Carbon tetrachloride hepatotoxicity: an example of lethal cleavage

Gossypetin targets the liver-brain axis to alleviate pre-existing liver fibrosis and hippocampal neuroinflammation in mice

Liver fibrosis occurs in response to chronic damage and inflammation to the liver. Leaving untreated, it can lead to decreased liver function and can eventually progress to cirrhosis, a more advanced and irreversible state of liver damage. Clinical investigations showed that chronic liver disease associated with neurological symptoms including anxiety, depression, and cognitive decline. However, few therapeutic options are available for treating liver and related brain pathologies simultaneously. In this study, we aim to find therapeutic candidates that target the liver-brain axis. Gossypetin, a flavonoid from sedum, shows promising capability in treating liver and brain pathologies in CCl4-induced mouse model. Short term of gossypetin administration is sufficient to ameliorate impaired liver function and pre-existing liver fibrosis, suppress MKK3/6-p38 MAPK and p53 activation, and abolish the activation of hepatic stellate cells and Kupffer cells. Although we observe no neuronal loss in the brain of mice with liver fibrosis, we do observe astrogliosis and microglial activation in certain brain regions, especially the hippocampus. Brief gossypetin administration also shows potential in alleviating neuroinflammation in these regions. These results suggest that gossypetin can target the liver-brain axis and be a promising candidate for treating chronic liver fibrosis patients with neurological symptoms.

Evaluation of the carcinogenicity of carbon tetrachloride

Carbon tetrachloride (CCl4) has been extensively used and reported to produce toxicity, most notably involving the liver. Carbon tetrachloride metabolism involves CYP450-mediated bioactivation to trichloromethyl and trichloromethyl peroxy radicals, which are capable of macromolecular interaction with cell components including lipids and proteins. Radical interaction with lipids produces lipid peroxidation which can mediate cellular damage leading to cell death. Chronic exposure with CCl4 a rodent hepatic carcinogen with a mode of action (MOA) exhibits the following key events: 1) metabolic activation; 2) hepatocellular toxicity and cell death; 3) consequent regenerative increased cell proliferation; and 4) hepatocellular proliferative lesions (foci, adenomas, carcinomas). The induction of rodent hepatic tumors is dependent upon the dose (concentration and exposure duration) of CCl4, with tumors only occurring at cytotoxic exposure levels. Adrenal benign pheochromocytomas were also increased in mice at high CCl4 exposures; however, these tumors are not of relevant importance to human cancer risk. Few epidemiology studies that have been performed on CCl4, do not provide credible evidence of enhanced risk of occurrence of liver or adrenal cancers, but these studies have serious flaws limiting their usefulness for risk assessment. This manuscript summarizes the toxicity and carcinogenicity attributed to CCl4, specifically addressing MOA, dose-response, and human relevance.

A white paper on Phospholipid Hydroperoxide Glutathione Peroxidase (GPx4) forty years later

The purification of a protein inhibiting lipid peroxidation led to the discovery of the selenoperoxidase GPx4 forty years ago. Thus, the evidence of the enzymatic activity was reached after identifying the biological effect and unambiguously defined the relationship between the biological function and the enzymatic activity. In the syllogism where GPx4 inhibits lipid peroxidation and its inhibition is lethal, cell death is operated by lipid peroxidation. Based on this rationale, this form of cell death emerged as regulated iron-enforced oxygen toxicity and was named ferroptosis in 2012. In the last decades, we learned that reduction of lipid hydroperoxides is indispensable and, in cooperation with prooxidant systems, controls the critical steady state of lipid peroxidation. This concept defined the GPx4 reaction as both the target for possible anti-cancer therapy and if insufficient, as cause of degenerative diseases. We know the reaction mechanism, but the details of the interaction at the membrane cytosol interface are still poorly defined. We know the gene structure, but the knowledge about expression control is still limited. The same holds true for post-transcriptional modifications. Reverse genetics indicate that GPx4 has a role in inflammation, immunity, and differentiation, but the observations emerging from these studies need a more specifically addressed biochemical evidence. Finally, the role of GPx4 in spermatogenesis disclosed an area unconnected to lipid peroxidation. In its mitochondrial and nuclear form, the peroxidase catalyzes the oxidation of protein thiols in two specific aspects of sperm maturation: stabilization of the mid-piece and chromatin compaction. Thus, although available evidence converges to the notion that GPx4 activity is vital due to the inhibition of lipid peroxidation, it is reasonable to foresee other unknown aspects of the GPx4 reaction to be disclosed.

Fabrication and evaluation of mannose decorated curcumin loaded nanostructured lipid carriers for hepatocyte targeting: In vivo hepatoprotective activity in Wistar rats

