Correlation between acetone-potentiated CCl4-induced liver injury and blood concentrations after inhalation or oral administration

Engineering chitosan nano-cocktail containing iron oxide and ceria: A two-in-one approach for treatment of inflammatory diseases and tracking of material delivery

In this study, modular two-in-one nano-cocktails were synthesised to provide treatment of inflammatory diseases and also enable tracking of their delivery to the disease sites. Chitosan nano-cocktails loaded with treatment module (cerium oxide nanoparticles) and imaging module (iron oxide nanoparticles) were synthesised by electrostatic self-assembly (Chit-IOCO) and ionic gelation method (Chit-TPP-IOCO), respectively. Their MRI capability, anti-inflammatory and anti-fibrosis ability were investigated. Results demonstrated that Chit-IOCO significantly reduced the expression of TNF-α and COX-2, while Chit-TPP-IOCO reduced IL-6 in the LPS-stimulated macrophages RAW264.7. Cytotoxicity studies showed that the nano-cocktails inhibited the proliferation of macrophages. Additionally, Chit-IOCO exhibited higher in vitro MRI relaxivity than Chit-TPP-IOCO, indicating that Chit-IOCO is a better MRI contrast agent in macrophages. It was possible to track the delivery of Chit-IOCO to the inflamed livers of CCl₄-treated C57BL/6 mice, demonstrated by a shortened T₂^⁎ relaxation time of the livers after injecting Chit-IOCO into mice. In vivo anti-inflammatory and blood tests demonstrated that Chit-IOCO reduced inflammation-related proteins (TNF-a, iNOS and Cox-2) and bilirubin in CCl₄ treated C57BL/6. Histology images indicated that the nano-cocktails at the treatment doses did not affect the organs of the mice. Importantly, the nano-cocktail reduced fibrosis of CCl₄-treated mouse liver. This is the first reported data on the anti-inflammation and anti-fibrosis efficacy of Chit-IOCO in C57BL/6 mouse liver inflammation model. Overall, Chit-IOCO nanoparticles have shown great potential in MR imaging/detecting and treating/therapeutic capabilities for inflammatory diseases.

Crataegus songarica methanolic extract accelerates enzymatic status in kidney and heart tissue damage in albino rats and its in vitro cytotoxic activity

CONTEXT

Crataegus songarica K. Koch (Rosaceae) has been used in folk medicine to treat various diseases.

OBJECTIVE

This study evaluates the effect of C. songarica methanol extract on the kidney and heart tissue damage of albino rats, and to determine cytotoxic activity of various extracts of songarica on various human cancer cell lines.

MATERIALS AND METHODS

Rats were divided into six groups, Group I received water only; Group II received CCl4 (1 mL/kg b wt) intraperitoneal; C. songarica extract (at doses of 100, 200 and 300 mg/kg b wt) orally for 15 days. Cytotoxic activity was determined by SRB method using MCF-7, HeLa, HepG2, SF-295, SW480 and IMR-32 cell lines.

RESULTS

Compared with CCl4 group, administration of C. songarica extract at the dose of 300 mg/kg b wt, significantly decreases serum creatinine (59.74%), urea (40.23%) and cholesterol (54 mg/dL), MDA (0.007 nmol/mg protein) in kidney and (0.025 nmol/mg protein) in heart tissue, along with evaluation of GSH (209.79 ± 54.6), GR (111.45 ± 2.84), GPx (94.01 ± 14.80), GST (201.71) in kidney tissue and GSH (51.47 ± 1.47), GR (45.42 ± 6.69), GPx (77.19 ± 10.94), GST (49.89) in heart tissue. In addition, methanol, ethanol and ethyl acetate extracts exhibited potent anticancer activity on six cancer cell lines with IC50 values ranging from 28.57 to 85.106 µg/mL.

DISCUSSION AND CONCLUSION

Crataegus songarica methanol extract has a potential antioxidant effect as it protects the kidney and heart tissue against CCl4-induced toxicity, prevents DNA damage and showed strong anticancer activity.

