Cephaloridine nephrotoxicity in streptozotocin induced diabetic Fischer 344 (F344) rats

The purpose of this study was to determine if cephaloridine nephrotoxicity is attenuated in streptozotocin (STZ)-induced diabetic rats. Fischer 344 (F344) rats (205-250 g) were given a single injection (i.p.) of STZ (27-35 mg/kg) or citrate buffer. The nephrotoxicity of (750 mg/kg) cephaloridine (i.p.) was then compared with normoglycemic and 14-day diabetic rats. Increased blood urea nitrogen (BUN) levels as well as diminished renal cortical slice accumulation of tetraethylammonium (TEA) and lactate-stimulated p-aminohippurate (PAH) were measured (P less than 0.05) in normoglycemic rats 48 h after cephaloridine administration. Cephaloridine failed to alter BUN levels and organic ion accumulation in diabetic rats. Diabetes did not totally protect against cephaloridine toxicity since kidney weights were elevated in normoglycemic and diabetic rats 48 h after administration of 750 mg/kg cephaloridine. A series of experiments also measured BUN levels, kidney weight and renal cortical slice uptake of PAH and TEA 24, 48 and 72 h after (1500 mg/kg) cephaloridine administration. Cephaloridine increased (P less than 0.05) kidney wt and decreased PAH and TEA uptake (P less than 0.05) in the normoglycemic group at 24-72 h. No change in kidney wt, PAH or TEA uptake was observed in the diabetic rats. These data indicate diabetes reduces cephaloridine nephrotoxicity.     

N-(3,5-dichlorophenyl)succinimide nephrotoxicity in streptozotocin-induced diabetic rats

N-(3,5-Dichlorophenyl)succinimide (NDPS) is an experimental fungicide which induces renal toxicity. The following study examined the nephrotoxicity induced by NDPS in streptozotocin (STZ) diabetic rats. Male Fischer 344 (F344) rats were injected with 35 mg/kg STZ (i.p.) or citrate buffer. Fourteen days after STZ or citrate buffer injection, the rats (4-6 rats/group) were injected with (0.4 or 1.0 mmol/kg) NDPS or vehicle (sesame oil, 2.5 ml/kg). Kidney weight, blood urea nitrogen (BUN) levels, morphology and renal cortical slice uptake of organic ions was quantitated 48 h after NDPS administration. A 0.4 mmol/kg dose of NDPS induced diuresis, increased kidney weight and a moderate elevation in BUN levels in the normoglycemic group. The 1.0 mmol/kg dose of NDPS produced diuresis, proteinuria, increased kidney weight and a marked increase in BUN levels in the normoglycemic group. The renal cortical slice uptake of p-aminohippurate (PAH) and tetraethylammonium (TEA) was also decreased 48 h after NDPS injection in the normoglycemic group. No alterations in kidney weight, BUN levels, morphology or renal cortical slice uptake of organic ions was observed in the diabetic animals treated with (0.4 or 1.0 mmol/kg) NDPS. The results of this study indicate that the renal toxicity of NDPS was reduced in the diabetic rat.     

Attenuation of Cisplatin Nephrotoxicity by Streptozotocin-Induced Diabetes

Attenuation of Cisplatin Nephrotoxicity by Streptozotocin-InducedDiabetes. SCOTT, L. A., MADAN, E., AND VALENTOVIC, M. A. (1989).Fundam. Appl. Toxicol 12, 530–539. The thera peutic useof cisplatin is associated with acute renal failure. The purposeof this study was to determine (a) if streptozotocin (STZ) wastoxic to renal proximal tubules and (b) the nephrotox icityof cisplatin in STZ-diabetic rats. Male Sprague-Dawley ratswere injected with STZ (55 mg/kg, ip) to induce a diabetic state.BUN and renal cortical slice uptake of p-aminohippurate (PAN)and tetraethylammonium (TEA) were not altered, relative to normoglycemicrats, 3, 16, and 28 days following STZ treatment. These resultsindicate that STZ is not toxic to renal proximal tubules. Cisplatinnephrotoxicity studies were then conducted in STZ-diabetic andnormo glycemic rats. Cisplatin nephrotoxicity was also evaluatedin diabetic rats pretreated for 8 days with insulin. Diabeticand normoglycemic rats were administered 5 mg/kg cisplatin orwater (ip). Increased kidney weight, BUN levels, glucosuna,and proteinuria were measured in normoglycemic rats 4 days aftercisplatin administration. Renal cortical TEA and lactate-stimulatedPAH uptake (p<0.05) were diminished in the normoglycemicrats 4 days after cisplatin injection. No change in kidney weight,BUN levels, or renal cortical slice accumulation of PAH andTEA was observed in diabetic rats treated with cisplatin. However,cisplatin administration to diabetic rats pretreated with insulinresulted in increased mortality, proteinurla, glucosuna andelevated kidney weight. These results indicate that the diabeticstate attenuates cisplatin nephro toxicity. Additionally, theseresults indicate that diabetes attenuation ofcisplatin nephrotoxicityis dependent on the severity of the diabetic state.     

