Protective effect of ebselen, a selenoorganic drug, against gentamicin-induced renal damage in rats

Impacts of gentamycin toxicity: nephroprotective role of guarana through different signaling pathways

Gentamicin is a widely used aminoglycosidic antibiotic since its discovery. Like any other medication gentamicin causes unwanted side effects such as hepatotoxicity and nephrotoxicity. This study aims to examine the antioxidant effect of the guarana seed extract in protecting renal tissue. Forty male mice were divided into four groups (group one was control with free access to food and water, group two was treated orally with 300 mg/kg of guarana seed extract daily, group three was injected intraperitoneally with 100 mg/kg of gentamicin daily and the fourth group was co-treated with both 300 mg/kg of guarana seed extract orally and injected intraperitoneally with 100 mg/kg of gentamicin daily) for two weeks. Serum levels of urea, creatinine, AST, ALT, IL-1β and IL-6 have significantly elevated in the gentamicin treated group and those changes were not found in the guarana co-treated group. In gentamicin treated mice, a significant reduction was observed in two antioxidants SOD and GPX accompanied by downregulation of Ho-1 and Nrf2 while, that did not happen in the guarana seed extract co-treated group. Histopathology and immunohistochemistry slides show that the guarana seed extract prevents degenerative and necrotic events in tubular epithelial tissues caused by gentamicin toxicity. In conclusion, current data suggest that gentamicin can damage renal tissues when given at 100 mg/kg/day, however, the guarana seed extract may be capable of preventing that event when cotreated with the gentamicin as a supplement.

A review on the traditional uses, nutritive importance, pharmacognostic features, phytochemicals, and pharmacology of Momordica cymbalaria Hook F

Momordica cymbalaria Hook F. (MC), belonging to the family Cucurbitaceae, is a plant with several biological activities. This detailed, comprehensive review gathers and presents all the information related to the geographical distribution, morphology, therapeutic uses, nutritional values, pharmacognostic characters, phytochemicals, and pharmacological activities of MC. The available literature showed that MC fruits are utilized as a stimulant, tonic, laxative, stomachic, and to combat inflammatory disorders. The fruits are used to treat spleen and liver diseases and are applied in folk medicine to induce abortion and treat diabetes mellitus. The phytochemical screening studies report that MC fruits contain tannins, alkaloids, phenols, proteins, amino acids, vitamin C, carbohydrates, β-carotenes, palmitic acid, oleic acid, stearic acid, α-eleostearic acid, and γ-linolenic acid. The fruits also contain calcium, sodium, iron, potassium, copper, manganese, zinc, and phosphorus. Notably, momordicosides are cucurbitacin triterpenoids reported in the fruits of MC. Diverse pharmacological activities of MC, such as analgesic, anti-inflammatory, antioxidant, hepatoprotective, nephroprotective, antidiabetic, cardioprotective, antidepressant, anticonvulsant, anticancer, antiangiogenic, antifertility, antiulcer, antimicrobial, antidiarrheal and anthelmintic, have been reported by many investigators. M. cymbalaria methanolic extract is safe up to 2,000 mg/kg. Furthermore, no symptoms of toxicity were found. These pharmacological activities are mechanistically interpreted and described in this review. Additionally, the microscopic, powder and physiochemical characteristics of MC tubers are also highlighted. In summary, possesses remarkable medicinal values, which warrant further detailed studies to exploit its potential benefits therapeutically.

Ebselen: A Review on its Synthesis, Derivatives, Anticancer Efficacy and Utility in Combating SARS-COV-2

