Ameliorative role of aspirin in paraquat‐induced lung toxicity via mitochondrial mechanisms (original) (raw)
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Pesticide Biochemistry and Physiology, 2007
Angiotensin-converting enzyme inhibitors (ACEi) were shown to ameliorate endothelial dysfunction in various human diseases and some of these inhibitors have been reported to enhance antioxidant defenses. The objective of the present study was to shown the abilities of enalapril and lisinopril as two nonthiol ACEi on mitochondrial toxicity due to paraquat. In this study, mitochondrial isolation from rat liver was divided into six groups. Group 1 was considered as control, group 2 received paraquat (5 mM), group 3 received enalapril (0.25 mM), group 4 received lisinopril (0.01 mM), group 5 received paraquat (5 mM) + enalapril (0.25 mM), and group 6 received paraquat(5 mM) + lisinopril (0.01 mM). Viability, lipid peroxidation, catalase activity, GSH (reduced glutathione) and GSSG (oxidized glutathione) concentrations were also determined. Simultaneous treatment of mitochondria with enalapril (0.25 mM) + paraquat (5 mM) and lisinopril (0.0.01 mM) + paraquat (5 mM) did not significantly ameliorate the mitochondrial toxicity induced by paraquat (5 mM) alone (p > 0.05). However, the nonthiol ACEi, enalapril showed to partially improve target of lipid peroxidation due to paraquat. In conclusion, nonthiol ACEi treatment did not improve the increased oxidative stress and the decreased antioxidant mechanisms.
Janus green B (JG-B) dye is used for vital staining of mitochondria and its reduction and oxidation shows the electron transfer chain alteration. The defect in electron transfer chain of mitochondria by paraquat is linked to free radical formation. In this present study we compared the abilities of different angiotensin-converting enzyme inhibitors, captopril (a thiol ACEi), enalapril, and lisinopril (two nonthiol ACEi) on mitochondria toxicity due to paraquat. The rat liver mitochondria were first isolated by centrifuge (at 4 • C at a speed of 7,000 g) in a mixture of 0.25 M saccharose solution and 0.05 M Tris buffer. Various concentrations of paraquat (1, 5, 10 mM), enalapril (0.25, 0.5, 1 mM), lisinopril (0.01, 0.05, 0.1 mM), and captopril (0.08, 0.1, 1 mM) on the mitochondria isolated from the liver with respect to time were investigated. Paraquat at a concentration of 5 mM was determined to be significantly different compared to control values (P < 0.05) and captopril at a concentration of 0.08 mM, lisinopril (0.01 mM), and enalapril (0.25 mM) were found not to be significantly different from controls as found by spectroscopy at wavelength of 607 nm. Simultaneous treatment of mitochondria with captopril (0.08 mM) and paraquat (5 mM) significantly ameliorates the mitochondria toxicity of paraquat (5 mM) alone (P < 0.05). Our results show that captopril is a more effective antioxidant than the nonthiol ACEi. Lisinopril (0.01 mM) and enalapril (0.25 mM) did not significantly change the mitochondrial toxicity by paraquat (5 mM) (P > 0.05). The antioxidative 98 GHAZI-KHANSARI et al.: PARAQUAT TOXICITY IN RAT LIVER MITOCHONDRIA 99
PloS one, 2012
We have previously reported that acetylsalicylic acid (aspirin, ASA) induces cell cycle arrest, oxidative stress and mitochondrial dysfunction in HepG2 cells. In the present study, we have further elucidated that altered glutathione (GSH)-redox metabolism in HepG2 cells play a critical role in ASA-induced cytotoxicity. Using selected doses and time point for ASA toxicity, we have demonstrated that when GSH synthesis is inhibited in HepG2 cells by buthionine sulfoximine (BSO), prior to ASA treatment, cytotoxicity of the drug is augmented. On the other hand, when GSH-depleted cells were treated with N-acetyl cysteine (NAC), cytotoxicity/apoptosis caused by ASA was attenuated with a significant recovery in oxidative stress, GSH homeostasis, DNA fragmentation and some of the mitochondrial functions. NAC treatment, however, had no significant effects on the drug-induced inhibition of mitochondrial aconitase activity and ATP synthesis in GSH-depleted cells. Our results have confirmed that...