Cephaloridine nephrotoxicity in diabetic rats: modulation by insulin treatment

Previous studies have indicated that cephaloridine nephrotoxicity was reduced in diabetic rats. This study determined whether the reduction in toxicity was due to streptozotocin or the diabetic state. Male Fischer-344 rats were injected intraperitoneally with 35 mg/kg streptozotocin to induce diabetes. Insulin (5 U/day, subcutaneously) was begun within 72 h and continued for 10 days. Toxicity was quantitated 48 h after injection of cephaloridine (1500 mg/kg i.p.) in normoglycemic (NC), diabetic (DC) and diabetic animals treated with insulin (DIC). Cephaloridine produced diuresis, glucosuria, proteinuria, elevated kidney weight and decreased renal cortical slice accumulation of organic ions in the NC group. Cephaloridine toxicity was reduced in the DC group since kidney weight, BUN level and renal cortical slice accumulation of organic anions were similar between treated and control animals. Cephaloridine treatment of the DIC group was associated with increased BUN levels, proteinuria and diminished renal cortical slice accumulation of organic cations. These results indicated that the diabetic state, and not streptozotocin, reduced cephaloridine nephrotoxicity.     

Gender differences in the potentiation of N-(3,5-dichlorophenyl)succinimide metabolite nephrotoxicity by phenobarbital

The agricultural fungicide N-(3,5-dichlorophenyl)succinimide (NDPS) induces acute nephrotoxicity characterized as polyuric renal failure with proximal tubular necrosis. Phenobarbital pretreatment potentiates NDPS and N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (NDHS, a nephrotoxic metabolite of NDPS) nephrotoxicity in male rats. The purpose of this study was to determine the ability of phenobarbital pretreatment to potentiate (1) NDHS nephrotoxicity in female rats and (2) N-(3,5-dichlorophenyl)-2-hydroxysuccinamic acid (2-NDHSA, a nephrotoxic metabolite of NDHS) nephrotoxicity in male and female rats. Age-matched male and female Fischer 344 rats (4/group) were pretreated intraperitoneally (ip) with phenobarbital (75 mg/d, 3 d). At 24 h after the last injection of phenobarbital, an ip injection of NDHS (0.025 mmol/kg), 2-NDHSA (0.025 mmol/kg, females; 0.05 mmol/kg, males), or vehicle was given and renal function was monitored at 24 and 48 h post NDPS metabolite or vehicle. Additional groups received the NDPS metabolite or vehicle only and were also monitored for 48 h. In a separate experiment, male Fischer 344 rats were pretreated with piperonyl butoxide (PIBX, 1360 mg/kg) or the PIBX vehicle. 2-NDHSA (0.1 mmol/kg) or vehicle was administered (ip) 30 min after PIBX, and renal function was monitored for 24 h. Phenobarbital markedly potentiated 2-NDHSA nephrotoxicity in male rats as evidenced by increased kidney weight, increased blood urea nitrogen (BUN) concentration, and decreased tetraethylammonium (TEA) accumulation by renal cortical slices. PIBX had no effect on 2-NDHSA nephrotoxicity. Phenobarbital pretreatment did not markedly enhance the nephrotoxic potential of NDHS or 2-NDHSA in female rats. These results indicate that phenobarbital exhibits differential potentiation of NDPS metabolite nephrotoxicity in male and female rats and that the potentiation of 2-NDHSA nephrotoxicity observed in males is not due to cytochrome P-450-mediated oxidative biotransformation.     

