Commiphora molmol protects against methotrexate-induced nephrotoxicity by up-regulating Nrf2/ARE/HO-1 signaling.

Commiphora molmol possesses multiple therapeutic benefits against various diseases; however, its protective role against methotrexate (MTX) renal toxicity has not been previously investigated. MTX is a dihydrofolate reductase inhibitor that can induce acute kidney injury (AKI). This study evaluated the in vitro antioxidant activity and the protective effect of C. molmol resin extract against MTX-induced oxidative stress, inflammation and renal injury. Male Wistar rats received 125 and 250 mg/kg C. molmol resin extract for 15 days and a single injection of MTX at day 16. C. molmol showed a radical scavenging activity against DPPH, superoxide and nitric oxide (NO) radicals. Rats received MTX showed renal injury evidenced by the significantly elevated serum creatinine and urea, and the histological alterations. The kidney of MTX-induced rats exhibited increased lipid peroxidation, NO, NF-κB and pro-inflammatory cytokines. Pre-treatment with C. molmol prevented MTX-induced kidney injury and attenuated oxidative stress and inflammation. C. molmol down-regulated Bax and enhanced the activity and expression of the antioxidant defenses. Furthermore, the expression of Bcl-2, Nrf2, NQO-1 and HO-1 was down-regulated in the kidney of MTX-induced rats. Pre-treatment with C. molmol resin up-regulated Bcl-2 and activated Nrf2/HO-1 signaling in the kidney of MTX-induced rats. In conclusion, C. molmol resin provided protection against MTX-induced AKI via activation of Nrf2 signaling and mitigation of oxidative stress.

Rho Kinase Inhibitor, Fasudil, Attenuates Contrast-induced Acute Kidney Injury.

In this study, we tested the hypothesis that fasudil, a Rho kinase inhibitor, would protect against contrast-induced acute kidney injury (CI-AKI) in a mouse model and attempted to elucidate the mechanism involved. Mice subjected to unilateral ligation of the left anterior renal pedicle were divided into four groups: (1) control group, (2) CI-AKI induced by contrast media (CM group), (3) CI-AKI plus low-dose fasudil (LD group) and (4) CI-AKI plus high-dose fasudil (HD group). Animals from groups 2-4 received iodixanol (4.0 g iodine/kg), and the control group received saline. At 12, 2 hr before iodixanol injection and 4 hr after iodixanol administration, the animals in groups 3-4 received 3 or 10 mg/kg fasudil, respectively. Renal blood flow, renal function parameters, kidney histology and the expression of proteins that regulates apoptosis and inflammation were determined 24 hr later. Fasudil treatment notably ameliorated contrast medium-induced medullary damage, restored renal function, suppressed renal tubular apoptosis, ameliorated redox imbalance and DNA damage. Fasudil had a nephroprotective effect that was partially attributed to its anti-inflammatory, anti-apoptotic and antioxidant effects of inhibiting the Rho/ROCK pathway.

Heme oxygenase-1 mitigates ferroptosis in renal proximal tubule cells.

Ferroptosis is an iron-dependent form of regulated nonapoptotic cell death, which contributes to damage in models of acute kidney injury (AKI). Heme oxygenase-1 (HO-1) is a cytoprotective enzyme induced in response to cellular stress, and is protective against AKI because of its antiapoptotic and anti-inflammatory properties. However, the role of HO-1 in regulating ferroptosis is unclear. The purpose of this study was to elucidate the role of HO-1 in regulating ferroptotic cell death in renal proximal tubule cells (PTCs). Immortalized PTCs obtained from HO-1+/+ and HO-1-/- mice were treated with erastin or RSL3, ferroptosis inducers, in the presence or absence of antioxidants, an iron source, or an iron chelator. Cells were assessed for changes in morphology and metabolic activity as an indicator of cell viability. Treatment of HO-1+/+ PTCs with erastin resulted in a time- and dose-dependent increase in HO-1 gene expression and protein levels compared with vehicle-treated controls. HO-1-/- cells showed increased dose-dependent erastin- or RSL3-induced cell death in comparison to HO-1+/+ PTCs. Iron supplementation with ferric ammonium citrate in erastin-treated cells decreased cell viability further in HO-1-/- PTCs compared with HO-1+/+ cells. Cotreatment with ferrostatin-1 (ferroptosis inhibitor), deferoxamine (iron chelator), or N-acetyl-l-cysteine (glutathione replenisher) significantly increased cell viability and attenuated erastin-induced ferroptosis in both HO-1+/+ and HO-1-/- PTCs. These results demonstrate an important antiferroptotic role of HO-1 in renal epithelial cells.

