Mitochondria-mediated mitigatory role of curcumin in cisplatin-induced nephrotoxicity

Protective Effect of Natural Antioxidants on Reducing Cisplatin-Induced Nephrotoxicity

The clinical application of cisplatin is limited by its adverse events, of which nephrotoxicity is the most commonly observed. In a cisplatin-induced pathological response, oxidative stress is one of the upstream reactions which inflicts different degrees of damages to the intracellular material components. Reactive oxygen species (ROS) are also one of the early signaling molecules that subsequently undergo a series of pathological reactions, such as apoptosis and necrosis. This review summarizes the mechanism of intracellular ROS generation induced by cisplatin, mainly from the consumption of endogenous antioxidants, destruction of antioxidant enzymes, induction of mitochondrial crosstalk between the endoplasmic reticulum by ROS and Ca²⁺, and destruction of the cytochrome P450 (CYP) system in the endoplasmic reticulum, all of which result in excessive accumulation of intracellular ROS and oxidative stress. In addition, studies demonstrated that natural antioxidants can protect against the cisplatin-induced nephrotoxicity, by reducing or even eliminating excess free radicals and also affecting other nonredox pathways. Therefore, this review on the one hand provides theoretical support for the research and clinical application of natural antioxidants and on the other hand provides a new entry point for the detailed mechanism of cisplatin nephrotoxicity, which may lay a solid foundation for the future clinical use of cisplatin.

Curcumin alleviates aristolochic acid nephropathy based on SIRT1/Nrf2/HO-1 signaling pathway

Aristolochic acid I (AA-I), presenting in a variety of natural medicinal plants, which could cause tubular epithelial cell injury. Curcumin (CUR), a polyphenolic substance isolated from turmeric, is a natural antioxidant. The aim of this experiment was to investigate whether CUR attenuated AA-I-induced renal injury in rats through the SIRT1/Nrf2/HO-1 signaling pathway. SD rats were treated with AA-I (10 mg/kg) or/and CUR (200 mg/kg) for 28 days to assess the protective effect of CUR on AA-I-induced renal injury in vivo. NRK-52E cells were treated with AA-I (40 μ M) or/and CUR (20 μ M) for 24 h in vitro. The intervention pathway of CUR against oxidative stress injury induced by AA-I was assessed by observing pathological changes, oxidative stress status, apoptosis and the expression of SIRT1/Nrf2/HO-1 signaling pathway-related factors. The results showed that AA-I exposure increased the contents of BUN, Cr, KIM-1, NGAL, ALT and AST in serum. It increased the content of MDA, decreased the activities of SOD, GST, GSH and the content of ATP in renal tissue. Pathological changes such as inflammatory cell infiltration and mitochondrial injury occurred in renal tissue. AA-I exposure resulted in a substantial rise in the levels of BAX, Ccaspase-9, Cleaved Caspase-9, Caspase-3, Cleaved Caspase-3 and a significant decrease in mRNA and protein expression levels of Bcl-2, SIRT1, Nrf2, NQO1, HO-1 and Keap1. However, these changes were reversed by CUR intervention. In summary, AA-I exposure caused mitochondrial dysfunction and triggered apoptosis through the oxidative stress pathway. However, CUR could reduce AA-I-induced renal injury by activating the SIRT1/Nrf2/HO-1 signaling pathway.

The Effect of Polyphenols on Kidney Disease: Targeting Mitochondria

Mitochondrial function, including oxidative phosphorylation (OXPHOS), mitochondrial biogenesis, and mitochondria dynamics, are essential for the maintenance of renal health. Through modulation of mitochondrial function, the kidneys are able to sustain or recover acute kidney injury (AKI), chronic kidney disease (CKD), nephrotoxicity, nephropathy, and ischemia perfusion. Therapeutic improvement in mitochondrial function in the kidneys is related to the regulation of adenosine triphosphate (ATP) production, free radicals scavenging, decline in apoptosis, and inflammation. Dietary antioxidants, notably polyphenols present in fruits, vegetables, and plants, have attracted attention as effective dietary and pharmacological interventions. Considerable evidence shows that polyphenols protect against mitochondrial damage in different experimental models of kidney disease. Mechanistically, polyphenols regulate the mitochondrial redox status, apoptosis, and multiple intercellular signaling pathways. Therefore, this review attempts to focus on the role of polyphenols in the prevention or treatment of kidney disease and explore the molecular mechanisms associated with their pharmacological activity.

