Protective effects of garlic powder against potassium dichromate-induced oxidative stress and nephrotoxicity

Cytoprotective remedies for ameliorating nephrotoxicity induced by renal oxidative stress

AIMS

Nephrotoxicity is the hallmark of anti-neoplastic drug metabolism that causes oxidative stress. External chemical agents and prescription drugs release copious amounts of free radicals originating from molecular oxidation and unless sustainably scavenged, they stimulate membrane lipid peroxidation and disruption of the host antioxidant mechanisms. This review aims to provide a comprehensive collection of potential cytoprotective remedies in surmounting the most difficult aspect of cancer therapy as well as preventing renal oxidative stress by other means.

MATERIALS AND METHODS

Over 400 published research and review articles spanning several decades were scrutinised to obtain the relevant data which is presented in 3 categories; sources, mechanisms, and mitigation of renal oxidative stress.

KEY-FINDINGS

Drug and chemical-induced nephrotoxicity commonly manifests as chronic or acute kidney disease, nephritis, nephrotic syndrome, and nephrosis. Renal replacement therapy requirements and mortalities from end-stage renal disease are set to rapidly increase in the next decade for which 43 different cytoprotective compounds which have the capability to suppress experimental nephrotoxicity are described.

SIGNIFICANCE

The renal system performs essential homeostatic functions that play a significant role in eliminating toxicants, and its accumulation and recurrence in nephric tissues results in tubular degeneration and subsequent renal impairment. Global statistics of the latest chronic kidney disease prevalence is 13.4 % while the end-stage kidney disease requiring renal replacement therapy is 4-7 million per annum. The remedial compounds discussed herein had proven efficacy against nephrotoxicity manifested consequent to impaired antioxidant mechanisms in preclinical models produced by renal oxidative stress activators.

Evaluation of the Antioxidant Activity of Levetiracetam in a Temporal Lobe Epilepsy Model

Epilepsy is a neurological disorder in which it has been shown that the presence of oxidative stress (OS) is implicated in epileptogenesis. The literature has shown that some antiseizure drugs (ASD) have neuroprotective properties. Levetiracetam (LEV) is a drug commonly used as an ASD, and in some studies, it has been found to possess antioxidant properties. Because the antioxidant effects of LEV have not been demonstrated in the chronic phase of epilepsy, the objective of this study was to evaluate, for the first time, the effects of LEV on the oxidant–antioxidant status in the hippocampus of rats with temporal lobe epilepsy (TLE). The in vitro scavenging capacity of LEV was evaluated. LEV administration in rats with TLE significantly increased superoxide dismutase (SOD) activity, increased catalase (CAT) activity, but did not change glutathione peroxidase (GPx) activity, and significantly decreased glutathione reductase (GR) activity in comparison with epileptic rats. LEV administration in rats with TLE significantly reduced hydrogen peroxide (H2O2) levels but did not change lipoperoxidation and carbonylated protein levels in comparison with epileptic rats. In addition, LEV showed in vitro scavenging activity against hydroxyl radical (HO•). LEV showed significant antioxidant effects in relation to restoring the redox balance in the hippocampus of rats with TLE. In vitro, LEV demonstrated direct antioxidant activity against HO•.

Nephroprotective Efficacy of Selenium and Zinc Against Potassium Dichromate-Induced Renal Toxicity in Pregnant Wistar Albino Rats

Hexavalent chromium (CrVI) compounds are potent toxicants commonly used in numerous industries. Thus, potential toxic effects and health hazards are of high relevance. Selenium (Se) and zinc (Zn) are known for their antioxidant and chemoprotective properties. However, little is known about their protective effects against CrVI-induced renal damage during pregnancy. In this context, the present study aimed to investigate the protective efficacy of these two essential elements against potassium dichromate-induced nephrotoxicity in pregnant Wistar Albino rats. Female rats were divided into control and four treated groups of six each receiving subcutaneously on the 3rd day of pregnancy, K₂Cr₂O₇ (10 mg/kg, s.c. single dose) alone, or in association with Se (0.3 mg/kg, s.c. single dose), ZnCl₂ (20 mg/kg, s.c. single dose) or both of them simultaneously. The nephrotoxic effects were monitored by the evaluation of plasma renal parameters, oxidative stress biomarkers, DNA damage, and renal Cr content. The obtained results showed that K₂Cr₂O₇ disturbed renal biochemical markers, induced oxidative stress and DNA fragmentation in kidney tissues, and altered renal histoarchitecture. The co-administration of Se and/or ZnCl₂ has exhibited pronounced chelative, antioxidant, and genoprotective effects against K₂Cr₂O₇-induced renal damage and attenuated partially the histopathological alterations. These results suggest that Se and Zn can be used as efficient nephroprotective agents against K₂Cr₂O₇-induced toxicity in pregnant Wistar Albino rats.