Curcumin is a well-recognized antioxidant phytoactive isolated from the rhizomes of Curcuma longa. Numerous landmark investigations have proved the antioxidant and hepatoprotective potential of curcumin. The aim of present study was to target curcumin loaded nanocarriers to hepatocytes using asialoglycoprotein receptors targeting strategy. Mannose, a water-soluble carbohydrate, was hydrophobized by anchoring stearylamine with an objective to conjugate mannose on the surface of curcumin loaded nanostructured lipid carriers for targeting asialoglycoprotein receptors on hepatocytes. Mannose conjugated stearylamine was synthesized and characterized using various analytical techniques. The synthesized targeting ligand was incorporated curcumin loaded nanostructured lipid carriers and characterized by photon correlation spectroscopy. Zeta potential measurement was used to confirm the conjugation of the synthesized ligand to the surface of drug-loaded nanostructured lipid carriers. CCl₄ induced hepatotoxicity in male Wistar rats was used as an experimental animal model to evaluate the hepatoprotective potential of formulated drug encapsulated nanostructured lipid carriers. The hepatoprotective potential was assessed by measuring serum liver injury markers and oxidative stress parameters in the liver post–mitochondrial supernatant. Mannose conjugated nanostructured lipid carriers showed acceptable particle size which revealed its suitability for hepatocyte targeting. In addition to this, mannose conjugated nanocarriers revealed significantly better (p ​< ​0.05) reduction of serum liver injury markers and proinflammatory cytokines compared to the unconjugated one which confirmed hepatocytes targeting potential of the synthesized ligand. Asialoglycoprotein receptors targeting could be a landmark strategy for hepatocyte targeting. Thus, the synthesized mannose anchored stearylamine could be a promising novel targeting ligand having hepatocyte targeting potential.

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The asialoglycoprotein receptors can be utilized for hepatocyte targeting.

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NLCs are major lipid based carrier used for phytoactive delivery.

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NLCs are promising lipid carrier for hepatocyte targeting.

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Curcumin is most prominent antioxidant phytoactive with hepatoprotective potential.

Hepatoprotective Potential of Pomegranate in Curbing the Incidence of Acute Liver Injury by Alleviating Oxidative Stress and Inflammatory Response

Hepatitis is an inflammatory disease of the liver and is considered one of the leading causes of death worldwide. Due to its scavenging activity, Punica granatum may be used for the treatment and prevention of liver diseases. The current study investigated the protective mechanism underlying the effects of pomegranate against a rat model of carbon tetrachloride–induced liver injury. Intraperitoneal injection of CCl₄ resulted in liver inflammation, oxidative stress, and accumulation of lipid in hepatocytes. CCl₄ induced a downregulation of superoxide dismutase (SOD), glutathione (GSH), and melonaldehyde (MDA). Pomegranate protection was assessed in terms of biochemical parameters, histopathology, and immunohistochemistry. Promegranate administration decreased inflammation, elevated serum enzymes and ROS production, and countered the debilitating effects caused by CCl₄. In addition, CCl₄-induced histological changes were absent in the crude pomegranate extract group, which also enhanced the scavenging activity of reactive oxygen species by enhancing the antioxidant defense mechanism as confirmed by detecting MDA, SOD, and GSH expressions. The migration of CD68⁺ macrophages was halted at the injured area of the central vein and the number of macrophages was reduced to the normal control by the crude extract compared to the positive control silymarin group. Likewise, protective effects of ethylacetate and the aqueous fraction of the crude extract were also observed. However, the butanol and n-hexane fractions displayed increased levels of ALT, AST, and ALP as compared to silymarin. About 25% damage to hepatocytes was observed in the butanol and n-hexane group by histopathological examination, which is a little better compared to the CCl₄-treated group. The crude extract and its ethyl acetate and aqueous fractions may be accountable for the hepatoprotective potential of Punica granatum, which was further confirmed by in vivo experiments. Together, these findings confirm that pomegranate exerts hepatoprotective activity against CCl₄-induced oxidative stress and liver damage.

Toxicity of carbon tetrachloride, free radicals and role of antioxidants

Several chemicals, including environmental toxicants and clinically useful drugs, cause severe cellular damage to different organs of our body through metabolic activation to highly reactive substances such as free radicals. Carbon tetrachloride is an organic compound of which chemical formula is CCl₄. CCl₄ is strong toxic in the kidney, testicle, brain, heart, lung, other tissues, and particularly in the liver. CCl₄ is a powerful hepatoxic, nephrotoxic and prooxidant agent which is widely used to induce hepatotoxicity in experimental animals and to create hepatocellular carcinoma, hepatic fibrosis/cirrhosis and liver injury, chemical hepatitis model, renal failure model, and nephrotoxicity model in recent years. The damage-causing mechanism of CCl₄ in tissues can be explained as oxidative damage caused by lipid peroxidation which starts after the conversion of CCl₄ to free radicals of highly toxic trichloromethyl radicals (•CCl₃) and trichloromethyl peroxyl radical (•CCl₃O₂) via cytochrome P450 enzyme. Complete disruption of lipids (i.e., peroxidation) is the hallmark of oxidative damage. Free radicals are structures that contain one or more unpaired electrons in atomic or molecular orbitals. These toxic free radicals induce a chain reaction and lipid peroxidation in membrane-like structures rich in phospholipids, such as mitochondria and endoplasmic reticulum. CCl₄-induced lipid peroxidation is the cause of oxidative stress, mitochondrial stress, endoplasmic reticulum stress. Free radicals trigger many biological processes, such as apoptosis, necrosis, ferroptosis and autophagy. Recent researches state that the way to reduce or eliminate these CCl₄-induced negative effects is the antioxidants originated from natural sources. For normal physiological function, there must be a balance between free radicals and antioxidants. If this balance is in favor of free radicals, various pathological conditions occur. Free radicals play a role in various pathological conditions including Pulmonary disease, ischemia / reperfusion rheumatological diseases, autoimmune disorders, cardiovascular diseases, cancer, kidney diseases, hypertension, eye diseases, neurological disorders, diabetes and aging. Free radicals are antagonized by antioxidants and quenched. Antioxidants do not only remove free radicals, but they also have anti-inflammatory, anti-allergic, antithrombotic, antiviral, and anti-carcinogenic activities. Antioxidants contain high phenol compounds and antioxidants have relatively low side effects compared to synthetic drugs. The antioxidants investigated in CCI₄ toxicity are usually antioxidants from plants and are promising because of their rich resources and low side effects. Data were investigated using PubMed, EBSCO, Embase, Web of Science, DOAJ, Scopus and Google Scholar, Carbon tetrachloride, carbon tetrachloride-induced toxicity, oxidative stress, and free radical keywords. This study aims to enlighten the damage-causing mechanism created by free radicals which are produced by CCl₄ on tissues/cells and to discuss the role of antioxidants in the prevention of tissue/cell damage. In the future, Antioxidants can be used as a therapeutic strategy to strengthen effective treatment against substances with high toxicity such as CCl₄ and increase the antioxidant capacity of cells.