Polyphenols and Their Metabolites in Renal Diseases: An Overview

Kidney diseases constitute a worldwide public health problem, contributing to morbidity and mortality. The present study aimed to provide an overview of the published data regarding the potential beneficial effects of polyphenols on major kidney diseases, namely acute kidney injury, chronic kidney disease, diabetic nephropathy, renal cancer, and drug-induced nephrotoxicity. This study consists of a bibliographical review including in vitro and in vivo studies dealing with the effects of individual compounds. An analysis of the polyphenol metabolome in human urine was also conducted to estimate those compounds that are most likely to be responsible for the kidney protective effects of polyphenols. The biological effects of polyphenols can be highly attributed to the modulation of specific signaling cascades including those involved in oxidative stress responses, anti-inflammation processes, and apoptosis. There is increasing evidence that polyphenols afford great potential in renal disease protection. However, this evidence (especially when in vitro studies are involved) should be considered with caution before its clinical translation, particularly due to the unfavorable pharmacokinetics and extensive metabolization that polyphenols undergo in the human body. Future research should consider polyphenols and their metabolites that indeed reach kidney tissues.

The Green Anti-Cancer Weapon. The Role of Natural Compounds in Bladder Cancer Treatment

Bladder cancer (BC) is the second most common genitourinary cancer. In 2018, 550,000 people in the world were diagnosed with BC, and the number of new cases continues to rise. BC is also characterized by high recurrence risk, despite therapies. Although in the last few years, the range of BC therapy has considerably widened, it is associated with severe side effects and the development of drug resistance, which is hampering treatment success. Thus, patients are increasingly choosing products of natural origin as an alternative or complementary therapeutic options. Therefore, in this article, we aim to elucidate, using the available literature, the role of natural substances such as curcumin, sulforaphane, resveratrol, quercetin, 6-gingerol, delphinidin, epigallocatechin-3-gallate and gossypol in the BC treatment. Numerous clinical and preclinical studies point to their role in the modulation of the signaling pathways, such as cell proliferation, cell survival, apoptosis and cell death.

Protective effect of curcumin on busulfan-induced renal toxicity in male rats

AIM

The aim of this study was to evaluate the effects of curcumin in an experimental model of busulfan-induced renal toxicity with emphasis on importance of histological alterations.

METHODS

In this study, we utilized 32 adult male Wistar rats (250 ± 10 g). All the animals were divided into four experimental groups randomly: (I) Control; (II) Busulfan (40 mg/kg); (III) Olive oil; and (IV) Curcumin (80 mg/kg/day). Finally, the rats were euthanized and kidney tissues were taken for histopathology experiments, serum BUN, and creatinine level, reactive oxygen species (ROS) production and glutathione disulfide (GSH) activity.

RESULTS

Our result showed that the reduction in body weight and kidney weight in busulfan groups in comparison with the control and curcumin groups. The result in this study also showed that the reduction in BUN, creatinine, and ROS production in curcumin groups in comparison with the busulfan group together with an increasing of GSH activity compared to busulfan induced rats.

CONCLUSION

Our results of this study indicated that that the reduction in body weight, kidney weight, total volume of kidney, total length of nephron tubules, and numerical density of glomeruli and nephron tubules in busulfan groups in comparison with the control and curcumin groups However, curcumin can be an alternative choice for therapeutically and research purposes in the disturbing kidney after treatment with busulfan.

Modulation of NADPH oxidase and Nrf2/HO-1 pathway by vanillin in cisplatin-induced nephrotoxicity in rats

OBJECTIVES

To investigate the protective effect of vanillin in cisplatin (CP)-induced nephrotoxicity in rats and elucidate the role of nrf-2 and its downstream antioxidant molecules.

METHODS

Rats received vanillin (100 mg/kg orally) for 10 constitutive days and CP (7.5 mg/kg, once, ip) on day 6 of vanillin administration.

KEY FINDINGS

Cisplatin suppressed body weight gain, increased serum urea and creatinine and renal malondialdehyde and nitric oxide while decreased renal total antioxidant capacity. Up-regulation of NADPH oxidase-4 (NOX-4) was marked in renal tissue of CP-treated rats along with down-regulation of the antioxidant genes (nuclear factor erythroid 2-related factor2 (NRF2) and haem oxygenase-1(HO-1)). Increased tumour necrosis factor-α and decreased interleukin-10 with increased myeloperoxidase activity were apparent in renal tissue of CP-treated rats along with marked tubular injury, neutrophil infiltration and increased apoptosis (caspase-3) and some degree of interstitial fibrosis. Vanillin prophylactic administration prevented the deterioration of kidney function, oxidative and nitrosative stress. It also suppressed NOX-4 and up-regulated NRF2 and HO-1 expression in renal tissue. Inflammation, apoptosis and tubular injury were also inhibited by vanillin.

CONCLUSIONS

The antioxidant mechanism by which vanillin protected against CP-induced nephrotoxicity involved the inhibition of NOX-4 along with the stimulation of Nrf2/HO-1 signalling pathway. These in turn inhibited inflammation and apoptosis.