The effect of probenecid on acute N-(3,5-dichlorophenyl)succinimide-induced nephrotoxicity in the Fischer 344 rat

N-(3,5-Dichlorophenyl)succinimide (NDPS), an experimental agricultural fungicide, has been shown to produce selective nephrotoxicity in rats. Previous studies have shown that a metabolite(s) of extrarenal origin contributes to acute NDPS-induced nephrotoxicity. The purpose of this study was to determine if the organic acid transport inhibitor probenecid could modify the renal toxicity produced by NDPS administration. Male Fischer 344 rats were administered a single intraperitoneal (i.p.) injection of probenecid (60, 90 and 120 mg/kg) or 0.9% saline (1.0 ml/kg) followed 30 min later by NDPS (0.4 or 1.0 mmol/kg, i.p.) or sesame oil (2.5 ml/kg, i.p.) Renal function was monitored at 24 h and 48 h. Probenecid (60 mg/kg) did not markedly alter NDPS-induced renal effects on either post-treatment day. However, pretreatment with probenecid (90 or 120 mg/kg) blocked or attenuated the diuresis, increased proteinuria, decreased tetraethylammonium (TEA), uptake, elevation in blood urea nitrogen (BUN) concentration and increased kidney weight produced by NDPS (0.4 mmol/kg) administration. Only increased kidney weight and BUN concentration, and decreased lactate-stimulated p-aminohippurate (PAH) uptake were altered by probenecid (120 mg/kg) pretreatment when NDPS (1.0 mmol/kg) was given. NDPS-induced changes in renal morphology were not prevented by pretreatment with any probenecid dose. These results suggest that at least one nephrotoxic metabolite of NDPS is an organic acid. However, this acidic metabolite might not be the major nephrotoxic metabolite or a precursor to the major nephrotoxic metabolite(s). The identity of these metabolites remains to be determined.     

The nephrotoxic effects of cis-diammine-dichloroplatinum (II) (NSC-119875) in male F344 rats

The nephropathologic effects of cis-diammine-dichloroplatinum (II) are described. Male F344 rats, 6 weeks of age, were injected ip with cis-diammine-dichloroplatinum (II)(NSC-119875) at doses from 0.5–12 mg/kg. The LD50 was 7.7 mg/kg. After one injection, many rats lost weight by 24 hr and died from 2–7 days later, depending on the dose, whereas rats receiving lower doses recovered and gained weight by 7–10 days. Increased blood urea nitrogen (BUN) concentrations and renal weights reached a peak on Day 5 and returned to control values by Day 15. Histologically, acute degenerative and necrotizing lesions involved tubules in the outer stripe of the renal medulla and regeneration was noted by 5 days. Death of rats after one or five daily injections was attributed to the necrotizing enteritis, thymic atrophy, lymphocytic and bone marrow depletion, and renal lesions. Weekly injections resulted in uremia and development of markedly cystic kidneys. The results indicate that the F344 rat is a sensitive strain for the study of platinum nephrotoxicity.     

Trigonelline ameliorates diabetic hypertensive nephropathy by suppression of oxidative stress in kidney and reduction in renal cell apoptosis and fibrosis in streptozotocin induced neonatal diabetic (nSTZ) rats

Oxidative stress and apoptotic cell death in kidney have been suggested as contributing factors in the development and complication of diabetes especially in diabetic nephropathy (DN). This study investigated the effects of trigonelline (TG) on the renal functional, morphological changes and renal apoptosis in neonatal diabetic rats, a model of non-insulin-dependent diabetes mellitus. Diabetes mellitus was induced in one day old neonatal Wistar rat pups by an intraperitoneal (i.p.) injection of streptozotocin (STZ) (50 mg/kg) and monitored for 16 weeks thereafter. The diabetic rats were divided as follows: the nSTZ diabetic group, the TG (50 mg/kg) treated diabetic group, and the TG (100 mg/kg) treated diabetic group. The age matched nondiabetic group received an injection of citrate buffer (0.1 M, pH 4.5). At the end kidney samples were taken for light microscopic examinations. The levels of serum creatinine and BUN were significantly low in TG (100 mg/kg) treated diabetic rats. Glomerular filtration rate was improved in TG treated rats. The activities of antioxidant enzyme and membrane bound enzyme were decreased and the levels of tumor necrotic factor (TNF-α) and hydroxyproline content were increased in renal tissues of the diabetic group. TG (100 mg/kg/day) treatment for a period of 4 weeks showed significant ameliorative effects on all the biochemical parameters studied. Biochemical findings were supported by histological studies. The degenerative changes in kidney tissue and fibrosis were alleviated in the TG treated groups. These results suggested that TG might have a significant role in alleviating kidney damage in nSTZ-diabetic rats.     