Govaniadine Ameliorates Oxidative Stress, Inflammation, and Kupffer Cell Activation in Carbon Tetrachloride-Induced Hepatotoxicity in Rats

Liver diseases such as hepatic carcinoma are one of the main health problems worldwide. Herbal drugs are largely used to treat liver injury in the indigenous system of medicine and may provide lead compounds for hepatoprotective drug discovery. The present study is investigated to test the Corydalis govaniana Wall. extract, fraction, and isolate therapeutically active constituents to explore their hepatoprotective, anti-inflammatory, and antioxidant activities. For this purpose, the antioxidant activity of govaniadine, caseadine, caseamine, and protopine was performed by assessing the scavenging events of the stable 2,2-diphenyl-1-picrylhydrazyl. Hepatoprotection of govaniadine was assessed in terms of reduction in serum enzymes (alanine aminotransferase, aspartate transaminase, and alkaline phosphatase) caused by CCl₄-induced liver injury in rats and by histopathological techniques. All the compounds showed significant antioxidant activity with a percentage inhibition of 92.2, 86.7, 85.3, and 79.7, respectively, compared to propyl gallate 90.3%. Treatment with govaniadine reduced the serum enzyme level down to normal levels in the CCl₄-treated group while inhibiting the increase of malondialdehyde, and the induction of superoxide dismutase and the glutathione level was upregulated. Histopathology showed ∼47% damage to the liver cells in the CCl₄-treated group; reduction in this damaged area was found to be better upon using govaniadine. Immunohistochemistry results showed that govaniadine as compared to silymarin has exceedingly decreased the inflammation by halting the CCl₄-induced activation of hepatic macrophages. In carrageenan-induced paw edema assay, govaniadine significantly alleviated the edema after 1-5 h at a dose of 20 mg/kg (26.00 and 28.5%), 50 mg/kg (22.05 and 27.0%), and 100 mg/kg (20.02 and 25.30%), respectively. The results of our experiments suggest that govaniadine showed antioxidant and hepatoprotective activity in liver injury. The hepatoprotective function of govaniadine may be associated to the scavenging of the free radical and attenuation of oxidative stress as well as inflammatory responses in the liver. Hence, govaniadine may be a lead compound for the hepatoprotective drug discovery process and further research is needed to find out their molecular mechanism of protection.

Period1 mediates rhythmic metabolism of toxins by interacting with CYP2E1

The biological clock is an endogenous biological timing system, which controls metabolic functions in almost all organs. Nutrient metabolism, substrate processing, and detoxification are circadian controlled in livers. However, how the clock genes respond to toxins and influence toxicity keeps unclear. We identified the clock gene Per1 was specifically elevated in mice exposed to toxins such as carbon tetrachloride (CCl₄). Mice lacking Per1 slowed down the metabolic rate of toxins including CCl₄, capsaicin, and acetaminophen, exhibiting relatively more residues in the plasma. Liver injury and fibrosis induced by acute and chronic CCl₄ exposure were markedly alleviated in Per1-deficient mice. These processes involved the binding of PER1 protein and hepatocyte nuclear factor-1alpha (HNF-1α), which enhances the recruitment of HNF-1α to cytochrome P450 2E1 (Cyp2e1) promoter and increases Cyp2e1 expression, thereby promoting metabolism for toxins in the livers. These results indicate that PER1 mediates the metabolism of toxins and appropriate suppression of Per1 response is a potential therapeutic target for toxin-induced hepatotoxicity.

An updated review of protective effects of rosemary and its active constituents against natural and chemical toxicities

Natural and chemical toxic agents cause severe adverse effects on people's health in a variety of exposing ways. Herbal medications have taken into consideration as alternative safe treatments for toxicities. Rosmarinus officinalis also known as rosemary belongs to the Lamiaceae family. Rosemary and its constituents including carnosic acid, rosmarinic acid, and carnosol have a lot of benefits such as anti-inflammatory, antioxidant, anti-mutagenic, anti-bacterial, antiviral, antinociceptive, and neuroprotective activities. In this literate review, we focused on the protective effects of rosemary and its main compounds against natural and chemical toxicities in both in vitro and in vivo studies. The protective effects of rosemary and its components are mostly mediated through different mechanisms such as the inhibition of oxidative stress, reduction of inflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-17 (IL-17), cyclooxygenase-2 (COX-2) and nuclear factor ĸB (NF-ĸB) as well as the modulation of apoptosis and mitogen-activated protein kinase (MAPK) signaling pathways.