Nephroprotective role of Echinacea purpurea against potassium dichromate-induced oxidative stress, inflammation, and apoptosis in rats

Environmental and occupational exposure to chromium compounds, especially hexavalent chromium [Cr(VI)], is widely recognized as a potential nephrotoxic in humans and animals. Its toxicity is associated with the overproduction of free radicals, which induces oxidative damage. Echinacea purpurea (L.) Moench is an herbaceous perennial plant rich in phenolic components and frequently used for its medicinal benefits. The current work evaluated the effectiveness of E. purpurea (EP) against oxidative stress and nephrotoxicity induced by potassium dichromate in male rats. Male Wistar rats were divided into four groups: control, E. purpurea (EP; 50 mg/kg; once daily for 3 weeks), hexavalent chromium (Cr(VI); 15 mg/kg; single intraperitoneal dose), and EP + Cr(VI) where rats were pretreated with EP for 3 weeks before receiving CrVI, respectively. Results revealed that rats exposed to Cr(VI) showed a significant increase in PC, TBARS, and H₂ O₂ , kidney function biomarkers (Urea, creatinine, and uric acid), lactate dehydrogenase activity (LDH), TNF-α, IL-18, nuclear factor kappa B (NFκB), and IGF-1 (Insulin-like growth factor-1) levels as well as a considerable decline in metallothionein (MT), glutathione (GSH) content, enzymatic antioxidants (SOD, CAT, GPx, GR, and GST), alkaline phosphatase (ALP) activities, and protein content. Cr(VI) induced apoptosis in kidney tissues as revealed by upregulation of Bax and caspase 3 and downregulation of Bcl-2. Furthermore, EP treatment ameliorated the Cr(VI)-induced histopathological and ultrastructure variations of kidney tissue, which was confirmed by the biochemical and molecular data. It is clear from the results of this study that EP exerts nephroprotective effects by improving the redox state, suppressing inflammatory reaction and cell apoptosis as well as ameliorating the performance of kidney tissue architecture, which is eventually reflected by the improvement of kidney function in rats.

Hexavalent chromium induces renal apoptosis and autophagy via disordering the balance of mitochondrial dynamics in rats

The use of hexavalent chromium (Cr(VI)) in many industrial processes has resulted in serious environmental pollution problems. Cr(VI) causes organ toxicity in animals after ingestion or inhalation. However, the exact mechanism by which Cr(VI) produces kidney damage remains elusive. Herein, we investigated whether Cr(VI)-induced kidney damage is related to the disorder of mitochondrial dynamics. In this study, 28 male rats were divided into four groups and intraperitoneally injected with 0, 2, 4, and 6 mg/kg body weight potassium dichromate for 5 weeks. Experiment included analysis of renal histopathology and ultrastructure, determination of biochemical indicators, and measurement of related protein content. The results showed that Cr(VI) induced kidney injury through promotion of oxidative stress, apoptosis, and disorder of mitochondrial dynamics in a dose-dependent manner. The protein levels of the silent information regulator two ortholog 1 (Sirt1), peroxisome proliferation-activated receptor-g coactivator-1a (PGC-1a), and autophagy-related proteins were significantly decreased after Cr(VI) exposure. These findings suggest that Cr(VI) leads to the disorder of mitochondrial dynamics by inhibiting the Sirt1/PGC-1a pathway, which leads to renal apoptosis and autophagy in rats.

Evaluating the effect of garlic extract on serum inflammatory markers of peritoneal dialysis patients: a randomized double-blind clinical trial study

BACKGROUND

Garlic can be considered as a useful natural herb in inhibition of inflammation. The aim of this study was to assess the effectiveness of garlic extract in lowering inflammatory markers in peritoneal dialysis (PD) patients.

METHODS

In this parallel-designed double blind randomized clinical trial, 42 PD patients at the Shafa dialysis center, Tehran in 2017 were included. The primary outcome in this study was systemic inflammation which was evaluated by measuring the concentrations of IL-6 and CRP and ESR in serum.

RESULTS

Baseline versus after-intervention median (IQR) of IL-6 (pg/ml), CRP (mg/L) and mean ± SD of ESR (mm) in garlic and placebo groups was 2.2 (0.8, 6.4) versus 0.7 (0.6, 1.2) (p <  0.001) and 2.0 (0.8, 2.1) versus 0.6 (0.6, 0.8) (p = 0.002), 13.0 (5.0, 14.0) versus 2.0 (1.0, 9.0) (p <  0.001) and 7.0 (2.0, 10.0) versus 6.0 (3.7, 7.5) (p = 0.547) and 35.4 ± 21.7 versus 50.7 ± 28.5 (p = 0.021) and 46.0 ± 26.0 versus 45.3 ± 22.3 (p = 0.797). Median (IQR) of Percentage Before-After change in CRP was - 71.4%(- 85.7, - 42.9%) and - 20.0%(- 30.0, 114.3%) in garlic and placebo group respectively. The Mann-Whitney U test indicated this difference is statistically significant (p <  0.001).

CONCLUSION

The results imply that administrating 400 mg of standardized garlic extract twice a day for 8 weeks resulted in a significant reduction in IL-6, CRP and ESR. Since inflammatory state can be a serious life threatening condition in PD patients, we suggest prescribing this safe and well-tolerated natural substance to attenuate the inflammatory state in these patients. However, assessment of these effects in a larger randomized trial is strongly recommended (IRCTID: IRCT2017072535305N1, 2017-10-16).