N-(3,5-Dichlorophenyl)succinimide nephrotoxicity in the Fischer-344 rat

The nephrotoxic potential of N-(3,5-dichlorophenyl)succinimide (NDPS) was examined, in male Fischer-344 rats. Rats were administered NDPS (0.1, 0.2, 0.4 or 1.0 mmol/kg intraperitoneally (i.p.) or sesame oil (2.5 ml/kg, i.p.), and renal function was monitored at 24 and 48 h. NDPS (0.1 mmol/kg) stimulated organic ion uptake at 48 h. NDPS (0.2 mmol/kg) produced diuresis but did not alter blood urea nitrogen (BUN), kidney weight or organic ion uptake by renal cortical slices at 48 h. High-dose NDPS (0.4 and 1.0 mmol/kg) administration produced diuresis, decreased accumulation of p-aminohippurate (PAH) and tetraethylammonium (TEA), increased BUN and kidney weight and caused acute tubular necrosis. At 24 h, NDPS (0.2 mmol/kg) decreased uptake of PAH and TEA and tended to increase BUN. These results are similar to previous reports of NDPS-induced nephrotoxicity in Sprague-Dawley rats and suggest that either rat model would be suitable for future studies on the mechanism(s) of NDPS-induced nephropathy.     

Contribution of acetone and osmotic-diuresis by streptozotocin-induced diabetes in attenuation of cephaloridine nephrotoxicity.

Previous studies have indicated that cephaloridine nephrotoxicity was reduced in streptozotocin (STZ)-induced diabetic rats. Experiments were performed to investigate if a shorter duration of diabetes would reduce cephaloridine nephrotoxicity. Studies were also conducted to examine the contribution of osmotic diuresis and ketone accumulation to the mechanism for reduced toxicity. Male Fischer 344 (F344) rats were injected with 30 mg/kg STZ or vehicle. Seven days after STZ or vehicle administration, the animals were treated (i.p.) with 1500 mg/kg cephaloridine. Increased kidney weight, blood urea nitrogen (BUN) level and decreased renal cortical slice accumulation of p-aminohippurate (PAH) and tetraethyl-ammonium (TEA) were measured in the normoglycemic group. No differences in renal function were detected between diabetic groups treated with cephaloridine or vehicle (PFC). Pretreatment of euglycemic rats with 0 or 10% dextrose in the drinking water and by oral gavage failed to prevent the renal damage produced by 1500 mg/kg cephaloridine despite glucosuria and urine output comparable to diabetic animals. However, dextrose-diuresis afforded a slight reduction in toxicity as indicated by changes in kidney weight and renal cortical slice accumulation of PAH and TEA. Pretreatment (oral) with 0 or 1.5 ml/kg acetone had no effect on cephaloridine toxicity (1000 mg/kg, i.p.). These findings suggested that attenuation of cephaloridine toxicity may be independent of the duration of diabetes. These results also indicated that glucose-mediated osmotic diuresis and acetone accumulation cannot account for reduced cephaloridine toxicity in diabetic rats.     

Acetone effects on N-(3,5-dichlorophenyl)succinimide-induced nephrotoxicity

Acetone has been shown to potentiate the toxicity of many halogenated hydrocarbons. The purpose of this study was to determine if acetone could alter the acute nephrotoxicity produced by the experimental fungicide N-(3,5-dichlorophenyl)succinimide (NDPS). Male Fischer 344 rats were administered acetone (1, 5 or 10 mmol/kg) or acetone vehicle (corn oil, 10 mg/kg) orally followed 16 h later by a single intraperitoneal injection of NDPS (0.2 or 0.4 mmol/kg) or NDPS vehicle (sesame oil, 2.5 ml/kg) and renal function was monitored at 24 and 48 h. Acetone (1 or 5 mmol/kg) did not alter NDPS (0.2 mmol/kg)-induced renal effects while acetone (10 mmol/kg) pretreatment attenuated NDPS (0.4 mmol/kg)-induced increases in blood urea nitrogen (BUN) concentration and kidney weight but had no effect on NDPS (0.4 mol/kg)-induced changes in urine volume or content, organic ion accumulation by renal cortical slices or renal morphology. These results suggest that acetone weakly attenuates NDPS-induced nephrotoxicity.     

