Protection against cisplatin-induced nephrotoxicity by Spirulina in rats

The effect of sildenafil on cisplatin nephrotoxicity in rats

Sildenafil, the first drug for erectile dysfunction, has cardiopulmonary protective actions. A recent study has reported that sildenafil given intraperitoneally (i.p.) attenuated cisplatin (CP)-induced nephrotoxicity. Here, we evaluated whether sildenafil, given by two different routes and at two different doses, can attenuate CP-induced nephrotoxicity and would also affect renal haemodynamics in CP-treated rats. Six groups of rats were treated with saline (controls), CP [5 mg/kg, intraperitoneally (i.p.) once], sildenafil (0.4 mg/kg/day, i.p. for 5 days), sildenafil (0.4 mg/kg/day i.p. for 5 days) plus CP (5 mg/kg, i.p., once), sildenafil [10 mg/kg/day, subcutaneous (s.c.) for 5 days] or sildenafil (10 mg/kg/day, s.c. for 5 days) plus CP (5 mg/kg, i.p. once). Five days after the end of the treatments, urine was collected from all rats, which were then anaesthetized for blood pressure and renal blood flow monitoring. This was followed by intravenous (i.v.) injection of norepinephrine for the measurement of renal vasoconstrictor responses. Thereafter, blood and kidneys were collected for measurement of several biochemical, functional and structural parameters. CP reduced body-weight and renal blood flow but did not affect norepinephrine-induced renal vasoconstriction. It increased the plasma concentrations of urea and creatinine, and reduced creatinine clearance. CP caused extensive renal tubular necrosis, increased urine volume and N-acetyl-β-D-glucosaminidase activity. When sildenafil (0.4 mg/kg/day, i.p. for 5 days) was combined with cisplatin, there was a dramatic improvement in renal histopathology, reduction in N-acetyl-β-D-glucosaminidase and increase in renal blood flow. However, sildenafil (10 mg/kg/day, s.c. for 5 days) did not affect CP nephrotoxicity, suggesting the importance of dose and route selection of sildenafil as a nephroprotectant.

Protective effect of aqueous extract from Spirulina platensis against cell death induced by free radicals

BACKGROUND

Spirulina is a commercial alga well known to contain various antioxidants, especially phycocyanin. Apart from being sold as a nutraceutical, Spirulina is incorporated as a functional ingredient in food products and beverages. Most of the previous reports on antioxidant activity of Spirulina were based on chemical rather than cell-based assays. The primary objective of this study was to assess the antioxidant activity of aqueous extract from Spirulina based on its protective effect against cell death induced by free radicals.

METHODS

The antioxidant activity of the cold water extract from food-grade Spirulina platensis was assessed using both chemical and cell-based assays. In the cell-based assay, mouse fibroblast cells (3T3) cells were incubated for 1 h in medium containing aqueous extract of Spirulina or vitamin C (positive control) at 25, 125 and 250 μg/mL before the addition of 50 μM 1,1-diphenyl-2-picrylhydrazyl (DPPH) or 3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The cells were incubated for another 24 h before being assessed for cell death due to apoptosis using the Cell Death Detection ELISA Kit. Spectrophotometric assays based on DPPH and ABTS were also used to assess the antioxidant activity of the extract compared to vitamin C and vitamin E (positive controls).

RESULTS

Spirulina extract did not cause cytotoxic effect on 3T3 cells within the range of concentrations tested (0 - 250 μg/mL). The extract reduced significantly (p < 0.05) apoptotic cell death due to DPPH and ABTS by 4 to 5-fold although the activity was less than vitamin C. Based on the DPPH assay, the radical scavenging activity of the extract was higher than phycocyanin and was at least 50% of vitamin C and vitamin E. Based on the ABTS assay, the antioxidant activity of the extract at 50 μmug/mL was as good as vitamin C and vitamin E.

CONCLUSIONS

The results showed that aqueous extract of Spirulina has a protective effect against apoptotic cell death due to free radicals. The potential application of incorporating Spirulina into food products and beverages to enhance their antioxidant capacity is worth exploring.