Impairment of striatal mitochondrial function by acute paraquat poisoning
Journal of Bioenergetics
Mitochondria are essential for survival. Their primary function is to support aerobic respiration and to provide energy for intracellular metabolic pathways. Paraquat is a redox cycling agent capable of generating reactive oxygen species. The aim of the present study was to evaluate changes in cortical and striatal mitochondrial function in an experimental model of acute paraquat toxicity and to compare if the brain areas and the molecular mechanisms involved were similar to those observed after chronic exposure. Sprague-Dawley rats received paraquat (25 mg/Kg i.p.) or saline and were sacrificed after 24 h. Paraquat treatment decreased complex I and IV activity by 37 and 21 % respectively in striatal mitochondria. Paraquat inhibited striatal state 4 and state 3 KCNsensitive respiration by 80 % and 62 % respectively, indicating a direct effect on respiratory chain. An increase of 2.2 fold in state 4 and 2.3 fold in state 3 in KCN-insensitive respiration was observed in striatal mitochondria from paraquat animals, suggesting that paraquat redox cycling also consumed oxygen. Paraquat treatment increased hydrogen peroxide production (150 %), TBARS production (42 %) and cardiolipin oxidation/depletion (12 %) in striatal mitochondria. Also, changes in mitochondrial polarization was induced after paraquat treatment. However, no changes were observed in any of these parameters in cortical mitochondria from paraquat treated-animals. These results suggest that paraquat treatment induced a clear striatal mitochondrial dysfunction due to both paraquat redox cycling reactions and impairment of the mitochondrial electron transport, causing oxidative damage. As a consequence, mitochondrial dysfunction could probably lead to alterations in cellular bioenergetics.
Using Janus Green B to Study Paraquat Toxicity in Rat Liver Mitochondria
Annals of the New York Academy of Sciences
Janus green B (JG-B) dye is used for vital staining of mitochondria and its reduction and oxidation shows the electron transfer chain alteration. The defect in electron transfer chain of mitochondria by paraquat is linked to free radical formation. In this present study we compared the abilities of different angiotensin-converting enzyme inhibitors, captopril (a thiol ACEi), enalapril, and lisinopril (two nonthiol ACEi) on mitochondria toxicity due to paraquat. The rat liver mitochondria were first isolated by centrifuge (at 4 • C at a speed of 7,000 g) in a mixture of 0.25 M saccharose solution and 0.05 M Tris buffer. Various concentrations of paraquat (1, 5, 10 mM), enalapril (0.25, 0.5, 1 mM), lisinopril (0.01, 0.05, 0.1 mM), and captopril (0.08, 0.1, 1 mM) on the mitochondria isolated from the liver with respect to time were investigated. Paraquat at a concentration of 5 mM was determined to be significantly different compared to control values (P < 0.05) and captopril at a concentration of 0.08 mM, lisinopril (0.01 mM), and enalapril (0.25 mM) were found not to be significantly different from controls as found by spectroscopy at wavelength of 607 nm. Simultaneous treatment of mitochondria with captopril (0.08 mM) and paraquat (5 mM) significantly ameliorates the mitochondria toxicity of paraquat (5 mM) alone (P < 0.05). Our results show that captopril is a more effective antioxidant than the nonthiol ACEi. Lisinopril (0.01 mM) and enalapril (0.25 mM) did not significantly change the mitochondrial toxicity by paraquat (5 mM) (P > 0.05).
Decreasing the oxidant stress from paraquat in isolated perfused rat lung using captopril and niacin
Archives of Toxicology, 2005
The abilities of captopril and niacin to protect against the lung toxicity of paraquat (PQ) were studied. The anti-oxidative action of captopril, an angiotensinconverting enzyme inhibitor, appears to be attributable to the sulphahydryl group (SH) in the compound, which gives captopril the ability to scavenge reactive oxygen species. Niacin replenishes the NAD and ATP depletion caused by reactive oxygen species. PQ causes lung damage in man and in several species of laboratory animals. The damage is initially manifested by hemorrhage and edema, and later by consolidation of the lung and fibrosis development. In this study, the lungs of male Wistar rats (250-300 g in weight) were perfused by Krebs-Ringer buffer alone (control), niacin (150 lM), captopril (10 lM) and PQ (600 lM) in perfusion fluid, and the biochemical changes that occurred in isolated rat lung were examined within 1 h and compared to PQ alone. The results show that captopril significantly decreases the lung weight/body weight ratio when used as a pretreatment and a post-treatment to captopril (p<0.0001). The results also show that captopril (10 lM) and niacin (150 lM) significantly decreases PQinduced lung toxicity. Lactate dehydrogenase (LDH) activity significantly decreased in treatment groups as compared to the PQ group (p<0.0001). This study suggests that paraquat causes increased lipid peroxidation and LDH activity and decreased glutathione (GSH) and total protein in isolated perfused rat lung. These effects are reduced under these experimental conditions by captopril and niacin.