Ebselen is a selenoorganic chiral compound with antioxidant properties comparable to glutathione peroxidase. It is also known as 2-phenyl-1,2-benzisoselenazol-3(2H)-one. In studies examining its numerous pharmacological activities, including antioxidant, anticancer, antiviral, and anti- Alzheimer's, ebselen has demonstrated promising results. This review's primary objective was to emphasize the numerous synthesis pathways of ebselen and their efficacy in fighting cancer. The data were collected from multiple sources, including Scopus, PubMed, Google Scholar, Web of Science, and Publons. The starting reagents for the synthesis of ebselen are 2-aminobenzoic acid and N-phenyl benzamide. It was discovered that ebselen has the ability to initiate apoptosis in malignant cells and prevent the formation of new cancer cells by scavenging free radicals. In addition, ebselen increases tumor cell susceptibility to apoptosis by inhibiting TNF-α mediated NF-kB activation. Ebselen can inhibit both doxorubicin and daunorubicin-induced cardiotoxicity. Allopurinol and ebselen administered orally can be used to suppress renal ototoxicity and nephrotoxicity. Due to excessive administration, diclofenac can induce malignancy of the gastrointestinal tract, which ebselen can effectively suppress. Recent research has demonstrated ebselen to inhibit viral function by binding to cysteinecontaining catalytic domains of various viral proteases. It was discovered that ebselen could inhibit the catalytic dyad function of Mpro by forming an irreversible covalent bond between Se and Cys145, thereby altering protease function and inhibiting SARS-CoV-2. Ebselen may also inhibit the activation of endosomal NADPH oxidase of vascular endothelial cells, which is believed to be required for thrombotic complications in COVID-19. In this review, we have included various studies conducted on the anticancer effect of ebselen as well as its inhibition of SARS-CoV-2.

Protective Effect of Neutral Electrolyzed Saline on Gentamicin-Induced Nephrotoxicity: Evaluation of Histopathologic Parameters in a Murine Model

Background and Objectives: Gentamicin (GM) is a nephrotoxic aminoglycoside. Neutral electrolyzed saline (SES) is a compound with anti-inflammatory, antioxidant, and immunomodulatory properties. The objective of the present study was to evaluate whether kidney damage by GM can be prevented and/or reversed through the administration of SES. Materials and Methods: The study was carried out as a prospective, single-blind, five-arm, parallel-group, randomized, preclinical trial. The nephrotoxicity model was established in male BALB/c mice by administering GM at a dose of 100 mg/kg/day intraperitoneally for 30 days, concomitantly administering (+) SES or placebo (physiologic saline solution), and then administering SES for another 30 days after the initial 30 days of GM plus SES or placebo. At the end of the test, the mice were euthanized, and renal tissues were evaluated histopathologically. Results: The GM + placebo group showed significant tubular injury, interstitial fibrosis, and increased interstitial infiltrate of inflammatory cells compared with the group without GM. Tubular injury and interstitial fibrosis were lower in the groups that received concomitant GM + SES compared with the GM + placebo group. SES administration for 30 days after the GM administration periods (GM + placebo and GM + SES for 30 days) did not reduce nephrotoxicity. Conclusions: Intraperitoneal administration of SES prevents gentamicin-induced histologic nephrotoxicity when administered concomitantly, but it cannot reverse the damage when administered later.

Toxicology and pharmacology of synthetic organoselenium compounds: an update

Here, we addressed the pharmacology and toxicology of synthetic organoselenium compounds and some naturally occurring organoselenium amino acids. The use of selenium as a tool in organic synthesis and as a pharmacological agent goes back to the middle of the nineteenth and the beginning of the twentieth centuries. The rediscovery of ebselen and its investigation in clinical trials have motivated the search for new organoselenium molecules with pharmacological properties. Although ebselen and diselenides have some overlapping pharmacological properties, their molecular targets are not identical. However, they have similar anti-inflammatory and antioxidant activities, possibly, via activation of transcription factors, regulating the expression of antioxidant genes. In short, our knowledge about the pharmacological properties of simple organoselenium compounds is still elusive. However, contrary to our early expectations that they could imitate selenoproteins, organoselenium compounds seem to have non-specific modulatory activation of antioxidant pathways and specific inhibitory effects in some thiol-containing proteins. The thiol-oxidizing properties of organoselenium compounds are considered the molecular basis of their chronic toxicity; however, the acute use of organoselenium compounds as inhibitors of specific thiol-containing enzymes can be of therapeutic significance. In summary, the outcomes of the clinical trials of ebselen as a mimetic of lithium or as an inhibitor of SARS-CoV-2 proteases will be important to the field of organoselenium synthesis. The development of computational techniques that could predict rational modifications in the structure of organoselenium compounds to increase their specificity is required to construct a library of thiol-modifying agents with selectivity toward specific target proteins.

