Superoxide dismutase mimetic drug tempol aggravates anti-GBM antibody-induced glomerulonephritis in mice

Total glycosides of Rhodiola rosea L. attenuate LPS-induced acute lung injury by inhibiting TLR4/NF-κB pathway

Acute lung injury (ALI) is a common respiratory disease in clinics, which is characterized by alveolar-capillary membrane loss, plasma protein leakage, pulmonary edema, massive neutrophil infiltration, and the release of proinflammatory cytokines and mediators. Rhodiola rosea L. an adaptogenic plant rich in phenylethanoloids, phenylpropanoids, monoterpenes, has anti-inflammatory and antioxidant effects. We hope to verify the relieving effect of total glycosides of Rhodiola rosea L. (RTG) on ALI in mice and clarify its mechanism through this study. In this study, we identified the effect and mechanism of RTG on ALI through LPS-induced ALI mice. After RTG treatment, the pathological structure of lung tissue in ALI mice induced by LPS was significantly improved, and the infiltration of inflammatory cells was reduced. In addition, RTG reduced the production of IL-6, IL-1β, and TNF-α in the serum of ALI mice and reduced the content or activity of MPO, T-SOD, GSH, and MDA in lung tissue. RNAseq analysis showed that RTG ameliorated LPS-induced ALI through anti-inflammatory, reduced immune response, and anti-apoptotic activities. The western blotting analysis confirmed that RTG could down-regulate the expression levels of TLR4, MyD88, NF-κB p65, and p-IκBα/IκBα. These results suggest that RTG can attenuate LPS-induced ALI through antioxidants and inhibition of the TLR4/NF-κB pathway.

Effect of N-Acetyl Cysteine on Renal Interstitial Fibrosis in Mice

This study examined the effect of N-acetyl cysteine (NAC), a reactive oxygen species (ROS) inhibitor, on renal interstitial fibrosis induced by unilateral ureteral obstruction (UUO) in mice. UUO led to a significant increase in the fibrotic area of obstructed kidneys, which was attenuated by NAC (84.8 mg/kg/d) in the drinking water. Renal expression of type III collagen and tumor necrosis factor (TNF)-α mRNAs was elevated in UUO mice and inhibited by NAC. Extracellular signal-regulated kinase (ERK1/2) phosphorylation was significantly elevated by UUO, and NAC significantly attenuated the elevation. UUO inhibited the activity of glutathione peroxidase, while NAC restored its activity. Together, the results of this study suggest that renal interstitial fibrosis induced by UUO was ameliorated by NAC via several mechanisms including increased glutathione peroxidase activity, reduced phosphorylation of ERK1/2, and reduced expression of TNF-α and type III collagen mRNAs.

Chromophore of an Enhanced Green Fluorescent Protein Can Play a Photoprotective Role Due to Photobleaching

Under stress conditions, elevated levels of cellular reactive oxygen species (ROS) may impair crucial cellular structures. To counteract the resulting oxidative damage, living cells are equipped with several defense mechanisms, including photoprotective functions of specific proteins. Here, we discuss the plausible ROS scavenging mechanisms by the enhanced green fluorescent protein, EGFP. To check if this protein could fulfill a photoprotective function, we employed electron spin resonance (ESR) in combination with spin-trapping. Two organic photosensitizers, rose bengal and methylene blue, as well as an inorganic photocatalyst, nano-TiO₂, were used to photogenerate ROS. Spin-traps, TMP-OH and DMPO, and a nitroxide radical, TEMPOL, served as molecular targets for ROS. Our results show that EGFP quenches various forms of ROS, including superoxide radicals and singlet oxygen. Compared to the three proteins PNP, papain, and BSA, EGFP revealed high ROS quenching ability, which suggests its photoprotective role in living systems. Damage to the EGFP chromophore was also observed under strong photo-oxidative conditions. This study contributes to the discussion on the protective function of fluorescent proteins homologous to the green fluorescent protein (GFP). It also draws attention to the possible interactions of GFP-like proteins with ROS in systems where such proteins are used as biological markers.