Renal Protein Degradation: A Biochemical Target of Specific Nephrotoxicants

Renal Protein Degradation: A Biochemical Target of SpecificNephrotoxicants. Cojocel, C., Smith, J.H., Maita, K., Sleight,S.D. and Hook, J.B. (1983). Fundam. Appl. Toxicol. 3: 278–284.Protein degradation in the kidney occurs mainly in lysosomes,organelles which may also accumulate nephrotoxic chemicals.The goal of this study was to evaluate the effects of intracellularaccumulation of gentamicin, cephaloridine and cisplatin on lysosomaldigestion of the protein lysozyme. Gentamicin (15 or 30 mg/kg/dayfor 3 or 5 days), cisplatin (2.5 or 5 mg/kg) or cephaloridine(500, 1000, 2000 or 2500 mg/kg) was administered ip to maleWistar rats. The main site of the nephrotoxic effects of thesecompounds was the proximal tubule where these agents differentiallyaffected S₁, S₂ and/or S₃ segments. A 2- and 4-fold increaseof the excretion of N-acetyl-ß-D-glucos-aminidase(NAG) was observed in the urine from cisplatinand gentamicin-treatedrats, respectively; no change in enzyme excretion occurred aftercephaloradine. One hour prior to sacrifice, rats were given0.3 mg of unlabelled lysozyme in combination with ¹²⁵I-lysozymein 0.3 mL saline. Renal cortical slices were prepared and incubatedfor 15, 30, 60 and 90 min. Release of trichloroacetic acid (TCA)solubleradioactivity into the medium was assumed to quantify lysosomaldegradation of lysozyme. Accumulation of p-amino-hippurate (PAH)in renal cortical slices and changes in blood urea nitrogen(BUN) concentration were used as indices of renal damage. TCA-solubleradioactivity increased in the medium from kidney slices fromcontrol rats to 50% of the total radioactivity after 90 minincubation. In gentamicin treated rats, lysozyme degradationwas significantly decreased by doses of 15 and 30 mg/kg/dayafter 3 and 5 days of exposure in the absence of any changesin BUN or PAH accumulation. Increased BUN and decreased PAHaccumulation was accompanied by reduced release of lysozymedegradation products from kidney slices of rats treated withboth doses of cisplatin. Cephaloridine appeared to have no effecton renal catabolism of lysozyme at 500 and 1000 mg/kg; howeverat higher doses lysozyme degradation decreased and changes inBUN and PAH occurred. Thus, all three compounds used were effectivein decreasing renal catabolism of lysozyme. Protein degradationwas an early and sensitive indicator of aminoglycoside-inducednephrotoxicity since a decrease in protein degradation in kidneyslices from gentamicin-treated rats was not associated withalterations in BUN or PAH accumulation but was associated withultrastructural changes.     

Acute and subchronic oral toxicities of benzo[a]pyrene in F-344 rats.

We have studied the acute and subchronic oral toxicities of benzo[a]pyrene (BaP) in male and female F-344 rats. Single acute BaP doses of 0, 100, 600, and 1000 mg /kg dissolved in peanut oil were administered by oral gavage. Subchronic doses of 0, 5, 50, and 100 mg/kg/day were administered for 90 days in the animal diet. The major toxicological endpoints examined included animal body weight, selected tissue weights, and histopathological examinations (liver, kidney, stomach, prostate, testes, and ovaries). In addition, we examined blood elements: red blood cells (RBC), white blood cells (WBC), hemoglobin (Hgb), hematocrit (Hct), mean cell volume (MCV), mean cell hematocrit (MCH), and mean cell hemoglobin concentration (MCHC), blood chemistry (ALT, AST, and BUN), and urine chemistry (glucose, bilirubin, specific gravity, pH, protein, urobilinogen, nitrite, occult blood, and leucocytes). In the acute study, WBC were significantly decreased and mean cell-hemoglobin concentration was significantly increased, both in males only. The liver:body weight ratio was significantly increased in males and females (up to 30%). None of the blood chemistry or urine parameters were significantly affected. In the subchronic study, mean body weight was significantly decreased in males only (13%), and the liver:body weight ratio in males was significantly increased. Several of the blood elements were significantly decreased in males and females after 90 days; RBCs (up to 10%), Hct (up to 12%), and Hgb (up to 12%). For blood chemistry parameters (AST, ALT, BUN), only BUN in males was significantly increased in the high dose group (100 mg/kg) at the 90 day time point. The histopathological examination of selected tissues showed significant abnormalities (tubular casts) only in the male kidney, at the 2 highest doses, after 90 days. These studies indicate that the acute and subchronic toxicities of BaP are relatively low, BaP affects specific blood elements and organs, and BaP has a greater effect on males than females. The induction of non-carcinogenic kidney abnormalities in males only may be indicative of renal dysfunction and further substantiates an apparent sex difference in tolerance to BAP:     

