Monitoring the exposure of rats to 2-acetylaminofluorene by the estimation of mutagenic activity in excreta, sister-chromatid exchanges in peripheral blood cells and DNA adducts in peripheral blood, liver and spleen

The sensitivity of various methods suitable for biomonitoring the exposure to genotoxicants was compared in an animal model. The results were related to the presence of genotoxic effects in the target organ. Groups of male Wistar rats were given one oral dose of 0, 0.1, 10 or 200 mg 2-acetylaminofluorene (2-AAF)/5 ml dimethyl sulphoxide/kg body weight. Peripheral blood cells, excreta, liver and spleen were collected at different time intervals after dosing. Mutagenicity in urine and extracts of faeces was determined using the Ames test with Salmonella typhimurium TA98 with and without S9 and with and without beta-glucuronidase. Genotoxic effects were studied by measuring DNA-adduct formation in lymphocytes, liver and spleen, and sister-chromatid exchanges (SCEs) in lymphocytes. DNA adducts were measured with immunochemical techniques and postlabelling methods. Mutagenicity in urine and faeces, collected during the first 24 h after treatment, was detected at 2-AAF doses of 1 mg/kg b.w. and higher. At these doses DNA adducts also became apparent in the liver, the main target organ for tumour induction by 2-AAF. The adduct detected appeared to be the N-(deoxyguanosin-8-yl)-2-AAF adduct. There was no evidence of the presence of any other types of DNA adducts. At doses of 1 and 10 mg/kg b.w. no mutagenicity was detected in excreta collected during the second and third day after dosing. The DNA-adduct level in liver cells of the 1 mg/kg b.w. group was maximal 24 h after dosing. At 200 mg/kg b.w. a delay in excretion of mutagenicity with urine and faeces was seen and at 10 and 200 mg/kg b.w. the amount of DNA adducts continued to increase with time after dosing. At 24 and 48 h after treatment with 10 mg, the adduct levels were of the same order of magnitude as those found after the 20-fold higher dose. This points to overloading of the metabolizing system which in combination with the enterohepatic circulation, may lead to an increased retention of 2-AAF in the body. A slightly increased incidence of SCEs of doubtful significance was seen in lymphocytes, but only at the very high dose of 200 mg/kg b.w. No DNA adducts could be detected in blood lymphocytes or spleen cells at any of the dose levels applied, either with the immunochemical or with the postlabelling method.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effects of an antisense oligonucleotide inhibitor of human ICAM-1 on fetal development in rabbits

The potential for reproductive toxicity of an antisense oligonucleotide designed to inhibit ICAM-1 was evaluated as part of the safety assessment for this compound. The human active ICAM-1 inhibitor (ISIS 2302) is not pharmacologically active in rabbits. Female rabbits were treated once daily on Day 6 through 18 of gestation. Rabbits were treated with 0, 1, 3, and 9 mg/kg ISIS 2302 by daily i.v. injection. Reproductive indices evaluated included estrus cycling, litter parameters, fetal development, and fetal body weight. Concentrations of oligonucleotide in plasma following the last dose, and in selected maternal target organs, placenta, and fetal tissues at scheduled necropsy were also measured. Maternal toxicity was evident as a decreased maternal body weight gain, decreased food consumption, and scant feces at doses > or =3 mg/kg. Increased spleen to body weight ratio and increased mononuclear cell infiltrates were indicative of a proinflammatory effect of ISIS 2302 at the 9 mg/kg dose level. Despite the maternal toxicity, there were no changes in litter parameters or fetal development in rabbits treated with ISIS 2302. The only change was a decrease in fetal body weight at the 9 mg/kg dose level, which was attributed to the maternal toxicity observed. Maternal liver and kidney contained dose-dependent concentrations of oligonucleotide, but there was relatively little or no oligonucleotide measured in placenta or fetal tissues. Thus, there was no dose-dependent exposure and maternal toxicity to ISIS 2302, but no reproductive toxicity in rabbits, and exposure of fetus or pups is negligible.     

Effect of nimesulide co-administration on pharmacokinetics of lithium

In a crossover study, lithium was given orally at a dose of 56 mg/kg, prepared as suspension (0.5%) in carboxymethyl cellulose (CMC) and blood samples (1 ml) collected after 0-24 hr after drug administration. After a washout period of two weeks, nimesulide (10 mg/kg) was administered alongwith lithium (56 mg/kg) and blood samples were drawn at the same time intervals (0-24 hr) after drug administration. Plasma was separated and assayed for lithium by M 654 Na+/K+/Li+ analyzer and various pharmacokinetic parameters were calculated. C(max), K(el), t(1/2el) and AUC(0-alpha) of lithium were significantly increased when nimesulide was administered along with lithium as compared to control group.     