Lipoxin A4 protects against paraquat‑induced acute lung injury by inhibiting the TLR4/MyD88‑mediated activation of the NF‑κB and PI3K/AKT pathways

Paraquat (PQ) causes serious oxidative stress and inflammatory responses, particularly to the lungs. Since lipoxin A4 (LXA4) functions as an anti‑inflammatory mediator, the present study aimed to explore its effects on PQ‑induced acute lung injury (ALI) and to elucidate the possible underlying mechanisms. PQ was administered to male SD rats and RAW264.7 cells to establish a model of poisoning, and LXA4 was used as an intervention drug. LXA4 treatment attenuated PQ‑induced lung injury, and this was accompanied by decreased tumor necrosis factor (TNF)‑α and interleukin (IL)‑1β secretion levels, and reduced oxidative stress damage. Additionally, LXA4 treatment inhibited the activation of the inflammation‑related signaling molecules, Toll‑like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), nuclear factor (NF)‑κB p65, p‑phosphoinositide 3‑kinase (PI3K) and p‑AKT. Furthermore, the in vitro experiments further confirmed that the beneficial effects of LXA4 on PQ‑induced damage were TLR4‑dependent. Hence, the present study demonstrated that LXA4 attenuated PQ‑induced toxicity in lung tissue and RAW264.7 macrophages, and that this protective effect may be closely related to the mitigation of inflammatory responses, oxidative stress damage and the TLR4/MyD88‑mediated activation of the PI3K/AKT/NF‑κB pathway.

Photocatalytic Nanowires-Based Air Filter: Towards Reusable Protective Masks

In the last couple decades, several viral outbreaks resulting in epidemics and pandemics with thousands of human causalities have been witnessed. The current Covid-19 outbreak represents an unprecedented crisis. In stopping the virus' spread, it is fundamental to have personal protective equipment and disinfected surfaces. Here, the development of a TiO2 nanowires (TiO2NWs) based filter is reported, which it is believed will work extremely well for personal protective equipment (PPE), as well as for a new generation of air conditioners and air purifiers. Its efficiency relies on the photocatalytic generation of high levels of reactive oxygen species (ROS) upon UV illumination, and on a particularly high dielectric constant of TiO2, which is of paramount importance for enhanced wettability by the water droplets carrying the germs. The filter pore sizes can be tuned by processing TiO2NWs into filter paper. The kilogram-scale production capability of TiO2NWs gives credibility to its massive application potentials.

Reactive oxygen species in renal vascular function

Reactive oxygen species (ROS) are produced by the aerobic metabolism. The imbalance between production of ROS and antioxidant defence in any cell compartment is associated with cell damage and may play an important role in the pathogenesis of renal disease. NADPH oxidase (NOX) family is the major ROS source in the vasculature and modulates renal perfusion. Upregulation of Ang II and adenosine activates NOX via AT1R and A1R in renal microvessels, leading to superoxide production. Oxidative stress in the kidney prompts renal vascular remodelling and increases preglomerular resistance. These are key elements in hypertension, acute and chronic kidney injury, as well as diabetic nephropathy. Renal afferent arterioles (Af), the primary resistance vessel in the kidney, fine tune renal hemodynamics and impact on blood pressure. Vice versa, ROS increase hypertension and diabetes, resulting in upregulation of Af vasoconstriction, enhancement of myogenic responses and change of tubuloglomerular feedback (TGF), which further promotes hypertension and diabetic nephropathy. In the following, we highlight oxidative stress in the function and dysfunction of renal hemodynamics. The renal microcirculatory alterations brought about by ROS importantly contribute to the pathophysiology of kidney injury, hypertension and diabetes.

Effects of Erdosteine in Experimental Sepsis Model in Rats

Objective

Erdosteine is a mucolytic agent that is known to possess antioxidant effects. This study investigated the effects of erdosteine on endothelin-1 (ET-1) levels and oxidative stress parameters superoxide dismutase (SOD) and malondialdehyde (MDA) in a rat sepsis model.

Methods

Four groups of Wistar albino rats (n=8 per group) were randomly allocated to the following groups: sham (group 1), sepsis (group 2), erdosteine control (group 3) and a sepsis group pretreated with erdosteine (group 4). Sepsis was induced using E. Coli ATCC 25922 inoculation. Serum ET-1, liver tissue SOD and MDA levels were determined in all groups.