Modulatory potentials of aqueous leaf and unripe fruit extracts of Carica papaya Linn. (Caricaceae) against carbon tetrachloride and acetaminophen-induced hepatotoxicity in rats

Introduction:

Carica papaya Linn is used in a traditional medicine for hepatobiliary disorders. This study investigated the hepatomodulatory effects of aqueous extracts of C. papaya leaf (CPL) and unripe fruit (CPF) at doses of 100 and 300 mg/kg on carbon tetrachloride (CCl₄) and acetaminophen (ACM)-induced liver toxicities in rats.

Materials and Methods:

Rats were administered CCl₄ (3 ml/kg in olive oil, i.p.) followed by oral administration of CPL and CPF at 2, 6 and 10 h intervals. The ACM model proceeded with the same method but inclusive of animals treated with N-acetyl cysteine (3 ml/kg i.p). At the end of the study, serum levels of liver biomarkers and antioxidant enzymes were assessed and histology of the liver tissues determined.

Results:

There was a significant (P < 0.05) reduction in CCl₄ and ACM-induced increases in serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and direct bilirubin at 100 and 300 mg/kg, respectively. The levels of catalase (CAT), superoxide dismutase and reduced GSH were decreased in both models with corresponding significantly (P < 0.05) elevated level of malondialdehyde. However, these antioxidant enzymes were significantly (P < 0.05) increased in CPL and CPF-treated rats. Histopathological assessment of the liver confirmed the protective effects of CPL and CPF on CCl₄ and ACM-induced hepatic damage evidenced by the normal presentation of liver tissue architecture.

Conclusion:

These results indicate that aqueous extracts of C. papaya may be useful in preventing CCl₄ and ACM-induced liver toxicities.

Hepatoprotective and antioxidant effects of Argyreia speciosa in rats

The present study has been designed to evaluate the liver protective and in-vivo antioxidant role of Ethanolic extract (EtAS) and Ethyl acetate extract (EAAS) of roots of Argyreia speciosa, an important 'rasayana' herb in Indian System of medicine, in CCl(4)-induced hepatotoxicity and oxidative stress in rats. Animals were treated with EtAS and EAAS at doses of 200 mg and 400 mg/kg body weight p.o. along with CCl(4) (0.7 ml/kg in olive oil, 1:1 v/v i.p. on every alternate days) for seven days. Serum biochemical parameters such as SGOT, SGPT, ALP, cholesterol, total and direct bilirubin were determined. Antioxidant status in liver was determined by measuring the activities of Super oxide dismutase (SOD), catalase and peroxidase. Histopathological study of isolated liver specimens was also carried out to know the protection offered by the extracts. There was a significant rise in the levels of serum GOT, GPT, and ALP and other biochemical parameters, decrease in the levels of SOD, catalase and peroxidase after administration of CCl(4). Suspensions of EtAS and EAAS (200 and 400 mg/kg) successfully prevented the alterations of these effects in rats (p< 0.001). Histopathological examination demonstrated that CCl(4) treated group induces ballooning degeneration and centrilobular necrosis. Groups treated with EtAS and EAAS showed recovery on ballooning degeneration and centrolobular bridging necrosis was occasionally present. Data also showed that these extracts possessed strong antioxidant activity, and were comparable to Silymarin, a well known liver protecting herbal formulation.