Probenecid-induced changes in the clearance of pranoprofen enantiomers

Probenecid is known to inhibit the elimination of several acidic drugs. Its influence on the pharmacokinetics of pranoprofen was investigated in rabbit after a single intravenous injection of racemic mixture (5 mg/kg). Levels of (-)-(R)- and (+)-(S)-pranoprofen and their glucuronide (after hydrolysis with sodium hydroxide) were determined in plasma, urine, and several tissues. The plasma concentration of the (+)-(S)-isomer was higher than that of the (-)-(R)-form. Oral coadministered probenecid (100 mg/kg) resulted in an increased plasma concentration of both enantiomers. Probenecid reduced the apparent total clearance and excretion of pranoprofen enantiomers in urine. It had a slight effect on the tissue distribution of pranoprofen at the dose used, but significantly reduced the formation of glucuronide for both enantiomers to the same extent in kidney microsomes. The differences caused by probenecid were significant with respect to its ability to inhibit glucuronidation in the kidney and subsequent excretion into urine, but enantioselective effects were negligible.     

Distribution of lithium in different CNS areas and other tissues of adult male and female vizcacha (Lagostomus maximus maximus).

In a previous study (1) we demonstrated that lithium administration (1.0 mmol/kg b.wt., per day for 4 weeks) in intact vizcacha (Lagostomus maximus maximus) leads to significant histological alterations in the kidneys, ovarie and testicles, while these three tissues were not damaged in rats. Male vizcachas died within 4 days when administered LiCl 3 mmol/kg b.wt., while females were not affected. The lithium renal clearance presented no changes in either males or females. The 1.0 mmol/kg b.wt. dose was used in the experiments (2). In this study we examined the distribution of lithium in various tissues of male and female vizcacha (Lagostomus maximus maximus) administered LiCl by injection (1 mmol/kg b.wt.) for one day (Group I) and thirty days (Group II). Blood sample was obtained after 24 hours (Group I) and 30 days (Group II). The tissues investigated were: pituitary, hypothalamus, cerebral cortex, cerebellum, corpus callous, small and large intestine, kidney and suprarenal. The concentration of lithium in tissues and serum was determined by atomic absortion spectrometry (3,4). In Group I a significant lithium concentration increment (mumol/g of tissue) was observed in all the tissues of male vizcachas as compared to female vizcacha. A similar distribution was obtained in animals treated for 30 days. In the pituitary, however this difference between males and females was not significant. The male lithium serum levels were significantly higher than those of female animals. In conclusion, we suggest that the particular structure of the cell membrane (e.g., number and characteristic of sodium channels) of each tissue and/or the intracellular mechanisms of transport, elimination and metabolism might explain the unequal lithium distribution and the difference recovery from the damage produced. The results suggest that the vizcacha could be a useful model for the study of lithium toxicity.     

Zea mays L. extracts modify glomerular function and potassium urinary excretion in conscious rats