Results

ET-1 levels were significantly higher in group 2 compared to groups 1, 3 and 4 (p<0.001, p=0.002 and p<0.001, respectively). Similarly, MDA levels in groups 1, 3 and 4 were significantly lower relative to group 2 (p<0.001, p=0.022 and p=0.010, respectively). Additionally, SOD activities in these same three groups were found to be significantly higher than those in group 2 (p<0.001, p=0.004 and p=0.028, respectively).

Conclusion

In conclusion, erdosteine decreases ET-1 levels and ameliorates oxidative stress parameters induced by sepsis in an experimental rat model of sepsis.

Differential effects of superoxide and hydrogen peroxide on myogenic signaling, membrane potential, and contractions of mouse renal afferent arterioles

Myogenic contraction is the principal component of renal autoregulation that protects the kidney from hypertensive barotrauma. Contractions are initiated by a rise in perfusion pressure that signals a reduction in membrane potential (Em) of vascular smooth muscle cells to activate voltage-operated Ca(2+) channels. Since ROS have variable effects on myogenic tone, we investigated the hypothesis that superoxide (O2 (·-)) and H2O2 differentially impact myogenic contractions. The myogenic contractions of mouse isolated and perfused single afferent arterioles were assessed from changes in luminal diameter with increasing perfusion pressure (40-80 mmHg). O2 (·-), H2O2, and Em were assessed by fluorescence microscopy during incubation with paraquat to increase O2 (·-) or with H2O2 Paraquat enhanced O2 (·-) generation and myogenic contractions (-42 ± 4% vs. -19 ± 4%, P < 0.005) that were blocked by SOD but not by catalase and signaled via PKC. In contrast, H2O2 inhibited the effects of paraquat and reduced myogenic contractions (-10 ± 1% vs. -19 ± 2%, P < 0.005) and signaled via PKG. O2 (·-) activated Ca(2+)-activated Cl(-) channels that reduced Em, whereas H2O2 activated Ca(2+)-activated and voltage-gated K(+) channels that increased Em Blockade of voltage-operated Ca(2+) channels prevented the enhanced myogenic contractions with paraquat without preventing the reduction in Em Myogenic contractions were independent of the endothelium and largely independent of nitric oxide. We conclude that O2 (·-) and H2O2 activate different signaling pathways in vascular smooth muscle cells linked to discreet membrane channels with opposite effects on Em and voltage-operated Ca(2+) channels and therefore have opposite effects on myogenic contractions.

Raman spectroscopy as a diagnostic tool for monitoring acute nephritis

Both acute nephritis and chronic nephritis account for substantial morbidity and mortality worldwide, partly due to the lack of reliable tools for detecting disease early and monitoring its progression non-invasively. In this work, Raman spectroscopy coupled with multivariate analysis are employed for the first time to study the accelerated progression of nephritis in anti-GBM mouse model. Preliminary results show up to 98% discriminant accuracy for the severe and midly diseased and the healthy among two strains of mice with different susceptibility to acute glomerulonephritis. This technique has the potential for non-invasive or minimally-invasive early diagnosis, prognosis, and monitoring of renal disease progression.

Silymarin attenuates paraquat-induced lung injury via Nrf2-mediated pathway in vivo and in vitro

The present study aims to investigate the impacts and mechanisms of silymarin on paraquat (PQ)-induced lung injury in vivo and in vitro. In in vivo experiments, a total of 32 male Sprague-Dawley (SD) rats were randomly divided into four groups. The rats were killed on day 3. Histopathological changes in lung tissue were examined using HE and Masson's trichrome staining. Biomarkers of neutrophil activation, pulmonary oedema, pulmonary fibrosis, lung permeability and oxidative stress were detected. Several proinflammatory mediators and antioxidant related proteins were measured. In in vitro experiments, A549 cells were transfected with Nrf2 special siRNA to investigate the roles of Nrf2. The results show that silymarin administration abated PQ-induced lung histopathologic changes, decreased inflammatory cell infiltration and lung wet weight/dry weight (W/D) ratio, suppressed myeloperoxidase (MPO) activity and nitric oxide (NO)/inducible nitric oxide synthases (iNOS) expression, downregulated hydroxyproline (HYP) levels, reduced total protein concentration and proinflammatory mediator release, and improved oxidative stress (malondialdehyde, MDA; superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GSH-Px) in lung tissue and serum. Meanwhile, treatment with silymarin upregulated the levels of nuclear factor-erythroid-2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase-1(NQO1). However, the addition of Nrf2 siRNA reduced the expression of Nrf2-mediated antioxidant protein HO-1 and thus reversed the protective effects of silymarin against oxidative stress and inflammatory response. These results suggest that silymarin may exert protective effects against PQ-induced lung injury. Its mechanisms were associated with the Nrf2-mediated pathway. Therefore, silymarin may be a potential therapeutic drug for lung injury.