Effect of various selenium doses on chromium(IV)-induced nephrotoxicity in a male chicken model

Our study aimed to explore whether Na₂SeO₃ (Se) can alleviate the nephrotoxicity induced by K₂Cr₂O₇ [Cr(VI)]. One hundred and five male chickens were randomly divided into seven groups with 15 chickens each group: The 6 experimental groups received K₂Cr₂O₇ alone or in combination with 0.31, 0.63, 1.25, 2.50, and 5.00 mg/kg for 42 days, respectively, while control group was treated with equivalent water. Exposure to Cr(VI) significantly increased MDA contents and organ coefficient, whereas decreased T-SOD activities, Ca²⁺-ATPase activities, mitochondrial membrane potential and GSH contents, and histological studies demonstrated renal damage. Above indicators were restored by Se supplement (0.31, 0.63, and 1.25 mg/kg), in which supplement with 0.63 mg/kg Se developed more effectively than the other two groups; on the contrary, in the groups of Se supplement with 2.50 and 5.00 mg/kg, the above indicators were not ameliorated and even exacerbated. This study demonstrated that Cr(VI) can result in kidney oxidative damage in male chickens, and Se of certain dose has the protective effects against Cr(VI)-induced nephrptoxicity.

The Remedial Efficacy of Spirulina platensis versus Chromium-Induced Nephrotoxicity in Male Sprague-Dawley Rats

This study was conducted to investigate the possible protective effect of Spirulina platensis against chromium-induced nephrotoxicity. A total of 36 adult male Sprague-Dawley rats were divided into 4 equal groups (Gps). Gp1 served as control, rats of Gps 2, 3, and 4 were exposed to Spirulina platensis (300 mg/kg b.wt per os) and sodium dichromate dihydrate (SDD) via drinking water at concentration of 520 mg /l respectively. Chromium administration caused alterations in the renal function markers as evidenced by significant increase of blood urea and creatinine levels accompanied with significant increase in kidney’s chromium residues and MDA level as well as decreased catalase activity and glutathion content in kidney tissue. Histologically, Cr provoked deleterious changes including: vascular congestion, wide spread tubular epithelium necrobiotic changes, atrophy of glomerular tuft and proliferative hyperplasia. The latter was accompanied with positive PCNA expression in kidney tissues as well as DNA ploidy interpretation of major cellular population of degenerated cells, appearance of tetraploid cells, high proliferation index and high DNA index. Morphometrical measurements revealed marked glomerular and tubular lumen alterations. On contrary, spirulina co-treatment with Cr significantly restored the histopathological changes, antioxidants and renal function markers and all the previously mentioned changes as well.

S-allylcysteine prevents cisplatin-induced nephrotoxicity and oxidative stress

Objectives

Cisplatin (CP) is an antineoplastic agent that induces nephrotoxicity and oxidative stress. S-allylcysteine (SAC) is a garlic-derived antioxidant. This study aims to explore whether SAC protects against CP-induced nephrotoxicity in rats.

Methods

In the first stage, the SAC protective dose was determined by measuring renal damage and the oxidative stress markers malondialdehyde, oxidized proteins and glutathione in rats injected with CP. In the second stage, the effect of a single dose of SAC on the expression of nuclear factor-erythroid 2-related factor-2 (Nrf2), protein kinase C beta 2 (PKCβ2) and nicotinamide adenine dinucleotide phosphate oxidase subunits (p47phox and gp91phox) was studied. In addition, the effect of SAC on oxidative stress markers and on the activity of catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) in isolated proximal and distal tubules were evaluated.

Key findings

SAC (25 mg/kg) prevented the CP-induced renal damage and attenuated CP-induced decrease in Nrf2 levels and increase in PKCβ2, p47phox and gp91phox expression in renal cortex and oxidative stress and decrease in the activity of CAT, GPx and GR in proximal and distal tubules.

Conclusions

These data suggest that SAC provides renoprotection by attenuating CP-induced oxidative stress and decrease in the activity of CAT, GPx and GR.

C-Phycocyanin prevents cisplatin-induced nephrotoxicity through inhibition of oxidative stress

The aim of this study was to evaluate whether the antioxidant C-phycocyanin (C-PC, 5–30 mg kg⁻¹ i.p.) was able to prevent cisplatin (CP, 18 mg kg⁻¹ i.p.) induced nephrotoxicity by reducing oxidative stress in CD-1 mice.

Punica granatum L. protects mice against hexavalent chromium-induced genotoxicity

This study investigated the chemoprotective effects of Punica granatum L. (Punicaceae) fruits alcoholic extract (PGE) on mice exposed to hexavalent chromium [Cr(VI)]. Animals were pretreated with PGE (25, 50 or 75 mg/kg/day) for 10 days and subsequently exposed to a sub-lethal dose of Cr(VI) (30 mg/kg). The frequency of micronucleated polychromatic erythrocytes in the bone marrow was investigated and the Cr(VI) levels were measured in the kidneys, liver and plasm. For the survival analysis, mice were previously treated with PGE for 10 days and exposed to a single lethal dose of Cr(VI) (50 mg/kg). Exposure to a sub-lethal dose of Cr(VI) induced a significant increase in the frequency of micronucleated cells. However, the prophylactic treatment with PGE led to a reduction of 44.5% (25 mg/kg), 86.3% (50 mg/kg) and 64.2% (75 mg/kg) in the incidence of micronuclei. In addition, the 50 mg/kg dose of PGE produced a higher chemoprotective effect, since the survival rate was 90%, when compared to that of the non-treated group. In these animals, reduced amounts of chromium were detected in the biological materials, in comparison with the other groups. Taken together, the results demonstrated that PGE exerts a protective effect against Cr(VI)-induced genotoxicity.

