Oxidative damage and stress response from ochratoxin a exposure in rats

Ochratoxin A (OTA) is a mycotoxin found in some cereal and grain products.It is a potent renal carcinogen in male rats, although its mode of carcinogenic action is not known. Oxidative stress may play a role in OTA-induced toxicity and carcinogenicity.In this study, we measured several chemical and biological markers that are associated with oxidative stress response to determine if this process is involved in OTA-mediated toxicity in rats. Treatment of male rats with OTA (up to 2 mg/ 24 h exposure) did not increase the formation of biomarkers of oxidative damage such as the lipid peroxidation marker malondialdehyde in rat plasma, kidney, and liver, or the DNA damage marker 8-oxo-7,8-dihydro-2' deoxyguanosine in kidney DNA. However, OTA treatment (1 mg/kg) did result in a 22% decrease in alpha-tocopherol plasma levels and a 5-fold increase in the expression of the oxidative stress responsive protein haem oxygenase-1, specifically in the kidney. The selective alteration of these latter two markers indicates that OTA does evoke oxidative stress, which may contribute at least in part to OTA renal toxicity and carcinogenicity in rats during long-term exposure.     

Doxorubicin-induced alterations in kidney functioning,oxidative stress,DNA damage,and renal tissue morphology; Improvement by Acacia hydaspica tannin-rich ethyl acetate fraction

Doxorubicin (DOX) is an anthracycline drug used for cancer treatment. However, its treatment is contiguous with toxic effects. We examined the nephroprotective potential of A. hydaspica polyphenol-rich ethyl acetate extract (AHE) against DOX persuaded nephrotoxicity. 36 male Sprague Dawley rats were randomly assorted into 6 groups. Control group received saline; DOX group: 3 mg/kg b.w. dosage of DOX intraperitoneally for 6 weeks (single dose/week). In co-treatment groups, 200 and 400 mg/kg b.w AHE was given orally for 6 weeks in concomitant with DOX (3 mg/kg b.w, i.p. injection per week) respectively. Standard group received silymarin 400 mg/kg b.w daily + DOX (single dose/week). Biochemical kidney function tests, oxidative stress markers, genotoxicity, antioxidant enzyme status, and histopathological changes were examined. DOX caused significant body weight loss and decrease kidney weight. DOX-induced marked deterioration in renal function indicators in both urine and serum, i.e., PH, specific gravity, total protein, albumin, urea, creatinine, uric acid, globulin, blood urea nitrogen, etc. Also, DOX treatment increases renal tissue oxidative stress markers, while lower antioxidant enzymes in tissue along with degenerative alterations in the renal tissue compared to control rats. AHE co-treatment ameliorates DOX-prompted changes in serum and urine chemistry. Likewise, AHE treatment decreases sensitive markers of oxidative stress and prevented DNA damages by enhancing antioxidant enzyme levels. DOX induction in rats also caused DNA fragmentation which was restored by AHE co-treatment. Moreover, the histological observations evidenced that AHE effectively rescued the kidney tissue from DOX interceded oxidative damage. Our results suggest that co-treatment of AHE markedly improve DOX-induced deleterious effects in a dose-dependent manner. The potency of AHE co-treatment at 400 mg/kg dose is similar to silymarin. These outcomes revealed that A. hydaspica AHE extract might serve as a potential adjuvant that avoids DOX-induced nephrotoxicity.     

Cytotoxic effect of ochratoxin A on the renal corpuscles of rat kidney: could ochratoxin A cause kidney failure?