Value of caffeic acid phenethyl ester pretreatment in experimental sepsis model in rats

Background and Aim. The aim of this study was to determine the actions of caffeic acid phenethyl ester (CAPE) on the changes of endothelin-1 (ET-1) level, tumor necrosis factor- (TNF-) alpha, and oxidative stress parameters such as superoxide dismutase (SOD) activities and malondialdehyde (MDA) levels in experimental sepsis model in rats. Materials and Methods. Twenty-four rats were randomly divided into three experimental groups: sham (group 1), sepsis (group 2), and sepsis + CAPE (group 3), n = 8 each. CAPE was administered (10 µmol/kg) intraperitoneally to group 3 before sepsis induction. Serum ET-1, serum TNF-alpha, tissue SOD activity, and tissue MDA levels were measured in all groups. Results. Pretreatment with CAPE decreased ET-1, TNF-alpha, and MDA levels in sepsis induced rats. Additionally SOD activities were higher in rats pretreated with CAPE after sepsis induction. Conclusion. Our results demonstrate that CAPE may have a beneficial effect on ET and TNF-alpha levels and oxidative stress parameters induced by sepsis in experimental rat models. Therefore treatment with CAPE can be used to avoid devastating effects of sepsis.

Green tea polyphenol (-)-epigallocatechin-3-gallate restores Nrf2 activity and ameliorates crescentic glomerulonephritis

Crescentic glomerulonephritis (GN) is the most severe form of GN and is associated with significant morbidity and mortality despite aggressive immunotherapy with steroids, cytotoxic drugs, and plasmapheresis. We examined the therapeutic efficacy of the green tea polyphenol (−)-epigallocatechin-3-gallate (EGCG, 50 mg/kg BW/day x3weeks), a potent anti-inflammatory and anti-oxidant agent, on experimental crescentic GN induced in 129/svJ mice by administration of rabbit anti-mouse glomerular basement membrane sera. Routine histology and key molecules involved in inflammatory and redox signaling were studied. EGCG treatment significantly reduced mortality, decreased proteinuria and serum creatinine, and markedly improved renal histology when compared with vehicle-treated mice. The improvements in renal function and histology were accompanied by the restoration of Nrf2 signaling (which was impaired in vehicle-treated mice) as shown by increased nuclear translocation of Nrf2 and cytoplasmic glutamate cysteine ligase catalytic subunit, glutamate cysteine ligase modifier subunit, and glutathione peroxidase. EGCG-treated mice also showed reduction in p-Akt, p-JNK, p-ERK1/2 and p-P38 as well as restoration of PPARγ and SIRT1 levels. Lower dose of EGCG (25 mg/kg BW/day x2 weeks) treatment also significantly decreased proteinuria and serum creatinine, and markedly improved renal histology when compared with vehicle-treated mice. Thus, our data illustrate the efficacy of EGCG in reversing the progression of crescentic GN in mice by targeting multiple signaling and inflammatory pathways as well as countering oxidative stress.

Glutathione S-transferase Mu 2-transduced mesenchymal stem cells ameliorated anti-glomerular basement membrane antibody-induced glomerulonephritis by inhibiting oxidation and inflammation

INTRODUCTION

Oxidative stress is implicated in tissue inflammation, and plays an important role in the pathogenesis of immune-mediated nephritis. Using the anti-glomerular basement membrane antibody-induced glomerulonephritis (anti-GBM-GN) mouse model, we found that increased expression of glutathione S-transferase Mu 2 (GSTM2) was related to reduced renal damage caused by anti-GBM antibodies. Furthermore, mesenchymal stem cell (MSC)-based therapy has shed light on the treatment of immune-mediated kidney diseases. The aim of this study was to investigate if MSCs could be utilized as vehicles to deliver the GSTM2 gene product into the kidney and to evaluate its potential therapeutic effect on anti-GBM-GN.