Curcumin pretreatment prevents potassium dichromate-induced hepatotoxicity, oxidative stress, decreased respiratory complex I activity, and membrane permeability transition pore opening

Curcumin is a polyphenol derived from turmeric with recognized antioxidant properties. Hexavalent chromium is an environmental toxic and carcinogen compound that induces oxidative stress. The objective of this study was to evaluate the potential protective effect of curcumin on the hepatic damage generated by potassium dichromate (K₂Cr₂O₇) in rats. Animals were pretreated daily by 9-10 days with curcumin (400 mg/kg b.w.) before the injection of a single intraperitoneal of K₂Cr₂O₇ (15 mg/kg b.w.). Groups of animals were sacrificed 24 and 48 h later. K₂Cr₂O₇-induced damage to the liver was evident by histological alterations and increase in the liver weight and in the activity of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and alkaline phosphatase in plasma. In addition, K₂Cr₂O₇ induced oxidative damage in liver and isolated mitochondria, which was evident by the increase in the content of malondialdehyde and protein carbonyl and decrease in the glutathione content and in the activity of several antioxidant enzymes. Moreover, K₂Cr₂O₇ induced decrease in mitochondrial oxygen consumption, in the activity of respiratory complex I, and permeability transition pore opening. All the above-mentioned alterations were prevented by curcumin pretreatment. The beneficial effects of curcumin against K₂Cr₂O₇-induced liver oxidative damage were associated with prevention of mitochondrial dysfunction.

Unexpected Nephrotoxicity in Male Ablactated Rats Induced by Cordyceps militaris: The Involvement of Oxidative Changes

Recently, many nutraceutical products containing the powdered or extracted parts of C. militaris have become available for health care. Due to the increased morbidity and mortality, poisonings associated with the use of herbs have raised the universal attention. Herein, we carried out the 28-day repeated toxicity test in male and female ablactated rats (three weeks old) given C. militaris powder orally at 0 (control), 1, 2, and 3 g/kg per day. Noticeable increments of serum aspartate and alanine aminotransferase (ALT and AST) levels were observed for both sexes, suggestive of weak hepatic toxicity. Nephrotoxicity characterized by tubular epithelium degeneration and necrosis was observed at the high dose, and the male rats were more susceptible to renal toxicity than female rats. In addition, the genes and protein expressions of novel markers of kidney toxicity, such as kidney injury molecule-1 (KIM-1) were enlarged in the renal cortex and the urine. Moreover, C. militaris treatment significantly decreased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities. However, the ratio of glutathione oxidized form (GSSG)/glutathione reduced form (GSH) was increased by C. militaris treatment. We conclude that dietary contamination with C. militaris may have renal toxicity potentials, at least in part by causing oxidative damage to the kidney.

The protective and toxic effects of rhubarb tannins and anthraquinones in treating hexavalent chromium-injured rats: the Yin/Yang actions of rhubarb

Chromium nephrotoxicity (CrNT) is thought to occur through the oxidant lesion mechanism. There is still a lack of specific remedies against CrNT. We primarily screened Chinese herbal medicines with a potential protective effect against CrNT, e.g., rhubarb (Rheum palmatum L.). However, the active constituents in rhubarb and its mechanisms remain unclear. In this study, the total rhubarb extract (TR) was successively separated into three parts: total anthraquinone extract (TA), total tannin extract (TT) and remaining component extract (RC). The effects of each extract on the potassium dichromate (K(2)Cr(2)O(7))-induced nephrotoxicity in rats were comparatively assessed. The results showed that only the administration of TT protected the kidney function in K(2)Cr(2)O(7)-injured rats. Besides, TT showed significant activity to scavenge hydroxyl radicals, which is considered to be the dominant lesion product generated by hexavalent chromium. TT also showed a reduced ability to transform toxic high valence chromium ions into non-toxic low valence ions. And TT was able to further precipitate chromium ions. These results suggested that rhubarb tannins treat CrNT as a free radical scavenger, reductant, and metal precipitant. The multiple protective routes of the plant tannins reveal a superior option for development into a promising natural remedy against CrNT. In addition, the opposite effects of rhubarb anthraquinones in treating CrNT were observed compared to rhubarb tannins, which suggested the duo-directional effects (Yin and Yang) of herbal medicines should be addressed.

Cr(VI) induces lipid peroxidation, protein oxidation and alters the activities of antioxidant enzymes in human erythrocytes

The effect of potassium dichromate (K(2)Cr(2)O(7)), a hexavalent chromium compound, on human erythrocytes was studied under in vitro conditions. Incubation of erythrocytes with different concentrations of K(2)Cr(2)O(7) resulted in marked hemolysis in a concentration-dependent manner. K(2)Cr(2)O(7) treatment also caused significant increase in protein oxidation, lipid peroxidation and decrease in total sulfhydryl content, indicating that it causes oxidative stress in human erythrocytes. However, there was no concomitant nitrosative stress as the nitric oxide levels in hemolysates from K(2)Cr(2)O(7)-treated erythrocytes were lower than in control. Exposure of erythrocytes to K(2)Cr(2)O(7) decreased the activities of catalase, glutathione peroxidase, thioredoxin reductase, glucose-6-phosphate dehydrogenase, and glutathione reductase, whereas the activities of Cu-Zn superoxide dismutase and glutathione S-transferase were increased. These results show that K(2)Cr(2)O(7) induces oxidative stress and alters the antioxidant defense mechanism of human erythrocytes.

