Captopril ameliorates toxicity induced by paraquat in mitochondria isolated from the rat liver

Effect of sub-dermal exposure of silver nanoparticles on hepatic, renal and cardiac functions accompanying oxidative damage in male Wistar rats

Silver nanoparticles (AgNPs) have been generally used due to their strong antibacterial, antiviral and antifungal and antimicrobial properties. However, their toxicity is a subject of sustained debate, thus requiring further studies. Hence, this study examines the adverse effects of the sub-dermal administered dose of AgNPs (200 nm) on the liver, kidney and heart of male Wistar rats. Thirty male rats were randomly distributed into six groups of five animals per group. Group A and D served as the control and received distilled water for 14 and 28 days respectively. Groups B and C were sub-dermally exposed to AgNPs at 10 and 50 mg/kg daily for 14 days while E and F were sub-dermally exposed to AgNPs at 10 and 50 mg/kg daily for 28 days. The liver, kidney and heart of the animals were collected, processed and used for biochemical and histological analysis. Our results revealed that the subdermal administration of AgNPs induced significant increased (p < 0.05) activities of aspartate aminotransferase (AST), alanine transferase (ALT), alkaline phosphatase (ALP), urea, creatinine, and malondialdehyde (MDA) while decreasing the levels of glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and total thiol groups in the rat tissues. Our findings suggest that the subdermal administration of AgNPs induced oxidative stress and impaired the hepatic, renal and cardiac functions of male Wistar rats.

Mitochondrial Effects of Common Cardiovascular Medications: The Good, the Bad and the Mixed

Mitochondria are central organelles in the homeostasis of the cardiovascular system via the integration of several physiological processes, such as ATP generation via oxidative phosphorylation, synthesis/exchange of metabolites, calcium sequestration, reactive oxygen species (ROS) production/buffering and control of cellular survival/death. Mitochondrial impairment has been widely recognized as a central pathomechanism of almost all cardiovascular diseases, rendering these organelles important therapeutic targets. Mitochondrial dysfunction has been reported to occur in the setting of drug-induced toxicity in several tissues and organs, including the heart. Members of the drug classes currently used in the therapeutics of cardiovascular pathologies have been reported to both support and undermine mitochondrial function. For the latter case, mitochondrial toxicity is the consequence of drug interference (direct or off-target effects) with mitochondrial respiration/energy conversion, DNA replication, ROS production and detoxification, cell death signaling and mitochondrial dynamics. The present narrative review aims to summarize the beneficial and deleterious mitochondrial effects of common cardiovascular medications as described in various experimental models and identify those for which evidence for both types of effects is available in the literature.

Where ferroptosis inhibitors and paraquat detoxification mechanisms intersect, exploring possible treatment strategies

Paraquat (PQ) is a fast-acting and effective herbicide that is used throughout the world to eliminate weeds. Over the past years, PQ was considered one of the most popular poisoning substances for suicide, and PQ poisoning accounts for about one-third of suicides around the world. Poisoning with PQ may cause multiorgan failure, pulmonary fibrosis, and ultimately death. Exposure to PQ results in the accumulation of PQ in the lungs, causing severe damage and, eventually, fibrosis. Until now, no effective antidote has been found to treat poisoning with PQ. In general, the toxicity of PQ is due to the formation of high energy oxygen free radicals and the peroxidation of unsaturated lipids in the cell. Ferroptosis is the result of the loss of glutathione peroxidase 4 (GPX4) activity that transforms iron-dependent lipid hydroperoxides to lipid alcohols, which are inert in the biological environment. Impaired iron metabolism and lipid peroxidation are increasingly known as the driving agents of ferroptosis. The contribution of ferroptosis to the development of cell death during poisoning with PQ has not yet been addressed. There is growing evidence about the relationship between PQ poisoning and ferroptosis. This raises the possibility of using ferroptosis inhibitors for the treatment of PQ poisoning. In this hypothesis-driven review article, we elaborated how ferroptosis inhibitors might circumvent the toxicity induced by PQ and may be potentially useful for the treatment of PQ toxicity.