Phytomedicinal activity of Terminalia arjuna against carbon tetrachloride induced cardiac oxidative stress

Chronic and acute overproduction of reactive oxygen species (ROS) plays a positive role in the development of cardiovascular diseases under pathophysiological conditions. However, very little is known about carbon tetrachloride (CCl(4)) induced cardiac oxidative stress. The present study was conducted to find out CCl(4) induced oxidative insult in cardiac tissue and the cardioprotective effect of the 70% ethanol extractable active constituents of the bark of Terminalia arjuna (TA) against that stress in mice. Oral administration of CCl(4) at a dose of 1ml/kg body weight for 2 days significantly reduced the activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST), as well as depleted the level of reduced glutathione (GSH) in the cardiac tissue. In addition, extent of lipid peroxidation and the level of oxidized glutathione (GSSG) were increased under the same experimental conditions. Oral treatment of the active constituents of TA at a dose of 50mg/kg body weight for 7 days prior to CCl(4) administration significantly restored the activities of all antioxidant enzymes as well as increased the level of GSH and decreased the level of lipid peroxidation end products. In addition, FRAP assay showed that the active constituents of TA enhanced the cardiac intracellular antioxidant activity. Histological studies also supported the cardioprotective role of the active constituents. The active constituents-induced protective effect was compared with a known antioxidant, vitamin C. To the best of our knowledge, this is the first report describing the CCl(4) induced cardiac oxidative stress and cardioprotective action of the active phytoconstituents of Terminalia arjuna against that oxidative insult.

Aqueous extract of Terminalia arjuna prevents carbon tetrachloride induced hepatic and renal disorders

Background

Carbon tetrachloride (CCl₄) is a well-known hepatotoxin and exposure to this chemical is known to induce oxidative stress and causes liver injury by the formation of free radicals. Acute and chronic renal damage are also very common pathophysiologic disturbances caused by CCl₄. The present study has been conducted to evaluate the protective role of the aqueous extract of the bark of Termnalia arjuna (TA), an important Indian medicinal plant widely used in the preparation of ayurvedic formulations, on CCl₄ induced oxidative stress and resultant dysfunction in the livers and kidneys of mice.

Methods

Animals were pretreated with the aqueous extract of TA (50 mg/kg body weight) for one week and then challenged with CCl₄ (1 ml/kg body weight) in liquid paraffin (1:1, v/v) for 2 days. Serum marker enzymes, namely, glutamate pyruvate transaminase (GPT) and alkaline phosphatase (ALP) were estimated in the sera of all study groups. Antioxidant status in both the liver and kidney tissues were estimated by determining the activities of the antioxidative enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST); as well as by determining the levels of thiobarbutaric acid reactive substances (TBARS) and reduced glutathione (GSH). In addition, free radical scavenging activity of the extract was determined from its DPPH radical quenching ability.

Results

Results showed that CCl₄ caused a marked rise in serum levels of GPT and ALP. TBARS level was also increased significantly whereas GSH, SOD, CAT and GST levels were decreased in the liver and kidney tissue homogenates of CCl₄ treated mice. Aqueous extract of TA successfully prevented the alterations of these effects in the experimental animals. Data also showed that the extract possessed strong free radical scavenging activity comparable to that of vitamin C.

Conclusion

Our study demonstrated that the aqueous extract of the bark of TA could protect the liver and kidney tissues against CCl₄-induced oxidative stress probably by increasing antioxidative defense activities.

Mechanisms of circadian rhythmicity of carbon tetrachloride hepatotoxicity

The toxicity of carbon tetrachloride (CCl(4)) and certain other chemicals varies over a 24-h period. Because the metabolism of some drugs follows a diurnal rhythm, it was decided to investigate whether the hepatic metabolic activation of CCl(4) was rhythmic and coincided in time with maximum susceptibility to CCl(4) hepatotoxicity. A related objective was to test the hypothesis that abstinence from food during the sleep cycle results in lipolysis and formation of acetone, which participates in induction of liver microsomal cytochrome P450IIE1 (CYP2E1), resulting in a diurnal increase in CCl(4) metabolic activation and acute liver injury. Groups of fed and fasted male Sprague-Dawley rats were given a single oral dose of 800 mg of CCl(4)/kg at 2- to 4-h intervals over a 24-h period. Serum enzyme activities, measured 24 h post dosing as indices of acute liver injury, exhibited distinct maxima in both fed and fasted animals dosed with CCl(4) near the beginning of their dark/active cycle. Blood acetone, hepatic CYP2E1 activity, and covalent binding of (14)CCl(4)/metabolites to hepatic microsomal proteins in untreated rats fed ad libitum followed circadian rhythms similar to that of susceptibility to CCl(4). Parallel fluctuations of greater amplitude were seen in rats fasted for 24 h. Hepatic glutathione levels were lowest at the time of greatest susceptibility to CCl(4). Acetone dose-response experiments showed high correlations between blood acetone levels, CYP2E1 induction, and CCl(4)-induced liver injury. Pretreatment with diallyl sulfide suppressed CYP2E1 and abolished the circadian rhythmicity of susceptibility to CCl(4). These findings provide additional support for acetone's physiological role in CYP2E1 induction and for CYP2E1's role in modulating CCl(4) chronotoxicity in rats.