Curcumin prevents Cr(VI)-induced renal oxidant damage by a mitochondrial pathway

We report the role of mitochondria in the protective effects of curcumin, a well-known direct and indirect antioxidant, against the renal oxidant damage induced by the hexavalent chromium [Cr(VI)] compound potassium dichromate (K(2)Cr(2)O(7)) in rats. Curcumin was given daily by gavage using three different schemes: (1) complete treatment (100, 200, and 400 mg/kg bw 10 days before and 2 days after K(2)Cr(2)O(7) injection), (2) pretreatment (400 mg/kg bw for 10 days before K(2)Cr(2)O(7) injection), and (3) posttreatment (400 mg/kg bw 2 days after K(2)Cr(2)O(7) injection). Rats were sacrificed 48 h later after a single K(2)Cr(2)O(7) injection (15 mg/kg, sc) to evaluate renal and mitochondrial function and oxidant stress. Curcumin treatment (schemes 1 and 2) attenuated K(2)Cr(2)O(7)-induced renal dysfunction, histological damage, oxidant stress, and the decrease in antioxidant enzyme activity both in kidney tissue and in mitochondria. Curcumin pretreatment attenuated K(2)Cr(2)O(7)-induced mitochondrial dysfunction (alterations in oxygen consumption, ATP content, calcium retention, and mitochondrial membrane potential and decreased activity of complexes I, II, II-III, and V) but was unable to modify renal and mitochondrial Cr(VI) content or to chelate chromium. Curcumin posttreatment was unable to prevent K(2)Cr(2)O(7)-induced renal dysfunction. In further experiments performed in curcumin (400 mg/kg)-pretreated rats it was found that this antioxidant accumulated in kidney and activated Nrf2 at the time when K(2)Cr(2)O(7) was injected, suggesting that both direct and indirect antioxidant effects are involved in the protective effects of curcumin. These findings suggest that the preservation of mitochondrial function plays a key role in the protective effects of curcumin pretreatment against K(2)Cr(2)O(7)-induced renal oxidant damage.

Interaction study on garlic and atorvastatin with reference to nephrotoxicity in dyslipidaemic rats

A total of 56 male Sprague dawley rats of uniform weight and age were randomly divided into seven groups consisting of eight rats in each group. Groups 1, 2, and 3 served as plain control, dyslipidaemic control (DL), and atorvastatin control, respectively. Groups 4, 5, 6, and 7 received 1, 0.5, 0.25, and 0.75% fresh garlic w/w in feed, respectively in addition to the high-fat and high-cholesterol diet and administered with atorvastatin orally for 12 weeks at the rate of 10, 5, 7.5, and 2.5 mg/kg b.wt., respectively. Plasma creatinine was estimated at 4-week intervals, whereas histopathology, electron microscopy, and estimation of TBARS concentration in kidney were conducted at the end of experiment. The TBARS concentration in DL was significantly (P<0.05) increased when compared with groups 1, 3, 6, and 7. On histopathological examination, kidney sections of group 3 had mild degenerative changes in the tubules with fatty change in few tubules, while groups 4 and 5 exhibited mild-to-moderate degenerative and fatty changes in tubules with inter tubular hemorrhages. The electron microscopy of group 2 showed hypertrophy of Bowman’s capsule, while that of group 4 showed secretary deposits in the cytoplasm. The interaction studies on kidney indicated that high dose of atorvastatin + garlic has negative safety profile when compared with groups having low dose of statin and high dose of garlic.

Protective effect of sulforaphane pretreatment against cisplatin-induced liver and mitochondrial oxidant damage in rats

In the present work was analyzed whether sulforaphane (SFN) may protect against cisplatin (CIS)-induced hepatic damage, oxidant stress and mitochondrial dysfunction. Four groups of male Wistar rats were studied: control, CIS, CIS+SFN and SFN. SFN was given i.p. (500 μg/kg/d × 3 days) before CIS administration (single i.p. injection, 10mg/kg). Rats were sacrificed 3 days after CIS injection to evaluate hepatic damage (histological analysis, liver/body weight ratio and serum activity of aspartate aminotransferase and alanine aminotransferase), oxidant stress (lipid peroxidation and protein carbonyl and glutathione content), antioxidant enzymes (catalase, glutathione reductase, glutathione peroxidase, glutathione-S-transferase and superoxide dismutase) in liver homogenates and isolated mitochondria and mitochondrial function (oxygen consumption using either malate/glutamate or succinate as substrates and the activity of mitochondrial complex I, II, II-III, IV and V). Furthermore it was evaluated if SFN is able to scavenge some reactive oxygen species in vitro. It was found that SFN prevents CIS-induced (a) hepatic damage, (b) oxidant stress and decreased activity of antioxidant enzymes in liver and mitochondria and (c) mitochondrial alterations in oxygen consumption and decreased activity of mitochondrial complex I. It was also found that the scavenging ability of SFN for peroxynitrite anion, superoxide anion, singlet oxygen, peroxyl radicals, hydrogen peroxide and hydroxyl radicals was very low or negligible. The hepatoprotective effect of SFN was associated to the preservation of mitochondrial function, antioxidant enzymes and prevention of liver and mitochondrial oxidant stress.