Hepatoprotective effect of N-acetylcystein loaded niosomes on liver function in paraquat-induced acute poisoning

Paraquat (PQ) is widely used as a herbicide around the world. PQ intoxication causes liver disease mainly in mammals. N-acetyl cysteine (NAC) is a medication that has positive effects in reducing the liver intoxication caused by PQ. Here, after formulating a NAC noisome nanoparticle (NACNP), we compared the niosomes and NAC on liver toxicity caused by PQ. Thirty male rats were divided into 5 groups and were treated intraperitoneally with PQ and NAC and NACNP for 24 h. PQ group received 35 mg/kg/day of PQ, while NAC and NACNP groups were administered with 25 mg/kg/day of NAC and NACNP, respectively. In addition, 6 rats receiving saline solution were considered as control group. Serum and liver tissue samples were collected from all rats. Alanine (AST) and aspartate (ALT) aminotransferase levels, and oxidative stress biomarkers including total antioxidant capacity (TAC), lipid peroxidation (LPO), and total thiol groups (TTG) levels were determined. Histological samples were also analyzed using hematoxylin and eosin staining slides. PQ administration resulted in hepatic injury as evidenced by increases in serum AST and ALT levels (p < .001). NACNP decreased LPO, TAC, and TTG levels compered to PQ group in liver tissue. Treatment of animals with NACNP was significantly more effective than free NAC in reducing PQ-induced hepatotoxicity (p < .05). Histological evaluation showed that PQ caused tissue inflammation, which was reduced by NAC treatment. This reduction was stronger for NACNP. Given these results, the use of NACNP, compared to NAC, was more protective against the development of the PQ-induced liver toxicity.

Possible involvement of transcriptional activation of nuclear factor erythroid 2-related factor 2 (Nrf2) in the protective effect of caffeic acid on paraquat-induced oxidative damage in Drosophila melanogaster

Paraquat (PQ) is a widely used herbicide with no antidote which is implicated in the pathogenesis of the Parkinson's disease. The present study then investigated the potential of caffeic acid (CA), a known antioxidant, cardioprotective and neuroprotective molecule to counteract oxidative stress mediated by PQ. In addition, molecular docking was performed to understand the mechanism underlying the inhibitory effect of CA against PQ poisoning. The fruit fly, Drosophila melanogaster, was exposed to PQ (0.44 mg/g of diet) in the absence or presence of CA (0.25, 0.5, 1 and 2 mg/g of died) for 7 days. Data showed that PQ-fed flies had higher incidence of mortality which was associated with mitochondrial dysfunction, increased free Fe(II) content and lipid peroxidation when compared to the control. Co-exposure with CA reduced mortality and markedly attenuated biochemical changes induced by PQ. The mechanism investigated using molecular docking revealed a strong interaction (-6.2 Kcal/mol) of CA with D. melanogaster transcriptional activation of nuclear factor erythroid 2-related factor 2 (Nrf2). This was characterized by the binding of CA to keap-1 domain of Nrf2. Taking together these results indicate the protective effect of CA against PQ-induced oxidative damage in D. melanogaster was likely through its coordination which hinders Nrf2-keap-1 binding leading to an increase of the antioxidant defense system.

Protective Role of Ce Nanoparticles Against the Hepatotoxicity Induced by Exposure to Paraquat

Objectives: The present study aimed to investigate the antioxidant activity of cerium oxide nanoparticles (CeNPs) against paraquat (PQ)-induced liver injury in rats. Methods: Thirty-two male rats were divided into four 8-member groups and treated intraperitoneally with PQ and/or CeNPs for 14 days. Group 1 received PQ (5 mg/kg/d), group 2 received CeNPs (15, 30, and 60 mg/kg/d), group 3 received a combination of PQ (5 mg/kg/d) and CeNPs (15, 30, and 60 mg/kg/d), and group 4 (control group) received saline solution. Serum samples along with liver tissue samples were collected from all the rats. Oxidative stress (OS) biomarkers including total antioxidant capacity, lipid peroxidation, total thiol groups, DNA damage, and nitric oxide levels were determined. Histological samples were also analyzed using hematoxylin and eosin staining slides. Results: Levels of oxidative stress and hepatic tissue damage were significantly higher in the PQ group compared to the control group. CeNPs at a dose of 15 mg/kg showed the antioxidant activity and compromised the PQ-induced damage. Conclusion: In the scenario tested in this study, CeNPs could reduce the levels of OS, as well as hepatic damage induced by PQ.