Diuretic and uricosuric properties have traditionally been attributed to corn silk, stigma/style of Zea mays L. Although the diuretic effect was confirmed, studies of the plant's effects on renal function or solute excretion were lacking. Thus, we studied the effects of corn silk aqueous extract on the urinary excretion of water, Na+, K+, and uric acid. Glomerular and proximal tubular function and Na+ tubular handling were also studied. Conscious, unrestrained adult male rats were housed in individual metabolic cages (IMC) with continuous urine collection for 5 and 3 h, following two protocols. The effects of 25, 50, 200, 350, and 500 mg/kg body wt. corn silk extract on urine volume plus Na+ and K+ excretions were studied in water-loaded conscious rats (2.5 ml/100 g body wt.) in the IMC for 5 h (Protocol 1). Kaliuresis was observed with doses of 350 (100.42 +/- 22.32-120.28 +/- 19.70 microEq/5 h/100 g body wt.; n = 13) and 500 mg/kg body wt. (94.97+/- 29.30-134.32 +/- 39.98 microEq/5h/100 g body wt.; n = 12; p<0.01), and the latter dose resulted in diuresis as well (1.98 +/- 0.44-2.41 +/- 0.41 ml/5 h/100 g body wt.; n = 12; p<0.05). The effects of a 500 mg/kg body wt. dose of corn silk extract on urine volume, Na+, K+ and uric acid excretions, and glomerular and proximal tubular function, were measured respectively by creatinine (Cler) and Li+ (ClLi) clearances and Na+ tubular handling, in water-loaded rats (5 ml/100 g body wt.) in the IMC for 3 h (Protocol 2). Clcr (294.6 +/- 73.2, n = 12, to 241.7 +/- 48.0 microl/ min/100 g body wt.; n = 13; p<0.05) and the Na+ filtered load (41.9 +/- 10.3, n = 12, to 34.3 +/- .8, n = 13, p<0.05) decreased and ClLi and Na+ excretion were unchanged, while K+ excretion (0.1044 +/- 0.0458, n=12, to 0.2289 +/- 0.0583 microEq/min/100 body wt.; n = 13; p<0.001) increased. For Na+ tubular handling, the fractional proximal tubular reabsorption (91.5 +/- 3.5, n = 12, to 87.5 +/- 3.4%; n = 13; p<0.01) decreased, and both fractional distal reabsorptions--I and II--increased (96.5 +/- 1.5, n = 12, to 97.8 +/- 0.9%; n = 13; p<0.01; and 8.2 +/- 3.5, n = 12, to 12.2 +/- 3.4%, n = 13, p<0.01, respectively). To summarize, in water-loaded conscious rats (2.5 ml/100 body wt.), corn silk aqueous extract is diuretic at a dose of 500 mg/kg body wt. and kaliuretic at doses of 350 and 500 mg/kg body wt. In water-loaded conscious rats (5.0 ml/100 g body wt.), corn silk aqueous extract is kaliuretic at a dose of 500 mg/kg body wt., but glomerular filtration and filtered load decrease without affecting proximal tubular function, Na+, or uric acid excretion.     

Pharmacokinetics of lithium in rats of various ages

The kinetics of lithium in serum was determined in rats aged 5 to 240 days, after 2 days of pretreatment with 0.15 mval Li+/100 g and a load of 0.3 mval Li+/100 g body weight at the day of experiments. In rats age differences in distribution and elimination of lithium can be described by a two-compartment model. The kinetic parameters were calculated (half-life(serum), apparent volume of distribution, rate constants of distribution and elimination, total plasma clearance) and, additionally, age differences in renal elimination were determined (renal clearance, half-life (urine)). The ability to excrete lithium is not fully developed in 5-day-old rats: t1/2serum (23 h) and especially t1/2urine (72 h) are much longer than in adult rats (t1/2serum = 12 h; t1/2urine = 6.4 h). The influence of administered lithium on the regulation of the electrolyte balance in the organism (sodium, potassium) occurred differently in dependence on age. Consequences of the investigations are discussed for the therapy with lithium in different age periods.     

Induction of lipid peroxidation in hamster organs by the carcinogen cadmium: melioration by melatonin

Cadmium is a well-known human carcinogen. Lipid peroxidation is involved in cadmium-related toxicity and carcinogenesis. Melatonin is an effective antioxidant and free radical scavenger. The potential protective effects of melatonin against cadmium-induced lipid peroxidation in hamster brain, heart, kidney, testes, lung, and liver were examined. Lipid peroxidation was induced by intraperitoneal injection of cadmium chloride [single dose of 1 mg/kg body weight (bw)]. To test whether melatonin would protect against the toxicity of the carcinogen, the melatonin was injected peritoneally at a dose of either 15 mg/kg bw or 5 mg/kg bw, 0.5 h before cadmium treatment and thereafter at 8 h intervals during the day in the 48 h interval following the cadmium injection. One group of hamsters received only a single melatonin injection (a dose of 15 mg/kg bw, 30 min prior to cadmium). Forty-eight hours after cadmium injection, lipid peroxidation increased in brain, heart, kidney, testes, and lung. Either multiple injections of melatonin at both the 5 and 15 mg/kg bw doses, or a single injection of 15 mg/kg bw, prevented the cadmium-related increases in lipid peroxidation in brain, heart and lung. Cadmium-induced lipid peroxidation in kidney was prevented by melatonin when it was given as a single dose of 15 mg/kg bw. Melatonin slightly, but not significantly, reduced cadmium-induced lipid peroxidation in testes. It is concluded that cadmium toxicity, at least with regard to the resulting lipid peroxidation, is reduced by administering melatonin. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of lithium augmentation on the trace elemental profile in diabetic rats.

