.5 mM. tBHP stimulated arachidonic acid (AA) release in a dose-dependent fashion. A PLA2 inhibitor mepacrine prevented tBHP-induced AA release, but it did not alter the inhibition of phosphate uptake and the decrease in cell viability induced by tBHP. tBHP-induced inhibition of phosphate transport was not affected by a PKC inhibitor, staurosporine. tBHP at 0.1 mM did not produce the inhibition of Na+-K+-ATPase activity in microsomal fraction, although it significantly inhibited at 1.0 mM. These results suggest that tBHP can inhibit phosphate uptake through a mechanism independent of PLA2 activation, irreversible cell injury, and lipid peroxidation in primary cultured rabbit renal proximal tubular cells.

Uranyl Nitrate Induced Polyuric Acute Tubular Necrosis in Rats

We investigated the pathobiological course of uranyl nitrate (UN) induced polyuric acute tubular necrosis (ATN) in male Sprague Dawley rats. UN (5mg/kg 15mg/kg and 3Omg/kg) in 5% NaHCO3 induced weight loss, polydipsia, and polyuria 24 hrs after injection when compared to the controls which were treated with 5% NaHCO3 only. Twenty four hours following the injection of UN, serum creatinine and blood urea nitrogen levels had increased. These changes continued for at least 72 hours, although the concentration of uranium had decreased. Light microscopic studies conducted 24 hours after injection, revealed partial degeneration and necrosis of the proximal tubules and many casts m the distal convoluted tubules. These changes progressed for 72 hours. Despite this tubular damage, the glomeruli were relatively intact. 5 days after injection, the epithelial cells lining the proximal tubules displayed regenerative activities; these findings were more prominent after 10 days. Through electron microscopic examination, we observed the destruction of mitochondria in the proximal tubular cells, a possible cause of polyuria. Ten days post injection regenerative activities in the proximal tubular cells showed that the maturation of intracellular organelles followed the proliferation of the premature cells.

Expression of Hypoxia Inducible Factor-1? in Human Renal Proximal Tubular Cells Injuried by Hypoxia/Reoxygenation and the Intervention Effect of Danshen / 实用儿科临床杂志

Objective To explore expression of hypoxia inducible factor-1?(HIF-1?)in kidney cells during hypoxia/reoxygenation injury,and to study the effect of Danshen on prevention of the hypoxia/reoxygenation injury to cells.Methods Human renal proximal tubular cells(HK-2)were used as the target cell.There were 3 groups:control group,model group,Danshen group.hypoxia/reoxygenation models after neonatal asphyxia were established with liquid paraffin covering method.Expression of HIF-1? were detected with strcp avidin biotin complex(SABC)immunohistochemistry at following different time points:hypoxia 1,4,8,12,24 h,which means 1,4,8,12,24 h respectively after hypoxia;and hypoxia/reoxygenation 1,4,8,12,24 h,which means 1,4,8,12,24 h respectively after hypoxia/reoxygenation.Results HIF-1? was expressed mainly in HK-2's nucleus.There had low expression of HIF-1? in HK-2 cells under the normal culture,and its expression level kept rising quickly during hypoxic/reoxygenatic culture,until 4 h after the beginning of reoxygenation.Compared with the study group,the expression level of HIF-1? in HK-2 cells of the Danshen group were significantly lower at different time points(Pa