To demonstrate that Ochratoxin A can cause kidney failure as the kidney is the primary target for OTA cytotoxicity. Ochratoxin A (OTA) is a mycotoxin found in our food. The cytotoxic effect of a low cumulative dose of OTA on the renal corpuscles of the kidney tissue has been investigated in this report. This study was based on two groups in which weaning albino rats were used: (1) control; (2) OTA-treated rats (289 μg/kg/day). After 28 days of treatment, a significant decrease in body weight, kidney weight and relative weight were detected in OTA treated rats. Serum creatinine and urea level were slightly elevated. These results revealed significant histological as well as ultrastructral lesions in the OTA treated group. The lesions included global congestion in the renal tissue and loss of demarcation between the cortex and medulla. The normal architecture of the renal corpuscles was destroyed and most of the corpuscles lost their ordinary look. The most apparent histopathological changes were urinary space disappearance and hypercellularity. In addition, congested, undifferentiated, atrophied, hypertrophied, fragmented, sclerotic, degenerated, and obliterated renal corpuscles were distinct. The ultrastructural lesions observed in the renal corpuscles in OTA on treated rats included; proliferation and swelling of the endothelial cells with occasional loss of fenestrae; narrowing of the capillary lumen; damaged podocytes with deteriorated secondary foot processes, hypertrophied and proliferated mesangial cells with expanded mesangial matrix. The endothelium was clearly defected and vacuolated, and lost its fenestrations in many glomerular capillaries. In addition, the glomerular basement membrane (GBM) became visibly thickened and tortuous. Necrotic glomerular cells were frequently observed. Pre-apoptotic cells were also seen. It was concluded that the exposure to relatively low OTA concentrations induced significant lesions to the renal corpuscles. Moreover, it activated oxidative damage and necrosis which can cause extensive damage to the kidney and ultimately kidney failure.     

Regression of Glomerular and Tubulointerstitial Injuries by Dietary Salt Reduction with Combination Therapy of Angiotensin II Receptor Blocker and Calcium Channel Blocker in Dahl Salt-Sensitive Rats

A growing body of evidence indicates that renal tissue injuries are reversible. We investigated whether dietary salt reduction with the combination therapy of angiotensin II type 1 receptor blocker (ARB) plus calcium channel blocker (CCB) reverses renal tissue injury in Dahl salt-sensitive (DSS) hypertensive rats. DSS rats were fed a high-salt diet (HS; 4% NaCl) for 4 weeks. Then, DSS rats were given one of the following for 10 weeks: HS diet; normal-salt diet (NS; 0.5% NaCl), NS + an ARB (olmesartan, 10 mg/kg/day), NS + a CCB (azelnidipine, 3 mg/kg/day), NS + olmesartan + azelnidipine or NS + hydralazine (50 mg/kg/day). Four weeks of treatment with HS diet induced hypertension, proteinuria, glomerular sclerosis and hypertrophy, glomerular podocyte injury, and tubulointerstitial fibrosis in DSS rats. A continued HS diet progressed hypertension, proteinuria and renal tissue injury, which was associated with inflammatory cell infiltration and increased proinflammatory cytokine mRNA levels, NADPH oxidase activity and NADPH oxidase-dependent superoxide production in the kidney. In contrast, switching to NS halted the progression of hypertension, renal glomerular and tubular injuries. Dietary salt reduction with ARB or with CCB treatment further reduced blood pressure and partially reversed renal tissues injury. Furthermore, dietary salt reduction with the combination of ARB plus CCB elicited a strong recovery from HS-induced renal tissue injury including the attenuation of inflammation and oxidative stress. These data support the hypothesis that dietary salt reduction with combination therapy of an ARB plus CCB restores glomerular and tubulointerstitial injury in DSS rats.     

Oxidative/Nitrative Stress and Inflammation Drive Progression of Doxorubicin-Induced Renal Fibrosis in Rats as Revealed by Comparing a Normal and a Fibrosis-Resistant Rat Strain

Chronic renal fibrosis is the final common pathway of end stage renal disease caused by glomerular or tubular pathologies. Genetic background has a strong influence on the progression of chronic renal fibrosis. We recently found that Rowett black hooded rats were resistant to renal fibrosis. We aimed to investigate the role of sustained inflammation and oxidative/nitrative stress in renal fibrosis progression using this new model. Our previous data suggested the involvement of podocytes, thus we investigated renal fibrosis initiated by doxorubicin-induced (5 mg/kg) podocyte damage. Doxorubicin induced progressive glomerular sclerosis followed by increasing proteinuria and reduced bodyweight gain in fibrosis-sensitive, Charles Dawley rats during an 8-week long observation period. In comparison, the fibrosis-resistant, Rowett black hooded rats had longer survival, milder proteinuria and reduced tubular damage as assessed by neutrophil gelatinase-associated lipocalin (NGAL) excretion, reduced loss of the slit diaphragm protein, nephrin, less glomerulosclerosis, tubulointerstitial fibrosis and matrix deposition assessed by periodic acid–Schiff, Picro-Sirius-red staining and fibronectin immunostaining. Less fibrosis was associated with reduced profibrotic transforming growth factor-beta, (TGF-β1) connective tissue growth factor (CTGF), and collagen type I alpha 1 (COL-1a1) mRNA levels. Milder inflammation demonstrated by histology was confirmed by less monocyte chemotactic protein 1 (MCP-1) mRNA. As a consequence of less inflammation, less oxidative and nitrative stress was obvious by less neutrophil cytosolic factor 1 (p47^phox) and NADPH oxidase-2 (p91^phox) mRNA. Reduced oxidative enzyme expression was accompanied by less lipid peroxidation as demonstrated by 4-hydroxynonenal (HNE) and less protein nitrosylation demonstrated by nitrotyrosine (NT) immunohistochemistry and quantified by Western blot. Our results demonstrate that mediators of fibrosis, inflammation and oxidative/nitrative stress were suppressed in doxorubicin nephropathy in fibrosis-resistant Rowett black hooded rats underlying the importance of these pathomechanisms in the progression of renal fibrosis initiated by glomerular podocyte damage.     