METHODS

The human GSTM2 gene (hGSTM2) was transduced into mouse bone marrow-derived MSCs via a lentivirus vector to create a stable cell line (hGSTM2-MSC). The cultured hGSTM2-MSCs were treated with 0.5 mM H2O2, and apoptotic cells were measured by terminal dUTP nick-end labeling (TUNEL) assay. The 129/svj mice, which were challenged with anti-GBM antibodies, were injected with 10⁶ hGSTM2-MSCs via the tail vein. Expression of hGSTM2 and inflammatory cytokines in the kidney was assayed by quantitative PCR and western blotting. Renal function of mice was evaluated by monitoring proteinuria and levels of blood urea nitrogen (BUN), and renal pathological changes were analyzed by histochemistry. Immunohistochemical analysis was performed to measure inflammatory cell infiltration and renal cell apoptosis.

RESULTS

MSCs transduced with hGSTM2 exhibited similar growth and differentiation properties to MSCs. hGSTM2-MSCs persistently expressed hGSTM2 and resisted H2O2-induced apoptosis. Upon injection into 129/svj mice, hGSTM2-MSCs migrated to the kidney and expressed hGSTM2. The anti-GBM-GN mice treated with hGSTM2-MSCs exhibited reduced proteinuria and BUN (58% and 59% reduction, respectively) and ameliorated renal pathological damage, compared with control mice. Mice injected with hGSTM2-MSCs showed alleviated renal inflammatory cell infiltration and reduced expression of chemokine (C-C motif) ligand 2 (CCL2), interleukin (IL)-1β and IL-6 (53%, 46% and 52% reduction, respectively), compared with controls. Moreover, hGSTM2-MSCs increased expression of renal superoxide dismutase and catalase, which may associate with detoxifying reactive oxygen species to prevent oxidative renal damage.

CONCLUSIONS

Our data suggest that the enhanced protective effect of GSTM2-transduced MSCs against anti-GBM-GN might be associated with inhibition of oxidative stress-induced renal cell apoptosis and inflammation, through over-expression of hGSTM2 in mouse kidneys.

Delivering Oxidation Resistance-1 (OXR1) to Mouse Kidney by Genetic Modified Mesenchymal Stem Cells Exhibited Enhanced Protection against Nephrotoxic Serum Induced Renal Injury and Lupus Nephritis

OBJECTIVE

To elucidate the role of oxidation resistance 1 (OXR1) gene. Oxidative stress plays a pivotal role in pathogenesis of immune-mediated nephritis. Recently we identified oxidation resistance 1 (OXR1) is conventionally expressed in eukaryotes and has an ability to prevent oxidative damage caused by various oxidative stresses. However the protective effect of OXR1 in immune-associated inflammatory response and oxidative damage is not clear and will be investigated in this study.

METHODS

We utilized mesenchymal stem cells (MSCs) as vehicles to carry OXR1 into the injured kidneys of nephritis model mice and investigated the influence of OXR1 on glomerulonephritis. Human OXR1 gene was integrated into genome of MSCs via lentiviral vector, and established hOXR1-MSC cell line which still maintains the differentiation property. 129/svj mice with anti-glomerular basement membrane (GBM) challenge and spontaneous lupus mice B6.Sle1.Sle2.Sle3 were injected with hOXR1-MSCs (i.v. injection) to evaluate the function of hOXR1. Immunohistochemistry was used to appraise the renal pathology and Tunel staining was applied to detect cell apoptosis.

RESULTS

Compared with control mice, hOXR1-MSCs administration showed significantly decreased blood urea nitrogen (BUN), proteinuria and ameliorated renal pathological damage. hOXR1-MSCs transplantation significantly reduced macrophage and T lymphocyte infiltration by inhibiting the expression of CCL2, CCL7, IL-1β, IL-6 and NFκB in mouse kidney. Moreover, hOXR1-MSCs prevented hydrogen peroxide (H₂O₂)-induced oxidative stress and its implantation reduced nitric oxide (NO) in mouse serum and urine to inhibit tubular cell apoptosis.

CONCLUSION

OXR1-MSCs transplantation may exert a certain protective effect on nephritis by suppressing inflammation and oxidative stress.