Captopril Attenuates Diazinon-Induced Oxidative Stress: A Subchronic Study in Rats

BACKGROUND

Diazinon (DZN) is an organophosphate pesticide commonly used for pest control in agriculture. It may engender a variety of negative effects in non-target species, including humans and animals. The objective of the present study was to evaluate the ameliorative properties of captopril (CAP), as a thiol containing an angiotensin-converting enzyme inhibitor, against DZN-induced oxidative stress.

METHODS

Twenty-eight male Wistar rats were divided randomly into 4 groups. All the rats were treated orally via gavage once a day for 7 weeks: control (corn oil), CAP (10 mg/kg), DZN (10 mg/kg), and CAP+DZN combination (as mentioned above). Oxidative stress indices in blood serum, liver and kidney homogenates (malondialdehyde [MDA], total thiol groups, and total antioxidant capacity), and erythrocyte hemolysis (superoxide dismutase [SOD] and glutathione peroxidase) were evaluated. Statistical analysis was performed using GraphPad Prism software, version 6.0 (GraphPad, San Diego, CA, USA), by ANOVA, followed by the Tukey post hoc analysis.

RESULTS

The MDA content and SOD activity increased significantly in the DZN group compared with those in the control group. Treatment with CAP in the DZN-exposed group significantly decreased (P<0.05) the MDA concentration and the SOD activity. The total thiol groups were decreased in the DZN group and elevated again by CAP treatment.

CONCLUSION

The co-administration of CAP and DZN was able to attenuate lipid peroxidation and enzyme changes caused by DZN.

Glyoxal toxicity in isolated rat liver mitochondria

Glyoxal is a physiological metabolite formed by lipid peroxidation, ascorbate autoxidation, oxidative degradation of glucose, and degradation of glycated proteins. Glyoxal has been linked to oxidative stress and can cause a number of cellular damages, including covalent modification of amino and thiol groups of proteins to form advanced glycation end products. However, the mechanism of glyoxal toxicity has not been fully understood. In this study, we have focused on glyoxal toxicity in isolated rat liver mitochondria. Isolated mitochondria (0.5 mg protein per milliliter) were prepared from the Wistar rat liver using differential centrifugation and incubated with various concentrations of glyoxal (1, 2.5, 5, 7.5, and 10 mM) for 30 min. The activity of mitochondrial complex II was determined by measurement of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) conversion. The mitochondrial membrane potential (MMP), lipid peroxidation (MDA), reactive oxygen species (ROS) formation, glutathione (GSH) content, and protein carbonylation were also assessed. After an incubation of isolated liver mitochondria with glyoxal, disrupted electron transport chain, increased mitochondrial ROS formation, lipid peroxidation, mitochondrial membrane damage, GSH oxidation, and protein carbonylation ensued as compared to the control group ( p < 0.05). Glyoxal toxicity in isolated rat liver mitochondria was dose-dependent. In conclusion, glyoxal impaired the electron transport chain, which is the cause of increased ROS and MDA production, depletion of GSH, and disruption of MMP. Mitotoxicity of glyoxal might be related to the pathomechanisms involved in diabetes and its complications.

Dithiothreitol (DTT) rescues mitochondria from nitrofurantoin-induced mitotoxicity in rat

Nitrofurantoin (N-(5-nitro-2-furfurylidine) 1-amino-hydantoine; NIT) is mainly used for the treatment of acute urinary tract infections. However, its administration can be associated with liver failure or cirrhosis. The aim of this study was to determine whether NIT is a mitochondrial toxicant, if so, what mechanism(s) is involved. The rat liver mitochondria were isolated and treated with different doses of NIT alone or in combination with a reagent of choice for protecting thiol groups, dithiothreitol (DTT). Several mitochondrial parameters, including succinate dehydrogenase activity (also called 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide assay), lipid peroxidation, superoxide dismutase activity, Reduced glutathione (GSH), and oxidized glutathione (GSSG), and GSSG (oxidized glutathione) levels were determined. The results from this study showed that simultaneous treatment of mitochondria with NIT and DTT significantly reduces the toxicity. Here, we provide evidence that mitochondrial dysfunction followed by depletion of reduced glutathione can be reversed by DTT administration.