Sodium sulfate potentiates N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (NDHS) and N-(3,5-dichlorophenyl)-2-hydroxysuccinamic acid (2-NDHSA) nephrotoxicity in the Fischer 344 rat

The agricultural fungicide N-(3,5-dichlorophenyl)succinimide (NDPS) induces nephrotoxicity as its major toxicity in rats. Previous studies have shown that NDPS induces nephrotoxicity following oxidation of the succinimide ring to form N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (NDHS) and the hydrolysis product of NDHS, N-(3,5-dichlorophenyl)-2-hydroxysuccinamic acid (2-NDHSA). Our recent work found that sodium sulfate potentiated NDPS nephrotoxicity, suggesting that sulfate conjugation of NDPS metabolites might be a bioactivation step mediating NDPS nephrotoxicity. The purpose of this study was to determine if sodium sulfate also potentiated the nephrotoxicity of the two nephrotoxic metabolites of NDPS and further to see if sodium sulfate potentiated NDHS and 2-NDHSA nephrotoxicity to the same degree. Male Fischer 344 rats (4-16 rats/group) received an intraperitoneal (ip) injection of sodium sulfate (10 mg/kg) 20 min before a non-nephrotoxic dose (0.05 mmol/kg, ip) of NDHS or 2-NDHSA, or vehicle (12.5% dimethyl sulfoxide in sesame oil). Renal function was then monitored over 48 h. Sodium sulfate pretreatment potentiated the renal effects of a non-nephrotoxic dose of NDHS and 2-NDHSA to induce nephrotoxicity. Nephrotoxicity was characterized by diuresis, increased proteinuria, elevated blood urea nitrogen (BUN) concentration, increased kidney weight and proximal tubular necrosis. Differences in the potentiation of NDHS and 2-NDHSA nephrotoxicity by sodium sulfate were also observed as NDHS nephrotoxicity was potentiated to a lesser degree than 2-NDHSA-induced nephrotoxicity. These results support the likelihood that one or more sulfate conjugate(s) of NDPS metabolites contribute to NDPS nephrotoxicity.     

Role of stereochemistry in N-(3,5-dichlorophenyl)-2-hydroxysuccinamic acid (2-NDHSA) nephrotoxicity.

The nephrotoxicity induced by the agricultural fungicide N-(3,5-dichlorophenyl)succinimide (NDPS) is mediated through oxidative metabolites of NDPS. Oxidation of the succinimide ring in NDPS yields the nephrotoxic metabolites N-(3,5-dichlorophenyl)-2-hydroxysuccinimide (NDHS) and its hydrolysis product N-(3,5-dichlorophenyl)-2-hydroxysuccinamic acid (2-NDHSA). The oxidation of NDPS on the succinimide ring also introduces an asymmetric carbon atom into these NDPS metabolites, so that R- and S- enantiomers of NDHS and 2-NDHSA are possible. The purpose of this study was to begin to explore the importance of the stereochemical orientation at the asymmetric carbon atom for the nephrotoxicity induced by NDPS metabolites. Male Fischer 344 rats were administered a single intraperitoneal (ip) injection of R-(+)- or S-(-)-2-NDHSA (0.05, 0.1 or 2.0 mmol/kg) or vehicle, and renal function was monitored for 48 h. R-2-NDHSA (0.1 mmol/kg) administration had little effect on renal function. R-2-NDHSA (0.2 mmol/kg) treatment induced mild diuresis on day 1, increased proteinuria, and a small increase in blood urea nitrogen (BUN) concentration, but no change in kidney weight or glucosuria. S-2-NDHSA (0.1 mmol/kg) induced marked nephrotoxicity as evidenced by diuresis on both post-treatment days, increased proteinuria, glucosuria, and increased kidney weight and BUN concentration. No evidence of hepatotoxicity was obtained in any treated group. Thus, the S-isomer of 2-NDHSA is a more potent nephrotoxicant than the R-isomer, and stereochemistry may play a role in NDPS metabolite-induced nephrotoxicity.     