Kallikrein transduced mesenchymal stem cells protect against anti-GBM disease and lupus nephritis by ameliorating inflammation and oxidative stress

Previously we have shown that kallikreins (klks) play a renoprotective role in nephrotoxic serum induced nephritis. In this study, we have used mesenchymal stem cells (MSCs) as vehicles to deliver klks into the injured kidneys and have measured their therapeutic effect on experimental antibody induced nephritis and lupus nephritis. Human KLK-1 (hKLK1) gene was transduced into murine MSCs using a retroviral vector to generate a stable cell line, hKLK1-MSC, expressing high levels of hKLK1. 129/svj mice subjected to anti-GBM induced nephritis were transplanted with 10⁶ hKLK1-MSCs and hKLK1 expression was confirmed in the kidneys. Compared with vector-MSCs injected mice, the hKLK1-MSCs treated mice showed significantly reduced proteinuria, blood urea nitrogen (BUN) and ameliorated renal pathology. Using the same strategy, we treated lupus-prone B6.Sle1.Sle3 bicongenic mice with hKLK1-MSCs and demonstrated that hKLK1-MSCs delivery also attenuated lupus nephritis. Mechanistically, hKLK1-MSCs reduced macrophage and T-lymphocyte infiltration into the kidney by suppressing the expression of inflammation cytokines. Moreover, hKLK1 transduced MSCs were more resistant to oxidative stress-induced apoptosis. These findings advance genetically modified MSCs as potential gene delivery tools for targeting therapeutic agents to the kidneys in order to modulate inflammation and oxidative stress in lupus nephritis.

Effects of the antioxidant drug tempol on renal oxygenation in mice with reduced renal mass

We tested the hypothesis that reactive oxygen species (ROS) contributed to renal hypoxia in C57BL/6 mice with &frac56; surgical reduction of renal mass (RRM). ROS can activate the mitochondrial uncoupling protein 2 (UCP-2) and increase O(2) usage. However, UCP-2 can be inactivated by glutathionylation. Mice were fed normal (NS)- or high-salt (HS) diets, and HS mice received the antioxidant drug tempol or vehicle for 3 mo. Since salt intake did not affect the tubular Na(+) transport per O(2) consumed (T(Na/)Q(O2)), further studies were confined to HS mice. RRM mice had increased excretion of 8-isoprostane F(2α) and H(2)O(2), renal expression of UCP-2 and renal O(2) extraction, and reduced T(Na/)Q(O2) (sham: 20 ± 2 vs. RRM: 10 ± 1 μmol/μmol; P < 0.05) and cortical Po(2) (sham: 43 ± 2, RRM: 29 ± 2 mmHg; P < 0.02). Tempol normalized all these parameters while further increasing compensatory renal growth and glomerular volume. RRM mice had preserved blood pressure, glomeruli, and patchy tubulointerstitial fibrosis. The patterns of protein expression in the renal cortex suggested that RRM kidneys had increased ROS from upregulated p22(phox), NOX-2, and -4 and that ROS-dependent increases in UCP-2 led to hypoxia that activated transforming growth factor-β whereas erythroid-related factor 2 (Nrf-2), glutathione peroxidase-1, and glutathione-S-transferase mu-1 were upregulated independently of ROS. We conclude that RRM activated distinct processes: a ROS-dependent activation of UCP-2 leading to inefficient renal O(2) usage and cortical hypoxia that was offset by Nrf-2-dependent glutathionylation. Thus hypoxia in RRM may be the outcome of NADPH oxidase-initiated ROS generation, leading to mitochondrial uncoupling counteracted by defense pathways coordinated by Nrf-2.

Protein adducts of malondialdehyde and 4-hydroxynonenal contribute to trichloroethene-mediated autoimmunity via activating Th17 cells: dose- and time-response studies in female MRL+/+ mice