Catalytic Antioxidants in the Kidney

Reactive oxygen species and reactive nitrogen species are highly implicated in kidney injuries that include acute kidney injury, chronic kidney disease, hypertensive nephropathy, and diabetic nephropathy. Therefore, antioxidant agents are promising therapeutic strategies for kidney diseases. Catalytic antioxidants are defined as small molecular mimics of antioxidant enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, and some of them function as potent detoxifiers of lipid peroxides and peroxynitrite. Several catalytic antioxidants have been demonstrated to be effective in a variety of in vitro and in vivo disease models that are associated with oxidative stress, including kidney diseases. This review summarizes the evidence for the role of antioxidant enzymes in kidney diseases, the classifications of catalytic antioxidants, and their current applications to kidney diseases.

New therapeutic targets in chronic kidney disease progression and renal fibrosis

INTRODUCTION

The current therapeutic armamentarium to prevent chronic kidney disease (CKD) progression is limited to the control of blood pressure and in diabetic patients, the strict control of glucose levels. Current research is primarily focused on the reduction of inflammation and fibrosis at different levels.

AREAS COVERED

This article examines the latest progress in this field and places an emphasis on inflammation, oxidative stress, and fibrosis. New therapeutic targets are described and evidence from experimental and clinical studies is summarized. We performed a search in Medline for articles published over the last 10 years.

EXPERT OPINION

The search for therapeutic targets of renal inflammation is hindered by an incomplete understanding of the pathophysiology. The determination of the specific inducers of inflammation in the kidney is an area of heightened potential. Prevention of the progression of renal fibrosis by blocking TGF-β signaling has been unsuccessful, but the investigation of signaling pathways involved in late stages of fibrosis progression could yield improved results. Preventive strategies such as the modification of microbiota-inducers of uremic toxins involved in CKD progression is a promising field because of the interaction between the gut microbiota and the renal system.

Protective effects of pharmacological agents against aminoglycoside-induced nephrotoxicity: A systematic review

Introduction: Aminoglycosides have been long used for antibacterial treatment and are still commonly used in clinical practice. Despite their extensive application and positive effects, drug-related toxicity is considered as the main obstacle for aminoglycosides. Aminoglycosides induce nephrotoxicity through the endocytosis and accumulation of the antibiotics in the epithelial cells of proximal tubule. Most importantly, however, a number of pharmacological agents were demonstrated to have protective activities against nephrotoxicity in experimental animals.Areas covered: In the present systematic review, the authors provide and discuss the mechanisms and epidemiological features of aminoglycoside-induced nephrotoxicity, and focus mainly on recent discoveries and key features of pharmacological interventions. In total, 39 articles were included in this review.Expert opinion: The majority of studies investigated gentamicin-induced nephrotoxicity in animal models. Antioxidants, chemicals, synthetic drugs, hormones, vitamins, and minerals showed potential values to prevent gentamicin-induced nephrotoxicity. Indicators used to evaluate the effectiveness of nephroprotection included antioxidative indexes, inflammatory responses, and apoptotic markers. Among the nephroprotective agents studied, herbs and natural antioxidant agents showed excellent potential to provide a protective strategy against gentamicin-induced nephrotoxicity.

Resveratrol Reverses Thioacetamide-Induced Renal Assault with respect to Oxidative Stress, Renal Function, DNA Damage, and Cytokine Release in Wistar Rats

Background

Thioacetamide (TAA), a class 2B-type carcinogen, is a potent toxicant. Toxicities caused by this compound in various tissues due to oxidative stress, increase of proinflammatory markers, and apoptosis have been reported; however, reports on kidney toxicity are negligible. Resveratrol (RSV), on the other hand, has demonstrated antioxidant and anti-inflammatory effects in different cases. Resveratrol's protective effects against TAA kidney toxicity were investigated in four rat groups.

Methodology

Four groups of rats were studied as follows (n = 8): control group, where rats were fed normal diet and water; TAA group, where rats received 0.3% TAA in water for two weeks; RSV group, where rats received 10 mg/kg body weight (bw) of RSV as oral suspension for two weeks; and treated group, where rats orally received 10 mg/kg bw RSV and simultaneously received 0.3% TAA for two weeks. Kidney homogenates from all groups were analyzed for cytokine release (IL-4, TNF-α, and IFN-γ) and oxidative stress (lipid peroxidation, catalase, and 8-OHdG). The serum of rats was analyzed for the quantification of renal function markers (blood urea nitrogen (BUN), creatinine, and creatine kinase).