Captopril ameliorates toxicity induced by paraquat in mitochondria isolated from the rat liver
Toxicology in Vitro, 2007
The aim of the present study was to show the abilities of captopril as a thiol ACEi (angiotensin converting enzyme inhibitor), on mitochondria toxicity due to paraquat. Mitochondrial isolation from rat liver was divided into 4 groups. Group 1 was considered as control, group 2 received paraquat (5 mM), group 3 received captopril (0.08 mM) and group 4 received paraquat (5 mM) + captopril (0.08 mM).
Aspirin induces apoptosis through mitochondrial cytochrome c release
Febs Letters, 2000
Aspirin and other non-steroidal anti-inflammatory drugs induce apoptosis in many cell types. Although the involvement of caspases has been demonstrated, the mechanism leading to caspase activation remains unknown. We have studied the role of the mitochondrial pathway in aspirin-induced apoptosis. The apoptotic effect of aspirin was analyzed in different cell lines (Jurkat, MOLT-4, Raji and HL-60) showing induction of mitochondrial cytochrome c release and caspases 9, 3 and 8 processing. Furthermore, early aspirin-induced cytochrome c release was not affected by the caspase inhibitor Z-VADW Wfmk and preceded loss of mitochondrial membrane potential. Therefore, aspirin-induced apoptosis involves caspase activation through cytochrome c release. ß Abbreviations: NSAIDs, non-steroidal anti-in£ammatory drugs; v8 m , mitochondrial membrane potential; PT, permeability transition; PI, propidium iodide; ECL, enhanced chemiluminescence FEBS 24037 FEBS Letters 480 (2000) 193^196
Sodium salicylate prevents paraquat-induced apoptosis in the rat lung
Free Radical Biology and Medicine, 2007
The nonselective contact herbicide, paraquat (PQ), is a strong pneumotoxicant, especially due to its accumulation in the lung through a polyamine uptake system and to its capacity to induce redox cycling, leading to oxidative stress-related damage. In the present study, we aimed to investigate the occurrence of apoptotic events in the lungs of male Wistar rats, 24, 48, and 96 h after PQ exposure (25 mg/kg ip) as well as the putative healing effects provided by sodium salicylate [(NaSAL), 200 mg/kg ip] when administered 2 h after PQ. PQ exposure resulted in marked lung apoptosis, in a time-dependent manner, characterized by the "ladder-like" pattern of DNA observed through electrophoresis and by the presence of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL)-positive cells (TPC) as revealed by immunohistochemistry. The two main caspase cascades (the extrinsic receptor-mediated and the intrinsic mitochondria-mediated) and the expressions of p53 and activator protein-1 (AP-1) were also evaluated, to obtain an insight into apoptotic cellular signaling. PQ-exposed rats suffered a time-dependent increase of caspase-3 and caspase-8 and a decrease of caspase-1 activities in lungs compared to the control group. A marked mitochondrial dysfunction evidenced by cytochrome c (Cyt c) release was also observed as a consequence of PQ exposure. In addition, fluorescence electrophoretic mobility shift assay (fEMSA) revealed a transcriptional induction of the p53 and AP-1 transcription factors in a timedependent manner as a consequence of PQ exposure. NaSAL treatment resulted in the remission of the observed apoptotic signaling and consequently of lung apoptosis. Taken together, the present results showed that PQ activates several events involved in the apoptotic pathways, which might contribute to its lung toxicodynamics. NaSAL, a recently implemented antidote for PQ intoxications, proved to protect lungs from PQinduced apoptosis.
Aspirin increases mitochondrial fatty acid oxidation
Biochemical and Biophysical Research Communications, 2017
The metabolic effects of salicylates are poorly understood. This study investigated the effects of aspirin on fatty acid oxidation. Aspirin increased mitochondrial long-chain fatty acid oxidation, but inhibited peroxisomal fatty acid oxidation, in two different cell lines. Aspirin increased mitochondrial protein acetylation and was found to be a stronger acetylating agent in vitro than acetyl-CoA. However, aspirin-induced acetylation did not alter the activity of fatty acid oxidation proteins, and knocking out the mitochondrial deacetylase SIRT3 did not affect the induction of long-chain fatty acid oxidation by aspirin. Aspirin did not change oxidation of medium-chain fatty acids, which can freely traverse the mitochondrial membrane. Together, these data indicate that aspirin does not directly alter mitochondrial matrix fatty acid oxidation enzymes, but most likely exerts its effects at the level of long-chain fatty acid transport into mitochondria. The drive on mitochondrial fatty acid oxidation may be a compensatory response to altered mitochondrial morphology and inhibited electron transport chain function, both of which were observed after 24 hr incubation of cells with aspirin. These studies provide insight into the pathophysiology of Reye Syndrome, which is known to be triggered by aspirin ingestion in patients with fatty acid oxidation disorders.