Energy dispersive X-ray fluorescence technique was employed to study the interactions among various elements, viz.: K, Zn, Br, Fe, Cu, Br & Rb in 4 groups of rats viz. control-GI, diabetic-GII (diabetes induced by i.p. administration of alloxan monohydrate at a dose level of 150 mg/kg b.w; single injection), lithium treated-GIII (lithium administered as Li2 Co3 at a dose level of 1.1 g of Li2 Co3/kg animal diet; free access; serum lithium levels--0.5-1.2 mEq/L) and lithium + diabetic rats-GIV. The different treatments continued for a total duration of 1 month. The K contents were found to be significantly lowered in all the treatment groups which was maximum (28%) in lithium treated diabetic rats. Depression in the levels of Rb was noticed in lithium treated and lithium treated diabetic (G-III and G-IV) groups. However, the levels (Rb) remained unaltered in diabetic (G-II) group. Interestingly, a significant decline was observed in Fe levels in G-III following lithium administration but the levels remained unchanged in G-IV with lithium administration to diabetic rats. On the other hand, lithium treatment to normal (G-III) and diabetic (G-IV) rats indicated statistically significant elevation in the levels of Cu and Br. However, diabetic (G-II) rats did not indicate any elevation in the levels of these two elements. Interestingly, the concentrations of Zn were found to be significantly elevated in all the treatment groups, which was maximum (37%) in G-III (lithium) group. A comparison of various elements from lithium treated diabetic group G-IV with the corresponding elements from the diabetic group G-II, implied a significant depression in K and Rb levels and a significant elevation in the levels of Br.     

Toxicological Evaluation of Lactase Derived from Recombinant Pichia pastoris

A recombinant lactase was expressed in Pichia pastoris, resulting in enzymatic activity of 3600 U/mL in a 5 L fermenter. The lactase product was subjected to a series of toxicological tests to determine its safety for use as an enzyme preparation in the dairy industry. This recombinant lactase had the highest activity of all recombinant strains reported thus far. Acute oral toxicity, mutagenicity, genotoxic, and subchronic toxicity tests performed in rats and mice showed no death in any groups. The lethal dose 50% (LD₅₀) based on the acute oral toxicity study is greater than 30 mL/kg body weight, which is in accordance with the 1500 L milk consumption of a 50 kg human daily. The lactase showed no mutagenic activity in the Ames test or a mouse sperm abnormality test at levels of up to 5 mg/plate and 1250 mg/kg body weight, respectively. It also showed no genetic toxicology in a bone marrow cell micronucleus test at levels of up to 1250 mg/kg body weight. A 90-day subchronic repeated toxicity study via the diet with lactase levels up to 1646 mg/kg (1000-fold greater than the mean human exposure) did not show any treatment-related significant toxicological effects on body weight, food consumption, organ weights, hematological and clinical chemistry, or histopathology compared to the control groups. This toxicological evaluation system is comprehensive and can be used in the safety evaluation of other enzyme preparations. The lactase showed no acute, mutagenic, genetic, or subchronic toxicity under our evaluation system.     

Ameltolide. I: Developmental toxicology studies of a novel anticonvulsant

Ameltolide, a novel anticonvulsant agent, has been shown in animal models to be effective in controlling seizures. The developmental toxicity of ameltolide was evaluated in two species. Naturally mated rats and rabbits were dosed once daily by gavage on gestation days (GD) 6-17 and 6-18, respectively. Rats were given doses of 0, 10, 25, or 50 mg/kg; rabbits were given 0, 25, 50, or 100 mg/kg. Laparotomy was performed on rats on GD 20 and on rabbits on GD 28. In rats, maternal toxicity was indicated at the 25- and 50-mg/kg dose levels by depressed body weight gain. Fetal body weight was depressed at the 50-mg/kg dose level. Fetal viability and morphology were not affected. The no-observed effect levels (NOEL) for adult and developmental toxicity in the rat were 10 and 25 mg/kg, respectively. In rabbits, maternal toxicity was indicated by a net loss in body weight at the 50- and 100-mg/kg dose levels. Fetal viability and body weight were depressed at the 100 mg/kg dose level. Shortened digits occurred on the right forepaw of one fetus at the 50-mg/kg dose level (in conjunction with severe maternal toxicity) and on the hindpaws of two fetuses from separate litters at the 100-mg/kg dose level. Incomplete ossification of the phalanges occurred on the forepaws of nine fetuses from four litters at the 100-mg/kg dose level. Ameltolide was weakly teratogenic in the rabbit. The NOEL for adult and developmental toxicity in the rabbit was 25 mg/kg.     