Milk thistle (Silybum Marianum) as an antidote or a protective agent against natural or chemical toxicities: a review

Biological and chemical agents cause dangerous effects on human health via different exposing ways. Recently, herbal medicine is considered as a biological and safe treatment for toxicities. Silybum marianum (milk thistle), belongs to the Asteraceae family, possesses different effects such as hepatoprotective, cardioprotective, neuroprotective, anti-inflammatory and anti-carcinogenic activities. Several studies have demonstrated that this plant has protective properties against toxic agents. Herein, the protective effects of S. marianum and its main component, silymarin, which is the mixture of flavonolignans including silibinin, silydianin and silychristin acts against different biological (mycotoxins, snake venoms, and bacterial toxins) and chemical (metals, fluoride, pesticides, cardiotoxic, neurotoxic, hepatotoxic, and nephrotoxic agents) poisons have been summarized. This review reveals that main protective effects of milk thistle and its components are attributed to radical scavenging, anti-oxidative, chelating, anti-apoptotic properties, and regulating the inflammatory responses.

Antioxidant and hepato-preventive effect of Citrus aurantium extract against carbon tetrachloride-induced hepatotoxicity in rats and characterisation of its bioactive compounds by HPLC-MS

The objective of this study is to explore the preventive effects of ethyl acetate fraction from Citrus aurantium leaf extract (EACA), associated with its phytochemical content, against the toxic impacts of acute exposure to carbon tetrachloride (CCl₄) in the liver of adult rats. HPLC analysis of ethyl acetate fraction from extract C. aurantium revealed eight compounds. Administration of a single dose of CCl₄ caused hepatoxicity as monitored by an increase in lipid peroxidation (thiobarbituric acid reactive substances) and in protein carbonyl level but a decrease in antioxidant markers in the liver tissue. The pre-treatment with EACA; significantly prevented the increased plasma levels of hepatic markers and lipid levels induced by CCl₄ in rats. Furthermore, this fraction ameliorated biochemical and histological parameters as compared to CCl₄-treated group. Our results suggest that C. aurantium contains promising substances to counteract the CCl₄ intoxication and can be efficient in the prevention of hepatotoxicity complications.

Anti-inflammatory, anti-oxidant and hepatoprotective effects of lactoferrin in rats

Carbon tetrachloride (CCl₄) is a strong hepatotoxic agent. The ability of the anti-inflammatory agent, lactoferrin (LF), to alleviate hepatic inflammation in a Wistar rat model administered with carbon tetrachloride (CCl₄) was examined. Thirty male Wistar rats were segregated into 5 groups (6 rats per group): Control group, LF group (300 mg LF/kg b. wt daily for three weeks), CCl₄ group (1 ml CCl₄/kg b. wt once orally), LF-protected group (300 mg LF/kg b. wt daily for 3 weeks followed by 1 mL CCl₄/kg b. wt once orally), and LF-treated group (1 mL CCl₄/kg b.wt once orally followed by 300 mg LF/kg b. wt orally every day for three weeks). Erythrogram, leukogram, activity of oxidative stress markers (Superoxide dismutase [SOD], Glutathione peroxidase [GPx], and Malondialdehyde [MDA]), and expression of hepatic paraoxonase-1 (PON1), interleukin (IL)-1β, and IL-10 mRNA were determined. Histopathological examination of the hepatic tissue was carried out. CCl₄ caused liver injury, loss of liver antioxidant activity of SOD and GPx, and a significant increase in the level of malondialdehyde in the serum. Moreover, CCl₄ induced up-regulation of hepatic pro-inflammatory (IL-1β) factors, and down-regulation of anti-inflammatory (IL-10 and PON1) factors. Based on histopathological examination, the hepatic tissues had severe inflammation and were damaged. However, LF mitigated the liver damage, oxidative stress, and hepatotoxicity caused by CCl₄. Overall, these results suggest that LF-mediated immunological mechanisms alleviate CCl4-induced hepatic toxicity and provide a novel perspective on the potential use of LF for prophylactic and therapeutic applications in treating liver diseases.

TAZ stimulates liver regeneration through interleukin-6-induced hepatocyte proliferation and inhibition of cell death after liver injury

In response to liver injury, the liver undergoes a regeneration process to retain its mass and function. However, the regeneration mechanism has not been fully clarified. This study investigated the role of transcriptional coactivator with PDZ-binding motif (TAZ), a Hippo-signaling effector, in liver regeneration. We observed that TAZ stimulates liver regeneration after liver injury. After partial hepatectomy (PHx) or carbon tetrachloride damage, TAZ was required for liver regeneration to increase hepatic cell proliferation and resist hepatic apoptosis, which were decreased in liver-specific TAZ knockout (LKO) mice. TAZ stimulated macrophage infiltration, resulting in IL-6 production, which induced liver regeneration. In LKO mice, IL-6-induced activation of signal transducer and activator of transcription 3, ERK, and PKB was decreased. We also observed that periductal fibrogenesis was significantly increased in LKO mice during liver regeneration after PHx, which was caused by increased hepatic apoptosis. Our results suggest that TAZ stimulates liver regeneration through IL-6-induced hepatocyte proliferation and inhibition of cell death after liver injury.-Kim, A. R., Park, J. I., Oh, H. T., Kim, K. M., Hwang, J.-H., Jeong, M. G., Kim, E.-H., Hwang, E. S., Hong, J.-H. TAZ stimulates liver regeneration through interleukin-6-induced hepatocyte proliferation and inhibition of cell death after liver injury.