Cadmium-induced oxidative stress and DNA damage in kidney of pregnant female rats

In the present study, we have investigated the influence of sub-acute treatment with cadmium (Cd) on some parameters indicative of oxidative stress and DNA damage in tissues of pregnant female rats. Pregnant female rats (n=6) were injected subcutaneously, daily with a dose of cadmium chloride of 3 mg/kg body weight (b.w.) from day 6 to day 19 of pregnancy, and they were allowed to deliver normally. MDA level and GPx, CAT and SOD activities were used as markers of oxidative stress in liver and kidney. The 8-oxo-dG level was measured by the HPLC-EC system. Cd treatment increased MDA (+116%, p<0.01) in kidney. Moreover, Cd treatment also decreased CuZn-SOD (-11%, p<0.05) and GSH level (-52%, p<0.05) in kidney. Treated rats displayed an increase of the liver metallothionein (MT) level. Induction of MT in liver was probably implicated in the detoxification of Cd. The high level of Cd (3 mg/kg) used in the present study is partially neutralized by MT in liver, whereas the free fraction could be implicated in the oxidative stress and DNA oxidation observed in kidney. Cd treatment failed to alter 8-oxodGuo, indicating the absence of DNA oxidation in liver; by contrast, the same treatment increased the 8-oxodGuo level (+51%, p<0.05) in the kidney of pregnant female rats, indicating an oxidative stress associated with DNA damage only in kidney.     

Calcium Channel Blocker Enhances Beneficial Effects of an Angiotensin II AT1 Receptor Blocker against Cerebrovascular-Renal Injury in type 2 Diabetic Mice

Recent clinical trials have demonstrated that combination therapy with renin-angiotensin system inhibitors plus calcium channel blockers (CCBs) elicits beneficial effects on cardiovascular and renal events in hypertensive patients with high cardiovascular risks. In the present study, we hypothesized that CCB enhances the protective effects of an angiotensin II type 1 receptor blocker (ARB) against diabetic cerebrovascular-renal injury. Saline-drinking type 2 diabetic KK-A^y mice developed hypertension and exhibited impaired cognitive function, blood-brain barrier (BBB) disruption, albuminuria, glomerular sclerosis and podocyte injury. These brain and renal injuries were associated with increased gene expression of NADPH oxidase components, NADPH oxidase activity and oxidative stress in brain and kidney tissues as well as systemic oxidative stress. Treatment with the ARB, olmesartan (10 mg/kg/day) reduced blood pressure in saline-drinking KK-A^y mice and attenuated cognitive decline, BBB disruption, glomerular injury and albuminuria, which were associated with a reduction of NADPH oxidase activity and oxidative stress in brain and kidney tissues as well as systemic oxidative stress. Furthermore, a suppressive dose of azelnidipine (3 mg/kg/day) exaggerated these beneficial effects of olmesartan. These data support the hypothesis that a CCB enhances ARB-associated cerebrovascular-renal protective effects through suppression of NADPH oxidase-dependent oxidative stress in type 2 diabetes.     