Relationship between blood/air partition coefficients of lipophilic organic solvents and blood triglyceride levels

The blood/air partition coefficient is one of the important parameters for understanding the pharmacokinetics of organic solvents. In conventional pharmacokinetic models, the partition coefficient has been used as a constant value for each solvent. However, blood triglyceride content varies according to a diet, and the variation may affect the partition coefficient of lipophilic organic solvents. In this study, the relationship between the blood/air partition coefficient of lipophilic organic solvents and plasma triglyceride concentrations was clarified. Corn oil (4.0 ml/kg) was administered orally to male Wistar rats, and blood samples were collected 3 h after the administration, when the plasma triglyceride level reached a peak. Control rats received the same amount of distilled water via the same route. The blood/air partition coefficients of five types of lipophilic solvents (m-xylene, trichloroethylene, 1,1,1-trichloroethane, chloroform and carbon tetrachloride) were determined in these two groups of blood samples. The hematological and biochemical parameters were also examined in the same blood samples. Although the mean plasma triglyceride level in the oil group increased about 3.3 times compared with that in the control group, the increase in the blood/air partition coefficients of the five lipophilic solvents was relatively low (approximately 1.2-1.5 times). We concluded that the diet has no significant effect on the blood/air partition coefficients of organic solvents, and the value can be used as a constant parameter for each solvent in a physiological simulation model.

Pharmacokinetics and hepatotoxicity of diclofenac using an isolated perfused rat liver

Pharmacokinetics and hepatotoxicity of diclofenac was studied in a recirculating model of isolated perfused rat liver. Ten male Sprague-Dawley rat (weighing 230-330 g) livers were perfused for 2 h with 250 mL Krebs-Henseleit bicarbonate buffer that contained 10.75 mg (group A, n = 5) and 1.075 mg (group B, n = 5) of diclofenac (approximately 100 and 10 times the therapeutic dose in man, respectively). Samples were collected from the efflux at regular time intervals for the determination of diclofenac concentrations by a high performance liquid chromatography (HPLC) method. Pharmacokinetic analyses were carried out using a computer program. To establish viability of the liver and toxicity of the drug, enzyme activity measurements of lactate dehydrogenase (LDH), aspartate aminotransferase (SGOT) and piruvate aminotransferase (SGPT) were performed by a spectrophotometric method. Oxygen consumption was also recorded during the entire perfusion period. Both groups presented bicompartmental kinetics. Concentration profiles showed that group B had a better metabolizing capacity, reflected in a 85.54 +/- 37.05 min half-life, a 0.52 +/- 0.19 mL min-1 g-1 liver clearance and a 0.517 +/- 0.188 extraction ratio, compared to group A, which presented a 123.95 +/- 88.13 min half-life, a 0.1164 +/- 0.067 mL min-1 g-1 liver clearance (P < 0.002) and a 0.116 +/- 0.680 extraction ratio (P < 0.002). LDH activity showed a significant increase in group A at 90 min in comparison with the control group, while in group B this increase was significantly higher at 10 min (P < 0.004). The aminotransferase levels did not show a significant increase. According to these results, diclofenac would not have a direct hepatotoxic effect, even at doses 100 times higher than therapeutic ones.