Seleno L-methionine acts on cyclophosphamide-induced kidney toxicity

The anticancer drug cyclophosphamide (CP) has nephrotoxic effects besides its urotoxicity, which both in turn limit its clinical utility. The nephrotoxicity of CP is less common compared to its urotoxicity, and not much importance has been given for the study of mechanism of CP-induced nephrotoxicity so far. Overproduction of reactive oxygen species (ROS) during inflammation is one of the reasons of the kidney injury. Selenoproteins play crucial roles in regulating ROS and redox status in nearly all tissues; therefore, in this study, the nephrotoxicity of CP and the possible protective effects of seleno L-methionine (SLM) on rat kidneys were investigated. Forty-two Sprague-Dawley rats were equally divided into six groups of seven rats each. The control group received saline, and other rats were injected with CP (100 mg/kg), SLM (0.5 or 1 mg/kg), or CP + SLM intraperitoneally. Malondialdehyde (MDA) and glutathione (GSH) levels in kidney homogenates of rats were measured, and kidney tissues were examined under the microscope. CP-treated rats showed a depletion of renal GSH levels (28% of control), while CP + SLM-injected rats had GSH values close to the control group. MDA levels increased 36% of control following CP administration, which were significantly decreased after SLM treatment. Furthermore, these biochemical results were supported by microscopical observations. In conclusion, the present study not only points to the therapeutic potential of SLM in CP-induced kidney toxicity but also indicates a significant role for ROS and their relation to kidney dysfunction.

Diesel exhaust particles in the lung aggravate experimental acute renal failure

Inhaled particles are associated with pulmonary and extrapulmonary effects. Also, acute renal failure (ARF) is associated with increased mortality, related to pulmonary complications. Here, we tested the possible potentiating effect of diesel exhaust particles (DEP) in an animal model of ARF induced by a single ip injection of cisplatin (CP, 6 mg/kg) in rats. Six days later, the rats were intratracheally instilled with either DEP (0.5 or 1 mg/kg) or saline (control) and renal, systemic, and pulmonary variables were studied 24 h thereafter. CP increased the serum concentrations of urea and creatinine and reduced glutathione (GSH) concentration and superoxide dismutase activity in renal cortex. CP caused renal tubular necrosis; increased urine volume, protein concentrations, and N-acetyl-beta-D-glucosaminidase (NAG) activity; and decreased urine osmolality. The combination of DEP and CP aggravated the CP-induced effects on serum urea and creatinine, urine NAG activity, and renal GSH. The arterial O(2) saturation and PO(2) were significantly decreased in CP + DEP versus CP + saline and CP + DEP versus DEP. The number of platelets was reduced in DEP compared to saline-treated rats and CP + DEP versus DEP alone or CP + saline. Increases in macrophage and neutrophils numbers in bronchoalveolar lavage were found in DEP versus saline group and CP + DEP versus CP. Histopathological changes in lungs of DEP-treated rats were aggravated by the combination of CP + DEP. These included marked interstitial cell infiltration and congestion. We conclude that the presence of DEP in the lung aggravated the renal, pulmonary, and systemic effects of CP-induced ARF.

Comparative protective effect of N-acetyl cysteine and tetramethylpyrazine in rats with gentamicin nephrotoxicity

Gentamicin (GM) is used against serious and life-threatening infections, but its use is limited by the occurrence of nephrotoxicity, which involves the generation of free radicals. In this work we tested the effect of a compound with antioxidant properties, tertamethylpyrazine (TMP), a major constituent of the Chinese medicinal plant Lingusticum wallichi, on GM-induced nephrotoxicity, and compared it with an established anti-oxidant compound N-acetyl cysteine (NAC). Six groups of rats were studied: (1) control, treated orally (p.o.) and intraperitoneally (i.p.) with saline; (2) treated i.p. with GM (80 mg kg(-1) per day for 6 days); (3) TMP, given p.o. (100 mg kg(-1) per day for 10 days) + GM (same dose as above during the last 6 days); (4) NAC, given i.p. (500 mg kg(-1) per day for 10 days) + GM as above; (5) TMP (100 mg kg(-1) per day for 10 days) + saline; (6) NAC (500 mg kg(-1) per day for 10 days) + saline. GM nephrotoxicity was characterized by reduced creatinine clearance, increased creatinine and urea concentrations in plasma, increased urinary excretion of N-acetyl-beta-d-glucosaminidase (NAG) and total protein. These functional and structural alterations were prevented or ameliorated by NAC treatment, while TMP had only a slight mitigating effect that was less marked than that produced by NAC. The concentration of GM in the renal cortex of the rats given GM + NAC (but not TMP) was lower than that found in rats treated with GM alone by about 25%. The mechanism by which NAC and, to a lesser extent TMP, protected against GM-induced nephrotoxicity may be related, at least in part, to the decrease in oxidative stress in renal cortex.