Restorative activity of aqueous extract Mangifera indica leaves against CCl4 induced hepatic damage in rats

Hepatic diseases remain problematic throughout the world. There are no drugs that completely restore hepatic capacity and help to regenerate liver cells. Therefore, the present examination was intended to investigate the hepatoprotective impacts of Mangifera indica (M. indica) leaf aqueous extract at two doses (200 and 400 mg/kg body weight (b w) for 6 weeks. Liver damage was induced by CCl₄ and the extent of damage was measured by body weight gain, feed efficiency, and liver index, and by assessing hematological, biochemical parameters, and liver histology. Results show that phytochemical analysis revealed the presence of important phytochemicals like flavonoids, phenols, steroids, glycosides, saponins and terpenoids. Also, aqueous extract of M. indica showed that the total phenolic contents (86.20 ± 2.6 μg GEA/mg),flavonoid contents (42.64 ± 3.1 μg QE/mg) and antioxidant activities (DPPH) were 92.58 ± 4.1. The 50% inhibitory concentration (IC50) was 0.467 μg ml^-1. CCl₄ caused a significant decrease in food intake, weight gain, feed efficiency ratio, and liver index, and also in the serum protein, albumin, globulin, high-density lipoprotein (HDLc), and CAT levels. CCl₄ also caused an increase in serum AST, ALT, total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDLc), very low-density lipoprotein (VLDLc), and MAD. However, treatment with M. indica revealed attenuation of liver function, serum biomarker levels that had been increased by chronic CCl₄ intoxication. M. indica (400 mg/kg of b w) showed a greater reduction in the biomarker levels compared with M. indica (200 mg/kg of b w) and silymarin. These results were supported by histopathological examination of liver sections. Collectively, this study indicates that M. indica leaf aqueous extract alleviates the harmful effect of CCl₄-induced hepatic damage.

Hepatoprotective and antioxidant effects of single clove garlic against CCl4-induced hepatic damage in rabbits

Background

The increase in demand and consumption of single clove garlic or ‘Solo garlic’ (Allium sativum) has resulted in an increase in research on its therapeutic properties. The present study aims to evaluate the antioxidant activities, oxidant-scavenging efficiency and preventive effects of SCG (single clove garlic) and MCG (multi clove garlic) on CCl₄-induced acute hepatotoxicity in male rabbits.

Methods

For this purpose, rabbits were orally administered with 3 ml of CCl₄ /kg of body weight, followed by 0.8 g of MCG or SCG/kg twice a week for three successive weeks. Oxidative hepatotoxicity was then assessed.

Results

SCG extracts exhibited higher antioxidant capacity than the MCG extract. Scavenging ability of SCG showed significant (p < 0.05) elevation against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radicals in comparison to MCG. In addition, total phenolic content of SCG was significantly elevated (p < 0.001), thereby suggesting that the composition of garlic storage constituents varies with the number of cloves present. CCl₄-induced hepatotoxicity demonstrated histological changes including severe damage in the structure of liver tissues which correlated well to oxidative stress levels. Simultaneously, administration of SCG resulted in a significant reduction of serum alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and total bilirubin (TB) levels in addition to improvement in some histological parameters. Low levels of lipid peroxidation (malondialdehyde, MDA) (p < 0.001), along with a huge reduction in peroxidase (POx) (p < 0.001) revealed protection against oxidative toxicity in the liver homogenate. Higher levels of catalase (CAT) (p < 0.001) and superoxide dismutase (SOD) (p < 0.05) when compared to the MCG test (TM) group indicates that removal of H₂O₂ is based on CAT activity in SCG test (TS) group rather than the POx activity demonstrated in the former group.

Conclusion

The present study indicates that SCG possesses more protective ability than MCG against CCl₄-induced liver injury and might be an effective alternative medicine against acute oxidative liver toxicity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1916-8) contains supplementary material, which is available to authorized users.

Pien Tze Huang Gan Bao attenuates carbon tetrachloride‑induced hepatocyte apoptosis in rats, associated with suppression of p53 activation and oxidative stress

Pien Tze Huang Gan Bao (PZH-GB), a traditional Chinese medicine, has been used for thousands of years as a protective remedy effective against liver injury induced by excessive alcohol and smoking. The present study aimed to evaluate the protective effects and potential mechanisms of PZH-GB against carbon tetrachloride (CCl₄)-induced hepatic injury. Rats were pre-treated with silymarin (50 mg/kg) or different doses of PZH-GB (150, 300 or 600 mg/kg) orally administered for 7 days. At the end of treatment, the rats were intraperitoneally injected with CCl₄, or control rats received a corn oil injection. The lactate dehydrogenase (LDH) levels in serum were evaluated. Apoptosis was assessed via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. p53, B-cell lymphoma 2 (Bcl-2), B cell-lymphoma 2-associated X protein (Bax), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and cytochrome P450 family 2 subfamily E member 1 (CYP2E1) were measured by reverse transcription-quantitative polymerase chain reaction and western blotting. The activity of caspase-9 and caspase-3 were measured by a colorimetric assay. The results indicated that silymarin and PZH-GB prevented CCl₄-induced serum LDH elevations, and CCl₄ induced high levels of LDH. Compared with the CCl₄ group, silymarin and PZH-GB treatment significantly decreased LDH levels. Histopathological results revealed that silymarin and PZH-GB ameliorated the CCl₄-induced liver histological alterations. The TUNEL results showed that compared with the control group, CCl₄ induced liver cell apoptosis, while silymarin and PZH-GB treatment inhibited apoptosis and the TUNEL-positive cells. The elevated expression of Bax, p53, iNOS, COX-2 and CYP2E1 were reduced by silymarin or PZH-GB pretreatment, whereas reduced Bcl-2 expression levels were increased. CCl₄ increased the activity of caspase-9 and −3 by 6.86- and 7.42-fold, respectively; however, silymarin and PZH-GB ameliorated this effect. In conclusion, silymarin and PZH-GB treatment prevented the deleterious effects on liver functions by attenuation of oxidative stress, inflammation and mitochondrial apoptosis via the p53 signaling pathway.