The role of oxidative stress in the ochratoxin A-mediated toxicity in proximal tubular cells

Balkan endemic nephropathy (BEN), a disease characterized by progressive renal fibrosis in human patients, has been associated with exposure to ochratoxin A (OTA). This mycotoxin is a frequent contaminant of human and animal food products, and is toxic to all animal species tested. OTA predominantly affects the kidney and is known to accumulate in the proximal tubule (PT). The induction of oxidative stress is implicated in the toxicity of this mycotoxin.In the present study, primary rat PT cells and LLC-PK(1) cells, which express characteristics of the PT, were used to investigate the OTA-mediated oxidative stress response. OTA exposure of these cells resulted in a concentration-dependent elevation of reactive oxygen species (ROS) levels, depletion of cellular glutathione (GSH) levels and an increase in the formation of 8-oxoguanine.The OTA-induced ROS response was significantly reduced following treatment with alpha-tocopherol (TOCO). However, this chain-braking anti-oxidant did not reduce the cytotoxicity of OTA and was unable to prevent the depletion of total GSH levels in OTA-exposed cells. In contrast, pre-incubation of the cell with N-acetyl-L-cysteine (NAC) completely prevented the OTA-induced increase in ROS levels as well as the formation of 8-oxoguanine and completely protected against the cytotoxicity of OTA. In addition, NAC treatment also limited the GSH depletion in OTA-exposed PT- and LLC-PK(1) cells.From these data, we conclude that oxidative stress contributes to the tubular toxicity of OTA. Subsequently, cellular GSH levels play a pivotal role in limiting the short-term toxicity of this mycotoxin in renal tubular cells.     

Molecular and biochemical investigations on the effect of quercetin on oxidative stress induced by cisplatin in rat kidney

The present study was aimed to investigate the ability of quercetin (QE) to ameliorate adverse effects of cisplatin (Cis.) on the renal tissue antioxidants by investigating the kidney antioxidant gene expression and the antioxidant enzymes activity. Forty rats divided into. Control rats. QE treated rats were orally administered 100 mg QE/kg for successive 30 days. Cis. injected rats were administered i.p. Cis. (12 mg/kg b.w.) for 5 mutual days. Cis. + QE rats were administered Cis. i.p. (12 mg/kg) and orally administered 100 mg QE/kg for consecutive 30 days. The obtained results indicated that Cis. induced oxidative stress in the renal tissue. That was through induction of free radical production, inhibition of the activity of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) as well their genes expression. At the same time, vitamin E, vitamin C and reduced glutathione (GSH) levels were decreased. QE had the ability to overcome cisplatin-induced oxidative stress through the reduction of free radical levels. The antioxidant genes expression and antioxidant enzymes activity were induced. Finally the vitamin E, vitamin C and GSH levels were increased. Our work, proved the renoprotective effects of QE against oxidative stress induced by cisplatin.     

Attenuation of Hyperlipidemia- and Diabetes-Induced Early-Stage Apoptosis and Late-Stage Renal Dysfunction via Administration of Fibroblast Growth Factor-21 Is Associated with Suppression of Renal Inflammation

Background

Lipotoxicity is a key feature of the pathogenesis of diabetic kidney disease, and is attributed to excessive lipid accumulation (hyperlipidemia). Increasing evidence suggests that fibroblast growth factor (FGF)21 has a crucial role in lipid metabolism under diabetic conditions.

Objective

The present study investigated whether FGF21 can prevent hyperlipidemia- or diabetes-induced renal damage, and if so, the possible mechanism.

Methods

Mice were injected with free fatty acids (FFAs, 10 mg/10 g body weight) or streptozotocin (150 mg/kg) to establish a lipotoxic model or type 1 diabetic model, respectively. Simultaneously the mice were treated with FGF21 (100 µg/kg) for 10 or 80 days. The kidney weight-to-tibia length ratio and renal function were assessed. Systematic and renal lipid levels were detected by ELISA and Oil Red O staining. Renal apoptosis was examined by TUNEL assay. Inflammation, oxidative stress, and fibrosis were assessed by Western blot.

Results

Acute FFA administration and chronic diabetes were associated with lower kidney-to-tibia length ratio, higher lipid levels, severe renal apoptosis and renal dysfunction. Obvious inflammation, oxidative stress and fibrosis also observed in the kidney of both mice models. Deletion of the fgf21 gene further enhanced the above pathological changes, which were significantly prevented by administration of exogenous FGF21.

Conclusion

These results suggest that FFA administration and diabetes induced renal damage, which was further enhanced in FGF21 knock-out mice. Administration of FGF21 significantly prevented both FFA- and diabetes-induced renal damage partially by decreasing renal lipid accumulation and suppressing inflammation, oxidative stress, and fibrosis.     