Vasopressin attenuates ischemia-reperfusion injury via reduction of oxidative stress and inhibition of mitochondrial permeability transition pore opening in rat hearts

Aim of this study was to investigate the involvement of the mitochondrial permeability transition pore (MPTP) and oxidative stress in the cardioprotective effect of vasopressin (AVP) on ischemia/reperfusion (I/R) injury. Anesthetized male wistar rats were subjected to regional 30 min ischemia and 120 min reperfusion and randomly divided into nine groups: (1) Control; saline was administered intravenously before ischemia, (2) vasopressin was administrated 10 min prior to ischemia, (3, 4) Atractyloside as MPTP opener, was injected 5 min prior to reperfusion without and with vasopressin, (5, 6) Cyclosporine A as a MPTP closer, was injected 5 min prior to reperfusion without and with vasopressin, (7) mitochondria were isolated from control group and CaCl2 was added as MPTP opener and swelling inducer, (8) isolated mitochondria from Control hearts was incubated with Cyclosporine A before adding the CaCl2 (9) CaCl2 was added to isolated mitochondria from vasopressin group. Infusion of vasopressin decreased infarct size (18.6±1.7% vs. control group 37.6±2.4%), biochemical parameters [LDH (Lactate Dehydrogenase), CK-MB (Creatine Kinase-MB) and MDA (Malondialdehyde) plasma levels, PAB (Prooxidant-antioxidant balance)] compared to control group. Atactyloside suppressed the cardioprotective effect of vasopressin (32.5±1.9% vs. 18.6±1.7%) but administration of the Cyclosporine A without and with vasopressin significantly reduced infarct size to 17.7±4% (P<0.001) and 22.7±3% (P<0.01) respectively, vs. 37.6±2.4% in control group. Also, vasopressin, similar to Cyclosporine A, led to decrease in CaCl2-induced swelling. It seems that vasopressin through antioxidant effect and MPTP inhibition has created a cardioprotection against ischemia/reperfusion injuries.

Clinical characteristics of paraquat poisoning in 22 Chinese children

OBJECTIVE

To retrospectively analyze the clinical characteristics and experience of Chinese children with paraquat poisoning.

METHODS

Twenty-two children with paraquat poisoning who presented to the hospital from October 2007 through September 2012 were enrolled into this study. The clinical indices of these cases were collected and analyzed.

RESULTS

All the children were poisoned due to oral ingestion of paraquat. Different degrees of damage were found in multiple systems in their bodies. All of them were administered pulse therapy using methylprednisolone (20 mg/kg/d × 3d) and Gamma globulin (total 2 g/kg divided into 3 d to 5 d) in the early stage. Prednisone was then given orally for 4 wk to 8 wk. The total mortality rate of the patients was 63.6 % (14 of 22 patients died). Statistical differences (P < 0.05) were found between the surviving and dead patients, with regard to age, plasma paraquat levels, the highest levels of alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, total bilirubin, direct bilirubin, indirect bilirubin, blood urea nitrogen, creatinine and pH value, the lowest levels of PaO2, PaCO2 and SaO2. Plasma paraquat level was positively related to pH value, but was negatively related to PaO2, PaCO2 and SaO2 levels. None of the patients died from hepatic and renal complications. Pulmonary fibrosis was the most severe complication and the primary cause of death.

CONCLUSIONS

Paraquat poisoning is difficult to cure. In this study, pulmonary fibrosis was the primary cause of death. Treatment by administering large doses of glucocorticoids and Gamma globulin proved to be effective in the early stage. However, the treatment may not reverse the development of pulmonary fibrosis. The long-term prognosis of paraquat poisoning was not optimistic. The plasma paraquat level could be a significant factor in predicting the prognosis.

