Protective effects of vitamin e and probucol against gentamicin-induced nephrotoxicity in rats

Investigation the effects of 2-aminoethoxydiphenyl borate (2-APB) on aminoglycoside nephrotoxicity

Investigation the protective effect of transient receptor potential channel modulator 2-Aminoethoxydiphenyl Borate (2-APB) on aminoglycoside nephrotoxicity caused by reactive oxygen species, calcium-induced apoptosis and inflammation was aimed. Forty Wistar rats were divided (n=8) as follows: Control group; DMSO group; 2-APB group; Gentamicin group (injected 100 mg/kg gentamicin intramuscularly for 10 days); Gentamicin+ 2-APB group (injected 2 mg/kg 2-APB intraperitoneally, then after 30 minutes 100 mg/kg gentamicin was injected intramuscularly for 10 days). Blood samples were collected for biochemical analyses, kidney tissue samples were collected for light, electron microscopic and immunohistochemical investigations. In gentamicin group glomerular degeneration, tubular dilatation, vacuolization, desquamation of tubular cells and hyaline cast formation in luminal space and leukocyte infiltration were seen. Disorganization of microvilli of tubular cells, apical cytoplasmic blebbing, lipid accumulation, myelin figure like structure formation, increased lysosomes, mitochondrial swelling and disorganization of cristae structures, apoptotic changes and widening of intercellular space were found. TNF-α, IL-6 and caspase 3 expressions were increased. BUN and creatinine concentrations were increased. Increase in MDA levels and decrease in SOD activities were determined. Even though degeneration still continues in gentamicin+2-APB treatment group, severity and the area it occupied were decreased and the glomerular and tubule structures were generally preserved. TNF-α, IL-6, caspase 3 immunoreactivities and BUN, creatinine, MDA concentrations were reduced and SOD activities were increased markedly compared to gentamicin group. In conclusion, it has been considered that 2-APB can prevent gentamicin mediated nephrotoxicity with its anti-oxidant, anti-apoptotic and anti-inflammatory effects.

Gentisic acid mitigates gentamicin-induced nephrotoxicity in rats

The current investigation was considered to evaluate the beneficial effects of gentisic acid (GA) on gentamicin (GEN)-induced nephrotoxicity in rat kidneys through assessment of oxidative stress, inflammatory cytokines, and histopathological changes. Rats were split into five equal groups. Rats were treated with GA (25, 50, and 100 mg/kg/day, p.o.) for 14 consecutive days and GEN (100 mg/kg, i.p.) was administrated from day 8 to day 14 of the experiment. On the 15th day, blood samples were collected to determine neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), blood urea nitrogen (BUN), and creatinine (Cr) levels. Malondialdehyde (MDA), glutathione (GSH), tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β), and nitric oxide (NO) levels and the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) were assessed in the renal tissue. Histopathological evaluations were done to confirm the biochemical results. GEN increased the levels of NGAL, KIM-1, BUN, and Cr in serum as well as MDA, NO, GSH, TNF-α, and IL-1β in renal tissue. Moreover, GEN administration reduced the activity of CAT, SOD, and GPx in renal tissue. Nonetheless, the administration of GA before and alongside GEN mitigated these deleterious effects. In conclusion, GA has a beneficial effect on biochemical, inflammatory, and oxidative stress indices against GEN-induced nephrotoxicity.

Assessment of gentamicin and cisplatin-induced kidney damage mediated via necrotic and apoptosis genes in albino rats

BACKGROUND

Gentamicin (GM) is a low-cost, low-resistance antibiotic commonly used to treat gram-negative bacterial diseases. Cisplatin (Csp) is a platinum-derived anti-neoplastic agent. This experiment aimed to identify the early signs of gentamicin and cisplatin-induced nephrotoxicity in rats. Thirty Wistar rats were divided into three groups of 10: a control group, which received no treatment; a gentamicin group administered by a dose of (100 mg/kg, IP) for 7 consecutive days, and a cisplatin group was administered intraperitoneal in a dose of (1.5 mg/kg body weight) repeated twice a week for 3 weeks.

RESULTS

Both experimental groups exhibited increased levels of creatinine, urea, and uric acid, with the cisplatin-treated group showing higher levels than the gentamicin group. Experimental groups also exhibited significantly increased Malondialdehyde (MDA), reduced glutathione (GSH), and glutathione peroxidase (GSH-Px) with more pronounced effects in the cisplatin-treated group. Further, both experimental groups exhibited significant up-regulation of Tumor Necrosis Factor α (TNF-α), caspase-3, and Bax and down regulation of Bcl-2.

CONCLUSION

These findings confirm the use of necrotic, apoptotic genes as early biomarkers in the detection of tubular kidney damage. Further, cisplatin was shown to have a greater nephrotoxic effect than gentamicin; therefore, its use should be constrained accordingly when co-administered with gentamicin.

Involvement of oxidative stress and toll-like receptor-4 signaling pathways in gentamicin-induced nephrotoxicity in male Sprague Dawley rats

Gentamicin (GM) is an antibiotic belonging to an aminoglycoside family that might induce nephrotoxicity in human and animal models via oxidative stress. Toll-like receptors (TLRs) are part of innate immune systems that participate in inflammatory responses. In this regard, we investigated the effect of GM on kidney functional and structural parameters, enzymatic antioxidant levels, and mRNA expression of TLR4 and IL6 in the rat kidney. Adult male Sprague Dawley rats were randomly divided into two groups (n = 10): Control and Gentamicin (100 mg/kg, i.p.). After ten days of GM administration, a blood sample was taken, and the kidneys were removed. The serum levels of creatinine (Cr) and blood urea nitrogen (BUN) were measured. Furthermore, the right kidney was preserved in formalin 10% for hematoxylin and eosin (H&E) staining, and the left kidney was kept at -80 °C for molecular and oxidative indexes analysis. Administration of GM caused tubular damages and functional disturbance. So that, Cr and BUN values in the GM group were higher than Control group. Furthermore, molecular findings showed upregulation of TLR4 and IL-6 mRNA expression in renal tissue of the GM-received group. In this study, superoxide dismutase (SOD) activity was slightly increased as a compensatory mechanism in response to elevated malondialdehyde (MDA) levels in the GM-treated group. On the other hand, the activity of catalase (CAT) and glutathione peroxidase (GPx) were significantly declined. Our results demonstrated that oxidative stress and subsequent TLR4 upregulation signaling pathways are involved in GM-induced nephrotoxicity.