Oxidative stress induced by chromium (VI) in bone of suckling rats

Exposure to hexavalent chromium Cr(VI) compounds is of concern in many Cr-related industries and their surrounding environments. K2Cr2O7 is widely recognized as an animal and human carcinogen, mutagen, and teratogen. The present study investigated the bone maturity of suckling rats whose mothers were treated with K2Cr2O7. Experiments were carried out on female Wistar rats given 700 ppm of K2Cr2O7 in their drinking water from the 14th day of pregnancy until day 14 after delivery. Exposing dams to K2Cr2O7 caused disorders in the bone of their progeny. As corollary to this, malondialdehyde levels increased, while glutathione, a non-protein thiol and vitamin C decreased. Alteration of the antioxidant system in the treated group was also confirmed by the significant decline of superoxide dismutase, catalase, and glutathione peroxidase activities. Furthermore, K2Cr2O7 induced changes in bone mineralization, especially calcium and phosphorus levels, which decreased. Whereas, in plasma and urine, they increased and decreased inversely. These results suggest that K2Cr2O7 accelerated bone resorption activity. In fact, in treated pups, total tartrate-resistant acid phosphatase, which reflected bone resorption, was enhanced while total alkaline phosphatase, which reflected bone formation, was reduced. The impairment of bone function was corresponded histologically.

Cardioprotective effects of selenium on chromium (VI)-induced toxicity in female rats

Acute exposure to hexavalent chromium compounds can cause cardiotoxicity. Our study pertains to the protective effect of selenium against K(2)Cr(2)O(7)-induced cardiotoxicity. Female Wistar rats were divided into four groups of six each: group I served as controls which received standard diet; group II received in drinking water K(2)Cr(2)O(7) alone (700 ppm); group III received both K(2)Cr(2)O(7) and Se (0.5 Na(2)SeO(3) mg/kg of diet); group IV received Se (0.5 mg/kg of diet) for 3 weeks. The exposure of rats to chromium promoted oxidative stress with an increase in malondialdehyde levels and a decrease in antioxidant non-enzymatic levels such as glutathione, non-protein thiol and vitamin C, while, an increase in glutathione peroxidase, superoxide dismutase and catalase activities was observed. However, plasma transaminases, lactate dehydrogenase activities, cholesterol, triglycerides and low density lipoprotein-cholesterol levels increased, and high density lipoprotein-cholesterol decreased. Coadministration of Se restored the parameters cited above to near-normal values. The histopathological findings confirmed the biochemical results.

The antioxidant effects of garlic saponins protect PC12 cells from hypoxia-induced damage

Hypoxia frequently occurs under several different cellular circumstances. Excess reactive oxygen species that are induced by hypoxia may result in cell injury and dysfunction. Recently, garlic has been found to possess some biological and pharmacological activities. The present study examined the effects of garlic saponins (GSP) on the survival of differentiated PC12 (dPC12) cells and the oxidative-antioxidant system. dPC12 cells were exposed to 2 % O2 in order to establish a neuronal insult model. Cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction assay and lactate dehydrogenase (LDH) release assay. The expression of selected genes (catalase (CAT), p65 and neuron-specific class III β-tubulin) was evaluated by real-time PCR and immunoblot assays. CAT activity, malondialdehyde (MDA) and 8-hydroxy-deoxyguanosine (8-OH-dG) concentrations were also determined. The data showed that hypoxia dramatically damaged dPC12 cells, while treatment with approximately 5 × 10- 2-10 ng/ml GSP improved cell viability, decreased LDH leakage and caused the cells to maintain neuronal-like characteristics in hypoxia. The production of MDA and 8-OH-dG was attenuated by GSP. CAT activity in dPC12 cells pretreated with GSP was higher than that of the hypoxic control. Moreover, GSP up-regulated CAT expression and decreased the total protein expression as well as the nuclear expression of p65 in hypoxic cells. These data indicate that GSP has antioxidant properties that can protect dPC12 cells from hypoxia-induced damage, which may be related to the up-regulation of CAT expression and activity as well as a decrease in the expression and nucleus distribution of p65 through effects on redox-sensitive signalling pathways.

Nephrotoxicity induced by chromium (VI) in adult rats and their progeny

To assess kidney damages in pregnant and lactating rats and in their suckling pups, Wistar female rats were given, through drinking water, 700 parts per million (ppm) of K2Cr2O7 from the 14th day of pregnancy until day 14 after delivery. Toxicity was objectified by a significant increase in malondialdehyde (MDA), glutathione (GSH) and nitric oxide (NO) levels in kidney of chromium-treated mothers and their suckling pups. Moreover, lactate dehydrogenase (LDH) was increased in kidney and decreased in plasma of K2Cr2O7-treated rats. Activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were increased in dams and decreased in their pups. Interestingly, these biochemical modifications were accompanied by higher plasma and lower urinary levels of creatinine, a specific indicator of glomerular function, and of urea than those of controls. Significant increase in creatinine clearance was also found in treated mothers and in their progeny. Histological studies showed an infiltration of mononuclear cells, necrosis and vascular congestion in kidney of pups and dams. Based on the present findings, K2Cr2O7 administrated to female rats during late pregnancy and early postnatal periods provoked kidney damages in dams and their offspring.