Diphenyl diselenide prevents hepatic alterations induced by paraquat in rats

This study aimed to investigate the beneficial effect of diphenyl diselenide (PhSe)₂ on paraquat (PQ) induced alterations in rats liver. Adult male Wistar rats received (PhSe)₂ at 10 mg kg(-1), by oral administration (p.o.), during five consecutive days. Twenty-four hours after the last (PhSe)₂ dose, rats received PQ at 15 mg kg(-1), in a single intraperitoneally injection (i.p.). Seventy-two hours after PQ exposure, animals were sacrificed by decapitation for blood and liver samples obtainment. Histological alterations induced by PQ exposure, such as inflammatory cells infiltration and edema, were prevented by (PhSe)₂ administration. Moreover, (PhSe)₂ prevented hepatic lipid peroxidation (LPO) induced by PQ and was effective in reducing the myeloperoxidase (MPO) activity in liver, which was enhanced by PQ exposure. (PhSe)₂ also was effective in protecting against the reduction in ascorbic acid and non-protein thiols (NPSH) levels induced by PQ. The inhibition of glutathione S-transferase (GST) activity, in rats exposed to PQ, was normalized by (PhSe)₂ pre-treatment, whereas the inhibition of catalase (CAT) activity was not prevented by (PhSe)₂. The serum alkaline phosphatase (ALP) inhibition, induced by PQ administration, was also prevented by (PhSe)₂ pre-treatment. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were not modified by PQ and/or (PhSe)₂ administration. Therefore, (PhSe)₂ pre-treatment was effective in protecting against the hepatic alterations induced by PQ in rats. This protective effect can involve the antioxidant and anti-inflammatory properties of (PhSe)₂.

Effect of captopril and the bradykinin-PKC pathway on ROS production in type 1 diabetic rats

The aim of this study was to investigate the possible effects of captopril as a promoter in modulating the oxidant-antioxidant balance in rats with type 1 diabetes, and the influence of protein kinase C (PKC) pathways in the production of reactive oxygen species (ROS) induced by bradykinin in type 1 diabetic rats. This study evaluated the redox status in both the cardiac tissue and at the cellular level (neutrophils). Two concentrations of captopril were utilized: (i) 5 mg·(kg body mass)(-1), which was considered a therapeutic dose; and (ii) 10 mg·(kg body mass)(-1). Body mass, plasma glucose, and serum insulin were evaluated. To investigate the redox status of the cardiac tissue, we analyzed lipid peroxidation, concentration of carbonylated protein, catalase activity, and the concentration of glutathione. For a more accurate assessment of the possible antioxidant effect of captopril, we also analyzed ROS in neutrophils (in vivo), and ROS production induced by bradykinin and the influence of the PKC pathway in this production (in vitro). Our data show that the hearts of diabetic animals have increased oxidative damage, exemplified by the increased concentration of carbonylated protein and thiobarbituric acid reactive substances (TBARS). However, animals treated with captopril at both concentrations showed lower concentrations of carbonylated protein compared with untreated diabetic animals. We found an increase of catalase activity in the heart of diabetic rats, which was reversed by captopril treatment at both of the dosages tested. Our data showed that captopril was able to reduce ROS production in the neutrophils of diabetic rats at a dose of 10 mg captopril·(kg body mass)(-1). However, the antioxidant effect of captopril is independent of bradykinin. Diabetes induces oxidative stress, and these results suggest that captopril has an antioxidant effect and can modulate the production of ROS in circulating neutrophils.

Alternative electron acceptors: Proposed mechanism of paraquat mitochondrial toxicity

Paraquat (PQ) is a relatively safe and effective herbicide used all over the world. PQ is very toxic to all living organisms; and many cases of acute poisoning and death have been reported over the past decade. The main suggested potential mechanism for PQ toxicity is the production of superoxide radicals from the metabolism of the PQ by microsomal enzyme systems, and by inducing mitochondrial toxicity. Mitochondria are considered to be a major source of reactive oxygen species in cells and according to this hypothesis, PQ, through suitable oxidation and reduction processes, is able to participate in the redox system in mitochondria. The potential ability of PQ to accept electrons from complex (I, II, III, IV) leads to rapid reaction with molecular oxygen to yield superoxide anion which can lead to the formation of more toxic reactive oxygen species, e.g., hydroxyl radical, often taken as the main toxicant. Lipid peroxidation due to PQ has been implicated in a number of deleterious effects such as increased membrane rigidity, osmotic fragility, decreased mitochondrial components, reduced mitochondrial survival and lipid fluidity. The biological effect of reactive oxygen species (ROS) is controlled by a wide spectrum of enzymatic and non-enzymatic defense mechanisms such as superoxide dismutas (SOD), catalase (CAT) and glutathione. According to this hypothesis, the chemical cascades lead to the reduction of PQ, which reacts quite rapidly with molecular oxygen to yield superoxide anion. The generation of free radicals and lipid peroxidation are the main factors that lead to mitochondrial damage.