Protective Effect of Opuntia dillenii (Ker Gawl.) Haw. Seed Oil on Gentamicin-Induced Nephrotoxicity: A Biochemical and Histological Analysis

Opuntia dillenii is a medicinal plant with frequent usage in folk medicine to treat many illnesses. The present study aims to investigate the protective effect of Opuntia dillenii seed oil against gentamicin-induced nephrotoxicity in rats. The animals (rats) were randomly divided into three groups (i) the normal control group treated only with distilled water (10 mL/kg), (ii) the gentamicin group treated with distilled water (10 mL/kg) and received an intraperitoneal injection of gentamicin (80 mg/kg), and (iii) the group treated with the Opuntia dillenii seed oil (2 mL/kg) and also received an intraperitoneal injection of gentamicin (80 mg/kg). The rats received their following treatments for 14 consecutive days orally. Serum urea, creatinine, gamma-glutamyl transferase, albumin, and electrolyte levels were quantified as the markers of acute renal and liver failure. Besides, the kidney and liver relative weight, kidney malondialdehydes, and kidney histological analysis were determined. The results have shown that daily pretreatment with Opuntia dillenii seed oil (2 mL/kg) prevented severe alterations of biochemical parameters and disruptions of kidney tissue structures. In addition, the results of the present study showed for the first time that Opuntia dillenii seed oil reduced renal toxicity in gentamicin-induced nephrotoxicity in rats. Therefore, Opuntia dillenii seed oil may represent a new therapeutic avenue to preserve and protect renal function in gentamicin-treated patients.

Vitamin E protects against gabapentin-induced chronic hepatic and renal damage associated with the inhibition of apoptosis and tissue injury in rats

AIMS

This study aimed to investigate the potential protective effects of vitamin E against gabapentin-induced chronic liver and kidney injury associated with the inhibition of biomarkers of apoptosis and tissue injury.

MATERIALS AND METHODS

Four groups of adult male rats were included; control, gabapentin (100 mg/kg/day), Vitamin E (80 mg/kg/day), and a combination of gabapentin and Vitamin E for 90 days. Serum levels of AST, ALT, LDH, ALP, urea, and creatinine were measured in addition to malondialdehyde (MDA), and reduced glutathione (GSH) tissue levels. P53 gene expression, histological, and immunohistochemical examinations were performed in liver and kidney tissue samples.

KEY FINDINGS

Gabapentin increased AST, ALT, LDH, ALP, urea, creatinine, MDA, and p53 gene expression and it reduced GSH. Moreover, gabapentin administration caused structural changes in the hepatic and renal architecture with a weak Periodic acid-Schiff (PAS) reaction that reflects glycogen deposition in the liver and kidney and a positive immunoreaction for BCL2-associated X protein (BAX) that reflects activated apoptosis. Vitamin E significantly (p<0.05) reversed the biochemical alterations associated with chronic gabapentin administration and improved the histopathological picture of hepatic and renal tissue with a partial inhibition of BAX.

SIGNIFICANCE

Chronic administration of gabapentin causes hepatic and renal impairments, which is ameliorated by Vitamin E; possibly due to the inhibition of biomarkers of apoptosis and tissue injury.

The protective efficacy of vitamin E and cod liver oil against cisplatin-induced acute kidney injury in rats

Cisplatin (CP) is a highly effective chemotherapeutic agent against neoplasms, but its clinical utility is limited due to the side effects of its dose-dependent nephrotoxicity. Vitamin E (Vit E) and cod liver oil (CLO) are natural substances with chemoprotective effects. The present study was conducted to evaluate the protective effects of Vit E and/or CLO for CP-induced acute kidney injury (AKI) in rats. This study involved 40 mature male Wistar albino rats that were equally allocated into eight groups: Veh, Vit E, CLO, Vit E + CLO, CP, Vit E + CP, CLO + CP, and Vit E + CLO + CP. The co-administration of Vit E and CLO significantly ameliorated CP-induced elevations in serum creatinine (Cr), blood urea nitrogen (BUN), interleukin 1 beta (IL-1β), and interleukin- 6 (IL-6). Further, rats that received Vit E and/or CLO showed significant decrease in malondialdehyde (MDA) and increases in superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels in renal tissues, compared to CP-intoxicated rats. Additionally, the treatment restored the normal histological architecture (except for few cast formations) and upregulated the immunostaining area% of aquaporin 3 (AQP3) and downregulated the immunostaining area% of Bcl2 associated X protein (BAX) and inducible nitric oxide synthase (iNOS). The observed effects were stronger in the combination treatment group. The obtained data revealed that Vit E and CLO co-administration protects against the CP-induced AKI more than monotherapy with Vit E or CLO.

Development of a Novel Pharmaceutical Formula of Nanoparticle Lipid Carriers of Gentamicin/α-Tocopherol and In Vivo Assessment of the Antioxidant Protective Effect of α-Tocopherol in Gentamicin-Induced Nephrotoxicity

Gentamicin is a potent antibiotic with a nephrotoxicity drawback which limits its use. D-α-tocopherol polyethylene glycol succinate (α-tocopherol) is widely used as a surfactant and have potent antioxidant properties. This study aimed to assess the protective effect of α-tocopherol on gentamicin-induced nephrotoxicity by loading gentamicin on nanostructured lipid carriers (NLC). In vivo, the product was administered intravenously to three groups of rabbits (control, gentamicin and gentamicin/α-tocopherol NLC) for 10 consecutive days. Blood was collected on days 1, 5 and 10 to assess renal function. A significant difference in all plasma parameters related to kidney function were observed in the gentamicin group compared to the control by day 5 and 10, confirming the nephrotoxicity effect. On the other hand, the same parameter levels of the NLC group were significantly different compared to the gentamicin group, confirming the protective effect on kidney function. Gentamicin also caused significant decreases in plasma levels of glutathione sulfhydryl (GSH) and superoxide dismutase (SOD) activity. However, gentamicin-α-tocopherol NLC significantly elevates both plasma levels of GSH as well as SOD activity. The present work indicates that, loading of gentamicin on NLC by using α-tocopherol, is an innovative strategy to protect against aminoglycoside-induced nephrotoxicity due to its antioxidant activity.

Ameliorative effects of gallic acid on gentamicin-induced nephrotoxicity in rats

The major side effect of gentamicin (GEN) is nephrotoxicity which in turn restricts the clinical use of this drug. In this study, the effect of gallic acid (GA) on gentamicin-induced nephrotoxicity was studied. A total number of 28 male Wistar rats were randomly divided into four experimental groups: control, GEN (100 mg/kg/day), GEN + GA (30 mg/kg/day), GA (30 mg/kg/day). All drug administrations were done intraperitoneally (i.p) for eight consecutive days. Twenty-four hours after the last administration, blood samples were collected to determine serum creatinine (Cr), blood urea nitrogen (BUN). The right kidney was used for histological examination. Malondialdehyde (MDA), glutathione (GSH), nitric oxide (NO) levels and catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activity were assayed in left renal tissue. Results showed a significant increase in the levels of MDA, NO, Cr, and BUN and decrease of GSH, CAT, GPx, and SOD by GEN administration. Co-administration with GA showed reduction in the levels of MDA, NO, Cr, and BUN and increase in GSH, CAT, GPx, and SOD. Also, the nephroprotective effect of GA was confirmed by the histological examination of the kidneys. The results of our study showed that GA exerts a significant nephroprotective effect against GEN-induced nephrotoxicity.

Gentamicin induced acute renal damage and its evaluation using urinary biomarkers in rats

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Gentamicin induced dose dependent and temporal change in urinary biomarkers.

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Histological changes were minimal to severe on Day 4 & 8 respectively at both doses.

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Several fold increase in urinary biomarkers on Day 4 and 8 at both doses.

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On Day 8, increase in urinary and serum markers and histological changes.

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Clusterin is highly sensitive urinary biomarkers.

