The role of lipid peroxidation in the nephrotoxicity of cisplatin.

The possible role of lipid peroxidation in the nephrotoxicity of the antitumour drug cisplatin was studied in vitro. In contrast to Adriamycin, cisplatin did not induce lipid peroxidation in rat kidney microsomes containing a NADPH-generating system. Pretreatment of rat kidney microsomes with cisplatin did not reduce the activity of a microsomal glutathione (GSH)-dependent protective factor against lipid peroxidation induced by Fe(2+)-ascorbate. However, pretreatment of rat kidney microsomes with 0.1 mM N-ethyl maleimide (NEM) did reduce this GSH-dependent protection. Cisplatin also did not reduce the activity of a cytosolic GSH-dependent protective factor against Fe(2+)-ascorbate-induced lipid peroxidation. The results of our experiments indicate that, in contrast to Adriamycin, cisplatin does not induce lipid peroxidation in vitro in various test systems. It also does not destroy microsomal and cytosolic GSH-dependent protective factors against lipid peroxidation.     

Lipid peroxidation: A possible mechanism of cephaloridine-induced nephrotoxicity

Cephloridine produces renal cortical injury, but the precise mechanism responsible for this nephrotoxicity remains unclear. Recently cephaloridine has been shown to deplete reduced glutathione (GSH) concentration selectively in renal cortex. Cephaloridine nephrotoxicity can be potentiated by diethyl maleate (a GSH depletor), but no glutathione conjugate can be detected. Thus, it was of interest to investigate further the mechanism of depletion of renal cortical GSH by cephaloridine. In the present study, cephaloridine markedly decreased GSH in rat and rabbit renal cortex while concomitantly increasing oxidized glutathione (GSSG). Furthermore, cephaloridine increased lipid peroxidation specifically in renal cortical cells. Conjugated diene formation (an index of lipid peroxidation) was increased in renal cortex but not in the liver shortly following administration of cephaloridine. Removal of selenium and/or vitamin E from the diet, which should enhance lipid peroxidation, potentiated cephaloridine nephrotoxicity and enhanced cephaloridine-induced morphological damage in the kidney. These findings are consistent with a major role of lipid peroxidation in the etiology of cephaloridine nephrotoxicity.     

Lipid peroxidation: a possible mechanism of trichloroethylene-induced nephrotoxicity

The purpose of this study was to investigate whether lipid peroxidation plays a role in (TCE) trichloroethylene-induced nephrotoxicity in mice at different oxygen concentrations. Male NMRI mice (25-30 g) were treated i.p. with TCE in a dosage of 125-1000 mg/kg in sesame oil. To determine the TCE-induced depletion of reduced glutathione (GSH) in the kidney cortex and liver tissue, mice were given 1000 mg/kg TCE i.p., then killed between 0 and 6 h after TCE administration and GSH was measured was non-protein sulfhydryls. In another series of experiments, mice were administered 125 to 1000 mg/kg TCE i.p. with or without a 2 h i.p. pretreatment with 1500 mg/kg L-buthionine-S-R-sulfoximine (BSO). Mice were then exposed to a 10, 15, 20 or 100% oxygen atmosphere for 3 h and lipid peroxidation in vivo was measured as exhalation of ethane. Subsequently, mice were killed and malondialdehyde (MDA) generation was measured in the liver and kidney cortex. Ethane evolution was estimated by gas chromatography and MDA was determined as thiobarbituric acid reactive substances. In a further series of experiments mice were treated in the same manner as for ethane and MDA determination and the changes in blood urea nitrogen (BUN) and accumulation of the organic ion p-aminohippurate (PAH) were determined. PAH accumulation by renal cortical slices were measured as the slice to medium (S/M) ratio. Six hours after administration of 1000 mg/kg TCE to mice, GSH was significantly depleted to about 60% of control in the kidney cortex but not in the liver. Three hours after TCE administration, MDA content in the kidney cortex and ethane exhalation increased in a dose-dependent manner only under a 10% oxygen atmosphere. Under the same experimental conditions, MDA content remained unchanged in the liver. BSO depletion of GSH prior TCE administration induced an increase of the MDA content in the kidney cortex and an increase of the ethane exhalation in vivo. At 10% oxygen concentration, TCE induced a dose-dependent increase in BUN and a dose-dependent decrease of PAH accumulation by the renal cortical slices. Thus, the results of the present study suggest that, under hypoxic conditions, lipid peroxidation plays a role in TCE nephrotoxicity.     