Galangin ameliorates cisplatin-induced nephrotoxicity by attenuating oxidative stress, inflammation and cell death in mice through inhibition of ERK and NF-kappaB signaling.

Cisplatin is a chemotherapeutic agent widely used in the treatment of various cancers. However, cisplatin can induce nephrotoxicity and neurotoxicity, limiting its dosage and usage. Galangin, a natural flavonol, has been found to exhibit anti-oxidant and anti-inflammatory effects in vivo. Here, we investigated the effects of galangin on cisplatin-induced acute kidney injury (AKI) and its molecular mechanisms in mice. Galangin administration reduced the cisplatin-induced oxidative stress by decreasing renal MDA and 3-NT formations. Galangin administration also increased renal anti-oxidative enzyme activities (SOD, GPx, and CAT) and GSH levels depleted by cisplatin. Furthermore, galangin administration inactivated stress-induced Nrf2 protein and its downstream products, HO-1 and GCLC. In terms of the inflammatory response, galangin administration reduced IκBα phosphorylation, NF-κB phosphorylation and nuclear translocation, and then inhibited cisplatin-induced secretions of pro-inflammatory TNF-α, IL-1ß and IL-6. In addition, cisplatin-induced ERK and p38 phosphorylations were inhibited by galangin administration. In terms of cell death, galangin administration reduced levels of p53, pro-apoptotic Bax and activated caspase-3 to inhibit the cisplatin-induced apoptosis. Galangin administration also reduced the expression levels of RIP1 and RIP3 to inhibit cisplatin-induced RIP1/RIP3-dependent necroptosis. Therefore, galangin administration significantly ameliorates cisplatin-induced nephrotoxicity by attenuating oxidative stress, inflammation, and cell death through inhibitions of ERK and NF-κB signaling pathways. Galangin might be a potential adjuvant for clinical cisplatin therapy.

Histone deacetylase­mediated silencing of AMWAP expression contributes to cisplatin nephrotoxicity.

Cisplatin-induced acute kidney injury is a serious problem in cancer patients during treatment of solid tumors. Currently, there are no therapies available to treat or prevent cisplatin nephrotoxicity. Since histone deacetylase (HDAC) inhibition augments cisplatin anti-tumor activity, we tested whether HDAC inhibitors can prevent cisplatin-induced nephrotoxicity and determined the underlying mechanism. Cisplatin upregulated the expression of several HDACs in the kidney. Inhibition of HDAC with clinically used trichostatin A suppressed cisplatin-induced kidney injury, inflammation, and epithelial cell apoptosis. Moreover, trichostatin A upregulated the novel anti-inflammatory protein, activated microglia/macrophage WAP domain protein (AMWAP), in epithelial cells which was enhanced with cisplatin treatment. Interestingly, HDAC1 and -2 specific inhibitors are sufficient to potently upregulate AMWAP in epithelial cells. Administration of recombinant AMWAP or its epithelial cell-specific overexpression reduced cisplatin-induced kidney dysfunction. Moreover, AMWAP treatment suppressed epithelial cell apoptosis, and siRNA-based knockdown of AMWAP expression abolished trichostatin A-mediated suppression of epithelial cell apoptosis in vitro. Thus, HDAC-mediated silencing of AMWAP may contribute to cisplatin nephrotoxicity. Hence, HDAC1 and -2 specific inhibitors or AMWAP could be useful therapeutic agents for the prevention of cisplatin nephrotoxicity.

Protective effect of ginsenoside against acute renal failure via reduction of renal oxidative stress and enhanced expression of ChAT in the proximal convoluted tubule and ERK1/2 in the paraventricular nuclei.