Tissue concentrations of methyl isobutyl ketone, methyl n-butyl ketone and their metabolites after oral or inhalation exposure

Quantitative relationships between plasma, liver and lung methyl isobutyl ketone (MiBK) and methyl n-butyl ketone (MnBK) concentrations after oral or inhalation exposure were established. Their respective metabolites (4-methyl-2-pentanol, 4-hydroxy-methyl isobutyl ketone, 2-hexanol, and 2,5-hexanedione) were also quantified. Male Sprague-Dawley rats were exposed for 3 days to MiBK or MnBK vapors (4 h/day) or treated orally for 3 days with a MiBK- or MnBK-corn oil solution. Both ketones and their respective metabolites in plasma or tissue concentrations were determined by gas chromatography. MiBK and MnBK plasma and tissue concentrations increased in a dose-related manner with the administered dose irrespective of the route of administration. Metabolite concentrations, however, were influenced by the route of administration.

Can serum bilirubin be an index of in vivo oxidative stress?

Bilirubin has been suggested as a physiological antioxidant, and recent studies suggest that its synthesis is induced in response to oxidative stress. Numerous reports in the literature show increases in serum bilirubin when using halogenated hydrocarbons as oxidative stress inducers. Analogously, these increases should also be expected for other inducers. On the other hand, bilirubin is destroyed by the same molecules that induce its production. The measurement of bilirubin may be a useful index of in vivo oxidative stress, although no big differences in bilirubin levels should be expected.

An introduction to the practice, prevalence and chemical toxicology of volatile substance abuse

1. Volatile substance abuse is largely a teenage practice; it is estimated that in the UK 3.5-10% of young people have at least experimented and that 0.5-1% are current users. 2. The products abused are many and varied but only about 20 chemical compounds, notably toluene, chlorinated solvents such as 1,1,1-trichloroethane, fuel gases such as butane and aerosol propellants, are commonly encountered. 3. The acute hazard varies with the compound, product and mode of abuse. Mortality in the UK is now about 100 per year, from all social classes, 90% of whom are male. 4. Chronic toxicity is difficult to assess, partly because of the diversity of products abused. However it is clear that some long-term abusers suffer permanent damage to the central nervous system, heart, liver and kidney. 5. Toxicological analysis may be relied upon for confirmation of diagnosis, providing attention is paid to the kinetics of excretion and stability in the sample. 6. Responses include codes of practice for the sale of products and educational strategies; legislation has also been enacted. There is little evidence that any of these measures have made a significant impact on the problem.

Potentiation of CCl4-induced liver injury by ketonic and ketogenic compounds: role of the CCl4 dose

Potentiation of haloalkane hepatotoxicity by ketones and ketogenic agents is a well-known phenomenon. The importance of the CCl4 dosage in these combinations, however, has not been explored. Its influence was investigated in male Sprague-Dawley rats. Dose-effect curves for potentiation were generated using 1,3-butanediol, methyl n-butyl ketone or methyl isobutyl ketone as potentiation agents. Animals were orally treated with these compounds prior to a challenge of CCl4 (0 to 0.5 ml/kg, ip). Liver injury was assessed by monitoring plasma ALT activity and bilirubin concentrations after CCl4 treatment. The minimal effective dosage (MED) for each potentiator was used as the criterion of comparison for each combination. The MED values were determined from the plasma ALT data. Results showed that when the CCl4 dosage was increased from 0.01 to 0.10 ml/kg, the MED of each potentiator decreased 10-fold. For a given potentiator, the product of the CCl4 dosage (H, "hepatotoxicant") by the corresponding MED value (P, "potentiator") remained the same in this range of CCL4 dosages. The severity of the liver injury was similar. These findings suggest that a given level of liver injury induced by a ketone/haloalkane combination could be evaluated on the basis of the [P X H] product.