Curcumin as a preventive or therapeutic measure for chemotherapy and radiotherapy induced adverse reaction: A comprehensive review

Curcumin has attracted much attention for medicinal purposes in wide range of illnesses including cancer. In some studies, its efficacy is evaluated against chemotherapy and radiotherapy induced adverse reaction and also as adjuvant to cancer treatment. Here we have tried to present a comprehensive review on protective and therapeutic effect of curcumin against these side effects. METHOD: The data were collected by searching Scopus, PubMed, Medline, and Cochrane database systematic reviews, using key words "nephrotoxicity", "cardiotoxicity", "genotoxicity", "ototoxicity", "hepatotoxicity", "reproductive toxicity", "myelosuppression", "pulmonary toxicity", "radiotherapy induced side effect" with "turmeric" and "curcumin". Although curcumin has low bioavailability, it has shown brilliant profile on prevention and management of chemotherapy and radiotherapy induced adverse reactions, particularly based on in vitro and in vivo studies and limited number of human studies on radiotherapy adverse reactions. Antioxidant and anti-inflammatory properties of the curcumin are the main proposed mechanism of action for management and prevention of adverse reactions. One of the major points regarding the protective effect of curcumin is its wide tolerable therapeutic range of dose with minimal side effects. Furthermore, new nano-formulations help to improve the bioavailability, increase in efficacy and lower the adverse effects. In conclusion, based on the present knowledge, curcumin has significant supportive potential in patients receiving chemotherapy or radiotherapy and may be suggested as adjutant with cancer treatments. Further well-designed human studies are recommended.

Platinum complexes of curcumin delivered by dual-responsive polymeric nanoparticles improve chemotherapeutic efficacy based on the enhanced anti-metastasis activity and reduce side effects

Platinum-based chemotherapy is used for non-small cell lung cancer (NSCLC). However, it has side effects and minimum efficacy against lung cancer metastasis. In this study, platinum-curcumin complexes were loaded into pH and redox dual-responsive nanoparticles (denoted as Pt-CUR@PSPPN) to facilitate intracellular release and synergistic anti-cancer effects. Pt-CUR@PSPPN was prepared by a nano-precipitation method and had a diameter of ∼100 nm. The nanoparticles showed increased anti-cancer effects both in vivo and in vitro. In addition, Pt-CUR@PSPPN blocked PI3K/AKT signal transduction pathway and inhibited MMP2 and VEGFR2, resulting in enhanced anti-metastatic activity. Furthermore, reduced side effects were also observed. In conclusion, Pt-CUR@PSPPN provided a novel and attractive therapeutic strategy for NSCLC.

Curcumin-A Viable Agent for Better Bladder Cancer Treatment

Although the therapeutic armamentarium for bladder cancer has considerably widened in the last few years, severe side effects and the development of resistance hamper long-term treatment success. Thus, patients turn to natural plant products as alternative or complementary therapeutic options. One of these is curcumin, the principal component of Curcuma longa that has shown chemopreventive effects in experimental cancer models. Clinical and preclinical studies point to its role as a chemosensitizer, and it has been shown to protect organs from toxicity induced by chemotherapy. These properties indicate that curcumin could hold promise as a candidate for additive cancer treatment. This review evaluates the relevance of curcumin as an integral part of therapy for bladder cancer.

Renoprotective Effects of a New Free Radical Scavenger, XH-003, against Cisplatin-Induced Nephrotoxicity

Acute renal injury has an incidence of 25%–30% in patients with tumors who are treated with cisplatin and in patients for whom no specific drugs are available for treatment. Amifostine is the only FDA-approved chemoprotective drug; however, its clinical application is limited because of side effects. The small-molecule antioxidant XH-003, an acute radiation syndrome- (ARS-) protective drug independently developed in our laboratory, with 100% intellectual property rights, overcomes the side effects of amifostine but retains its high efficacy. In this study, XH-003 showed a chemoprotective effect similar to that of amifostine. A mechanistic study showed that XH-003 could significantly reduce cisplatin-induced increases in serum creatinine and urea nitrogen, increase the activity of antioxidant enzymes (SOD, CAT, and GSH-Px), reduce oxidative stress and tissue inflammation, and alleviate renal tissue damage by blocking the activity of the mitochondrial apoptosis pathway. Most importantly, XH-003 could reduce the accumulation of cisplatin in renal tissue by regulating the expression of proteins involved in cisplatin uptake and excretion, such as organic cation transporter 2 and MRP2. Moreover, in an in vivo xenotransplantation model, XH-003 did not interfere with the antitumor effect of cisplatin. These data provide strong evidence that the ARS-protective agent has a great potential for protecting against chemotherapy-induced toxicity. Thus, XH-003 can be considered in antitumor therapy.