Generation of reactive oxygen species significantly contributes to the pathogenesis of acute renal failure (ARF) induced by myoglobin release. Ginsenosides (GS), the principal active ingredients of ginseng, is considered as an extremely good antioxidative composition of Chinese traditional and herbal drugs. The purpose of the present study was to investigate the protective effect of ginsenoside in rats with ARF on the changes of cholinergic nervous system in the kidney as well as on the involvement of mitogen-activated protein kinases (MAPK) in the hypothalamic paraventricular nuclei (PVN). In our assay, glycerol-induced acute renal failure in rats was employed to study the protective effects of ginsenoside. Our results indicated that the treatment of ARF rats with ginsenosides for 48 h significantly reduced lipid peroxidation, restored the superoxide dismutase (SOD) level. Meanwhile, the obvious increase of choline acetyltransferase-immunoreactivity (ChAT-IR) in the proximal convoluted tubular cells (PCT) was observed by immunohistochemistry in ARF+GS group. The same effect was also observed in the changes of p-ERK1/2-IR in the hypothalamic paraventricular nuclei. Our results suggest that ginsenoside administered orally may have a strong renal protective effect against glycerol-induced ARF, reduce the renal oxidative stress, and ginsenoside can also activate the cholinergic system in PCT, simultaneously MAPK signal pathway in the PVN was also activated.

Antioxidant effect of Phyllanthus emblica extract prevents contrast-induced acute kidney injury.

BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) occurs after the administration of intravenous iodinated contrast agents. Oxidative stress has been proposed as one of the most important mechanisms in the pathogenesis of CI-AKI. The objective of this study was to investigate the antioxidant effect of the extract from Phyllanthus emblica (PE) in preventing CI-AKI. METHODS: Male Sprague Dawley rats were subjected into eight groups, were given water (control) or PE extract (125 or 250 or 500 mg/kg/day) for 5 days before the induction of CI-AKI. Renal function and oxidative stress markers; malondialdehyde (MDA), total antioxidant capacity (TAC), superoxide dismutase (SOD) and catalase (CAT) activity were determined in plasma and renal tissue. Kidney sections were performed for histopathological examination. RESULTS: In the contrast media (CM) group, increases in blood urea nitrogen and serum creatinine were demonstrated which correlated with severity of tubular necrosis, peritubular capillary congestion and interstitial edema. Moreover, an increase in MDA and a decrease in TAC SOD and CAT activity in CM group were significantly changed when compared with the control (P<0.05). In contrast, CI-AKI-induced rats administrated with PE extract 250 and 500 mg/kg/day significantly preserved renal function and attenuated the severity of pathological damage (P<0.05) as well as significantly lower MDA and higher TAC, SOD and CAT than the CM group (P<0.05). CONCLUSIONS: This study demonstrated the protective role of PE extract against CI-AKI.

The water-soluble triptolide derivative PG490-88 protects against cisplatin-induced acute kidney injury.

Triptolide, a traditional Chinese medicine, has anti-inflammatory, antiproliferative, and proapoptotic properties. As interstitial inflammation and tubular apoptosis are features of cisplatin-induced acute kidney injury (AKI), we determined the effect of the water-soluble triptolide derivative 14-succinyl triptolide sodium salt (PG490-88) in a mouse model of cisplatin-induced AKI. PG490-88 resulted in a significant decrease in blood urea nitrogen (BUN), serum creatinine, and acute tubular necrosis (ATN) score, and a nonsignificant increase in tubular apoptosis score in AKI. The mitogen-activated protein kinase (MAPK) pathway is activated in AKI. On immunoblot analysis, phosphoextracellular signal-regulated kinase (p-ERK) was increased 3.6-fold in AKI and 2.0-fold inhibited by PG490-88. Phospho-c-Jun N-terminal kinase (p-JNK) was increased in AKI. PG490-88 resulted in a nonsignificant decrease in p-JNK. Phospho-p38 was not affected by cisplatin or PG490-88. MAPK phosphatase-1 (MKP-1) that negatively regulates MAPK signaling has not previously been studied in AKI. MKP-1 activity was not affected by cisplatin or PG490-88. Changes in p-ERK, p-JNK, and MKP-1 were confirmed on reverse protein phase analysis. The ERK inhibitor U0126 resulted in lower BUN and serum creatinine, suggesting a mechanistic role of ERK in AKI. The increase in interleukin-1α (IL-1α), IL-1ß, IL-6, CXCL1, and IL-33 in the kidney in AKI was unaffected by PG490-88. In summary, PG490-88 protects against AKI and ATN despite no decrease in tubular apoptosis. The protection of PG490-88 against AKI was associated with a decrease in p-ERK and was independent of MKP-1 and proinflammatory cytokines. In conclusion, PG490-88 protects against cisplatin-induced AKI possibly by decreasing p-ERK.

False positivity of gamma-glutamyl transpeptidase measurement in urine.