Consistent, sensitive biomarkers of acute kidney injury in animal models and humans have historically represented a poorly met need for investigators and clinicians. Detection of early kidney damage using urinary biomarkers is essential to assess the adversity in preclinical toxicology studies, which will help in reducing attrition of lead candidates in drug development. This study was undertaken to evaluate recently identified urinary biomarkers use in identifying acute kidney injury compared to traditional serum markers in experimentally induced nephrotoxicity in male Sprague Dawley (SD) rats. Gentamicin induced nephrotoxicity in Sprague Dawley rats is commonly detected using serum markers and histological evaluation of kidneys. Gentamicin, an aminoglycoside was administered at 30 and 100 mg/kg/day dose (subcutaneous) for seven consecutive days to induce nephrotoxicity. On day 4 and day 8 post treatment, serum and urine samples from these rats were analyzed for traditional serum/urine and novel urinary biomarkers and microscopic evaluation of kidneys.

On Day 4, no statistically significant change in serum BUN and creatinine level, but increase in urinary microalbumin (mALB) and urinary protein (UP) noticed in both doses of Gentamicin treated rats. On Day 8 significant increase in serum blood urea nitrogen (BUN), serum creatinine, UP and urinary mALB at 100 mg/kg/day, increase in total protein and decrease in albumin in 30 and 100 mg/kg/day and decrease in BUN and creatinine at 100 mg/kg of Gentamicin treated rats. The BUN and creatinine levels or fold change was comparable between control and 30 mg/kg of Gentamicin on Day 8, however, there was 5.6 and 3.4 fold change in BUN and Creatinine level noticed at 100 mg/kg/day of Gentamicin. On Day 4 and 8, significant increase in urinary levels of Clusterin was noted with animals administered both doses of Gentamicin. Similarly, significant increase in urinary levels of kidney injury molecule 1 (Kim-1), Cystatin C and neutrophil gelatinase-associated lipocalin (NGAL) were noticed with animals administered Gentamicin at 100 mg/kg/day on both Day 4 and 8. All these markers have shown dose-dependent change.

Histological changes seen on Day 4 and Day 8 were of minimal to mild and moderate to severe in nature at both doses, respectively. The results demonstrated the sensitiveness and accuracy of detecting acute renal damage with novel urinary biomarkers, and their use in diagnosing early kidney damage. This helps in adversity assessment in animal toxicology studies and advocating right treatment to patients who have early renal injury which otherwise can only be diagnosed by elevated levels of traditional biomarkers in blood only after >30% of kidneys is damaged.

Preventive Effect of L-Carnitine on Scar Formation During Acute Pyelonephritis: A Randomized Placebo-Controlled Trial

BACKGROUND

Urinary tract infection and pyelonephritis are clinical problems that frequently occur in children. Several factors are responsible for renal tissue injury, morbidity, and renal scarring after pyelonephritis. The aim of this study was to evaluate the preventive effect of L-carnitine on renal scarring in acute pyelonephritis.

METHODS

A randomized double-blind clinical trial was conducted on 65 children aged 6 months to 10 years. Patients were randomized into 2 groups to receive 7-day treatment with only antibiotics without L-carnitine (control group; n = 32) and 7-day treatment with L-carnitine (case group; n = 33) during the acute phase of infection. Technetium-99m-labeled dimercaptosuccinic acid (DMSA) scintigraphy was performed for all children during the acute phase (in 2-7 days of hospitalization) and late phase. P-value less than 0.05 was statistically significant.

RESULTS

We recruited 65 participants in the study: 32 children in control group and 33 children in case group. Three children in the control group and 2 children in the case group refused to perform the second DMSA scan. Overall, data analysis at the end of the study was done on 60 patients. Age distribution of girl patients with upper urinary infection was 6.5% in girl children aged between 6 months and 12 months, 41.1% aged between 1 and 5 years, 33.3% aged between 5 and 10 years, respectively. There was no significant difference between 2 groups in age and sex. There was no significant difference between 2 groups in systolic blood pressure, diastolic blood pressure, the lab data including urine white blood cells and serum erythrocyte sedimentation rate, and antibiogram profiles. Voiding dysfunction was detected in 10% of the participants. The baseline DMSA was not significantly difference in 2 groups, but worsening of kidney lesions was significantly higher in control group after 6 months (P = 0.012).

CONCLUSION

Our study showed that L-carnitine significantly decreased renal scarring because of acute pyelonephritis.

α-Tocopherol Reduces Morphological Changes and Oxidative Stress during Gentamicin-Induced Acute Renal Failure

We studied the effect of α-tocopherol on gentamicin-induced morphological and functional changes in the kidneys of Wistar rats. Special attention was paid to the ability of α-tocopherol administered in combination with gentamicin to correct ultrastructural changes in the glomerular basal membrane and tubules. Combined treatment with α-tocopherol (100 mg/kg) and gentamicin (100 mg/kg) led to correction of histopathological and biochemical changes and oxidative injury to the kidneys induced by this antibiotic.

Key role of oxidative stress in animal models of aminoglycoside nephrotoxicity revealed by a systematic analysis of the antioxidant-to-nephroprotective correlation

The clinical utility of aminoglycoside antibiotics is partly limited by their nephrotoxicity. Co-administration of a variety of candidate nephroprotectants has been tested at the preclinical level. According to a recent meta-analytic study, antioxidants are the only family of compounds with enough preclinical documentation to draw solid conclusions on their class nephroprotective capacity in animal models. In this study a systematic analysis of the relation between the level of antioxidation and the level of nephroprotection was performed. A regression model is presented which crosses the y-axis (i.e. the axis representing the level of nephroprotection) very nearly the zero value, meaning that maximal prevention of the oxidative stress induced by aminoglycosides results in almost maximal nephroprotection. This indicates that oxidative stress plays a central role in the hierarchy of pathophysiological mechanisms underlying aminoglycoside nephrotoxicity. In addition, this model may potentially serve: i) as a standard to evaluate the role of the antioxidant effect of candidate nephroprotectants; ii) to reveal additional, antioxidant-independent effects among those compounds providing more nephroprotection than that expected from its antioxidant activity; and thus iii) to discriminate and focus most effective nephroprotectants on clinical usage.

Gentamicin nephrotoxicity in animals: Current knowledge and future perspectives

Due to high relative blood flow the kidney is prone to drug-induced damage. Aminoglycoside type antibiotic gentamicin is one of the leading cause of drug-induced nephrotoxicity. In recent years gentamicin nephrotoxicity is significantly reduced by shifting to once daily dosage as well as by eliminating known risk factors. Application of gentamicin is still related to serious side effects which are reported more often compared to other antibiotics. Because gentamicin is still heavily used and is highly efficient in treating infections, it is important to find mechanisms to reduce its nephrotoxicity. This aim can only be achieved through better understanding of kidney metabolism of gentamicin. This problem has been extensively researched in the last 20 years. The experimental results have provided evidence for almost complete understanding of mechanisms responsible for gentamicin nephrotoxicity. We now have well described morphological, biochemical and functional changes in kidney due to gentamicin application. During the years, this model has become so popular that now it is used as an experimental model for nephrotoxicity per se. This situation can mislead an ordinary reader of scientific literature that we know everything about it and there is nothing new to discover here. But quite opposite is true. The precise and complete mechanism of gentamicin nephrotoxicity is still point of speculation and an unfinished story. With emerge of new and versatile technics in biomedicine we have an opportunity to reexamine old beliefs and discover new facts. This review focuses on current knowledge in this area and gives some future perspectives.