Progesterone-Calcitriol Combination Enhanced Cytotoxicity of Cisplatin in Ovarian and Endometrial Cancer Cells In Vitro

: Initially, patients that respond to cisplatin (DDP) treatment later relapse and develop chemoresistance. Agents that enhance DDP effectiveness will have a significant impact on cancer treatment. We have shown pronounced inhibitory effects of the progesterone-calcitriol combination on endometrial and ovarian cancer cell growth. Here, we examined whether and how progesterone-calcitriol combination potentiates DDP anti-tumor effects in cancer cells. Ovarian and endometrial cancer cells treated with various concentrations of DDP showed a concentration-dependent decrease in cell proliferation. Concurrent treatment of cells with DDP and progesterone-calcitriol ombination potentiated anticancer effects of DDP compared to DDP-calcitriol, or DDP-progesterone treated groups. The anticancer effects were mediated by increased caspase-3, BAX, and decreased BCL2 and PARP-1 expression in DDP and progesterone-calcitriol combination-treated cells. Stimulation of the PI3K/AKT and MAPK/ERK pathways seen in cancer cells was reduced in DDP-progesterone-calcitriol treated cells. Pretreatment of cells with specific inhibitors further diminished AKT and ERK expression. Furthermore, progesterone-calcitriol potentiated the anti-growth effects of DDP on cancer cells by attenuating the expression of SMAD2/3, multidrug resistance protein- 1 (MDR-1), and ABC transporters (ABCG1, and ABCG2), thereby impeding the efflux of chemo drugs from cancer cells. These results suggest a potential clinical benefit of progesterone-calcitriol combination therapy when used in combination with DDP.

Efficacy of curcumin on prevention of drug-induced nephrotoxicity: A review of animal studies

Drug-induced nephrotoxicity is a frequent serious adverse effect, contributing to morbidity and increased healthcare utilization. Prevention or reversal is key. Curcumin has useful biological features that include antioxidant, anti-inflammatory, and anticancer properties. This review covers aspects of curcumin in relation to prevention of drug-induced nephrotoxicity: dosage and schedule, effect on kidney biomarkers and histological changes, and mechanisms of curcumin's protective effects. Despite success in some animal models, human studies and clinical administration of curcumin for nephroprotection remains limited due to difficulty in achieving therapeutic levels following oral administration and in determining the optimal dosing schedule. Lack of sufficient evidence from animal studies, coupled with low systemic bioavailability, continues to limit the utilization of curcumin in addressing and controlling drug-induced nephrotoxicity. Therefore, human studies are required to fully assess and validate the therapeutic potential of curcumin.

Combinations of the antioxidants sulforaphane or curcumin and the conventional antineoplastics cisplatin or doxorubicin as prospects for anticancer chemotherapy

Drugs used in clinical oncology have narrow therapeutic indices with adverse toxicity often involving oxidative damage. Chemoresistance to these conventional antineoplastics is usually mediated by oxidative stress-upregulated pathways such as those of nuclear factor-kappa B (NF-κB) and hypoxia-inducible factor-1 alpha (HIF-1α). Accordingly, the use of antioxidants in combinational approaches has begun to be considered for fighting cancer because of both the protective role against adverse effects and the ability to sensitize chemoresistant cancer cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) has been identified as a mediator of the cytoprotection but it is not regularly associated with tumor chemosensitization. However, some Nrf2 inducers could be exerting cytoprotective and chemosensitizing roles through a simple integrated mechanism in which the cellular level of reactive oxygen species is controlled, thus inhibiting the oxidative damage in non-target tissues and the tumor chemoresistance mediated by NF-κB or HIF-1α. As examples to show the general idea of this antioxidant combination chemotherapy, this review explores the preclinical information available for four combinations, each composed by a paradigmatic oncological drug (cisplatin or doxorubicin) and a recognized antioxidant (sulforaphane or curcumin). The issues for translating these outcomes to clinical trials are briefly discussed.

Curcumin loading potentiates the neuroprotective efficacy of Fe3O4 magnetic nanoparticles in cerebellum cells of schizophrenic rats

BACKGROUND

The aim of this study was to investigate the neurotoxic effects of Fe₃O₄ magnetic- CurNPs on isolated schizophrenia mitochondria of rats as an in vivo model.

METHODS

We designed CMN loaded superparamagnetic iron oxide nanoparticles (SPIONs) (Fe₃O₄ magnetic- CurNPs) to achieve an enhanced therapeutic effect. The physicochemical properties of Fe₃O₄ magnetic- CurNPs were characterized using X-ray diffraction (XRD), and dynamic laser light scattering (DLS) and zeta potential. Further, to prove Fe₃O₄ magnetic- CurNPs results in superior therapeutic effects, and also, the mitochondrial membrane potential collapse, mitochondrial complex II activity, reactive oxygen species generation, ATP level, cytochrome c release and histopathology of cerebellums were determined in brains of schizophrenic rats.