Steroidal Alkaloids as an Emerging Therapeutic Alternative for Investigation of Their Immunosuppressive and Hepatoprotective Potential

The compounds, sarcovagine-D, alkaloid-C, and holaphylline isolated from Sarcococca saligna were found to possess immunosuppressive activities. These compounds were characterized for in vitro inhibition on human T-cells proliferation and IL-2 production. The compounds showed significant immunosuppressive effect on IL-2 production as well as on phytohemagglutinin stimulated T-cell proliferation in a dose dependent manner. Of all the tested compounds holaphylline was found to be less toxic and safe. These compounds were then evaluated for their in vivo hepatoprotective potential against CCl₄, in which alkaloid-C and holaphylline showed markedly reduced liver inflammation and biochemical parameter (ALT, AST, and ALP) of liver injury. The decrease in the activity of hepatic antioxidant enzyme (SOD) was significantly prevented by holaphylline, likewise gradually the levels of MDA and GSH were also normalized compared to silymarin. The CCl₄ induced inflammation and necrosis around the central vein of liver was reduced by sarcovagine-D, alkaloid-C and holaphylline, to 8%, 4% to 1% respectively as assessed by histopathology, thus having better hepatoprotective effect compared to positive control. Steroidal alkaloids attenuated the inflammation of liver around the injured central vein region by down regulating the CCl₄ induced activation of hepatic macrophages as well as their number respectively. Therefore, the in vitro and in vivo results suggest that steroidal alkaloids from S. saligna could be excellent immunosuppressive and hepatoprotective agents.

Toxicological Implications of Mitochondrial Localization of CYP2E1

Cytochrome P450 2E1 (CYP2E1) metabolizes an extensive array of pollutants, drugs, and other small molecules, often resulting in bioactivation to reactive metabolites. Therefore, it is unsurprising that it has been the subject of decades of research publications and reviews. However, while CYP2E1 has historically been studied in the endoplasmic reticulum (erCYP2E1), active CYP2E1 is also present in mitochondria (mtCYP2E1). Relatively few studies have specifically focused on mtCYP2E1, but there is growing interest in this form of the enzyme as a driver in toxicological mechanisms given its activity and location. Many previous studies have linked total CYP2E1 to conditions that involve mitochondrial dysfunction (fasting, diabetes, non-alcoholic steatohepatitis, and obesity). Furthermore, a large number of reactive metabolites that are formed by CYP2E1 through metabolism of drugs and pollutants have been demonstrated to cause mitochondrial dysfunction. Finally, there appears to be significant inter-individual variability in targeting to the mitochondria, which could constitute a source of variability in individual response to exposures. This review discusses those outcomes, the biochemical properties and toxicological consequences of mtCYP2E1, and highlights important knowledge gaps and future directions. Overall, we feel that this exciting area of research is rich with new and important questions about the relationship between mtCYP2E1, mitochondrial dysfunction, and pathology.

Early-Phase Alcoholic Liver Disease: An Update on Animal Models, Pathology, and Pathogenesis

Alcoholic liver disease (ALD) remains to be one of the most common etiology of liver disease and is a major cause of morbidity and mortality worldwide. The pathologic stages of ALD comprises of steatosis, steatohepatitis, and fibrosis/cirrhosis. Steatosis and steatohepatitis represents the early phase of ALD and are precursor stages for fibrosis/cirrhosis. Numerous research efforts have been directed at recognizing cofactors interacting with alcohol in the pathogenesis of steatosis and steatohepatitis. This review will elucidate the constellation of complex pathogenesis, available animal models, and microscopic pathologic findings mostly in the early-phase of ALD. The role of endotoxin, reactive oxygen species, alcohol metabolism, and cytokines are discussed. Understanding the mechanisms of early-phase ALD should provide insight into the development of therapeutic strategies and thereby decrease the morbidity and mortality associated with ALD.

Protective effects of green tea and its main constituents against natural and chemical toxins: A comprehensive review

Toxins are natural or chemical poisonous substances with severe side effects on health. Humans are generally exposed by widespread toxic contaminations via air, soil, water, food, fruits and vegetables. Determining a critical antidote agent with extensive effects on different toxins is an ultimate goal for all toxicologists. Traditional medicine is currently perceived as a safe and natural approach against toxins. In this regard, we focused on the protective effects of green tea (Camellia sinensis) and its main components such as catechin, epicatechin, epicatechin gallate, gallocatechin, epigallocatechin and epigallocatechin gallate as a principal source of antioxidants against both natural and chemical toxins. This literate review demonstrates that protective effects of green tea and its constituents were mainly attributed to their anti-oxidative, radical scavenging, chelating, anti-apoptotic properties and modulating inflammatory responses. Although, some studies reveal they have protective effects by increasing toxin metabolism and neutralizing PLA₂, proteases, hyaluronidase and l-amino acid oxidase enzymes.