Amikacin induced renal damage and the role of the antioxidants on neonatal rats

Amikacin (AK) is frequently used on the treatment of Gram-negative infections on neonates, but its usage is restricted because of nephrotoxicity. In this study, on neonatal rats, we aimed to investigate the effects of erythropoietin and vitamin E on AK induced nephrotoxicity. A total of 35 newborn Wistar Albino rats were divided into four groups: (1) injected with saline (serum physiological was administered to placebo controls), (2) injected with AK (1200 mg/kg), (3) injected with AK + vitamin E (150 mg/kg), (4) injected with AK + erythropoietin (EPO) (300 IU/kg/day). In renal tissue, AK levels were significantly high in all groups except the control. Tissue malondialdehyde (MDA) and nitric oxide (NO) levels were statistically higher in AK -treated group than the control. MDA and NO levels were significantly decreased with the administration of vitamin E and EPO. Glutathione peroxidase (GPX) levels were statistically low in AK group compared with the controls. The levels of GPX, in vitamin E group, were increased significantly. However, superoxide dismutase and catalase levels were not significantly different in none of the groups. Insulin-like growth factor-1 values in AK, EPO and vitamin E groups were significantly higher than the control group. Histomorphological changes such as tubular epithelial necrosis were seen in AK treated group. Histopathological improvements observed with EPO and vitamin E administration. AK nephrotoxicity is related to oxidative stress and is supported with biochemical and histopathological findings. Vitamin E and EPO, as antioxidants, can be useful renoprotective agents for ameliorating AK induced nephrotoxicity in neonates.

Chitosan Prevents Gentamicin-Induced Nephrotoxicity via a Carbonyl Stress-Dependent Pathway

Aminoglycosides are widely used to treat infections; however, their applications are limited by nephrotoxicity. With the increase of antibiotic resistance, the use of aminoglycosides is inevitable. Low-molecular-weight chitosan (LMWC) has shown renal protective effects in dialysis patients. However, no study has evaluated LMWC for preventing aminoglycoside-induced nephrotoxicity or determined the mechanisms underlying the renal protective effects. In this study, LMWC (165 or 825 mg/kg/day) or metformin (100 mg/kg/day) was orally administered for 13 days to rats with nephropathy induced by gentamicin (GM), a kind of aminoglycoside (150 mg/kg/day i.p. for 6 days). Both LMCW doses improved renal function. Serum creatinine levels improved in rats treated with 165 and 825 mg/kg/day LMWC (from 2.14 ± 0.74 mg/dL to 1.26 ± 0.46 mg/dL and 0.69 ± 0.12 mg/dL, resp., P < 0.05). Blood urea nitrogen levels were also improved in these rats (from 73.73 ± 21.13 mg/dL to 58.70 ± 22.71 mg/dL and 28.82 ± 3.84 mg/dL, resp., P < 0.05). Additionally, renal tissue morphology improved after LMWC treatment, and accumulation of renal methylglyoxal, a damage factor associated with carbonyl stress, was reversed. These results show that LMWC prevents GM-induced renal toxicity via a carbonyl stress-dependent pathway.

Umbelliferone β-d-galactopyranoside inhibits chemically induced renal carcinogenesis via alteration of oxidative stress, hyperproliferation and inflammation: possible role of NF-κB

Umbelliferone (7-hydroxycoumarin) compound possesses strong anti-inflammatory and free radical scavenging activity.

Evaluation of efficacy of natural astaxanthin and vitamin E in prevention of colistin-induced nephrotoxicity in the rat model

OBJECTIVE

We evaluated the effect of astaxanthin (ASX) and vitamin E (vit E) on colistin methanesulfonate (CMS) induced-nephrotoxicity in rats.

METHODS

Animals were treated with sterile saline, 300000 or 450 000 IU/kg/day of CMS, CMS + ASX (20 mg/kg), CMS + vit E (100 mg/kg), or CMS + 1 ml/kg olive oil (OO) for 7 days. The plasma/urine creatinine (Cr) level, urine γ-glutamyl-transferase (GGT) level, and renal tissue activities in malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reductase (GSH), as well as renal histology were performed.

RESULTS

CMS induced a tubular damage, increased the GGT and MDA levels, and decreased the activities of SOD, CAT, GPx and GSH. Co-treatment with ASX or vit E restored all biochemical parameters cited above and improved the histopathological damage.

CONCLUSION

Nephrotoxicity induced by CMS might be due to oxidative damage. The improvement by ASX or vit E seems to be related to their antioxidant properties.

Protective Effects of Houttuynia cordata Thunb. on Gentamicin-induced Oxidative Stress and Nephrotoxicity in Rats

Development of a therapy providing protection from, or reversing gentamicin-sulfate (GS)-induced oxidative stress and nephrotoxicity would be of great clinical significance. The present study was designed to investigate the protective effects of Houttuynia cordata Thunb. (HC) against gentamicin sulfate-induced renal damage in rats. Twenty-eight Sprague-Dawley rats were divided into 4 equal groups as follows: group 1, control; group 2, GS 100 mg/kg/d, intraperitoneal (i.p.) injection; group 3, GS 100 mg/kg/d, i.p. + HC 500 mg/kg/d, oral; and group 4, GS 100 mg/kg/d i.p. + HC 1000 mg/kg/d, oral administration). Treatments were administered once daily for 12 d. After 12 d, biochemical and histopathological analyses were conducted to evaluate oxidative stress and renal nephrotoxicity. Serum levels of creatinine, malondialdehyde (MDA), and blood urea nitrogen (BUN), together with renal levels of MDA, glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) were quantified to evaluate antioxidant activity. Animals treated with GS alone showed a significant increase in serum levels of creatinine, BUN, and MDA, with decreased renal levels of GSH, SOD, and CAT. Treatment of rats with HC showed significant improvement in renal function, presumably as a result of decreased biochemical indices and oxidative stress parameters associated with GS-induced nephrotoxicity. Histopathological examination of the rat kidneys confirmed these observations. Therefore, the novel natural antioxidant HC may protect against GSinduced nephrotoxicity and oxidative stress in rats.

The effects of vitamin d on gentamicin-induced acute kidney injury in experimental rat model

Introduction. Acute kidney injury (AKI) pathogenesis is complex. Findings of gentamicin nephrotoxicity are seen in 30% of the AKI patients. Vitamin D has proven to be effective on renin expression, inflammatory response, oxidative stress, apoptosis, and atherosclerosis. We aimed to investigate the effect of vitamin D in an experimental rat model of gentamicin-induced AKI. Methods. Thirty nonuremic Wistar albino rats were divided into 3 groups: Control group, 1 mL saline intramuscular (im) daily; Genta group, gentamicin 100 mg/kg/day (im); Genta + vitamin D, gentamicin 100 mg/kg/day (im) in addition to 1 α , 25 (OH)2D3 0.4 mcg/kg/day subcutaneously for 8 days. Blood pressures and 24-hour urine were measured. Blood urea and creatinine levels and urine tubular injury markers were measured. Renal histology was semiquantitatively assessed. Results. Urea, creatinine and urine neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1 were all increased in Genta group indicating AKI model. Systolic blood pressure decreased, but urine volume and glutathione increased in Genta + Vit D group compared to Control group. Histological scores indicating tubular injury increased in Genta and Genta + Vit D groups. Conclusions. Vitamin D does not seem to be effective on histological findings although it has some beneficial effects via RAS system and a promising effect on antioxidant system.