RESULTS

We showed that effective treatment with CMN reduced or prevented Fe₃O₄ magnetic-induced oxidative stress and mitochondrial dysfunction in the rat brain probably, as well as mitochondrial complex II activity, MMP, and ATP level were remarkably reduced in the cerebellum mitochondria of treated group toward control (p < 0.05). Therewith, ROS generation, and cytochrome c release were notably (p < 0.05) increased in the cerebellum mitochondria of treated group compared with control group.

CONCLUSION

Taken together, Fe₃O₄ magnetic- CurNPs exhibits potent antineurotoxicity activity in cerebellums of schizophrenic rats. This approach can be extended to preclinical and clinical use and may have importance in schizophernia treatment in the future. To our knowledge this is the first report that provides the Fe₃O₄ magnetic- CurNPs could enhance the neuroprotective effects of CMN in the Schizophrenia.

Physiological culture conditions alter myotube morphology and responses to atrophy treatments: implications for in vitro research on muscle wasting

Standard in vitro myotube culture conditions are nonphysiological and there is increasing evidence that this may distort adaptations to both catabolic and anabolic stimuli and hamper preclinical research into mechanisms and treatments for muscle atrophy in cancer and other chronic diseases. We tested a new model of myotube culture which mimics more accurately the basal conditions for muscle tissue in patients with chronic disease, such as cancer. Myotubes derived from C2C12 myoblasts, cultured under the modified conditions were thinner, more numerous, with more uniform morphology and an increased proportion of mature myotubes. Furthermore, modified conditions led to increased expression of mir-210-3p, genes related to slow-twitch, oxidative phenotype and resistance to commonly used experimental atrophy-inducing treatments. However, treatment with a combination of drugs used in anti-cancer treatment (doxorubicin and dexamethasone) under the modified culture conditions did lead to myotube atrophy which was only partially prevented by co-administration of curcumin. The results underline the importance and potential advantages of using physiological conditions for in vivo experiments investigating mechanisms of muscle atrophy and especially for preclinical screening of therapies for cancer-related muscle wasting.

Protective effect of ferulic acid on cisplatin induced nephrotoxicity in rats

This study aims to determine the potential protective effects of ferulic acid against cisplatin-induced nephrotoxicity and to compare its effect with curcumin, a well-known protective agent against cisplatin- induced toxicity in rats. Administration of cisplatin resulted in high BUN (Blood Urea Nitrogen), creatinine, MDA (Malondialdehyde), MPO (Myeloperoxidase), TOS (Total Oxidative Status), PtNT (Protein Nitrotyrosine) levels (p<0.05). Histological observations showed abnormal morphology of kidney; in addition with appearance of TUNEL positive cells indicating apoptosis in cisplatin administered group. HO-1 (Heme Oxygenase-1) levels measured by RT-PCR (Real Time Polymerase Chain Reaction), and TAS (Total Antioxidative Status) revealed antioxidant depletion due to cisplatin toxicity in animals (p<0.05). All parameters showed improvement in groups treated with ferulic acid (p<0.05). Ferulic acid treatment was found significant in preventing oxidative stress, increasing antioxidative status and regaining histological parameters to normal, indicating nephroprotective and antioxidant effects of this phenolic compound.

Curcumin prevents cisplatin-induced decrease in the tight and adherens junctions: relation to oxidative stress

Curcumin is a polyphenol and cisplatin is an antineoplastic agent that induces nephrotoxicity associated with oxidative stress, apoptosis, fibrosis and decrease in renal tight junction (TJ) proteins. The potential effect of curcumin against alterations in TJ structure and function has not been evaluated in cisplatin-induced nephrotoxicity. The present study explored whether curcumin is able to prevent the cisplatin-induced fibrosis and decreased expression of the TJ and adherens junction (AJ) proteins occludin, claudin-2 and E-cadherin in cisplatin-induced nephrotoxicity. Curcumin (200 mg kg(-1)) was administered in three doses, and rats were sacrificed 72 h after cisplatin administration. Curcumin was able to scavenge, in a concentration-dependent way, superoxide anion, hydroxyl radical, peroxyl radical, singlet oxygen, peroxynitrite anion, hypochlorous acid and hydrogen peroxide. Cisplatin-induced renal damage was associated with alterations in plasma creatinine, expression of neutrophil gelatinase-associated lipocalin and of kidney injury molecule-1, histological damage, increase in apoptosis, fibrosis (evaluated by transforming growth factor β1, collagen I and IV and α-smooth muscle actin expressions), increase in oxidative/nitrosative stress (evaluated by Hsp70/72 expression, protein tyrosine nitration, superoxide anion production in isolated glomeruli and proximal tubules, and protein levels of NADPH oxidase subunits p47(phox) and gp91(phox), protein kinase C β2, and Nrf2) as well as by decreased expression of occludin, claudin-2, β-catenin and E-cadherin. Curcumin treatment prevented all the above-described alterations. The protective effect of curcumin against cisplatin-induced fibrosis and decreased proteins of the TJ and AJ was associated with the prevention of glomerular and proximal tubular superoxide anion production induced by NADPH oxidase activity.