A red orange and lemon by-products extract rich in anthocyanins inhibits the progression of diabetic nephropathy

The major cause of end-stage renal disease is the diabetic nephropathy. Oxidative stress contributes to the development of type II diabetes mellitus (T2DM). In this study we have evaluated the effect of a diet with a new standardized of red orange and lemon extract (RLE) rich in anthocyanins (ANT) in the progression of the kidney disease on Zucker diabetic fatty rats. Oxidative stress and renal function were analyzed. In diabetic rats, the RLE restored the blood glucose levels, body weight, and normalized the reactive oxygen species (ROS) total pathways. The kidney inflammation, in diabetic rats, has not shown significant change, showing that the oxidative stress rather than to inflammatory processes is a triggering factor in the renal complication associated with T2DM. Therefore, the administration of the RLE prevents this complication and this effect could be related to the inhibition of ROS production.     

Effects of organoselenium compound 2-(5-selenocyanato-pentyl)-benzo[de]isoquinoline 1,3-dione on cisplatin induced nephrotoxicity and genotoxicity: an investigation of the influence of the compound on oxidative stress and antioxidant enzyme system

Cisplatin is one of the most active cytotoxic agents used in the treatment of cancer. However, cisplatin therapy is also associated with severe side effects like nephrotoxicity and genotoxicity. Free oxygen radicals are known to play a major role in cisplatin induced toxicities. Selenium is believed to be an important trace element and dietary antioxidant because of its ability to scavenge free oxygen radicals, thereby preventing cells from oxidative stress. The purpose of this study is to evaluate the protective role of a novel naphthalimide based organoselenium compound 2-(5-selenocyanato-pentyl)-benzo[de]isoquinoline 1,3-dione against cisplatin induced toxicities in Swiss albino mice. Cisplatin was administered intraperitoneally (5 mg/kg b.w.) and the organoselenium compound was given by oral gavages (3 mg/kg b.w.) in concomitant and pretreatment schedule. The results showed that the test compound substantially reduced cisplatin induced reactive oxygen species generation and lipid peroxidation in kidney as well as blood urea nitrogen and creatinine levels in serum. Treatment with organoselenium compound was also able to restore the renal antioxidant system by modulating the cisplatin induced depleted activities of glutathione S-transferase, thioredoxin reductase, superoxide dismutase, catalase, glutathione peroxidase and reduced glutathione level. In addition, the organoselenium compound could efficiently minimize cisplatin induced chromosomal aberrations in bone marrow cells and extent of DNA damage in lymphocytes. Furthermore, the chemoprotective efficacy of the compound against cisplatin induced toxicity was confirmed by histopathological evaluation. The results suggest that the organoselenium compound has the potential to protect against cisplatin induced nephrotoxicity and genotoxicity in part by scavenging reactive oxygen species and by up regulating the antioxidant enzyme system.     

Effect of rMnSOD on Sodium Reabsorption in Renal Proximal Tubule in Ochratoxin A—Treated Rats

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium that represent toxic real threat for human beings and animal health. In this study we evaluated the effect of a new recombinant mitochondrial manganese containing superoxide dismutase (rMnSOD) on oxidative stress and on the alterations of fluid reabsorption in renal proximal tubule (PT) as possible causes of OTA nephrotoxicity. Finally, we have measured the concentration of O₂^? in the kidney through dihydroethidium assay (DHE) and nitric oxide (NO) concentration through nitrites and nitrates assay. Male Sprague Dawley rats weighing 120–150 g were treated for 14 days by gavage, as follows: Control group, 12 rats received a corresponding amount of saline solution (including 10% DMSO); rMnSOD group, 12 rats treated with rMnSOD (10 µg/kg bw); OTA group, 12 rats treated with OTA (0.5 mg/kg bw) dissolved in 10% DMSO and then scaled to required volume with corn oil; rMnSOD + OTA, 12 rats treated with rMnSOD (10 µg/kg bw) plus OTA (0.5 mg/kg bw). Our results have shown that rMnSOD restores the alteration of reabsorption in PT in rats treated with OTA plus rMnSOD, probably through the response to pressure natriuresis, where nitric oxide plays a key role. Moreover, rMnSOD prevents the nephrotoxicity induced by OTA probably restoring the balance between superoxide and NO that is most probably the cause of hypertension and renal functional alterations through the inhibition of NO synthase. In conclusion these data provide important information for understanding of mechanism of toxic action of OTA. J. Cell. Biochem. 119: 424–430, 2018. © 2017 Wiley Periodicals, Inc.     