A possible mechanism of naproxen-induced lipid peroxidation in rat liver microsomes

Previous papers from our laboratory report that naproxen and salicylic acid induced lipid peroxidation in rat liver microsomes, however, the mechanism is still unclear. In the present paper, ferrous iron release, nicotinamide-adenine dinucleotide phosphate reduced form (NADPH) oxidation and hydrogen peroxide (H2O2) formation have been measured to find out which mechanisms are involved in naproxen- and salicylic acid-induced lipid peroxidation. While the increase of ferrous iron release was observed with high concentrations of naproxen, salicylic acid did not stimulate ferrous iron release. Neither of these drugs stimulated NADPH oxidation and H2O2 formation. However hexobarbital and perfluorohexane, known as uncouplers of cytochrome P450, stimulated microsomal NADPH oxidation, O2 consumption, H2O2 formation and water (H2O) formation involving four-electron oxidase reaction. These results suggest that ferrous iron release contributes to naproxen-induced microsomal lipid peroxidation and that naproxen and salicylic acid are not uncouplers of cytochrome P450. Apparently H2O2 does not play an important role in naproxen- and salicylic acid-induced microsomal lipid peroxidation.     

Effect of deferrioxamine and diethyldithiocarbamate on paracetamol-induced hepato- and nephrotoxicity. The role of lipid peroxidation

In mice subjected to glutathione depletion by pretreatment with phorone (diisopropylidene acetone, 200 mg/kg i.p. in 10 ml/kg olive oil) paracetamol (acetaminophen, 300 mg/kg p.o. in 10 ml/kg tylose 2 h later) led to a marked hepatotoxicity as evidenced by increased plasma activities of the liver-specific enzymes sorbitol dehydrogenase (SDH) and glutamate-pyruvate-transaminase (GPT) 3 and 24 h after treatment. Nephrotoxicity was also indicated at both timepoints by an increased creatinine concentration in plasma, while neither the urine volume nor its content in gamma-glutamyl transpeptitase over 20 h were affected. Hepato- and nephrotoxicity were also assessed histomorphologically. In vivo lipid peroxidation (LPO), as measured by ethane exhalation over 3 h, was clearly enhanced by paracetamol. Malondialdehyde content was increased and glutathione concentration diminished in the liver, but not in the kidney. Diethyldithiocarbamate (DTC, 200 mg/kg i.p.) or deferrioxamine (DFO, 500 mg/kg i.p.) both given 30 min before PA, inhibited in vivo LPO. However, only DTC was capable of antagonizing the hepato- and nephrotoxic effects of paracetamol, while DFO only delayed the onset of nephrotoxicity but left the hepatotoxicity unaffected. Both agents inhibited the rise in hepatic malondialdehyde-content, but only DTC prevented paracetamol-induced glutathione depletion. These results indicate that LPO is not mainly responsible for paracetamol toxicity towards liver or kidney.     

镉所致肾损害与脂质过氧化的实验

每天以２ｍｇ／ｋｇ氯化镉生理盐水溶液给大鼠腹腔注射１５天，结果显示：氯化镉可引起肾功能的改变和脂质过氧化指标ＭＤＡ的升高及ＳＯＤ的下降，说明镉可诱发肾脏的脂质过氧化。亚细胞组分分析表明镉诱导的脂质过氧化主要发生在线粒体及微粒体中。比较脂质过氧化与肾损害出现的时间，可见染镉动物肾皮质及亚细胞组分ＭＤＡ的升高及ＳＯＤ的下降的时间均晚于肾功能异常。可以认为肾脏脂质过氧化并非镉引起肾损害的直接原因     

Studies on membrane factors in iron-supported lipid peroxidation

Lipid peroxidation in biomembranes is mediated by free radical reactions. It leads to membrane damage and has been proposed to be associated with the pathogenesis to tissue injuries. Iron is known as a catalyst of lipid peroxidation. Microsomal lipid peroxidation by both NADPH and iron-chelate, such as Fe(3+)-ADP or Fe(3+)-PPi, is believed to be enzymatically associated with iron reduction. On the other hand, the addition of free Fe2+ to microsomes or liposomes produces a lag phase before the maximal rates of lipid peroxidation. We examined the interaction of iron with membrane in iron-supported lipid peroxidation and microsomal membrane components associated with iron reduction in NADPH-supported lipid peroxidation. Iron-supported lipid peroxidation was affected by the surface charges of liposomal membrane. Liposomes containing phosphatidylserine (PS) were most sensitive to iron-supported lipid peroxidation. The effect of PS on iron-supported lipid peroxidation indicates that iron participates in binding to membrane surface charges and also indicates that Fe2+ at high level bound to membranes plays a role in producing a lag phase. The mechanism producing a lag phase in Fe(2+)-PPi-supported lipid peroxidation is discussed. In NADPH-supported lipid peroxidation in microsomes, it seemed unlikely that superoxide may be involved in iron reduction. Alternatively, under anaerobic conditions, NADPH-supported iron reduction in microsomes was not dependent on cytochrome P450 content and not inhibited by CO. A cholate-solubilized fraction of microsomes was applied to a laurate-Sepharose column and an active fraction for lipid peroxidation was obtained. Involvement of a heat-labile component, distinct from cytochrome P450, responsible for iron reduction in microsomal lipid peroxidation was demonstrated.     