Effects of STZ-induced diabetes and its treatment with vanadyl sulphate on cyclosporine A-induced nephrotoxicity in rats

The aim of this study was to analyze the effect of streptozotocin (STZ)-induced diabetic state and the insulin-like acting, vanadyl sulphate (VS) on cyclosporine A (CyA) related nephrotoxicity in rats. Male Wistar rats were divided into six groups, of 12 animals each: The control, diabetic rats and diabetic rats whose drinking VS in the drinking water in a concentration of 1 mg/ml. Another three similarly treated groups were injected intra-peritoneally (ip) with CyA in a dose of 25 mg/kg/day for ten doses, 10 days after diabetic induction by using a single dose of STZ of 65 mg/kg. Rats were sacrificed 48 h after the last CyA dose and serum as well as kidneys were isolated and analyzed. Treatment with CyA to control normoglycemic rats resulted in significant increases in kidney weight, serum creatinine, urea nitrogen, cholesterol and triglycerides (TG) levels. Also, the kidney tissue of CyA-treated control animals showed significant increases in total nitrate/nitrite (NO_x) concentration and malondialdehyde (MDA) production level as well as depletion of glutathione (GSH) content and glutathione peroxidase (GSH-P_x) activity level. Histopathologic evaluation of CyA-treated control rats revealed tubular atrophy, hyaline casts and focal tubular necrosis. However, treatment of diabetic rats with CyA showed significant reduction in serum creatinine and elevation in TG level as well as reductions in the kidney NO_x concentration and MDA production level and increase in GSH concentration compared to CyA-treated control rats. Moreover, histopathology of the kidney of CyA-treated diabetics showed typical changes of the diabetic controls revealing glomerular hypertrophy and tubular dilation. On the other hand, treatment with CyA to those diabetic animals administered VS in the drinking water resulted in exacerbation of renal dysfunction, manifested by significant increases in serum indices of nephrotoxicity, cholesterol, TG and bilirubin levels. Also, VS administration to CyA-treated diabetics showed significant increase in kidney NO_x concentration compared to those CyA-treated diabetics drinking plain tap water, and to a level significantly lower than those CyA-treated controls. Histopathologically, kidney of CyA/VS-treated diabetic showed marked CyA related changes. In conclusion, STZ-induced diabetes might provide partial protection against CyA-induced renal dysfunction. Also, treatment of hyperglycemia with VS might exacerbate CyA related nephrotoxicity.     

cis-Dichlorodiammineplatinum nephrotoxicity: Time course and dose response of renal functional impairment

Although administration of cis-dichlorodiammineplatinum (CDDP) is known to induce acute proximal tubular necrosis, more subtle functional damage of the kidney could occur. This study was initiated to examine the renal functional correlates of CDDP nephrotoxicity in male F-344 rats receiving a single iv dose of 0, 1.25, 2.5, 5, 10, or 15 mg/kg CDDP. When compared to pair-fed controls, the following effects were observed 2 days following CDDP treatment: (a) increased 24-hr uv (5, 10, and 15 mg/kg), (b) reduced U_osm (2.5 and 5 mg/kg), (c) increased 24-hr urinary K⁺ excretion (10 and 15 mg/kg), (d) glucosuria, accompanied by hyperglycemia (10 and 15 mg/kg), and (e) elevated BUN (15 mg/kg). On Day 4, increased 24-hr uv and reduced U_osm persisted in surviving drug treated animals (2.5 or 5 mg/kg). In addition, glucosuria, unaccompanied by hyperglycemia, was observed in the 2.5 and 5 mg/kg group and an elevated BUN was apparent only in the latter treatment group. C_inulin (GFR) and C_PAH (ERPF) were significantly compromised in drug-treated animals (5 mg/kg) on Day 4, findings consistent with the increased BUN. CDDP administration did not impair the ability of renal cortical slices to accumulate a prototype organic anion (p-aminohippurate) or cation (tetraethylammonium) in vitro on Day 4. However, accumulation of these organic ions was significantly depressed in kidney slices obtained from untreated animals when 500 or 600 μg/ml CDDP was added to incubation medium. Inasmuch as alterations in urinary excretory function, but not BUN, were apparent in the lower dosage groups on Day 2, these results suggest that urine analyses may provide a more sensitive test for the early detection of CDDP nephrotoxicity than the commonly used measurement of BUN.     