Protective effect of L-carnitine against cisplatin-induced liver and kidney oxidant injury in rats

The present study was designed to investigate the protective effects of L-carnitine (LC) on changes in the levels of lipid peroxidation and endogenous antioxidants induced by cisplatin (cis-diamminedichloroplatinum II, CDDP) in the liver and kidney tissues of rats. Twenty-four Sprague Dawley rats were equally divided into four groups of six rats each: control, cisplatin, L-carnitine, and L-carnitine plus cisplatin. The degree of protection produced by L-carnitine was evaluated by determining the level of malondialdehyde (MDA). The activity of glutathione (GSH), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST), and superoxide dismutase (SOD) were estimated from liver and kidney homogenates, and the liver and kidney were histologically examined as well. L-carnitine elicited significant liver and kidney protective activity by decreasing the level of lipid peroxidation (MDA) and elevating the activity of GSH, GSHPx, GST, and SOD. Furthermore, these biochemical observations were supported by histological findings. In conclusion, the present study indicates a significant role for reactive oxygen species (ROS) and their relation to liver and kidney dysfunction, and points to the therapeutic potential of LC in CDDP-induced liver and kidney toxicity.

Squalene selectively protects mouse bone marrow progenitors against cisplatin and carboplatin-induced cytotoxicity in vivo without protecting tumor growth

Squalene, an isoprenoid antioxidant is a potential cytoprotective agent against chemotherapy-induced toxicity. We have previously published that squalene protects light-density bone marrow cells against cis-diamminedichloroplatinum( II) (cisplatin)-induced toxicity without protecting tumor cells in vitro. Here, we developed an in vivo mouse model of cisplatin and cis-diammine (cyclobutane-1,1-dicarboxylato) platinum(II) (carboplatin)-induced toxicity to further investigate squalene-mediated LD-BM cytoprotection including the molecular mechanism behind selective cytoprotection. We found that squalene significantly reduced the body weight loss of cisplatin and carboplatin-treated mice. Light-density bone marrow cells from squalene-treated mice exhibited improved formation of hematopoietic colonies (colony-forming unit-granulocyte macrophage). Furthermore, squalene also protected mesenchymal stem cell colonies (colony-forming unit-fibroblast) from cisplatin and carboplatin-induced toxicity. Squalene-induced protection was associated with decreased reactive oxygen species and increased levels of glutathione and glutathione peroxidase/glutathione-S-transferase. Importantly, squalene did not protect neuroblastoma, small cell carcinoma, or medulloblastoma xenografts against cisplatin-induced toxicity. These results suggest that squalene is a potential candidate for future development as a cytoprotective agent against chemotherapeutic toxicity.

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.

Role of oxidative and nitrosative stress in cisplatin-induced nephrotoxicity

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

Antioxidant potential of selected Spirulina platensis preparations

Recent studies suggest that Spirulina, a unicellular blue-green alga, may have a variety of health benefits and therapeutic properties and is also capable of acting as an antioxidant and antiinflammatory agent. In this study, a cell-free and a cell-based test assay were used to examine the antioxidant and antiinflammatory properties of four selected Spirulina platensis preparations: (1) Biospirulina, (2) SpiruComplex, a preparation with naturally bound selenium, chromium and zinc, (3) SpiruZink, a preparation with naturally bound zinc, (4) Zinkspirulina + Acerola, a preparation with naturally bound zinc and acerola powder. The cell-free test assay used potassium superoxide as a donor for superoxide radicals, whereas the cell-based test assay used the formation of intracellular superoxide radicals of functional neutrophils upon stimulation by phorbol-12-myristate-13-acetate as a model to investigate the potential of Spirulina preparations to inactivate superoxide radicals. In accordance with the recommended daily dosage, test concentrations ranging from 50 to 1000 microg/mL were chosen. The results showed a dose-dependent inactivation of free superoxide radicals (antioxidant effect) as well as an antiinflammatory effect characterized by a dose-dependent reduction of the metabolic activity of functional neutrophils and a dose-dependent inactivation of superoxide radicals generated during an oxidative burst. The results demonstrate that the tested Spirulina preparations have a high antioxidant and antiinflammatory potential. Especially SpiruZink and Zinkspirulina + Acerola might be useful as a supportive therapeutic approach for reducing oxidative stress and/or the generation of oxygen radicals in the course of inflammatory processes.