The role of lipid peroxidation and antioxidant defence system of the kidneys in the predisposition to gentamicin-induced nephrotoxicity in rabbits

A correlation is established between individual features of the lipid peroxidation processes and the state of the system of antioxidant protection of the kidney in intact rabbits and their susceptibility to gentamicin nephrotoxicity. The level of gentamicin-induced damage of the kidney is more significant in rabbits with increased concentration of malonic dialdehyde in the kidney, which is generated by a NADPH-dependent enzyme system. A decreased level of reduced glutathione, as well as the enzymopathy with respect to superoxide dismutase and catalase are among the factors aggravating gentamicin-induced kidney lesion.     

Cocaine-induced hepatotoxicity: lipid peroxidation as a possible mechanism

In vitro experiments with hepatic washed microsomal preparations showed that malondialdehyde (MDA) formation was increased in a time- and concentration-dependent manner using COC or NC as the substrate. Though 1 mM COC or NC inhibited MDA formation, significant elevations were observed for 100, 10 or 1 microM concentrations. NC at 10 microM after a 30 minute incubation produced a 34% decrease in hepatic microsomal cytochrome P450 whereas 1 mM NC had no such effect. MDA formation in vivo, measured as total absorbance at 535 nm per gram liver, was found to be maximal 4 hours after 40 mg/kg NC ip. Elevations of serum transaminase (SGPT) however were not found until 6 hours after NC. We conclude from these studies that COC and NC induce lipid peroxidation in the liver of PB-pretreated Swiss-origin mice and that peroxidative attack may be a mechanism for hepatotoxicity of these compounds.     

Cadmium-induced lipid peroxidation in rat liver slices: A possible involvement of hydroxyl radicals

Cadmium-induced lipid peroxidation (LPO) in the presence of various hydroxyl radical-generating media was studied in rat liver slices. In the absence of such media, Cd showed an inhibitory action on LPO in vitro. Cd-induced LPO in liver slices in the presence of OH radical-generating media was inhibited by antioxidants. The findings indicate that Cd induced LPO as a result of the presence of transition metal ions and the generation of hydroxyl radicals.     

A possible cellular mechanism of cisplatin-induced nephrotoxicity

Cisplatin, a relatively new antitumor agent, is associated with renal function impairment. The mechanism of cisplatin-induced nephrotoxicity is unknown. A mouse model was used to examine nephrotoxicity induced by cisplatin. This study demonstrates both morphologically and biochemically that mitochondrial damage may be associated with cisplatin-induced cellular toxicity. The morphological changes are evident after 72 h following a single 10 mg/kg i.p. dose of cisplatin. Biochemical changes also follow the morphological abbreviations. In vitro incubation of cisplatin with cells also shows a decline in Rhodamine 123 fluorescence with time, which is indicative of mitochondrial damage. The present findings suggest the possibility that the nephrotoxic effects of cisplatin may be related to a mitochondrial damage.     

Anti-malondialdehyde antibodies in MRL+/+ mice treated with trichloroethene and dichloroacetyl chloride: possible role of lipid peroxidation in autoimmunity