Blood chemical changes and renal histological alterations induced by gentamicin in rats

Gentamicin is an effective widely used antibiotic, but the risk of nephrotoxicity and oxidative damage limit its long-term use. Hence, the current study aims to elucidate such hazardous effects. To achieve the study aim male Wistar albino rats (Rattus norvegicus) were exposed to gentamicin to investigate the resultant blood chemical changes and renal histological alterations. In comparison with control rats, gentamicin produced outstanding tubular, glomerular and interstitial alterations that included degeneration, necrosis, cytolysis and cortical tubular desquamation together with mesangial hypercellularity, endothelial cell proliferation and blood capillary congestion. Compared with control animals significant blood chemical changes (P < 0.05) including free radicals, ALT, AST, ALP, serum creatinine and serum urea were recorded in gentamicin-injected animals. The findings revealed that exposure to gentamicin can induce significant histological alterations in the kidney as well as remarkable blood chemical changes that might indicate marked renal failure.

Effect of rosmarinic acid on inhibition of gentamicin induced nephrotoxicity in rats

The present investigation reports the effect of rosmarinic acid (RA), an antioxidant on gentamicin sulphate (GS)-induced renal oxidative damage in rats. Rosmarinic acid (RA) has been demonstrated to have antioxidant, free radical scavenger and anti-inflammatory effects. Twenty-eight Sprague-Dawley rats were divided in to four equal groups as follows: group 1 (control), group 2 (GS 100 mg/kg/d ip), group 3 (GS 100 mg/kg/d ip+RA 50 mg/kg/d) and group 4 (GS 100 mg/kg/d ip+RA 100 mg/kg/d). Treatments were administrated once daily for 12 days. After 12 days 24h urine was collected, blood was sampled and kidneys were removed. Serum and kidney tissue MDA assessed by thiobarbituric acid. Kidney paraffin sections (5 μm thickness) from the left kidney stained with periodic acid Schiff. Tubular necrosis was studied semiquantitatively and glomerular volume and volume density of proximal convoluted tubule (PCT) estimated stereologically. Kidney homogenize were prepared from right kidney. Serum creatinine, urea and kidney antioxidant enzymes activity were assessed by special kits. Data were compared by SPSS 13 software and Mann-Whitney test at p < 0.05. Co treatment of GS and RA (High dose) significantly decreased serum creatinine, MDA, urea, tubular necrosis (p < 0.05) and increase renal GSH, GPX, CAT, SOD, volume density of PCT and creatinine clearance significantly in comparison with GS group (p < 0.05). Treatment with RA (high dose) maintained serum creatinine, volume density of PCT, renal GSH, GPX, SOD and MDA as the same level as control group significantly (p < 0.05). In conclusion, RA alleviates GS nephrotoxicity via antioxidant activity, increase of renal GSH content and increase of renal antioxidant enzymes activity.

Evaluation of Effectiveness of Vitamins C and E on Prevention of Renal Scar due to Pyelonephritis in Rat

Aim was evaluation of the effects of cosupplementation of, vitamins E and C, in preventing renal scarring in acute pyelonephritis. Animals and Treatments. Sixty rats were used, bacteria was injected through kidney. The rats were arranged randomly in 3 groups of 20 rats each. Rats in groups 1 and 2 were given once-daily intraperitoneal injections of gentamicin for ten consecutive days, beginning on the third day after inoculation. In group 2, vitamins E and C cotreatment and in group 3, vitamins E and C cotreatment without gentamicin injection were started. Three rats in each group were killed 24 hours after the inoculation (for infection and inflammation document) and forty-eight hours after the antibiotic injection (for efficacy of treatment). After eight weeks, the rest of rats were killed, and kidneys evaluated for percent of scaring. Result. There was also significant difference of degree of scar formation (1.4 and 3.4% versus 8.6%, P = .001). The group which received gentamicin only had moderate to severe scaring, but the two groups which received vitamin C and vitamin E showed no or mild renal scaring. Conclusion. The study showed that administration of antioxidants can protect scaring due to pyelonephritis with or without antibiotic administration.

New insights into the mechanism of aminoglycoside nephrotoxicity: an integrative point of view

Nephrotoxicity is one of the most important side effects and therapeutical limitations of aminoglycoside antibiotics, especially gentamicin. Despite rigorous patient monitoring, nephrotoxicity appears in 10-25% of therapeutic courses. Traditionally, aminoglycoside nephrotoxicity has been considered to result mainly from tubular damage. Both lethal and sub-lethal alterations in tubular cells handicap reabsorption and, in severe cases, may lead to a significant tubular obstruction. However, a reduced glomerular filtration is necessary to explain the symptoms of the disease. Reduced filtration is not solely the result of tubular obstruction and tubular malfunction, resulting in tubuloglomerular feedback activation; renal vasoconstriction and mesangial contraction are also crucial to fully explain aminoglycoside nephrotoxicity. This review critically presents an integrative view on the interactions of tubular, glomerular, and vascular effects of gentamicin, in the context of the most recent information available. Moreover, it discusses therapeutic perspectives for prevention of aminoglycoside nephrotoxicity derived from the pathophysiological knowledge.

Management of aminoglycosides in the intensive care unit

Antibacterial resistance is increasing throughout the world, while the development of new agents is slowly progressing. In addition, the increasing prevalence of fluoroquinolone resistance may force many practitioners to choose an aminoglycoside agent in gram-negative regimens. Aminoglycosides are bactericidal agents with potent activity against gram-negative infections and activity against gram-positive infections when added to a cell wall active antimicrobial-based regimen. These agents may be dosed multiple times a day or consolidated as high-dose, extended-interval dosing to maximize pharmacokinetic and pharmacodynamic properties to achieve possible improved efficacy with reduced toxicity. Clinical application includes the treatment of bacteremia, endocarditis, health-care and nosocomial pneumonias, intra-abdominal infections, and others. Nephrotoxicity and ototoxicity are potential risks of aminoglycoside therapy that may be minimized with serum monitoring and short courses of therapy.