Protective effects of crude garlic by reducing iron-mediated oxidative stress, proliferation and autophagy in rats

The impact of garlic, known for its antioxidant activities, on iron metabolism has been poorly investigated. The aim of this work was to study the effect of crude garlic pre-treatment on iron-mediated lipid peroxidation, proliferation and autophagy for 5 weeks. Rats were fed distilled water or garlic solution (1 g/kg body weight) by gavage for the first 3 weeks as pre-treatment and received a basal diet supplemented or not with ferrous sulfate (650 mg Fe/kg diet) for the last 2 weeks of treatment. Immunohistochemistry labeling and ultrastuctural observations were used to evaluate the iron deleterious effects in the liver. Iron supplementation induced cell proliferation predominantly in non parenchymal cells comparing to hepatocytes, but not apoptosis. In addition, iron was accumulated within the hepatic lysosomes where it triggers autophagy as evidenced by the formation of autophagic vesicles detected by LC3-II staining. It also induced morphologic alterations of the mitochondrial membranes due to increased lipid peroxidation as shown by elevated iron and malondialdehyde concentrations in serum and tissues. Garlic pre-treatment reduced iron-catalyzed lipid peroxidation by decreasing the malondialdehyde level in the liver and colon and by enhancing the status of antioxidants. In addition, garlic reduced the iron-mediated cell proliferation and autophagy by lowering iron storage in the liver and protected mitochondrial membrane. Based on these results, garlic treatment significantly prevented iron-induced oxidative stress, proliferation and autophagy at both biochemical and histological levels due to its potent free radical scavenging and antioxidant properties.

Protective effects of Selenium (Se) on Chromium (VI) induced nephrotoxicity in adult rats

Chromium is a toxic metal implicated in human diseases. This study was focused on investigating the possible protective effect of Se against K(2)Cr(2)O(7). Female Wistar rats, used in this study, were divided into four groups of six animals each: group I served as control which received standard diet; group II received orally only K(2)Cr(2)O(7) (700 ppm equivalent to 67 mg/kgbw); group III received both K(2)Cr(2)O(7) and Se (0.5 mg/kg of diet); group IV received Se (0.5mg Na(2)SeO(3)/kg of diet). The exposure of rats to K(2)Cr(2)O(7) for 21 days provoked renal damages with a significant increase in kidney malondialdehyde, superoxide dismutase, plasma creatinine, and uric acid levels, while catalase, glutathione peroxidase, non-protein thiol, Metallothionein and plasma urea levels decreased. Coadministration of Se in the diet of chromium-treated group improved malondialdehyde, renal biomarkers levels and antioxidant enzyme activities. Kidney histological studies confirmed biochemical parameters and the beneficial role of selenium.

Nutraceutical use of garlic sulfur-containing compounds

Garlic is one of the world's oldest medicines that has been employed not only for flavouring but also as a medical herb for its prophylactic and therapeutic actions. Most garlics' beneficial effects are due to the presence of the organosulphate molecule allicin. Allicin is a highly unstable molecule and, during processing, is rapidly transformed into a variety of organosulfur components. The enzyme alliinase, which is responsible for the conversion of alliin to allicin, is irreversibly destroyed at the acidic environment of stomach. This is the reason why most garlic supplements contain garlic powder or granules, but do not contain allicin itself. Garlic alliinase could be encapsulated and coated with materials which would protect it in the harsh conditions of the stomach. The objective of this chapter is to summarize the most important garlic health benefits and to discuss promising encapsulation/stabilization approaches.

Pycnogenol prevents potassium dichromate K2Cr2O7-induced oxidative damage and nephrotoxicity in rats

Environmental and occupational exposure to chromium compounds, especially hexavalent chromium [Cr(VI)], is widely recognized as a potential nephrotoxic in humans and animals. Its toxicity is associated with overproduction of free radicals, which induces oxidative damage. Recent evidence indicates that Pycnogenol (PYC), French maritime pine bark extract, exhibits antioxidant potential and protects against various oxidative stressors. The aim of the present study was to examine the modulating impacts of PYC on potassium dichromate K2Cr2O7-induced oxidative damage and nephrotoxicity in rats. Male Wistar rats were divided into four groups. The first group was control, the second group was control plus pre-treated with PYC (10 mg/kg, body weight; in saline; intraperitoneally; once daily for 3 weeks) as drug control and the third group was saline pre-treated plus treated with a single injection of K2Cr2O7 (15 mg/kg, body weight; in saline; intraperitoneally) as toxicant group. The fourth group was PYC pre-treated plus K2Cr2O7 injected. Forty-eight hours after K2Cr2O7-treatment, blood was drawn for estimation of renal injury markers in serum. Rats were then sacrificed, and their kidneys were dissected for biochemical and histopathological assays. K2Cr2O7-treated rats showed significant increases in markers of renal injury in serum, including blood urea nitrogen (BUN), serum creatinine (Scr), and alkaline phosphatase (ALP), which were significantly (P < 0.05) decreased by PYC pre-treatment. Moreover, prophylactic pre-treatment of rats with PYC significantly (P < 0.05) ameliorated increased thiobarbituric reactive substances (TBARS), malonaldehyde (MDA) and protein carbonyl (PC), and decreased levels of glutathione (GSH) and catalase activity in the kidney homogenate of K2Cr2O7-treated rats. These results were also supported and confirmed with histopathological findings. The study suggests that PYC is effective in preventing K2Cr2O7-induced oxidative mediated nephrotoxicity, but more studies are needed to confirm the effects of PYC as a nephroprotective agent.