Trichloroethene (TCE) and one of its metabolites dichloroacetyl chloride (DCAC) are known to induce/accelerate autoimmune (AI) response in MRL+/+ mice as evident from anti-nuclear, anti-ssDNA, anti-cardiolipin, and DCAC-specific antibodies in the serum (Khan et al., Toxicol. Appl. Pharmacol. 134, 155-160, 1995). In the present study, we measured anti-malondialdehyde antibodies (AMDA) in the serum of TCE- or DCAC-treated mice in order to understand the contribution of lipid peroxidation to this AI response. Female MRL+/+ mice (5 weeks old) received ip injections of 10 mmol/kg TCE or 0.2 mmol/kg of DCAC in corn oil (100 microl) every 4(th) day for 6 weeks, while controls received an equal volume of vehicle only, and AMDA was measured in the sera of these animals by an ELISA established in our laboratory. While TCE treatment caused only marginal induction of AMDA, DCAC treatment elicited a significant AMDA response. Furthermore, a time-response study of DCAC (0.2 mmol/kg, every 4(th) day, for 2, 4, 6, or 8 weeks) showed an induction of AMDA (3/4) after 4 weeks of treatment, which was even greater at both 6 and 8 weeks of DCAC treatment (5/5). These findings were further substantiated by the presence of AMDA in systemic lupus erythematosus-prone MRL-lpr/lpr mice as early as 6 weeks of age. Presence of AMDA, as observed in this study, not only indicates increased lipid peroxidation (oxidative stress), but also suggests a putative role of oxidative stress in inflammatory autoimmune diseases.     

Changed cellular membrane lipid composition and lipid peroxidation of kidney in rats with chronic fluorosis

An animal model of chronic fluorosis was produced by subjecting Wistar rats to high doses of fluoride in drinking water for a prolonged period. Phospholipid and neutral lipid contents in rat kidney were then analyzed by high-performance liquid chromatography (HPLC), and fatty acid compositions from individual phospholipids were measured by gas chromatography. Lipid peroxidation was detected by the thiobarbituric-acid-reactive substance assay. Results showed that the total phospholipid content significantly decreased in the kidney of the rats treated with high doses of fluoride and the main species influenced were phosphatidylethanolamine (PE) and phosphatidylcholine (PC). Decreased proportions of polyunsaturated fatty acids were observed in PE and PC in kidney of fluoride-treated animals compared to controls. No changes could be detected in the amounts of cholesterol and dolichol in kidneys between the rats treated with fluoride and controls. A significant decrease of ubiquinone in rat kidney was observed in the groups treated with excessive fluoride. High levels of lipid peroxidation were detected in kidney of the rats with fluorosis. It is plausible that the specific modification of lipid composition results from lipid peroxidation. The oxidative stress and modification of cellular membrane lipids may be involved in the pathogenesis of chronic fluorosis and provide a possible explanation for the gross system damage observed in the body, especially in soft tissues and organs.     

Effects of the antioxidants curcumin or selenium on cisplatin-induced nephrotoxicity and lipid peroxidation in rats.

A large number of natural products and dietary components have been evaluated as potential chemoprotective agents. In the present investigation we report the effects of pre-treatment with two dietary antioxidants, curcumin (8 mg kg-1 body wt.) or selenium (1 mg kg-1 body wt.), on cisplatin-induced lipid peroxidation and nephrotoxicity in Wistar rats. Adult male rats were divided into six treatment and control groups of six rats each. The animals were pre-treated by gavage with two doses of each antioxidant, one dose 24 h and the second 10 min before cisplatin intraperitoneal injection (5 mg kg-1 body wt.). The rats were killed 3 days after cisplatin injection and serum, urine and kidney were isolated and analysed. Cisplatin administration resulted in significant reduction of body weight and higher urinary volumes were observed in all groups treated with this antitumor drug (P< 0.05). The animals treated with cisplatin showed a depletion of renal glutathione, increased lipid peroxidation, and an increase in serum creatinine levels (P< 0.05). The administration of curcumin or selenium alone did not increase lipid peroxidation compared to the control group (P> 0.05). Three days after curcumin or selenium plus cisplatin treatments, the renal damage induced by cisplatin did not recover at a significant statistically level. This study suggests that the natural antioxidants curcumin or selenium did not offer protection against cisplatin-induced nephrotoxicity and lipid peroxidation in adult Wistar rats.     

Role of red cell membrane lipid peroxidation in hemolysis due to phenylhydrazine

Although red cell membrane lipid peroxidation has been identified as a consequence of certain oxidizing hemolytic drugs, the relative contribution of lipid peroxidation to red cell damage leading to hemolysis is unclear. This has been evaluated by studying the response to phenylhydrazine of vitamin E-deficient rats as compared to vitamin E-supplemented rats. Following repetitive phenylhydrazinc injections, a lower hematocrit was observed in the vitamin E-deficient group which was associated with higher levels of lipid peroxidation, as indicated by the fluorescence of lipid-containing red cell extracts. However, no significant difference in the initial extent of hemolysis following phenyl-hydrazine injection was observed. Evidence was also obtained suggesting that malonaldehyde, a decomposition product of polyunsaturated fatty acids, is capable of cross-linking hemoglobin to the red cell membrane. These findings suggest that red cell membrane lipid peroxidation is of relatively minor consequence in the acute response to phenylhydrazine but may be of importance in chronic hemolysis due to this oxidizing drug.     