Result

A significant increase in the renal function markers (BUN, 240%; creatinine, 187%; and creatine kinase, 117%), oxidative stress parameters (lipid peroxidation, 192% increase; catalase, 30.5% decrease), cytokines (IL-4, 120%; TNF-α, 129%; and IFN-γ, 133%), and DNA damage was observed in the TAA-treated group. All changes were significantly reversed in the group treated with RSV and TAA (P < 0.05) in combination, with no significant difference compared to the control group.

Conclusion

We conclude that resveratrol shows protection against TAA toxicity in rat kidney with respect to DNA damage, oxidative stress, renal function and cytokine release.

Oxidant Mechanisms in Renal Injury and Disease

SIGNIFICANCE

A common link between all forms of acute and chronic kidney injuries, regardless of species, is enhanced generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) during injury/disease progression. While low levels of ROS and RNS are required for prosurvival signaling, cell proliferation and growth, and vasoreactivity regulation, an imbalance of ROS and RNS generation and elimination leads to inflammation, cell death, tissue damage, and disease/injury progression.

RECENT ADVANCES

Many aspects of renal oxidative stress still require investigation, including clarification of the mechanisms which prompt ROS/RNS generation and subsequent renal damage. However, we currently have a basic understanding of the major features of oxidative stress pathology and its link to kidney injury/disease, which this review summarizes.

CRITICAL ISSUES

The review summarizes the critical sources of oxidative stress in the kidney during injury/disease, including generation of ROS and RNS from mitochondria, NADPH oxidase, and inducible nitric oxide synthase. The review next summarizes the renal antioxidant systems that protect against oxidative stress, including superoxide dismutase and catalase, the glutathione and thioredoxin systems, and others. Next, we describe how oxidative stress affects kidney function and promotes damage in every nephron segment, including the renal vessels, glomeruli, and tubules.

FUTURE DIRECTIONS

Despite the limited success associated with the application of antioxidants for treatment of kidney injury/disease thus far, preventing the generation and accumulation of ROS and RNS provides an ideal target for potential therapeutic treatments. The review discusses the shortcomings of antioxidant treatments previously used and the potential promise of new ones. Antioxid. Redox Signal. 25, 119-146.

Effects of iron overload condition on liver toxicity and hepcidin/ferroportin expression in thalassemic mice

AIMS

Although iron-overload conditions can be found in β-thalassemic patients, resulting in cellular damage, particularly in the liver, the mechanism for this iron-mediated hepatic injury specifically in β-thalassemic (HT) mice is unclear. This study aimed to investigate the roles of L-type calcium channels (LTCC), T-type calcium channels (TTCC) and divalent metal transporter1 (DMT1) in iron-mediated hepatic injury in HT mice.

MAIN METHODS

Iron chelator deferoxamine (DFO), LTCC blocker, TTCC blocker and DMT1 blocker were used to determine the roles of these channels regarding liver iron accumulation, apoptosis and iron regulatory protein expression in HT mice.

KEY FINDINGS

TTCC and DMT1 blockers and DFO decreased liver iron and malondialdehyde (MDA) in HT mice indicating their antioxidant effects, whereas LTCC blocker produced no decrease in liver iron or MDA. However, only DFO decreased liver apoptosis through the reduced Bax/Bcl-2 ratio in wild type (WT) mice. The levels of iron regulatory hormone hepcidin were markedly higher in HT mice even before iron loading while ferroportin levels did not alter. Each of the pharmacological interventions increased ferroportin protein back to normal levels only in WT while HT mice showed no difference.

SIGNIFICANCE

Thalassemic mice have different hepcidin/ferroportin and apoptotic protein expression as a defense mechanism to iron-overload compared with those in WT mice. DFO was the most effective intervention in preventing liver apoptosis under iron-overload conditions in WT but did not have the same effect in HT mice.