Turmeric extract and its active compound, curcumin, protect against chronic CCl4-induced liver damage by enhancing antioxidation

Background

Curcumin, a major active component of turmeric, has previously been reported to alleviate liver damage. Here, we investigated the mechanism by which turmeric and curcumin protect the liver against carbon tetrachloride (CCl₄)-induced injury in rats. We hypothesized that turmeric extract and curcumin protect the liver from CCl₄-induced liver injury by reducing oxidative stress, inhibiting lipid peroxidation, and increasing glutathione peroxidase activation.

Methods

Chronic hepatic stress was induced by a single intraperitoneal injection of CCl₄ (0.1 ml/kg body weight) into rats. Turmeric extracts and curcumin were administered once a day for 4 weeks at three dose levels (100, 200, and 300 mg/kg/day). We performed ALT and AST also measured of total lipid, triglyceride, cholesterol levels, and lipid peroxidation.

Result

We found that turmeric extract and curcumin significantly protect against liver injury by decreasing the activities of serum aspartate aminotransferase and alanine aminotransferase and by improving the hepatic glutathione content, leading to a reduced level of lipid peroxidase.

Conclusions

Our data suggest that turmeric extract and curcumin protect the liver from chronic CCl₄-induced injury in rats by suppressing hepatic oxidative stress. Therefore, turmeric extract and curcumin are potential therapeutic antioxidant agents for the treatment of hepatic disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1307-6) contains supplementary material, which is available to authorized users.

Hepatoprotective effects of sesamol loaded solid lipid nanoparticles in carbon tetrachloride induced sub-chronic hepatotoxicity in rats

Sesamol is a phenolic component of sesame seed oil, which has been established as an antioxidant and also possesses potential for hepatoprotection. However, its protective role in carbon tetrachloride (CCl4 ) induced sub-chronic hepatotoxicity has not been studied. Limited oral bioavailability (BA) and rapid elimination (as conjugates) in rats is reported for sesamol. Considering its significant antioxidant potential and compromised BA, we packaged sesamol into solid lipid nanoparticles (S-SLNs) to enhance its hepatoprotective bioactivity. S-SLNs prepared by microemulsification method were nearly spherical in shape with an average particle size of 120.30 nm and their oral administration at 8 mg/kg body weight (BW) showed significantly (p < 0.001) better hepatoprotection than free sesamol (FS) and a well established hepatoprotective antioxidant silymarin [SILY (25 mg/kg BW); p < 0.05) in CCl4 induced sub-chronic liver injury in rats. Evaluations were done in terms of histological changes in the liver tissue, liver injury markers (serum alanine aminotransferase, serum aspartate aminotransferase, and serum lactate dehydrogenase); oxidative stress markers (lipid peroxidation, superoxide dismutase, and reduced glutathione) and proinflammatory response marker (tumor necrosis factor-alpha).

Riboflavin conjugated temperature variant ZnO nanoparticles with potential medicinal application in jaundice

Significant ameliorative efficiency of riboflavin conjugated ZnO nanoparticles against jaundice stress at molecular and cellular levels.

Hepatoprotective effect of oral application of a silymarin extract in carbon tetrachloride-induced hepatotoxicity in rats

Background

Silymarin derived from the milk thistle plant “Silybum marianum” is composed of four major flavonolignans. Clinical as well as experimental studies indicate hepatoprotective effects of silymarin. However, the underlying mechanisms are only incompletely understood.

The aim of this study was to assess the effect of oral administration of a defined silymarin extract in the model of acute carbon tetrachloride (CCl4) induced liver injury.

Methods

A single dose of a silymarin extract (SE; 20 or 100 mg/kg body weight) was given to rats by oral gavage. Subsequently, rats were injected with a single dose of CCl4 (2 ml/kg body weight).

Results

After 24h, analysis of liver to body weight ratio, serum levels of transaminases and histological analysis revealed a marked liver damage which was inhibited by SE in a dose dependent manner. CCl4-induced expressions of pro-inflammatory and pro-fibrogenic genes were significantly reduced in SE treated rats. Molecular analysis revealed that SE reduced the expression of the pro-inflammatory chemokine MCP-1, the pro-fibrogenic cytokine TGF-beta as well as collagen I in isolated human hepatic stellate cells (HSC), which are the key effector cells of hepatic fibrosis.

Conclusion

Oral administration of the tested silymarin extract inhibited hepatocellular damage in a model of acute liver injury. Moreover, we newly found that the silymarin extract had direct effects on pro-inflammatory and pro-fibrogenic gene expression in HSCs in vitro. This indicates that direct effects on HSC also contribute to the in vivo hepatoprotective effects of silymarin, and further promote its potential as anti-fibrogenic agent also in chronic liver disease.

Safe and symptomatic medicinal use of surface-functionalized Mn3O4 nanoparticles for hyperbilirubinemia treatment in mice

Aim: Testing the potential of citrate-capped Mn3O4 nanoparticles (NPs) as a therapeutic agent for alternative rapid treatment of hyperbilirubinemia through direct removal of bilirubin (BR) from blood in mice. Materials & methods: NPs were synthesized and the mechanism of BR degradation in presence and absence of biological macromolecules were characterized in vitro. To test the in vivo BR degradation ability of NPs, CCl4-intoxicated mice were intraperitoneally injected with NPs. Results: We demonstrated ultrahigh efficacy of the NPs in symptomatic treatment of hyperbilirubinemia for rapid reduction of BR in mice compared with conventional medicine silymarin without any toxicological implications. Conclusion: These findings may pave the way for practical clinical use of the NPs as safe medication of hyperbilirubinemia in human subjects.