Although enzymuria tends to be associated to renal injury, there are no studies that have evaluated the presence of the enzyme gamma-glutamyl transpeptidase (GGT) spectrophotometry in the urine using a non-nephrotoxic agent (Nerium oleander) in order to evaluate the possibility of false positive results. The urinary GGT/urinary creatinine concentration ratio (uGGT/uCr) of 10 healthy dogs was calculated and posteriorly confronted with data from clinical evaluation, hematological and serum biochemical profiles, creatinine clearance (CrC), urinalysis, urine protein/creatinine ratio (UPC), electrocardiogram, systemic blood pressure (SBP) and light and electron microscopy. The results for kidney histology, SBP, UPC and CrC were not significantly different in any of the time-points analyzed. However, uGGT/uCr was significantly higher when measured 4 hours and 24 hours after administration of N. oleander. The measurement of the urinary GGT enzyme, as performed in many studies, yielded false positive results in dogs poisoned by a non-nephrotoxic agent.

Phenolic antioxidants tert-butyl-bisphenol and vitamin E decrease oxidative stress and enhance vascular function in an animal model of rhabdomyolysis yet do not improve acute renal dysfunction.

Rhabdomyolysis (RM) caused by severe burn releases extracellular myoglobin (Mb) that accumulates in the kidney. Extracellular Mb is a pro-oxidant. This study tested whether supplementation with tert-butyl-bisphenol (BP) or vitamin E (Vit E, as α-tocopherol) at 0.12% w/w in the diet inhibits acute renal failure (ARF) in an animal model of RM. After RM-induction in rats, creatinine clearance decreased (p < 0.01), proteinuria increased (p < 0.001) and renal-tubule damage was detected. Accompanying ARF, biomarkers of oxidative stress (lipid oxidation and hemeoxygenase-1 (HO-1) gene and protein activity) increased in the kidney (p < 0.05). Supplemented BP or Vit E decreased lipid oxidation (p < 0.05) and HO-1 gene/activity and restored aortic cyclic guanylyl monophosphate in control animals (p < 0.001), yet ARF was unaffected. Antioxidant supplementation inhibited oxidative stress, yet was unable to ameliorate ARF in this animal model indicating that oxidative stress in kidney and vascular cells may not be causally related to renal dysfunction elicited by RM.

Protective effect of ginsenoside against acute renal failure and expression of tyrosine hydroxylase in the locus coeruleus.

Acute renal failure (ARF) is mainly characterized by acute tubular necrosis. No significant change was found for mortality rates over the past few decades despite significant advances in supportive care. In recent years, great effort has been focused on traditional and herbal medicine, which is much less toxic than those agents conventionally used and which is nowadays considered as a novel therapeutic agent for ARF. However, the effect of ginsenosides (GS) administered orally on ARF has not been reported yet and little is known about its cellular and molecular mechanism. The purpose of the study is to investigate the protective effect of ginsenoside in rats with ARF on the changes of tyrosine hydroxylase immunoreactivity (TH-IR) as well as on the involvement of mitogen-activated protein kinases (MAPK) in the locus coeruleus. In our assay, glycerol-induced acute renal failure in rats was employed to study the protective effects of ginsenoside. Our results indicated that the treatment of ARF rats with ginsenosides for 48 h significantly reduced the serum blood urea nitrogen, creatinine level, and lipid peroxidation, restored the GSH level and the normal renal morphology. Immunohistochemistry showed that an obvious increase of TH-IR was further enhanced in ARF+GS group. The same effect was also observed in the changes of p-ERK1/2-IR in the locus coeruleus. Our results suggest that ginsenoside administered orally may have a strong renal protective effect against glycerol-induced ARF, and ginsenoside can also activate the brain catecholaminergic neurons in the locus coeruleus. Our future attention will be focused to the question whether there is a correlation between the renal protective effect of ginsenosides against acute renal failure and the activation of tyrosine hydroxylase in the locus coeruleus.

Rehmannia glutinose ameliorates renal function in the ischemia/reperfusion-induced acute renal failure rats.