Evaluation of ameliorative effect of curcumin on imidacloprid-induced male reproductive toxicity in wistar rats

This study was undertaken to investigate the toxic effects of imidacloprid (IM) on male reproductive system and ameliorative effect of curcumin (CMN) in male Wistar rats. For this purpose, IM (45 and 90 mg/kg, body weight) and CMN (100 mg/kg, body weight) were administered orally to the rats either alone or in combinations for a period of 28 days. At the end of experiment, male reproductive toxicity parameters (total sperm count and sperm abnormalities), testosterone level, steroidal enzymatic activity [3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β-HSD], and oxidative stress indicators were estimated in testis and plasma. IM treatments resulted in significant decrease (p < 0.05) in total epididymal sperm count, sperm motility, live sperm count, and increase (p < 0.05) in sperm abnormalities. Activities of gamma-glutamyl transpeptidase, lactate dehydrogenase-x, and sorbitol dehydrogenase were significantly increased (p < 0.05), while, 3β-HSD and 17β-HSD enzymatic activity along with testosterone concentration in testis and plasma were decreased significantly (p < 0.05) in IM-treated rats. IM exposure resulted in significant increase (p < 0.05) in LPO and decrease (p < 0.05) in GSH level along with decreased activities of CAT, SOD, GPx, and GST. IM-treated rats showed histopathological alterations in testis and epididymis. However, the reproductive toxicity parameters, oxidative stress indicators, and histopathological changes were minimized and functional restorations were noticed by co-administration of CMN in IM-treated rats. The results of this study suggest that IM-induced male reproductive toxic effects could be ameliorated by CMN supplementation. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1250-1263, 2016.

Mitochondrial function and disturbances in the septic kidney

Per milligram of tissue, only the heart exceeds the kidney's abundance of mitochondria. Not surprisingly, renal mitochondria are most densely concentrated in the epithelium of the nephron, at sites where the chemical work of moving solutes against electrochemical gradients places large and constant demands for adenosine triphosphate. Derangements of renal epithelial mitochondria appear to be a hallmark for diverse forms of acute kidney injury (AKI). The pathogenesis of multiple-organ dysfunction syndrome in sepsis is complex, but a substantial body of experimental and observational human data supports the twin concepts that mitochondrial dysfunction contributes to impaired filtration and that recovery of mitochondrial structure and function is essential for recovery from sepsis-associated AKI. These insights have suggested novel methods to diagnose, stratify, prevent, or even treat this common and deadly complication of critical illness. This review will do the following: (1) describe the structure and functions of healthy mitochondria and how renal energy metabolism relates to solute transport; (2) provide an overview of the evidence linking mitochondrial pathology to renal disease; (3) summarize the mitochondrial lesions observed in septic AKI; (4) analyze the role of mitochondrial processes including fission/fusion, mitophagy, and biogenesis in the development of septic AKI and recovery from this disease; and (5) explore the potential for therapeutically targeting mitochondria to prevent or treat septic AKI.

C-phycocyanin prevents cisplatin-induced mitochondrial dysfunction and oxidative stress

The potential of C-phycocyanin (C-PC) to prevent cisplatin (CP)-induced kidney mitochondrial dysfunction was determined in CD-1 male mice. The CP-induced mitochondrial dysfunction was characterized by ultrastructural abnormalities and by decrease in the following parameters in isolated kidney mitochondria: adenosine diphosphate (ADP)-induced oxygen consumption (state 3), respiratory control ratio, ADP/oxygen (ADP/O) ratio, adenosine triphosphate synthesis, membrane potential, calcium retention, glutathione (GSH) content, and activity of respiratory complex I, aconitase, catalase, and GSH peroxidase. These mitochondria also showed increase in hydrogen peroxide production, malondialdehyde, and 3-nitrotyrosine protein adducts content. The above-described changes, as well as CP-induced nephrotoxicity, were attenuated in mice pretreated with a single injection of C-PC. Our data suggest that the attenuation of mitochondrial abnormalities is involved in the protective effect of C-PC against CP-induced nephrotoxicity. This is the first demonstration that C-PC pretreatment prevents CP-induced mitochondrial dysfunction in mice.