Tenofovir-induced nephrotoxicity: incidence, mechanism, risk factors, prognosis and proposed agents for prevention

OBJECTIVE

In this study, data regarding epidemiology, risk factors, pathogenesis and outcome of tenofovir-induced nephrotoxicity will be reviewed, and current and future approaches for prevention will be discussed.

METHOD

The data were collected by searching Scopus, PubMed, Medline, Science direct, Clinical trials and Cochrane database systematic reviews. The keywords used as search terms were "Tenofovir", "TDF", "NRTI", "Nephrotoxicity", "Renal failure", "Kidney damage", "HIV" and "AIDS".

RESULTS AND CONCLUSION

Several predisposing factors including elevated baseline SCr, concomitant nephrotoxic medications, low body weight, advanced age, tenofovir disoproxil fumarate (TDF) dose and duration of treatment and lower CD4 cell count were identified as risk factors for development of TDF-induced nephrotoxicity. Cellular accumulation through increased entry from the human organic anion transporters and decreased efflux into tubular lumen is main mechanism of nucleotide analogue antiviral induced nephrotoxicity. Renal function assessment and monitoring at baseline and during TDF treatment are the main approach of prevention of TDF-induced nephrotoxicity. Rosiglitazone may be helpful in patients presenting with TDF-induced nephrotoxicity. Pretreatment with melatonin prevented all known histological changes in proximal tubular mitochondira induced by TDF. Use of antioxidants with mitochondria-targeted properties such as MitoQ or Mito-CP may prevent proximal tubular mitochondrial against TDF damage. Vitamin E, ebselen, lipoic acid, plastoquinone, nitroxides, SOD enzyme mimetics, Szeto-Schiller (SS) peptides, and quercetin are other potential agents for prevention of TDF-induced nephrotoxicity. However, data regarding effectiveness of nephroprotective agents against TDF-induced nephrotoxicity are not conclusive. Before extrapolation of the preclinical evidence to clinical practice, these evidence should be confirmed in future human studies.

Association of oxidative stress to the genesis of anxiety: implications for possible therapeutic interventions

Oxidative stress caused by reactive species, including reactive oxygen species, reactive nitrogen species, and unbound, adventitious metal ions (e.g., iron [Fe] and copper [Cu]), is an underlying cause of various neurodegenerative diseases. These reactive species are an inevitable by-product of cellular respiration or other metabolic processes that may cause the oxidation of lipids, nucleic acids, and proteins. Oxidative stress has recently been implicated in depression and anxiety-related disorders. Furthermore, the manifestation of anxiety in numerous psychiatric disorders, such as generalized anxiety disorder, depressive disorder, panic disorder, phobia, obsessive-compulsive disorder, and posttraumatic stress disorder, highlights the importance of studying the underlying biology of these disorders to gain a better understanding of the disease and to identify common biomarkers for these disorders. Most recently, the expression of glutathione reductase 1 and glyoxalase 1, which are genes involved in antioxidative metabolism, were reported to be correlated with anxiety-related phenotypes. This review focuses on direct and indirect evidence of the potential involvement of oxidative stress in the genesis of anxiety and discusses different opinions that exist in this field. Antioxidant therapeutic strategies are also discussed, highlighting the importance of oxidative stress in the etiology, incidence, progression, and prevention of psychiatric disorders.

The protective effect of ebselen on radiocontrast-induced nephrotoxicity

AIM

Radiocontrast-induced nephropathy has become one of the most important causes of renal acute failure. The most effective management of reducing the incidence of contrast nephropathy is to understand and prevent its causes. We aimed to investigate the protective role of ebselen against radiocontrast-induced nephrotoxicity in terms of tissue oxidant/antioxidant parameters and light microscopy in rats.

METHODS

Albino Wistar rats were randomly separated into four groups. The Group 1 rats were treated with sodium chloride as the control group, Group 2 with radiocontrast, Group 3 with radiocontrast plus ebselen, and Group 4 with ebselen alone. After 24 h, the animals over the experimental period were euthanized and blood samples were analyzed for blood urea nitrogen (BUN) and serum creatinine (Cr) levels. Kidney sections were analyzed for malondialdehyde (MDA) levels and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities, as well as histopathological changes.