The present study was designed to examine whether aqueous extract of steamed root of Rehmannia glutinose (ARR) has an ameliorative effect on renal functional parameters in association with the expressions of aquaporin 2 (AQP 2), Na,K-ATPase, and heme oxygenase-1 (HO-1) in the ischemia-reperfusion induced acute renal failure (ARF) rats. Polyuria caused by down-regulation of renal AQP 2 in the ischemia-induced ARF rats was markedly restored by administration of ARR (200 mg/kg, p.o.) with restoring expression of AQP 2 in the kidney. The expressions of Na,K-ATPase alpha1 and beta1 subunits in the renal medullar and cortex of the ARF rats were also restored in the ARF rats by administration of ARR. On the other hand, administration of ARR lowered the renal expression of HO-1 up-regulated in rats with ischemia-induced ARF. The renal functional parameters including creatinine clearance, urinary sodium excretion, urinary osmolality, and solute-free reabsorption were also markedly restored in ischemia-ARF rats by administration of ARR. Taken together, these data indicate that RSR ameliorates renal defects in rats with ischemia-induced ARF.

The role of ginsenoside-Rd in cisplatin-induced acute renal failure.

Ginsenoside-Rd has been proved to decrease the severity of renal injury induced by cisplatin, in which proximal urinaferous tubules represent the main site of injury. When ginsenoside-Rd was given orally at a dose of 1 or 5 mg/kg body weight/day for 30 consecutive days prior to cisplatin injection, the activities of the antioxidation enzymes superoxide dismutase and catalase were higher, while malondialdehyde levels in serum and renal tissue were lower in the treated rats than in the controls. The levels of urea nitrogen and creatinine in serum were decreased in rats given ginsenoside-Rd. Decreased urinary levels of glucose, sodium and potassium reflected a protective action against the renal dysfunction caused by cisplatin. In addition, it was demonstrated that ginsenoside-Rd affected cultured proximal tubule cells exposed to cisplatin.

[Selenium and antioxidant status in various diseases]. / Der Selen- und Antioxidanzienstatus bei verschiedenen Krankheitsbildern.

All healthy mammalian organisms are characterized by an equilibrium between the occurrence of highly reactive oxygen species and their destruction by anti-oxidants. Numerous diseases go hand in hand with a disturbance of the homoeostatis. In order to avoid or minimize the destructive effect of the oxidant stress on biological structures, therapies utilizing drugs with anti-oxidant effects are increasingly being applied. Preconditions for these therapies are a characterisation and a follow-up of the anti-oxidant status in the diseased organism. In the course of the present study selenium, glutathione peroxidase and malondialdehyde were determined in patients with various clinical pictures (terminal renal insufficiency, septic shock, high-risk gravidieties, arterioscleroisis, pulmonary carcinoma, acute myocardial infarction, test patients taking the contraceptive pill). Patients with terminal renal insufficiency and those suffering from septic shock syndromes clearly show a selenium decrease in serum and whole blood as well as a drop in the GSH-Px-activity, and increased malondialdehyde concentrations in the serum. Both are a reflection of an increased lipid peroxidation. First results of a selenium therapy are available for patients with therminal renal insufficiency and post-traumatically induced renal failure. The interpretation of the findings in the categories "high-risk gravidity" and "women on the contraceptive pill", which show a normal GSH-Px-activity and significantly increased malondialdehyde concentrations, seems problematic. The organism counteracts an increased lipid peroxidation with a normal plasma-GSH-Px-activity, clearly a sign of a still normal anti-oxidant potential.

Mechanism of intestinal adaptation in rats with acute renal failure.

Acute renal failure (ARF) was experimentally induced in rats and the specific activity of mucosal Na-K-ATPase activity in segments of the small intestine and colon was measured. Bilateral nephrectomy (BN) resulted in a significant evaluation of the enzyme activity in all segments examined. With an additional procedure of adrenalectomy (BN + Ax), the enzyme activity failed to show any increase in ARF rats produced by BN. However, a supplementation of a maintenance dose of dexamethasone to adrenalectomized ARF rats (BN + Ax + DM 10) resulted in a significant resumption of the activity in all intestinal segments, although its increase was insignificant in the duodenum. Addition of a high dose of DOCA (BN + Ax + DOCA 500) was effective in increasing the enzyme activity only in the colon but not in the small intestine. With a high dose of DM or a maintenance dose of DM plus a high dose of DOCA (BN + Ax + DM 30 or BN + Ax + DM 10 + DOCA 500), there was an increase in the enzyme activity of all intestinal segments. In ARF rats induced by bilateral lower ureteral ligation (BLUL), the enzyme activity did not show any increase at all. Addition of a high dose of DOCA to this animal model (BLUL + DOCA 500) brought about the increase of the enzyme activity in the intestinal segments but for the jejunum.(ABSTRACT TRUNCATED AT 250 WORDS)