Expression of COX-2 and hsp72 in peritoneal macrophages after an acute ochratoxin A treatment in mice

Ochratoxin A (OTA) is a secondary fungal metabolite produced by Aspergillus and Penicillium strains that elicits a broad spectrum of toxicological effects in animals and man. A single oral OTA administration (10 mg/kg) in mice induced after 24 h oxidative damage and polymorphonuclear leukocyte (PMN) infiltration in parenchymal organs. In fact, OTA treatment increased lipid peroxidation (via malondialdehyde formation) in kidney and liver and PMN accumulation in duodenum, as shown by myeloperoxidase activity. Following in vivo OTA treatment an increase of cyclooxygenase-2 and of heat shock protein 72 expression was evidenced in peritoneal macrophage lysates by Western blot. That OTA modulates these proteins involved in the inflammatory process indicates that the mycotoxin is able to activate immune cells. This study suggests that the oxidative stress, the neutrophil accumulation in parenchymal tissues and the modulation of inflammatory parameters in peritoneal macrophages induced by OTA are involved in its toxicity, and represent early events related to several aspects of OTA mycotoxicosis.     

Augmentation of hepatic and renal oxidative stress and disrupted glucose homeostasis by monocrotophos in streptozotocin-induced diabetic rats

Several recent studies have demonstrated that organophosphorus insecticides (OPI) possess the potential to disrupt glucose homeostasis leading to hyperglycemia in experimental animals. The propensity of OPI to induce hyperglycemia along with oxidative stress may have far-reaching consequences on diabetic outcomes and associated complications. The primary objective of this study was to assess the potential of monocrotophos (MCP), an extensively used OPI, on hepatic and renal oxidative stress markers and dysregulation of hepatic glucose homeostasis in experimentally induced diabetic rats. Rats rendered diabetic by a single dose of streptozotocin (60 mg/kg b.w) were orally administered MCP (0.9 mg/kg b.w/d for 5 d). Monocrotophos per se caused only a marginal increase in blood glucose levels but significantly elevated the blood glucose levels and also disrupted glucose homeostasis by depleting liver glycogen content and increasing the gluconeogenetic enzyme activities in diabetic rats. Experimentally induced diabetes was also associated with alterations in antioxidant enzymes in liver and kidney. MCP markedly enhanced lipid peroxidation in kidney and altered the enzymatic antioxidant defense mechanisms in both liver and kidney of diabetic rats. Collectively our data provides evidence that MCP has the propensity to augment the oxidative stress and further disrupt glucose homeostasis in diabetic rats.     

Cyclophosphamide-induced nephrotoxicity, genotoxicity, and damage in kidney genomic DNA of Swiss albino mice: the protective effect of Ellagic acid

Cyclophosphamide (CPM), an alkylating agent is used as an immunosuppressant in rheumatoid arthritis and in the treatment of several cancers as well. In this study, Ellagic acid (EA), a naturally occurring plant polyphenol, was evaluated for its antigenotoxicity and antioxidant efficacy against the CPM-induced renal oxidative stress and genotoxicity in Swiss albino mice. The mice were given a prophylactic treatment of EA orally at a dose of 50 and 100 mg/kg body weight (b wt) for seven consecutive days before the administration of a single intraperitoneal (i.p.) injection of CPM at 50 mg/kg b wt. The modulatory effects of EA on CPM-induced nephrotoxicity and genotoxicity were investigated by assaying oxidative stress biomarkers, serum kidney toxicity markers, DNA fragmentation, alkaline unwinding assay, micronuclei (MN) assay, and by histopathological examination of kidney tissue. A single intraperitoneal administration of CPM in mice increased malondialdehyde level with depletion in glutathione content, antioxidant enzymes activities, viz. glutathione peroxidase, glutathione reductase, catalase, quinone reductase, induced DNA strand breaks, and MN induction. EA oral administration at both doses caused significant reduction in their levels, restoration in the activities of antioxidant enzymes, reduction in MN formation, and DNA fragmentation. Serum toxicity marker enzymes like BUN, creatinine, and LDH were also increased after CPM treatment which was significantly decreased in EA pretreated groups. Present findings suggest a prominent role of EA against CPM-induced renal injury, DNA damage, and genotoxicity.     