RESULTS

In the radiocontrast group, BUN, MDA, and GSH-Px levels increased while SOD activity decreased compared with the control group. These decays were improved by ebselen administration in the radiocontrast group. Significant histological deteriorations were observed in the radiocontrast group. We noted improvement in the histologic findings with ebselen administration.

CONCLUSION

These results indicate that ebselen might produce a protective mechanism against radiocontrast-induced nephrotoxicity.

Renoprotective effects of the crude extract and solvent fractions of the leaves of Euclea divinorum Hierns against gentamicin-induced nephrotoxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Euclea divinorum Hierns (Ebenaceae) is used in Ethiopian folklore medicine to treat scabies, inflammation of the skin, eczema, abdominal pain, gonorrhea, and kidney problems. However, the claim has not been scientifically validated.

AIM OF THE STUDY

To assess the renoprotective effects of the crude extract and solvent fractions of E. divinorum leaves against gentamicin-induced nephrotoxicity in rats.

MATERIALS AND METHOD

Rats of either sex were divided into seven experimental groups, each comprising six animals. Group I served as control and given vehicle (Tween 80, 2%, v/v in water) and Group II were treated with gentamicin intraperitoneally (100mg/kg/day) for eight days. Group III-V received crude extract at three different doses 100mg/kg, 150mg/kg and 200mg/kg, respectively. Group VI received 100mg/kg of the methanolic fraction and Group VII 100mg/kg of the aqueous fraction. The extract was administered orally two days before and eight days concomitantly with gentamicin. Following treatment, blood and renal tissue were used to assess creatinine, blood urea nitrogen (BUN), malondialdehyde (MDA), antioxidant enzymes and tubular necrosis using recommended procedures. In addition, free radical scavenging activity was determined using in vitro methods.

RESULTS

Gentamicin significantly increased serum creatinine and BUN, MDA and tubular necrosis in rats. It also decreased activity of catalase and superoxide dismutase as well as levels of gluthatione. Pre- and co-treatment with the crude extract and solvent fractions of Euclea divinorum leaves reversed gentamicin-induced alterations as evidenced by a decrease in tubular necrosis, serum and oxidant markers as well as by an increase in antioxidant molecules. Effect was found to decrease with dose when the crude extract was used and maximum protection was conferred by 100mg/kg of the methanolic fraction in both in vivo and in vitro studies.

CONCLUSIONS

Euclea divinorum reversed gentamicin-induced nephrotoxicity, probably via its antioxidant activity. The fact that the methanol fraction conferred maximum protection suggests that semi-polar antioxidant principles might be responsible for the observed effect.

Attenuation of gentamycin-induced nephrotoxicity in rats by dietary inclusion of ginger (Zingiber officinale) and turmeric (Curcuma longa) rhizomes

This study sought to investigate the modulatory effects of dietary inclusion of ginger (Zingiber officinale) and turmeric (Curcuma longa) rhizomes on antioxidant status and renal damage induced by gentamycin in rats. Renal damage was induced in albino rats pretreated with dietary inclusion of ginger and turmeric (2% and 4%) by intraperitoneal (i.p.) administration of gentamycin (100 mg/kg body weight) for three days. Assays for renal damage biomarkers (plasma creatinine, plasma urea, blood urea nitrogen and plasma uric acid), malondialdehyde (MDA) content and reduced glutathione (GSH) content as well as renal antioxidant enzymes (catalase, glutathione-S-transferase (GST), glutathione peroxidase (GPx) and superoxide dismutase (SOD)) were carried out. The study revealed significant (p < 0.05) increases in renal damage biomarkers following gentamycin administration with severe alteration in kidney antioxidant status. However, pretreatment with ginger and turmeric rhizome (2% and 4%) prior to gentamycin administration significantly (p < 0.05) protected the kidney and attenuated oxidative stress by modulating renal damage and antioxidant indices. This finding therefore suggests that dietary inclusion of ginger and turmeric rhizomes may protect against gentamycin-induced nephrotoxicity and oxidative stress.