Trichloroethene (TCE), a common occupational and environmental toxicant, is known to induce autoimmunity. Previous studies in our laboratory showed increased oxidative stress in TCE-mediated autoimmunity. To further establish the role of oxidative stress and to investigate the mechanisms of TCE-mediated autoimmunity, dose- and time-response studies were conducted in MRL+/+ mice by treating them with TCE via drinking water at doses of 0.5, 1.0 or 2.0mg/ml for 12, 24 or 36 weeks. TCE exposure led to dose-related increases in malondialdehyde (MDA)-/hydroxynonenal (HNE)-protein adducts and their corresponding antibodies in the sera and decreases in GSH and GSH/GSSG ratio in the kidneys at 24 and 36 weeks, with greater changes at 36 weeks. The increases in these protein adducts and decreases in GSH/GSSG ratio were associated with significant elevation in serum anti-nuclear- and anti-ssDNA-antibodies, suggesting an association between TCE-induced oxidative stress and autoimmune response. Interestingly, splenocytes from mice treated with TCE for 24 weeks secreted significantly higher levels of IL-17 and IL-21 than did splenocytes from controls after stimulation with MDA-mouse serum albumin (MSA) or HNE-MSA adducts. The increased release of these cytokines showed a dose-related response and was more pronounced in mice treated with TCE for 36 weeks. These studies provide evidence that MDA- and or HNE-protein adducts contribute to TCE-mediated autoimmunity, which may be via activation of Th17 cells.

The green tea polyphenol (-)-epigallocatechin-3-gallate ameliorates experimental immune-mediated glomerulonephritis

The unchecked overproduction of reactive oxygen and nitrogen species by inflammatory cells can cause tissue damage, intensify inflammation, promote apoptosis, and accelerate the progression of immune-mediated glomerulonephritis (GN). Here we tested whether the anti-inflammatory and antioxidant properties of the green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) favorably affect the development of immune-mediated GN. Pretreatment of 129/svJ mice with EGCG from 2 days before to 2 weeks after the induction of GN led to reduced proteinuria and serum creatinine, and marked improvement in renal histology when compared with vehicle-pretreated diseased mice. This pretreatment reduced oxidative stress, and normalized osteopontin, p65/nuclear factor-κB, inducible nitric oxide synthase, nitric oxide metabolites, p-Akt, phosphorylated extracellular signal-regulated kinases 1 and 2, p47phox, and myeloperoxidase, all of which were elevated in vehicle-pretreated diseased mice. Levels of glutathione peroxidase and peroxisome proliferator-activated receptor-γ (PPARγ), both reduced in the vehicle-pretreated diseased mice, were normalized. This renoprotective effect was reversed by concomitant administration of the PPARγ antagonist GW9662 throughout the EGCG pretreatment period. Importantly, mortality and renal dysfunction were significantly attenuated even when the polyphenol treatment was initiated 1 week after the onset of GN. Thus, EGCG reversed the progression of immune-mediated GN in mice by targeting redox and inflammatory pathways.

Superoxide modulates myogenic contractions of mouse afferent arterioles

Reactive oxygen species enhance or impair autoregulation. Because superoxide is a vasoconstrictor, we tested the hypothesis that stretch generates superoxide that mediates myogenic responses. Increasing perfusion pressure of mouse isolated perfused renal afferent arterioles from 40 to 80 mm Hg reduced their diameter by 13.3±1.8% (P<0.001) and increased reactive oxygen species (ethidium: dihydroethidium fluorescence) by 9.8±2.3% (P<0.05). Stretch-induced fluorescence was reduced significantly (P<0.05) by incubation with Tempol (3.7±0.8%), pegylated superoxide dismutase (3.2±1.0%), or apocynin (3.5±0.9%) but not by pegylated catalase, L-nitroarginine methylester, or Ca(2+)-free medium, relating it to Ca(2+)-independent vascular superoxide. Compared with vehicle, basal tone and myogenic contractions were reduced significantly (P<0.05) by pegylated superoxide dismutase (5.4±0.8), Tempol (4.1±1.0%), apocynin (1.0±1.3%), and diphenyleneiodinium (3.9±0.9%) but not by pegylated catalase (10.1±1.6%). L-Nitroarginine methylester enhanced basal tone, but neither it (15.8±3.3%) nor endothelial NO synthase knockout (10.2±1.8%) significantly changed myogenic contractions. Tempol had no further effect after superoxide dismutase but remained effective after catalase. H(2)O(2) >50 μmol/L caused contractions but at 25 μmol/L inhibited myogenic responses (7.4±0.8%; P<0.01). In conclusion, increasing the pressure within afferent arterioles led to Ca(2+)-independent increased vascular superoxide production from nicotinamide adenine dinucleotide phosphate oxidase, which enhanced myogenic contractions largely independent of NO, whereas H(2)O(2) impaired pressure-induced contractions but was not implicated in the normal myogenic response.