Amelioration of streptozotocin-induced diabetes mellitus, oxidative stress and dyslipidemia in rats by tomato extract lycopene

The effects of various doses of lycopene were studied in streptozotocin (STZ)-induced hyperglycaemic rats to evaluate its possible hypoglycaemic, hypolipidaemic and antioxidant activity in diabetes. Compared to the normoglycaemic group, the treatment of rats with a single dose of STZ (65 mg/kg body weight) revealed a significant increase (p<0.05) only in plasma hydrogen peroxide (H(2)O(2)), i.e. by 230%; it increased the thiobarbituric acid reactive substances (TBARS) as index of the lipid peroxidation level by 69%, while total antioxidant activity was decreased by 36%, with a consistently significant decrease (p<0.05) in the activity of erythrocytes antioxidative enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx). The levels of total lipid, triglycerides and total cholesterol in serum of hyperglycaemic rats were increased by 14%, 65% and 36%, respectively, while HDL-C decreased by 22% compared to the normoglycaemic group. Exogenous administration of individual gradual doses of lycopene to hyperglycaemic rats causes a dose-dependent decrease in glucose level, an increase of insulin concentration, a decrease of H(2)O(2) and TBARS levels, as well as increased total antioxidant status with increased antioxidant enzyme activities (CAT, SOD and GPx) with improvement in serum lipid profile. It is obvious from this study that lycopene acts as an antidiabetic agent through lowering the free radical and has an improving effect on serum that reaches the normal level; the greatest effect of lycopene was observed at 90 mg/kg body weight.

Spirulina platensis protects against gentamicin-induced nephrotoxicity in rats

The present study aimed to investigate the protective effect of Spirulina platensis (SP) on gentamicin sulphate (GS)-induced changes in the levels of lipid peroxidation and endogenous antioxidants in the kidney of rats. Sprague-Dawley rats were treated in separate groups as follows for 7 consecutive days: control (C), gentamicin sulphate (100 mg/kg i.p.) (GS), Spirulina platensis (1000 mg/kg orally) (SP) and Spirulina platensis (1000 mg/kg orally) plus gentamicin sulphate (100 mg/kg i.p.) (SP + GS). The degree of protection was evaluated by determining the effects of Spirulina platensis on malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPX) and nitric oxide (NO), and plasma creatinine and urea levels were estimated in kidney homogenates to evaluate antioxidant activity, and the kidney was histologically examined as well. Spirulina platensis elicited significant nephroprotective activity by decreasing lipid peroxidation (MDA) and elevated the levels of GSH, SOD, GPX, NO, creatinine and urea. Furthermore, these biochemical observations were supplemented by histological examination of the rat kidneys. In conclusion, the present study indicates a very important role of reactive oxygen species (ROS) and the relation to renal dysfunction and point to the therapeutic potential of Spirulina platensis in gentamicin sulphate induced nephrotoxicity.

Effects of co-supplementation of vitamins E and C on gentamicin-induced nephrotoxicity in rat

Gentamicin (GM) is an effective antibiotic against severe gram-negative infections. However it can produce nephrotoxicity in human. Reactive oxygen species (ROS) have been proposed as the causative factors of the renal side effects the drug. This study was performed to investigate the protective role of antioxidant vitamins against GM-mediated nephropathy in an in situ model of isolated rat kidney. Male Sprague-Dawley rats were randomly assigned to one of the following groups of seven rats: group 1 (Control) was perfused with Tyrode solution; group 2 (GM), 200 microg ml(-1) GM was added to the perfusate; group 3 (GM + Vit C), as group 2 with vitamin C added to the drinking water for 3 days (200 mg l(-1)) and to the perfusate (100 mg l(-1)); group 4 (GM + Vit E), as group 2 with vitamin E (100 mg (100 g body weight)(-1), i.m.) injected 12 h before the start of the experiment; group 5 (GM + Vit C + Vit E) as group 2 with vitamin E and C co-administered (concentrations and conditions as in groups 3 and 4). To compare the groups, urinary lactate dehydrogenase (LDH), N-acetyle-beta-D-glucosaminidase (NAG) and alkaline phosphatase (ALP) activities, inulin clearance (glomerular filtration rate, GFR) and renal tissue glutathione (GSH) content were measured. GM caused a significant nephrotoxicity demonstrated by an increase in urinary LDH, NAG and ALP activities. Reduction in GSH content and a marked decrease in GFR were observed compared to controls. Vitamin C inhibited the GM-induced increase in urinary enzyme activities but did not show a significant effect on the GSH content or GFR. Vitamin E prevented the GM-induced reduction in GSH level without a significant improvement in GFR. Co-administration of vitamins C and E significantly prevented the GM-induced nephrotoxicity demonstrating by preservation of GFR and GSH levels and prevention of increase in urinary enzyme activities. We conclude that co-administration of moderate doses of vitamins C and E has beneficial effects on renal preservation in GM-induced nephrotoxicity.

An overview of drug-induced acute kidney injury

The complex nature of critical illness often necessitates the use of multiple therapeutic agents, many of which may individually or in combination have the potential to cause renal injury. The use of nephrotoxic drugs has been implicated as a causative factor in up to 25% of all cases of severe acute renal failure in critically ill patients. Acute tubular necrosis is the most common form of renal injury from nephrotoxin exposure, although other types of renal failure may be seen. Given that this is a preventable cause of a potentially devastating complication, a comprehensive strategy should be used to avoid nephrotoxicity in critically ill patients including: accurate estimation of pre-existing renal function using serum creatinine-based glomerular filtration rates, avoidance of nephrotoxins if possible, ongoing monitoring of renal function, and immediate discontinuation of suspected nephrotoxins in the event of renal dysfunction.

Effect of silymarin and vitamin E on gentamicin-induced nephrotoxicity in dogs

Drug-induced nephrotoxicity is an important cause of renal failure in dogs. Aminoglycoside antibiotics, such as gentamicin, can produce nephrotoxicity in dogs, due to in part to an imbalance of pro- and antioxidants (oxidative stress). Silymarin (the mixture of flavonolignans extracted from Silybum marianum) has potentially beneficial antioxidant properties. A control group (saline, group 1, n = 5) was compared with dogs that were administrated gentamicin by intramuscular injection, at dosage of 20 mg/kg, once daily for 9 days (groups 2-5, n = 5 per group). The effects of vitamin E (group 3) and silymarin (group 4) alone and in combination (group 5) were compared for induced nephrotoxicity. Renal function was assessed using serum biochemical markers (creatinine and urea). Malondialdehyde (MDA) concentration were measured as a marker of lipid peroxidation. The activity of total serum antioxidants (TSAO) was assessed as a marker of antioxidant defences. Serum creatinine and urea concentrations were increased significantly and TSAO was decreased significantly in group 2 compared with group 1. Serum creatinine concentrations but not urea concentrations were significantly lower in groups 3 and 4 than in group 2 (P = 0.001). Serum MDA concentrations was significantly different between groups 2 and 3 (P = 0.01), 2 and 4 (P < 0.001) and 4 and 5 (P = 0.01). TSAO activity was significantly in group 4 (silymarin) than in group 2 (P = 0.002). Silymarin and vitamin E decreased gentamicin-induced nephrotoxicity in dogs.

Ascorbic acid and α-tocopherol protect anticancer drug cisplatin induced nephrotoxicity in mice: a comparative study

BACKGROUND

Oxidative stress, resulting from an imbalance between prooxidant and antioxidant systems in favor of the former, largely contributes to immune system deregulation and complications observed in end-stage renal disease (ESRD) and patients treated with hemodialysis. Reactive oxygen species and free radicals are involved in the nephrotoxicity induced by a synthetic anticancer drug cisplatin.

METHODS

A comparative study on the nephroprotective effects of antioxidant vitamins (250 and 500 mg/kg, p.o.), vitamin C (ascorbic acid) and vitamin E (alpha-tocopherol), was evaluated using cisplatin (10 mg/kg body wt, i.p.) induced oxidative renal damage in mice. Urea and creatinine in serum were estimated for the renal function. Antioxidant status was estimated in kidney homogenate.