Side effects of low serum lithium concentrations on renal, thyroid, and sexual functions in male and female rats

The present study, carried out in rats, is a contribution to explore physiological mechanisms underlying lithium toxicity. Male and female mature rats were divided into three groups and fed on commercial pellets: group (C) was control, group (Li1) was given 2000 mg lithium carbonate/kg of food, and group (Li2) was given 4000 mg lithium carbonate/kg of food. If we take into account the BW of the rats and the quantity of food they eat every day, we can estimate that the quantities of lithium carbonate ingested per day and kilogram of BW are, respectively, for the groups Li1 and Li2, of 212 mg (5,738 mmol Li) and 323 mg (8,742 mmol Li) for the males, and about 190 mg (5,142 mmol Li) and 289 mg (7,822 mmol Li) for the females. After 7, 14, 21 and 28 days, serum concentrations of lithium, creatinine, free triiodothyronine (FT3) and thyroxine (FT4), testosterone and estradiol were measured. Attention was also paid to growth rate and a histological examination of testes or vaginal mucosa was carried out. In treated rats, a dose-dependent loss of appetite and a decrease in growth rate were observed together with polydipsia, polyuria, and diarrhoea. Lithium serum concentrations were found to increase from 0.44 mM (day 7) to 1.34 mM (day 28) in Li1 rats and from 0.66 to 1.45 mM (day 14) in Li2 rats. Treatment was stopped at day 14 in Li2 rats because of a high mortality. The significant increase of creatinine that appeared, respectively, at day 7 and 14 in Li2 and Li1 rats shows that serum lithium concentrations ranging from 0.62 to 0.75 mM were able to induce renal insufficiency, secondarily leading to a time-dependent rise in lithium serum concentrations. A significant decrease of serum thyroxine (FT4) and triiodothyronine (FT3) levels was observed for lithium concentrations ranging from: 0.66 to 0.75 mmol l(-1) (Li2 rats) to 1.27 mmol l(-1) (Li1 rats). This effect was more pronounced for FT3, suggesting a defect of FT4/FT3 conversion. Under lithium treatment, the testosterone level decreased and spermatogenesis was stopped. By contrast, in treated female rats, estradiol level was found to be increased in a dose-dependent manner and animals were blocked in the diestrus phase at day 28. These results show that lithium can rapidly induce toxic effects in the rat at concentrations used for the treatment of bipolar disorders in human.     

Experimental study on interactions between selenium and tin in mice

The organ distributions of tin and selenium, and their excretion into urine and feces, were determined in mice. There were four groups; (A) control, (B) Sn (5 μmol/kg/d) ip injection, (C) Se (5 μmol/kg/d) sc injection, and (D) Sn plus Se (5 μmol/kg/d, each). Animals received injections once a day for 12 consecutive days. The results were the following (1) Simultaneous injection of Sn and Se enhanced accumulation of both elements in the body, i.e., in group B, 14.1% of the total injected amount of Sn was excreted into urine and feces; in group C, 46.2% of total injected Se was excreted into urine and feces; in group D, 10.9% of total Sn and 37.5% of total Se were found in excreta. (2) Large amounts of Sn were found in bone, liver, spleen, and kidney in group B. When Se was administered jointly with Sn, the concentrations of Sn in bone and liver were suppressed, whereas those in spleen and pancreas were increased. (3) The effects of Se-injections at this dose on concentrations of Se in organs were small. (4) In plasma, chemical reduction of selenite by stannous chloride was not observed.     