Clinical potential of Spirulina as a source of phycocyanobilin

Recent research reveals that free bilirubin functions physiologically as a potent inhibitor of NADPH oxidase activity. The chromophore phycocyanobilin (PCB), found in blue-green algae and cyanobacteria such as Spirulina, also has been found to be a potent inhibitor of this enzyme complex, likely because in mammalian cells it is rapidly reduced to phycocyanorubin, a close homolog of bilirubin. In light of the protean roles of NADPH oxidase activation in pathology, it thus appears likely that PCB supplementation may have versatile potential in prevention and therapy -- particularly in light of rodent studies demonstrating that orally administered Spirulina or phycocyanin (the Spirulina holoprotein that contains PCB) can exert a wide range of anti-inflammatory effects. Until PCB-enriched Spirulina extracts or synthetically produced PCB are commercially available, the most feasible and least expensive way to administer PCB is by ingestion of whole Spirulina. A heaping tablespoon (about 15 g) of Spirulina can be expected to provide about 100 mg of PCB. By extrapolating from rodent studies, it can be concluded that an intake of 2 heaping tablespoons daily would be likely to have important antioxidant activity in humans -- assuming that humans and rodents digest and absorb Spirulina-bound PCB in a comparable manner. An intake of this magnitude can be clinically feasible if Spirulina is incorporated into "smoothies" featuring such ingredients as soy milk, fruit juices, and whole fruits. Such a regimen should be evaluated in clinical syndromes characterized and in part mediated by NADPH oxidase overactivity in affected tissues.

Iron-chelating ability and antioxidant properties of phycocyanin isolated from a protean extract of Spirulinaplatensis

The invitro scavenger activities of different reactive oxygen species (superoxide radical, hydroxyl radical, hydrogen peroxide, hypochlorous acid and peroxyl radical), the effects on lipid peroxidation and the iron-chelating ability of a Spirulinaplatensis protean extract and the biliprotein, phycocyanin, isolated from this microalga were studied. S. platensis protean extract inhibited the generation of hydroxyl radical (IC50=537μg/ml for the system with EDTA and 1500μg/ml without EDTA), the production of peroxyl radical (IC50=230μg/ml), and the lipid peroxidation process (IC50=2320μg/ml for the enzymatic system and 2180μg/ml for the non-enzymatic system). Besides, phycocyanin inhibited hydroxyl and peroxyl radicals and the lipid peroxidation process. The iron ions decreased the maximum fluorescence emission spectra of S. platensis protean extract and phycocyanin and it was an indicator of the metal-chelating activity. The antioxidant properties of S. platensis and phycocyanin may arise from both radical-scavenging and metal chelation. Our results suggest that S. platensis could be used as a dietary supplement to prevent some diseases where free radicals are involved.

The ameliorative effect of cysteine prodrug L-2-oxothiazolidine-4-carboxylic acid on cisplatin-induced nephrotoxicity in rats

Pathogenesis of nephrotoxicity of the synthetic anticancer drug cisplatin (CP) involves generation of reactive oxygen species and free radicals in the kidney cortex, and cysteine prodrug l-2-oxothiazolidine-4-carboxylic acid (OTC) has been confirmed to have a strong antioxidant action. Therefore, in the present work, we aimed at testing the possible protective or palliative effect of OTC on CP nephrotoxicity in rats. OTC was given at an oral dose of 150 mg/kg/day for 7 days. On day 7, some of these rats were given a single intraperitoneal injection of CP (or vehicle) at a dose of 6 mg/kg. Rats were killed, blood and urine samples were collected, and the kidneys were removed 6 days after CP treatment. Nephrotoxicity was evaluated histopathologically by light microscopy, and biochemically by measuring the concentrations of creatinine and urea in serum, reduced glutathione (GSH) concentration and superoxide dismutase (SOD) activity in renal cortex, and by urinalyses. CP significantly increased the concentrations of urea and creatinine (P < 0.05) by about 128% and 170% respectively. CP treatment reduced cortical GSH concentration by about 34% (P < 0.05), and the activity of SOD by about 28% (P < 0.05). CP treatment significantly increased urine volume and N-acetyl-beta-D-glucosaminidase (NAG) activity, and significantly decreased osmolality and protein concentrations. OTC significantly mitigated all these effects. Sections from saline- and OTC-treated rats showed apparently normal proximal tubules. However, kidneys of CP-treated rats had a moderate degree of necrosis. This appeared to be lessened when CP was given simultaneously with OTC. The concentration of CP in the cortical tissues was not significantly altered by OTC treatment. The results suggested that OTC had ameliorated the histopathological and biochemical indices of nephrotoxicity in rats. Pending further pharmacological and toxicological studies, OTC may potentially be useful as a nephroprotective agent.