The effect of nordihydroguaiaretic acid on iodoacetate-induced toxicity in cultured neurons

Nordihydroguaiaretic acid (NDGA) is present in high concentrations in the desert shrub Creosote bush, Larrea tridentate. This plant has been used in traditional medicine because of its beneficial effects related, at least in part, to its antioxidant properties. Taking into account some evidence about neuroprotective effects elicited by NDGA, we evaluated the effect of this compound on the neurotoxicity induced by iodoacetate (IAA), an inhibitor of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), on cerebellar granule neurons. In addition, as reactive oxygen species play an important role in IAA-induced cytotoxicity, we also studied the enzymatic antioxidant system in IAA-treated cells. We found that IAA caused a dose-dependent decrease in cell viability of cultured neurons with an IC(50) of 18.4 microM and induced increased activity of catalase, glutathione peroxidase, and glutathione-S-transferase. Moreover, NDGA attenuated the toxicity induced by 18.4, 25, and 30 microM of IAA without abolishing the inhibitory effect of IAA on GAPDH activity. Furthermore, NDGA could prevent the inhibitory effect of IAA on aconitase activity, a marker of oxidative stress, suggesting that the protective effect of NDGA on IAA neurotoxicity was associated with the prevention of oxidative stress.

Differences in immunolocalization of Kim-1, RPA-1, and RPA-2 in kidneys of gentamicin-, cisplatin-, and valproic acid-treated rats: potential role of iNOS and nitrotyrosine

The present study compared the immunolocalization of Kim-1, renal papillary antigen (RPA)-1, and RPA-2 with that of inducible nitric oxide synthase (iNOS) and nitrotyrosine in kidneys of gentamicin sulfate (Gen)- and cisplatin (Cis)-treated rats. The specificity of acute kidney injury (AKI) biomarkers, iNOS, and nitrotyrosine was evaluated by dosing rats with valproic acid (VPA). Sprague-Dawley (SD) rats were injected subcutaneously (sc) with 100 mg/kg/day of Gen for six or fourteen days; a single intraperitoneal (ip) dose of 1, 3, or 6 mg/kg of Cis; or 650 mg/kg/day of VPA (ip) for four days. In Gen-treated rats, Kim-1 was expressed in the epithelial cells, mainly in the S1/S2 segments but less so in the S3 segment, and RPA-1 was increased in the epithelial cells of collecting ducts (CD) in the cortex. Spatial expression of iNOS or nitrotyrosine with Kim-1 or RPA-1 was detected. In Cis-treated rats, Kim-1 was expressed only in the S3 segment cells, and RPA-1 and RPA-2 were increased in the epithelial cells of medullary CD or medullary loop of Henle (LH), respectively. Spatial expression of iNOS or nitrotyrosine with RPA-1 or RPA-2 was also identified. These findings suggest that peroxynitrite formation may be involved in the pathogenesis of Gen and Cis nephrotoxicity and that Kim-1, RPA-1, and RPA-2 have the potential to serve as site-specific biomarkers for Gen or Cis AKI.

Role of oxidative and nitrosative stress in cisplatin-induced nephrotoxicity

cis-Diamminedichloroplatinum (II) (cisplatin) is an important chemotherapeutic agent useful in the treatment of several cancers; however, it has several side effects such as nephrotoxicity. The role of the oxidative and nitrosative stress in cisplatin-induced nephrotoxicity is additionally supported by the protective effect of several free radical scavengers and antioxidants. Furthermore, in in vitro experiments, antioxidants or reactive oxygen species (ROS) scavengers have a cytoprotective effect on cells exposed to cisplatin. Recently, the participation of nitrosative stress has been more explored in cisplatin-induced renal damage. The use of a water-soluble Fe(III) porphyrin complex able to metabolize peroxynitrite (ONOO(-)) has demonstrated that this anion contributes to both in vivo and in vitro cisplatin-induced toxicity. ONOO(-) is produced when nitric oxide (NO*) reacts with superoxide anion (O(2)(*-)); currently, there are evidences suggesting alterations in NO* production after cisplatin treatment and the evidence appear to NO* has a toxic effect. This article goes through current evidence of the mechanism by more than a few compounds have beneficial effects on cisplatin-induced nephrotoxicity, contribute to understanding the role of oxidative and nitrosative stress and suggest several points as part of the mechanism of cisplatin toxicity.

Protective effects of apocynin against cisplatin-induced oxidative stress and nephrotoxicity

Cis-diamminedichloroplatinum (II) (cisplatin) is an effective chemotherapeutic agent successfully used in the treatment of a wide range of tumors; however, nephrotoxicity has restricted its clinical use. Several studies have shown that reactive oxygen species are involved in cisplatin-induced nephrotoxicity, including hydrogen peroxide, hydroxyl radical and superoxide anion (O(2)(-)). The source of O(2)(-) in cisplatin-induced renal damage has not been established. The aim of this study was to investigate if NADPH oxidase is involved in cisplatin-induced nephrotoxicity using apocynin, a widely used NADPH oxidase inhibitor. Rats were studied 3 days after a single injection of cisplatin (7.5mg/kg, i.p.). Apocynin was given in the drinking water (2g/L) 7 days before and 3 days after cisplatin injection. Apocynin treatment was able to ameliorate the renal histological damage and the increase in blood urea nitrogen, serum creatinine, and urinary excretion of total protein, N-acetyl-beta-d-glucosaminidase and glutathione-S-transferase induced by cisplatin. In addition, the protective effect of apocynin was associated with the amelioration of cisplatin-induced oxidative and nitrosative stress. Our data suggest that O(2)(-) derived from NADPH oxidase triggers some of the side effects due to cisplatin administration.