Effects of low doses of Li carbonate injected into mice. Functional changes in kidney seem to be related to the oxidative status

Effects of daily injections of lithium carbonate (20, 40 or 80 mg/kg body weight) during 14 and 28 days were investigated in Wistar mice. Attention was paid (1) to changes in concentrations of lithium, creatinine and urea in serum, (2) to level of oxidative stress by measuring lipids peroxidation level and catalase, superoxide-dismutase and glutathione-peroxidase activities, and (3) to changes in the histological structure of brain. The first intraperitoneal injection was followed by a transitory peak of lithium in the blood, reaching 0.25 mM and 1.1 mM and disappearing 6 and 12 h later for the 20 and 80 mg/kg doses, respectively. From the first to the last day of treatment, lithium concentrations in the blood, measured 12 h after the injections, increased from 0 to 0.11 mM (20 mg/kg dose) or 0.25 mM (80 mg/kg dose). The 80 mg/kg treatment induced a renal insufficiency evidenced by an increase of blood creatinine and urea levels. Lithium treatment was found to trigger an oxidative stress in kidney, but not in brain. In kidney, the lipid peroxidation level (TBARS) and the superoxide dismutase and catalase activities were increased. No change in glutathione peroxidase activity was detected. Histology of the brain cortex revealed interesting modifications: thicker neuronal cells and a denser network of dendrites, as compared to controls.     

Extrahpetic distribution of sulfobromophthalein.

Plasma clearance of sulfobromophthalein (BSP) is widely used as a measure of hepatic function. Its validity depends upon its exclusive elimination from the body via bile. For example, in the present study, when BSP was administered intravenously (i.v.) to rats at four different doses (18.75, 37.5, 75, and 150 mg/kg), less than 0.5% of each dose was excreted into the urine and between 70 and 85% was excreted into the bile within 6 h after administration. It has been assumed that the distribution of BSP is limited to the blood and liver witith very little appearing in other tissues. When we measured the amount of BSP in the plasma, liver, and the bile 10 min after the i.v. administration of either a high (150 mg/kg) or a low (18.75 mg/kg) dose of BSP, only 60% of the dose was accounted for. The concentration of BSP and 12-I-labelled albumin (RISA) was measured in various tissue samples 10 min after administration of 17.5 or 150 mg of BSP or RISA per kilogram. More BSP was found in all tissues than was contained in the plasma entrapped therein. Thus, the distribution of BSP is not limited to the liver and plasma. During excretion BSP leaves other tissue (kidney, spleen, lung, etc.) and is ultimately excreted into the bile.     

Lithium-stimulated recovery of granulopoiesis after sublethal irradiation is not mediated via increased levels of colony stimulating factor (CSF)

We have previously demonstrated that lithium (Li) is an effective agent in accelerating the recovery of granulopoiesis following sublethal (2 Gy) whole body irradiation. In this report, studies are described that further define this Li-mediated recovery by measuring the levels of colony-stimulating factor (CSF) present in serum from mice administered 105 micrograms/mouse (total dose) of ultra-pure Li2CO3 for 3 days immediately following irradiation. On days 1-28 following the last lithium dose, the serum was tested for its CSF activity against both normal non-adherent derived bone marrow target cells and non-adherent marrow cells from mice administered cyclophosphamide (200 mg/kg body weight). Serum was assayed at 0.01, 0.1, 1 and 10 per cent final concentration. No significant difference in the total number of CFU-GM was observed from normal marrow using either serum from irradiated mice or lithium-treated and irradiated mice, although the irradiation did produce a 300 per cent rise in CFU-GM colonies compared to normal serum (days 4 and 10-15). From regenerating marrow, we observed a significant difference (P less than or equal to 0.01) in CFU-GM cultured with serum at 0.1 per cent concentration from irradiated and lithium-treated mice compared to irradiated mice without lithium. The presence of CSF was confirmed by its reduced activity in the presence of anti-(CSF). These results suggest (Li) may increase the sensitivity of CFU-GM to CSF, thereby producing more CFU-GM ultimately providing more circulating granulocytes.     

Identification of 1- and 3-methylhistidine as biomarkers of skeletal muscle toxicity by nuclear magnetic resonance-based metabolic profiling