RESULTS

We found that both vitamins at 500 mg/kg significantly (P<0.01) protected the nephrotoxicity induced by cisplatin. The cisplatin induced increase of urea and creatinine concentrations were reduced in the vitamins plus cisplatin (250 and 500 mg/kg, p.o.)-treated groups. However the cisplatin induced decline of renal antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities were increased only in the 500 mg/kg vitamins treated groups. Both vitamins at 250 and 500 mg/kg could increase the concentration of reduced glutathione (GSH) and protected the increase of cisplatin induced lipid peroxidation.

CONCLUSIONS

Higher doses of vitamins are effective to protect oxidative renal damage and vitamin C is the better nephroprotective agent than vitamin E. The protection is mediated partially by preventing the decline of renal antioxidant status.

Selective nuclear factor κ-B inhibitors, pyrolidium dithiocarbamate and sulfasalazine, prevent the nephrotoxicity induced by gentamicin

OBJECTIVE

To investigate the effect of selective nuclear factor kappa-B (NFkappa-B) inhibitors, pyrolidium dithiocarbamate (PD) and sulfasalazine (SZ) on renal tubular necrosis and inducible nitric oxide synthase (iNOS) and NFkappa-B expression induced by gentamicin in rats.

MATERIALS AND METHODS

In all, 48 adult male Sprague-Dawley rats were divided into six equal groups; group 1, control; group 2, injected with gentamicin for 10 days (100 mg/kg/day, intraperitoneal, i.p.); group 3, injected with gentamicin plus PD (100 mg/kg/day, i.p.); group 4, injected with gentamicin plus SZ (75 mg/kg/day, i.p.); group 5, injected with gentamicin plus distilled water (vehicle for PD); and group 6, injected with gentamicin plus ammonium hydroxide (75 mg/day, 1 m, vehicle for SZ) for 10 days. At 24 h after the last injection, rats were killed and the renal cortex separated from the medulla. A small sample was fixed in formaldehyde solution for histological and immunohistochemical examination. Blood samples were also taken to assess the serum levels of urea, creatinine, Na(+), K(+) and gamma-glutamyl transpeptidase (GT). Crude extracts of the cortex were used to determine reduced glutathione (GSH-Px), NO and malondialdehyde (MDA). Immunohistochemically, iNOS and the active subunit of NFkappaB, P65, were evaluated using mouse monoclonal antibodies.

RESULTS

On haematoxylin and eosin staining, compared with the controls rats, gentamicin caused widespread tubular necrosis (grade 3 and 4) but in group 3 and 4 there was a marked reduction in the extent of tubular damage. Immunohistochemically there was more marked staining for iNOS and P65 expression in rats given gentamicin than in the control and group 3 and 4 (P < 0.001). In groups 3 and 4 iNOS and P65 expression were significantly less than in rats given only gentamicin. There was no significant difference in serum levels of Na(+), K(+), blood urea nitrogen and creatinine. Compared with control rats, gentamicin caused hyperproteinuria, a marked increase in levels of serum gamma-GT, MDA and NO, and a decrease in GSH-Px (P < 0.001).

CONCLUSION

These results indicate that gentamicin induces iNOS expression through activation of NFkappa-B (P65). It is possible to prevent gentamicin-induced nephrotoxicity using selective NFkappa-B inhibitors.

Protective effect of lycopene on gentamicin-induced oxidative stress and nephrotoxicity in rats

A potential therapeutic approach to protect or reverse gentamicin-induced oxidative stress and nephrotoxicity would have more importance for clinical consequences. Therefore, the present study was designed to investigate the possible protective effects of lycopene against gentamicin-induced renal damage in rats. Male Sprague-Dawley rats were divided into four groups of six rats in each one; first group served as control. The other groups were treated intraperitoneally with gentamicin alone (100 mg kg(-1) per day) for six successive days, gentamicin for 6 days following 10 days of orally lycopene (4 mg kg(-1) per day) pre-treatment and 6-days of simultaneous lycopene and gentamicin. Biochemical and histopathological examinations were utilized for evaluation of the oxidative stress and renal nephrotoxicity. Creatinine, urea, Na(+) and K(+) levels in plasma and malondialdehyde (MDA), reduced glutathione (GSH) levels and glutathione peroxidase (GSH-Px) and catalase (CAT) activities were determined in kidney tissue. Administration of gentamicin to rats induced a marked renal failure, characterized by a significant increase in plasma creatinine and urea concentrations. The animals treated with gentamicin alone showed a significantly higher kidney MDA and lower GSH-Px and CAT activities but unaffected GSH concentrations when compared with the control group. Pre-treatment with lycopene produced amelioration in biochemical indices of nephrotoxicity in plasma. However, little changes were observed in the kidney MDA and GSH levels and GSH-Px and CAT activities when compared with the gentamicin treated group. The histological structures of the renal proximal tubules showed similar patterns. On the other hand, administration of simultaneous lycopene to rats produced amelioration in MDA and GSH levels and GSH-Px and CAT activities when compared with gentamicin group. In addition, simultaneous lycopene was found to reduce the degree of kidney tissue damage in histopathological findings. These results indicate that specially simultaneous treatment of lycopene might have produced amelioration in biochemical indices and oxidative stress parameters against gentamicin-induced nephrotoxicity, but pre-treatments with lycopene had no beneficial effects on these parameters. It was concluded that lycopene as a novel natural antioxidant might have protective effects against gentamicin-induced nephrotoxicity and oxidative stress in rats.

Protective role of caffeic acid phenethyl ester (cape) on gentamicin-induced acute renal toxicity in rats

The toxicity of gentamicin (GEN) in the kidney seems to relate to the generation of reactive oxygen species (ROS). Caffeic acid phenethyl ester (CAPE) has been demonstrated to have antioxidant, free radical scavenger and anti-inflammatory effects. It has been proposed that antioxidant maintain the concentration of reduced glutathione (GSH) may restore the cellular defense mechanisms and block lipid peroxidation thus protect against the toxicity of wide variety of nephrotoxic chemicals. We investigated the effects of CAPE on GEN-induced changes in renal malondialdehyde (MDA), a lipid peroxidation product, nitric oxide (NO) generation, superoxide dismutase (SOD), catalase (CAT) activities, GSH content, blood urea nitrogen (BUN) and serum creatinine (Cr) levels. Morphological changes in the kidney were also examined. A total of 32 rats were equally divided into four groups which were: (1) control, (2) injected with intraperitoneally (i.p.) GEN, (3) injected with i.p. GEN+CAPE and (4) injected with i.p. CAPE. GEN administration to control rats increased renal MDA and NO generation but decreased SOD and CAT activities, and GSH content. CAPE administration with GEN injections caused significantly decreased MDA, NO generation and increased SOD, CAT activities and GSH content when compared with GEN alone. Serum level of BUN and Cr significantly increased as a result of nephrotoxicity. CAPE also, significantly decreased serum BUN and Cr levels. Morphological changes in the kidney due to GEN, including tubular necrosis, were evaluated qualitatively. In addition, CAPE reduced the degree of kidney tissue damage induced by GEN. Both biochemical findings and histopathological evidence showed that administration of CAPE reduced the GEN-induced kidney damage. Our results indicated that CAPE acts in the kidney as a potent scavenger of free radicals to prevent the toxic effects of GEN both at the biochemical and histological level. Thus, CAPE could be effectively combined with GEN treatment.