T-type calcium channel blockade improves survival and cardiovascular function in thalassemic mice

OBJECTIVES

Iron-overload cardiomyopathy is a major cause of morbidity and mortality in patients with thalassemia. However, the precise mechanisms of iron entry and sequestration in the heart are still unclear. Our previous study showed that Fe(2+) uptake in thalassemic cardiomyocytes are mainly mediated by T-type calcium channels (TTCC). Nevertheless, the role of TTCC as well as other transporters such as divalent metal transporter1 (DMT1) and L-type calcium channels (LTCC) as possible portals for iron entry into the heart in in vivo thalassemic mice under an iron-overload condition has not been investigated.

METHODS

An iron-overload condition was induced in genetically altered β-thalassemic mice and adult wild-type mice by feeding them with an iron diet (0.2% ferrocene w/w) for 3 months. Then, blockers for LTCC (verapamil and nifedipine), TTCC (efonidipine), and DMT1 (ebselen) as well as iron chelator desferoxamine (DFO) were given for 1 month with continuous iron feeding.

RESULTS

Treatment with LTCC, TTCC, DMT1 blockers, and DFO reduced cardiac iron deposit, cardiac malondialdehyde (MDA), plasma non-transferrin-bound iron, and improved heart rate variability and left ventricular (LV) function in thalassemic mice with iron overload. Only TTCC and DMT1 blockers and DFO reduced liver iron accumulation, liver MDA, plasma MDA, and decreased mortality rate in iron-overloaded thalassemic mice.

CONCLUSIONS

DMT1, LTCC, and TTCC played important roles for iron entry in the thalassemic heart under an iron-overloaded condition. Unlike LTCC blocker, TTCC blocker provided all benefits including attenuating iron deposit in both the heart and liver, reduced oxidative stress, and decreased mortality in iron-overloaded mice.

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.

Protective effect of daily sesame oil supplement on gentamicin-induced renal injury in rats

Gentamicin, an aminoglycoside antibiotic, is widely used in the treatment of Gram-negative infections; however, dose-limiting nephrotoxicity restricts its optimal use. We investigated the effect of a daily sesame oil supplement on oxidative-stress-associated renal injury induced by a single daily dose of gentamicin in rats. Renal injury was induced by a single subcutaneous daily dose of gentamicin (100 mg kg(-1) d(-1) for 7 days), and then the effects of oral sesame oil (0.25, 0.5, and 1 mL kg(-1) d(-1) for 7 days) on renal injury, oxidative stress, hydroxyl radical, superoxide anion, and NO were assessed after treatment. Sesame oil inhibited gentamicin-induced renal injury, lipid peroxidation, hydroxyl radical, and superoxide anion, as well as NO production. In addition, sesame oil inhibited xanthine oxidase activity and inducible NOS expression in gentamicin-challenged rats. We hypothesize that a daily sesame oil supplement attenuates oxidative-stress-associated renal injury by reducing oxygen free radicals and lipid peroxidation in gentamicin-treated rats.

Ebselen increases cytosolic free Ca2+ concentration, stimulates glutamate release and increases GFAP content in rat hippocampal astrocytes

We have investigated the effect of the seleno-organic compound and radical scavenger ebselen on rat hippocampal astrocytes in culture. Throughout our study we carried out determinations of [Ca2+](c) in fura-2-loaded cells by single cell imaging, glutamate secretion employing an enzymatic-based assay and GFAP expression, which was monitorized by immunocytochemistry and confocal microscopy. Our results show that ebselen (1-20microM) dose dependently increases [Ca2+](c), stimulates glutamate release and increases GFAP content, a hallmark of astrocyte reactivity. Ebselen did not alter significantly cell viability as assayed by determination of LDH release into the extracellular medium. Ebselen-evoked glutamate release and increase in GFAP content were Ca2+-dependent, because incubation of astrocytes in the absence of extracellular Ca2+ (medium containing 0.5mM EGTA) and in the presence of the intracellular Ca2+ chelator BAPTA (10microM) significantly reduced ebselen-evoked changes in these parameters. The effects of ebselen we have observed may underline various signalling pathways which are important for cell proliferation, differentiation and function. However, aberrations in astroglial physiology could significantly compromise brain function, due to their role as modulators of neuron activity. Therefore, we consider that careful attention should be paid when employing ebselen as a prophylactic agent against brain damage.