Role of ellagic acid against cisplatin-induced nephrotoxicity and oxidative stress in rats

The aim of this study was to investigate the possible protective role of antioxidant treatment with ellagic acid on cisplatin-induced nephrotoxicity using biochemical and histopatological approaches. Adult male Sprague-Dawley rats were randomly divided into four groups. The control group received 0.9% saline; animals in the ellagic acid group received only ellagic acid (10 mg/kg); animals in the cisplatin group received only cisplatin (7 mg/kg); animals in the cisplatin + ellagic acid group received ellagic acid for 10 days after cisplatin. The effects of ellagic acid on cisplatin-induced nephrotoxicity were evaluated by plasma creatinine, urea, sodium and calcium concentrations; kidney tissue malondialdehyde, reduced glutathione (GSH), glutathione peroxidase (GSH peroxidase) and catalase activities and histopatological examinations. Administration of cisplatin to rats induced a marked renal failure, characterized by significant increases in plasma creatinine, urea and calcium concentrations. Cisplatin also induced oxidative stress, as indicated by increased kidney tissue concentrations of malondialdehyde, and reduced activities of GSH peroxidase and catalase. Furthermore, treatment with cisplatin caused a marked tubular necrosis, degeneration and desquamation, luminal cast formation, karyomegaly, tubular dilatation, interstitial mononuclear cell infiltration and inter-tubular haemorrhagia. Ellagic acid markedly reduced elevated plasma creatinine, urea and calcium levels and counteracted the deleterious effects of cisplatin on oxidative stress markers. In the same way, ellagic acid ameliorated cisplatin-induced pathological changes including tubular necrosis, degeneration, karyomegaly, tubular dilatation when compared to the cisplatin alone group. These results indicate that the antioxidant ellagic acid might have a protective effect against cisplatin-induced nephrotoxicity and oxidative stress in rat, but not enough to inhibit cisplatin-induced renal dysfunction.

Co-administration of C-Phycocyanin ameliorates thioacetamide-induced hepatic encephalopathy in Wistar rats

Fulminant hepatic failure (FHF) is a condition with a sudden onset of necrosis followed by degeneration of hepatocytes, without any previously established liver disease, generally occurring within hours or days. FHF is associated with a wide spectrum of neuropsychiatric alterations ranging from stupor to coma, culminating in death. In the present study FHF was induced in rats by the administration of thioacetamide (TAA). Oxidative stress is thought to play a prominent role in the pathophysiology of cerebral changes during FHF leading to the assumption that antioxidants might offer protection. Hence, in the present study the protective effect of C-Phycocyanin (C-PC), a natural antioxidant, was evaluated on TAA-induced tissue damage. C-Phycocyanin was administered intraperitoneally twice at 24 h interval (50 mg/kg body weight) along with the hepatotoxin TAA (300 mg/kg body weight). The animals were sacrificed 18 h after the second injection of TAA treatment and various biochemical parameters were analysed in liver, serum and brain tissues. These studies revealed significant prevention of TAA-induced liver damage by C-PC, as evidenced by a) increase in survival rate; b) the prevention of leakage of liver enzymes (AAT and AST) and ammonia into serum; c) increase in prothrombin time and d) liver histopathology. Ultrastructural studies of astrocytes of different regions of brain clearly showed a decrease in edema after C-PC treatment. TAA-induced histopathological lesions in different regions of the brain namely cerebral cortex, cerebellum and pons medulla were significantly reduced by the co-administration of C-PC with TAA. Further C-PC treatment resulted in a) decrease in the levels of tryptophan and markers of lipid peroxidation and b) elevation in the activity levels of catalase, glutathione peroxidase in different regions of brain. These studies reveal the potential of C-PC in ameliorating TAA-induced hepatic encephalopathy by improving antioxidant defenses.