Melatonin reduces oxidative stress induced by ochratoxin A in rat liver and kidney

Melatonin (MEL) displays antioxidant and free radical scavenger properties. In the present study, the effect of MEL on the oxidative stress induced by ochratoxin A (OTA) administration in rats was investigated. Four groups of 15 rats each were used: controls, MEL-treated rats (5 mg/kg body mass), OTA-treated rats (250 μg/kg) and MEL+OTA-treated rats. After 4 weeks of treatment, the levels of malondialdehyde (MDA), a lipid peroxidation product (LPO) were measured in serum and homogenates of liver and kidney. Also, the levels of glutathione (GSH), and activities of glutathione reductase (GR), glutathione peroxidase (GSPx), superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) in liver and kidney were determined. In OTA-treated rats, the levels of LPO in serum and in both liver and kidney were significantly increased compared to levels in controls. Concomitantly, the levels of GSH and enzyme activities of SOD, CAT, GSPx and GR in both liver and kidney were significantly decreased in comparison with controls. In rats received MEL+OTA, the changes in the levels of LPO in serum and in liver and kidney were not statistically significant compared to controls. Concomitantly, the levels of GSPx, GR and GST activities in both liver and kidney tissues were significantly increased in comparison with controls. Similar increases in GSPx, GR and GST activities were also observed in MEL-treated rats when compared with controls. In conclusion, the oxidative stress may be a major mechanism for the toxicity of OTA. MEL has a protective effect against OTA toxicity through an inhibition of the oxidative damage and stimulation of GST activities. Thus, clinical application of melatonin as therapy should be considered in cases of ochratoxicosis.     

Bilirubin clearance and antioxidant activities of ethanol extract of Phyllanthus amarus root in phenylhydrazine-induced neonatal jaundice in mice

The ability of ethanol extract of Phyllanthus amarus root (EEPA) to decrease bilirubin level and oxidative stress in phenylhydrazine-induced neonatal jaundice in mice was investigated. Administration of phenylhydrazine (75 mg/kg b.w.) significantly elevated total and unconjugated serum bilirubin level compared to control mice. EEPA (5, 10, and 20 mg/kg b.w., oral) dose-dependently reduced the bilirubin level. EEPA treatment also upregulated hepatic CAR and CYP3A1, accounting for its ability to facilitate bilirubin clearance. A single dose of EEPA (20 mg/kg b.w.) induced higher level of bilirubin clearance than phototherapy, widely used for treating neonatal jaundice. Furthermore, phenylhydrazine administration significantly increased MDA, protein carbonyl, and total thiol content and lowered the GSH level along with superoxide dismutase and catalase activity in erythrocyte compared to the control group. Single administration of EEPA (20 mg/kg b.w.) significantly reversed the trend. Presence of gallic acid, gentisic acid, and ortho-coumaric acid in EEPA was identified by HPLC analysis. Amongst these, the major phenolic constituent, gallic acid, exhibited significant bilirubin-lowering effect. These results suggested that P. amarus may be beneficial in reducing bilirubin level as well as oxidative stress in neonatal jaundice.     

Metabolism and toxicokinetics of the mycotoxin ochratoxin A in F344 rats

Male (n=18) and female (n=18) F344 rats were administered a single dose of OTA (0.5 mg/kg b.w.) in corn oil by gavage. Animals (n=3) were sacrificed 24, 48, 72, 96, 672 and 1,344 hours after OTA administration and concentrations of OTA and OTA-metabolites in urine, feces, blood, liver and kidney were determined by HPLC with fluorescence detection and/or by LC-MS/MS. Recovery of unchanged OTA in urine amounted to 2.1% of dose in males and 5.2% in females within 96 h. In feces, only 5.5% resp. 1.5% of dose were recovered. The major metabolite detected was OTalpha, low concentrations of OTA-glucosides were also present in urine. Other postulated metabolites were not observed. The maximal blood levels of OTA were observed between 24 and 48h after administration and were app. 4.6 µmol/l in males and 6.0 µmol/l in females. Elimination of OTA from blood followed first-order kinetics with a half-life of app. 230h calculated from 48h to 1344h. In liver of both male and female rats OTA-concentrations were less than 12 pmol/g tissue, with a maximum at 24h after administration. In contrast, OTA accumulated in the kidneys, reaching a concentration of 480 pmol/g tissue in males 24h after OTA-administration. In general, tissue concentrations in males were higher than in females. OTalpha was not detected in liver and kidney tissue of rats administered OTA and OTalpha concentrations in blood were low (10–15 nmol/1). The high concentrations of OTA in kidneys of male rats may explain the organ- and gender-specific toxicity of OTA.