Mitochondrial modulation by Epigallocatechin 3-Gallate ameliorates cisplatin induced renal injury through decreasing oxidative/nitrative stress, inflammation and NF-kB in mice

Cancer chemotherapy drug cisplatin is known for its nephrotoxicity. The aim of this study is to investigate whether Epigallocatechin 3-Gallate (EGCG) can reduce cisplatin mediated side effect in kidney and to understand its mechanism of protection against tissue injury. We used a well-established 3-day cisplatin induced nephrotoxicity mice model where EGCG were administered. EGCG is a major active compound in Green Tea and have strong anti-oxidant and anti-inflammatory properties. EGCG protected against cisplatin induced renal dysfunction as measured by serum creatinine and blood urea nitrogen (BUN). EGCG improved cisplatin induced kidney structural damages such as tubular dilatation, cast formation, granulovaculoar degeneration and tubular cell necrosis as evident by PAS staining. Cisplatin induced kidney specific mitochondrial oxidative stress, impaired activities of mitochondrial electron transport chain enzyme complexes, impaired anti-oxidant defense enzyme activities such as glutathione peroxidase (GPX) and manganese superoxide dismutase (MnSOD) in mitochondria, inflammation (tumor necrosis factor α and interleukin 1β), increased accumulation of NF-κB in nuclear fraction, p53 induction, and apoptotic cell death (caspase 3 activity and DNA fragmentation). Treatment of mice with EGCG markedly attenuated cisplatin induced mitochondrial oxidative/nitrative stress, mitochondrial damages to electron transport chain activities and antioxidant defense enzyme activities in mitochondria. These mitochondrial modulations by EGCG led to protection mechanism against cisplatin induced inflammation and apoptotic cell death in mice kidney. As a result, EGCG improved renal function in cisplatin mediated kidney damage. In addition to that, EGCG attenuated cisplatin induced apoptotic cell death and mitochondrial reactive oxygen species (ROS) generation in human kidney tubular cell line HK-2. Thus, our data suggest that EGCG may represent new promising adjunct candidate for cisplatin.

Curcuma longa (curcumin) decreases in vivo cisplatin-induced ototoxicity through heme oxygenase-1 induction

HYPOTHESIS

To investigate whether curcumin may have in vivo protective effects against cisplatin ototoxicity by its direct scavenger activity and/or by curcumin-mediated upregulation of HO-1.

BACKGROUND

Cisplatin-induced ototoxicity is a major dose-limiting side effect in anticancer chemotherapy. A protective approach to decrease cisplatin ototoxicity without compromising its therapeutic efficacy remains a critical goal for anticancer therapy. Recent evidences indicate that curcumin exhibits antioxidant, anti-inflammatory, and chemosensitizer activities.

METHODS

In male adult Wistar rats, a curcumin dose of 200 mg/kg, selected from a dose-response curve, was injected 1 hour before cisplatin administration and once daily for the following 3 days. A single dose of cisplatin (16 mg/kg) was administered intraperitoneally. Rats were divided as follows: 1) control, 2) curcumin control, 3) vehicle control, 4) cisplatin, 5) cisplatin+ vehicle, and 6) curcumin+cisplatin. ABRs were measured before and at Days 3 and 5 after cisplatin administration. Rhodamine-phalloidin staining, 4-hydroxy-2-nonenal and heme-oxigenase-1 immunostainings, and Western blot analyses were performed to assess and quantify OHC loss, lipid peroxidation, and the endogenous response to cisplatin-induced damage and to curcumin protection.

RESULTS

Curcumin treatment attenuated hearing loss induced by cisplatin, increased OHC survival, decreased 4-HNE expression, and increased HO-1 expression.

CONCLUSION

This preclinical study demonstrates that systemic curcumin attenuates ototoxicity and provides molecular evidence for a role of HO-1 as an additional mediator in attenuating cisplatin-induced damage.