Nuclear magnetic resonance (NMR)-based metabolomic profiling identified urinary 1- and 3-methylhistidine (1- and 3-MH) as potential biomarkers of skeletal muscle toxicity in Sprague–Dawley rats following 7 and 14 daily doses of 0.5 or 1 mg/kg cerivastatin. These metabolites were highly correlated to sex-, dose- and time-dependent development of cerivastatin-induced myotoxicity. Subsequently, the distribution and concentration of 1- and 3-MH were quantified in 18 tissues by gas chromatography–mass spectrometry. The methylhistidine isomers were most abundant in skeletal muscle with no fiber or sex differences observed; however, 3-MH was also present in cardiac and smooth muscle. In a second study, rats receiving 14 daily doses of 1 mg/kg cerivastatin (a myotoxic dose) had 6- and 2-fold elevations in 1- and 3-MH in urine and had 11- and 3-fold increases in 1- and 3-MH in serum, respectively. Selectivity of these potential biomarkers was tested by dosing rats with the cardiotoxicant isoproterenol (0.5 mg/kg), and a 2-fold decrease in urinary 1- and 3-MH was observed and attributed to the anabolic effect on skeletal muscle. These findings indicate that 1- and 3-MH may be useful urine and serum biomarkers of drug-induced skeletal muscle toxicity and hypertrophy in the rat, and further investigation into their use and limitations is warranted.     

Alleviation of lindane induced toxicity in testis of Swiss mice (Mus musculus) by combined treatment with vitamin C, vitamin E and alpha-lipoic acid

Mitigation of lindane induced toxicity in testis of Swiss mice by combined treatment with vitamin C, vitamin E and alpha-lipoic acid has been evaluated. Male healthy mice (40), 8-10 weeks old were randomly selected and divided into 4 groups, control (C); lindane (L); antioxidant (A) and antioxidant plus lindane (A+L). Group C animals were administered only the vehicle (olive oil); in group L lindane was administered orally at a dose of 40 mg/kg body wt.; in group A combination of antioxidants at a dose of 125 mg/kg body wt.(vitamin C: 50 mg/kg body wt., vitamin E: 50 mg/kg body wt. and alpha-lipoic acid: 25 mg/kg body wt.) was administered orally; in group A+L both antioxidants (125 mg/kg body wt.) and lindane (40 mg/kg body wt.) were administered at their respective doses. In group A+L antioxidants were administered 1 h prior to lindane administration. All treatments were continuously given for 60 days. Histopathological changes due to lindane intoxication indicated shrunken and distorted seminiferous tubules, sparse Leydig cells and blood vessels and atrophy in the tissue. The testis weight also decreased significantly. Lindane treated group showed increased lipid peroxidation, whereas glutathione, glutathione peroxidase, superoxide dismutase, catalase and protein were significantly decreased compared to control. Lindane induced damage was minimized by administration of antioxidants. Results suggest that combined pretreatment with antioxidants can alleviate the damage caused to testis by lindane.     

Effects of etretinate on the distribution of elements in rats

We studied in the rat the effects of the drug etretinate (Tigason), given at three doses 3, 10, and 30 mg/kg body wt for 1 mo, on the concentrations of Na, K, Ca, Mg, Fe, S, P, Cu, and Zn in the plasma, brain, thymus, heart, liver, lung, kidney, testicle, muscle, and bone. The elements were simultaneously determined in tissues after nitric acid dissolution by inductively coupled plasma emission spectrometry using a JY 48 instrument. At the dose of 3 mg/kg, etretinate did not induce any statistically significant modifications of the element distribution. At the dose of 10 mg/kg, the main observed modifications were in plasma an increase of copper (+38%) and a decrease of zinc (-25%). At the highest dose of 30 mg/kg, some variations of the concentrations of elements in tissues were observed. But, on no account did retinoids induce an alteration of the mineral composition of bone, despite obvious macroscopic bone alterations.     

Urinary enzyme excretion in acute and subacute experimental lithium administration

Blood lithium (Li) levels, renal functional parameters and urine excretion of enzymatic activities having different intracellular sites were investigated on rats submitted to acute and subacute Li chloride administration. In acute experiments increased levels of all detected enzymes were assayed following Li single doses of 5 and 10 mEq/kg b.w. In subacute poisoning, urine output of lactate dehydrogenase, aspartate transaminase and alanine transaminase was significantly over the basal ranges following 15 days in concomitance with marked elevation of plasma Li levels and exhibited progressive increase until 30 days; on the 10th day following Li withdrawal, elevated excretion of enzymatic activities was still assayed. The results are in agreement with data about the localization of the histologic lesions involving different sites of the nephron in acute Li poisoning and the distal tubular tract in subacute toxicity. In subacute administration the output of cytoplasmic and mitochondrial activities can be assumed as an index of damage of the nephron cells which can persist following Li withdrawal. Our findings indicate that the urine enzyme assay is a valuable tool to detect renal damage in experimental Li nephropathy.