Protective effect of chelerythrine on gentamicin-induced nephrotoxicity

Despite their beneficial effects, aminoglycosides including gentamicin (GEN) have considerable nephrotoxic side-effects. The toxicity of GEN at the level of the kidney seems to relate to the generation of reactive oxygen species (ROS). ROS have been reported to be involved in the activation of protein kinase C (PKC). The unique structural aspects of PKC cause it to function as a sensor for oxidative stress. It seems likely that the increased NAD(P)H oxidase-derived superoxide (O2) production is at least in part mediated by PKC. We investigated the effects of chelerythrine, a commonly used PKC inhibitor, on GEN-induced changes of renal malondialdehyde (MDA), nitric oxide (NO) generation, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities, glutathione (GSH) content, and serum creatinine (Cr), blood urea nitrogen (BUN) levels. Morphological changes in the kidney were also examined. GEN administration to control rats increased MDA and NO generation but decreased CAT, SOD and GSH-Px activities, and GSH content. Chelerythrine administration with GEN caused significantly decreased MDA, NO generation and increased CAT, SOD and GSH-Px activities, and GSH content when compared with GEN alone. Chelerythrine also significantly decreased serum Cr and BUN levels. Morphological changes in the kidney including tubular necrosis were evaluated qualitatively. Both biochemical findings and histopathological evidence showed that administration of chelerythrine reduced the GEN-induced kidney damage. We propose that chelerythrine acts in the kidney as a potent scavenger of free radicals to prevent the toxic effects of GEN via the inhibition of a PKC pathway.

Protective effect of fosfomycin on gentamicin-induced lipid peroxidation of rat renal tissue

Fosfomycin is clinically recognized to reduce the aminoglycoside antibiotics-induced nephrotoxicity. However, little has been clarified why fosfomycin protects the kidney from the aminoglycosides-induced nephrotoxicity. Gentamicin, a typical aminoglycoside, is reported to cause lipid peroxidation. We focused on lipid peroxidation induced by gentamicin as a mechanism for the aminoglycosides-induced nephrotoxicity. The aim of this study is to investigate the effect of fosfomycin on the gentamicin-induced lipid peroxidation. In rat renal cortex mitochondria, fosfomycin was shown to depress the gentamicin-induced lipid peroxidation, which was evaluated by formation of thiobarbituric acid reactive substances (TBARS). Interestingly, this effect was observed in rat renal cortex mitochondria, but not in rat liver microsomes. However, fosfomycin did not affect lipid peroxidation of arachidonic acid caused by gentamicin with iron. Fosfomycin inhibited the gentamicin-induced iron release from rat renal cortex mitochondria. These results indicated that fosfomycin inhibited the gentamicin-induced lipid peroxidation by depressing the iron release from mitochondria. This may possibly be one mechanism for the protection of fosfomycin against the gentamicin-induced nephrotoxicity.

Antioxidants: a possible role in kidney protection

Oxidative stress contributes to the pathophysiology of kidney injury. Beneficial renal effects of some medications, such as angiotensin-converting enzyme inhibitors, angiotensin II type 1 receptor antagonists, calcium channel blockers, beta-blockers and lipid lowering agents depend at least partially on the ability to alleviate oxidative stress. The administration of various natural or synthetic antioxidants has been shown to be of benefit in prevention and attenuation of renal scaring in numerous animal models of kidney diseases. These include vitamins, N-acetylcysteine, alpha-lipoic acid, melatonin, dietary flavonoids and phytoestrogens, and many others. Human studies are limited in this regard. Under certain conditions, surprisingly, the antioxidant supplements may exhibit pro-oxidant properties and even worsen renal damage. To date, the evidence is insufficient to recommend antioxidant supplements in patients with kidney disease. Prospective, controlled clinical trials on safety and effectiveness of different therapeutic antioxidant strategies are indispensable.

Effects of Vitamin E pretreatment on subacute toxicity of mixture of Co, Pb, and Hg nitrate-induced nephrotoxicity in rats

The aim of the study was to prove that Vitamin E has some beneficial effects on the kidneys of rats by protecting them from the toxicity of certain heavy metals. The protective effect of Vitamin E on Co, Pb, or Hg nitrate and a mixture of them induced nephrotoxicity was tested in a 3-months-old Norway strain (inberd) rat (Raltus norvigus) weighing 100-120g. A study was carried out, which comprised one control group and five experimental groups. In this experiment, nitrate salts of Co, Pb, or Hg were administered subcutaneously (s.c.) either alone (0.5mg/100g body weight) for 4 weeks or as a mixture (0.25mg/100g body weight); Vitamin E internal control (250IU/100g body weight) was administered by oral gavage for 4 weeks, Vitamin E pretreatment for 7 days was followed by concomitant administration of Co, Pb, and Hg, respectively and Vitamin E pretreatment for 7 days, followed by concomitant administration of mixture of three heavy metals for 4 weeks. Blood and kidney tissue samples were taken from the control and all the experimental groups for biochemical and histological study. Nephrotoxicity was characterized by histopathological as well as renal function data. The main pathological changes in the kidney after Co administration were shrunken and degeneration of renal tubule cells, disturbance in their position, size, shape, and staining affinity. Treatment with Hg caused desquamation, necrosis, atrophy, and loss of renal tubule cells and glomeruli. Lead intoxication had a profound effect on the structure and consequently on the function of the rat kidney. Most renal tubule cells were very dense, dehydrated with obscure cytoplasmic details. Most nuclei were shrunken and pyknotic. Also, most glomeruli revealed shrinkage and widening of capsular space. On the other hand, subacute exposure with the mixture of the three heavy metals showed marked destruction and distortion of the renal tubule cells. Marked fibrosis between the damaged tubules was also seen. On the other hand in the recovery groups, i.e., in groups II and III, the previously observed histopathological changes were still present with regression of their intensity. Four-week oral administration with Vitamin E (250IU/100g body weight) revealed no abnormal histological findings as compared with the normal kidney of the control animal, except for some Malpighian corpuscles which demonstrated wide capsular space, and spherical masses were seen within the glomeruli. After pretreatment with Vitamin E for 7 days, followed by treatment with (0.5mg/100g body weight ) Co, Pb, or Hg nitrate alone or with their mixture (0.25mg/100g body weight) for 4 weeks, an improvement in the histological changes were observed compared to those previously seen in groups II and III. The glomeruli showed minimal degenerated changes, the tubular arrangement and cytoplasmic basophilia more or less similar to the normal control. It was also found that the heavy metals were investigated both alone and in combination; the serum creatinine and blood urea level were significantly increased, and this elevation was diminished by Vitamin E pretreatment. According to the present results, it is concluded that combined exposure to a mixture of Vitamin E and examined heavy metals can minimize the histological alteration and diminish the serum creatinine and blood urea level. Also, it was found that the rank order of metal cytotoxicities was Hg > Co > Pb.