Nephroprotective activities of quercetin with potential relevance to oxidative stress induced by valproic acid

Valproic acid (VPA) is ubiquitously used as a major drug in the intervention of epilepsy and in the control of several kinds of seizures. Cellular toxicities are the serious dose-limiting side effects of VPA when applied in the treatment of diseases. Oxidative stress has been proven to be involved in VPA-induced toxicity. Accumulating evidence intimates that oxidative stress caused by free radicals and in kidney cells contributes to the pathogenesis of VPA-induced nephrotoxicity. The pathogenesis of these forms of VPA nephrotoxicity is still not clear. The aim of our investigation was to evaluate the nephrotoxic potential of VPA and protective effects of quercetin (QR) against VPA-induced nephrotoxicity by using rat kidney tissue preparation as an in vitro model. Oxidative stress indexes such as lipid peroxidation (LPO) and protein carbonyl (PC) content were appraised. The levels of oxidative stress markers, LPO, and PC were significantly elevated. Nonenzymatic antioxidants effect was also demonstrated as a significant increase in reduced glutathione (GSH) and nonprotein thiol level (NP-SH). VPA exposure altered the activities of glutathione metabolizing enzymes such as glutathione-S-transferase, glutathione peroxidase, and glutathione reductase. Pre-treatment with QR could reverse the VPA-induced effects in kidney tissue preparation of rat. Based on reno-protective and antioxidant action of QR, we suggest that this flavonoid compound could be considered as a potential safe and effective approach in attenuating the adverse effect of VPA-induced nephrotoxicity.

Mitochondrial dysregulation and protection in cisplatin nephrotoxicity

Nephrotoxicity is a major side effect of cisplatin in chemotherapy. Pathologically, cisplatin nephrotoxicity is characterized by cell injury and death in renal tubules. The research in the past decade has gained significant understanding of the cellular and molecular mechanisms of tubular cell death, revealing a central role of mitochondrial dysregulation. The pathological changes in mitochondria in cisplatin nephrotoxicity are mainly triggered by DNA damage response, pro-apoptotic protein attack, disruption of mitochondrial dynamics, and oxidative stress. As such, inhibitory strategies targeting these cytotoxic events may provide renal protection. Nonetheless, ideal approaches for renoprotection should not only protect kidneys but also enhance the anticancer efficacy of cisplatin in chemotherapy.

The use of functional chemical-protein associations to identify multi-pathway renoprotectants

Typically, most nephropathies can be categorized as complex human diseases in which the cumulative effect of multiple minor genes, combined with environmental and lifestyle factors, determines the disease phenotype. Thus, multi-target drugs would be more likely to facilitate comprehensive renoprotection than single-target agents. In this study, functional chemical-protein association analysis was performed to retrieve multi-target drugs of high pathway wideness from the STITCH 3.1 database. Pathway wideness of a drug evaluated the efficiency of regulation of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in quantity. We identified nine experimentally validated renoprotectants that exerted remarkable impact on KEGG pathways by targeting a limited number of proteins. We selected curcumin as an illustrative compound to display the advantage of multi-pathway drugs on renoprotection. We compared curcumin with hemin, an agonist of heme oxygenase-1 (HO-1), which significantly affects only one KEGG pathway, porphyrin and chlorophyll metabolism (adjusted p = 1.5×10⁻⁵). At the same concentration (10 µM), both curcumin and hemin equivalently mitigated oxidative stress in H₂O₂-treated glomerular mesangial cells. The benefit of using hemin was derived from its agonistic effect on HO-1, providing relief from oxidative stress. Selective inhibition of HO-1 completely blocked the action of hemin but not that of curcumin, suggesting simultaneous multi-pathway intervention by curcumin. Curcumin also increased cellular autophagy levels, enhancing its protective effect; however, hemin had no effects. Based on the fact that the dysregulation of multiple pathways is implicated in the etiology of complex diseases, we proposed a feasible method for identifying multi-pathway drugs from compounds with validated targets. Our efforts will help identify multi-pathway agents capable of providing comprehensive protection against renal injuries.

Curcumin ameliorates methotrexate-induced nephrotoxicity in rats

Methotrexate is an effective anticancer and immunosuppressive agent. However, nephrotoxicity is one of the complications of its use. On the other hand, curcumin, a naturally occurring polyphenolic compound, is reported to have antioxidant and anti-inflammatory properties. Those two properties are likely to prevent methotrexate-induced nephrotoxicity. The aim of this study is to evaluate the possible protective effect of curcumin against methotrexate-induced nephrotoxicity and delineate various mechanism(s) underlies this effect in rats. Nephrotoxicity was induced in Wistar rats by intraperitoneal administration of methotrexate (7 mg/kg/day) for three consecutive days. Curcumin administration in methotrexate-intoxicated rats resulted in nephroprotective effects as evidenced by the significant decrease in levels of serum creatinine and urea as well as renal malondialdehyde, nitric oxide, and tumor necrosis factor- α with a concurrent increase in renal glutathione peroxidase and superoxide dismutase activities compared to nephrotoxic untreated rats. Additionally, immunohistochemical analysis demonstrated that curcumin treatment markedly reduced cyclooxygenase-2 expression. Histopathological examination confirmed the protective effects of curcumin. In conclusion, curcumin protected rats from methotrexate nephrotoxicity, at least in part, through its antioxidant and anti-inflammatory activities.

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

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