Loss of membrane protein thiols and lipid peroxidation in allyl alcohol hepatotoxicity

The data reported suggest that--following initiation of lipid peroxidation--membrane protein thiols can be attacked by lipid-derived radicals and/or reactive, lipid-soluble aldehydes like 4-hydroxynonenal and other hydroxyalkenals originated within the lipid core of cell membranes, resulting in a membrane protein thiol loss which is in turn associated with the development of hepatocellular injury.     

Electrophysiologic alterations in the rabbit nodal cells induced by membrane lipid peroxidation

To investigate cellular electrophysiologic alterations due to lipid peroxidation of the cell membrane by free radicals as a possible cause of coronary reperfusion arrhythmias, we studied the effects of t-butyl hydroperoxide on the spontaneous action potential and membrane currents of the rabbit sinoatrial and atrioventricular node preparations (0.2 × 0.2 × 0.1 mm). 1–5 min of superfusion with t-butyl hydroperoxide (100–500 μM) caused a transient increase in the spontaneous firing frequency by 9%, accompanied by a 4% increase in the action potential amplitude and a 33% increase in the maximal rate of depolarization (P<0.05, n = 6). t-Butyl hydroperoxide then gradually suppressed physiological automaticity, but induced abnormal repetitive firing due to early and delayed after-depolarizations. 15 min of superfusion with t-butyl hydroperoxide caused a complete standstill of nodal cells at a resting potential of −46 ± 3 mV (n = 12). Such effects of t-butyl hydroperoxide on the spontaneous action potential were attenuated by pretreating the cells with butylated hydroxytoluene, a lipid peroxidation inhibitor. Voltage clamp experiments using double microelectrode methods revealed that t-butyl hydroperoxide transiently increased the Ca²⁺ current by 22% after 5 min of superfusion but subsequently reduced it to 46% of the control value after 15 min (P<0.05, n = 6). Similar biphasic changes were observed in the delayed rectifying K⁺ current and hyperpolarization-activated inward current (n = 6). Background current was progressively increased without any change in its reversal potential (n = 6). These results suggest that membrane lipid peroxidation may accelerate or suppress physiological automaticity and induce abnormal automaticity by both impairing cellula metabolic function and damaging the lipid membrane structure as well as ionic channel protein.     

An underlying role for hepatobiliary dysfunction in cyclosporine A nephrotoxicity

Renal-derived cysteinyl leukotrienes (cysLT), such as leukotrienes C(4) (LTC(4)) and D(4) (LTD(4)) are thought to mediate acute and chronic cyclosporine A (CSA) nephrotoxicity. However, whole-body cysLT elimination is regulated primarily by hepatobiliary excretion. Since CSA is known to alter hepatobiliary function, the effects of CSA on whole-body cysLT elimination were investigated in vivo, with respect to hepatobiliary and renal function. Male rats were anesthetized and cannulated (jugular vein, bile duct, and urinary bladder). A tracer dose of tritiated LTC(4) ((3)H-LTC(4)) was administered systemically (i.v.) immediately following vehicle and then 90 min later after vehicle or CSA. In vehicle/vehicle controls, hepatobiliary (3)H-cysLT elimination predominated over renal elimination without altering glomerular filtration rate (GFR), bile flow, and urine production. (3)H-cysLT elimination kinetics were comparable between each 90 min collection period. In vehicle/CSA-treated rats, an acutely nephrotoxic dose of CSA (20 mg/kg, i.v.) reduced urine flow 74+/-9% and caused a transient reduction in GFR, while total bile flow decreased 40+/-13%. Hepatobiliary and renal (3)H-cysLT elimination was also impaired 59+/-5 and 61+/-18%, respectively. In contrast, a non-nephrotoxic dose (2 mg/kg i.v.) increased renal (3)H-cysLT elimination due to impaired hepatobiliary elimination without affecting GFR, bile flow or urine production. Both doses caused (3)H-cysLT retention in hepatic and renal tissue. These findings demonstrate that CSA alters whole-body handling of cysLT by disrupting hepatobiliary cysLT elimination. This disruption leads to increased renal exposure to systemically derived cysLT and renal cysLT tissue retention. Renal exposure to and accumulation of systemically derived cysLT products may be underlying factors in CSA nephrotoxicity.