Increased excretion of urinary 20-HETE in rats with cyclosporine-induced nephrotoxicity

The present study examined the contribution of 20-hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE) in cyclosporine A (CsA)-induced renal nephrotoxicity. Treatment of rats with CsA (50 mg/kg) for 9 days induced renal damage as indicated by marked increase in urine flow (from 9.0 +/- 0.3 ml/day to 46.6 +/- 7.1 ml/day) and a 3 - 5-fold rise in blood urea nitrogen (BUN) levels. The urinary excretion of 20-HETE increased from 164 +/- 5 ng/day (N = 5) to 2432 +/- 290 ng/day (N = 5, P<0.01) after 9 days of CsA treatment. The increase in the urinary excretion of 20-HETE in the CsA treated rats was highly correlated with the increase in BUN levels (r = 0.819, P<0.001) and urine volume (r = 0.832, P<0.001). Immunohistochemical examination of kidney revealed that expression of cytochrome P450 4A (CYP4A) protein was markedly enhanced in the proximal tubules of CsA-treated rats. These results indicate that CsA-induced nephrotoxicity in rats is associated with a marked elevation in the renal production of 20-HETE and that 20-HETE may contribute to the pathophysiological condition of CsA-induced nephrotoxicity.     

Developed resistance to mercuric chloride nephrotoxicity: failure to protect against other nephrotoxicants

Daily, oral treatment of rats for 14 days with 5 mg/kg of mercuric chloride (HgCl2) caused hypertrophy of the kidney, but no change in percent tissue water, or serum urea nitrogen (BUN) or creatinine concentrations. Upon histological examination, hypercellularity and increased basophilia of the outer medulla were observed. A single, subcutaneous injection of 20 mg/kg of potassium chromate (K2CrO4) increased kidney size and water content, as well as BUN and serum creatinine concentrations, and produced coagulative necrosis of the proximal convoluted tubules. Intraperitoneal injection of 125 mg/kg of hexachloro-1,3-butadiene (HCBD) increased kidney weight, percent water, BUN and serum creatinine, and produced necrosis of the proximal straight tubules in approximately half of the animals. 1 g/kg biphenyl, orally, produced only diffuse tubular swelling. Rats treated with 20 mg/kg K2CrO4, 125 mg/kg HCBD or 1 g/kg biphenyl following 14 days of treatment with 5 mg/kg HgCl2 generally displayed the symptoms of both types of treatment, and the severity of the K2CrO4, HCBD and biphenyl effects were substantially the same as in those without HgCl2 pretreatment. Developed resistance to HgCl2 nephrotoxicity, therefore, appears to have little effect on response of the kidney to other nephrotoxicants.     

Regucalcin down-regulation in rat kidney tissue after treatment with nephrotoxicants

Gene expression of regucalcin (Rgn), a calcium-binding protein, was investigated in kidney of male Wistar rats treated with proximal tubule segment-specific nephrotoxicants, namely hexachloro-1:3-butadiene (HCBD), specific for S(3) segment (pars recta) and potassium dichromate (chromate) specific for S(1)-S(2) segments (pars convoluta), according to age of animals and dose of chemicals. In the age-dependent study, male Wistar rats were treated with a single injection of HCBD (100mg/kg b.w. i.p.) or chromate (25 mg/kg b.w. s.c.) at 5 weeks or 12 weeks of age; in dose-response study, rats were treated with a single injection of three doses of HCBD (25, 50, and 100 mg/kg b.w. i.p.) or chromate (8, 12.5, and 25mg/kg b.w. s.c.) at 8 weeks of age. Forty-eight hours after treatment, Rgn and glutamine synthetase (GS) activity in kidney cortex, blood urea nitrogen (BUN) and plasma creatinine were measured; light microscopy was performed also. The results show that young rats are less susceptible to chromate (severe necrosis is evident only in adult rats), whereas age does not influence HCBD nephrotoxicity. Rgn is down regulated by HCBD at both age points, but not by chromate at 5 weeks of age. In addition, HCBD causes down-regulation of Rgn from the low dose in 8-week-old rats, whereas chromate causes the same effect at the high dose only. GS activity in kidney cortex shows a similar behavior, even if sensitive to low doses of chromate also, whereas BUN and creatinine increase after the high dose of both chemicals only. Accordingly, light microscopy shows a segment-specific, dose-dependent increase of severity of damage caused by the chemicals. Rgn gene expression appears a sensitive genomic marker to evaluate the renal impairment caused by chemicals and its down-regulation seems to be related to damage, early or already established, to S(3) segment of the proximal tubule.