Attenuation of carbon tetrachloride-induced hepatic injury with curcumin-loaded solid lipid nanoparticles

BACKGROUND AND OBJECTIVES

Curcumin, an established pleiotropic agent, has potential for hepatoprotection owing to its powerful antioxidant, anti-inflammatory, and antifibrogenic properties. However, its poor bioavailability limits its use in therapeutics. In this study, we aimed to package curcumin into solid lipid nanoparticles (C-SLNs) to improve its bioavailability and compare the efficacy of C-SLNs with that of free curcumin and silymarin, a well-established hepatoprotectant in clinical use, against carbon tetrachloride (CCl4)-induced hepatic injury in rats, post-induction. A self-recovery group to which no treatment was given was also employed for quantifying self-healing of hepatic tissue, if any.

MATERIAL AND METHODS

C-SLNs (particle size 147.6 nm), prepared using a microemulsification technique, were administered to rats post-treatment with CCl4 (1 ml/kg body weight [BW] twice weekly for 2 weeks, followed by 1.5 ml/kg BW twice weekly for the subsequent 2 weeks). The extent of liver damage and repair in terms of histopathology and levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), oxidative stress markers (malondialdehyde, superoxide dismutase, and reduced glutathione) and a pro-inflammatory response marker, tumor necrosis factor (TNF)-α, were determined in both the CCl4 group and the treatment groups.

RESULTS

C-SLNs (12.5 mg/kg) significantly (p < 0.001-0.005) attenuated histopathological changes and oxidative stress, and also decreased induction of ALT, AST, and TNF-α in comparison with free curcumin (100 mg/kg), silymarin (25 mg/kg), and self-recovery groups.

CONCLUSION

Curcumin could be used as a therapeutic agent for hepatic disorders, provided it is loaded into a suitable delivery system.

Anti-inflammatory and hepatoprotective effects of total flavonoid C-glycosides from Abrus mollis extracts

The aim of this study was to evaluate the anti-inflammatory and hepatoprotective effects of the total flavonoid C-glycosides isolated from Abrus mollis extracts (AME). In the anti-inflammatory tests, xylene-induced ear edema model in mice and carrageenan-induced paw edema model in rats were applied. The hepatoprotective effects of AME were evaluated with various in vivo models of acute and chronic liver injury, including carbon tetrachloride (CCl4)-induced hepatitis in mice, D-galactosamine (D-GalN)-induced hepatitis in rats, as well as CCl4-induced hepatic fibrosis in rats. In the acute inflammation experiment, AME significantly suppressed xylene-induced ear edema and carrageenan-induced paw edema, respectively. In the acute hepatitis tests, AME significantly attenuated the excessive release of ALT and AST induced by CCl4 and D-GalN. In CCl4-induced hepatic fibrosis model, AME alleviated liver injury induced by CCl4 shown by histopathological sections of livers and improved liver function as indicated by decreased liver index, serum ALT, AST, TBIL, and ALP levels and hydroxyproline contents in liver tissues, and increased serum ALB and GLU levels. These results indicated that AME possesses potent anti-inflammatory activity in acute inflammation models and hepatoprotective activity in both acute and chronic liver injury models. In conclusion, AME is a potential anti-inflammatory and hepatoprotective agent and a viable candidate for treating inflammation, hepatitis, and hepatic fibrosis.

Sesamol loaded solid lipid nanoparticles: a promising intervention for control of carbon tetrachloride induced hepatotoxicity

Background

Sesamol, a component of sesame seed oil, exhibited significant antioxidant activity in a battery of in vitro and ex vivo tests including lipid peroxidation induced in rat liver homogenates. Latter established its potential for hepatoprotection. However, limited oral bioavailability, fast elimination (as conjugates) and tendency towards gastric irritation/toxicity (especially forestomach of rodents) may limit its usefulness. Presently, we packaged sesamol into solid lipid nanoparticles (S-SLNs) to enhance its biopharmaceutical performance and compared the efficacy with that of free sesamol and silymarin, a well established hepatoprotectant, against carbon tetrachloride induced hepatic injury in rats, post induction. A self recovery group in which no treatment was given was used to observe the self-healing capacity of liver.

Methods

S-SLNs prepared by microemulsification method were administered to rats post-treatment with CCl₄ (1 ml/kg body weight (BW) twice weekly for 2 weeks, followed by 1.5 ml/kg BW twice weekly for the subsequent 2 weeks). Liver damage and recovery on treatment was assessed in terms of histopathology, serum injury markers (alanine aminotransferase, aspartate aminotransferase), oxidative stress markers (lipid peroxidation, superoxide dismutase, and reduced glutathione) and a pro-inflammatory response marker (tumor necrosis factor alpha).

Result

S-SLNs (120.30 nm) at a dose of 8 mg/kg BW showed significantly better hepatoprotection than corresponding dose of free sesamol (FS; p < 0.001). Effects achieved with S-SLNs were comparable with silymarin (SILY), administered at a dose of 25 mg/kg BW. Self recovery group confirmed absence of regenerative capacity of hepatic tissue, post injury.

Conclusion

Use of lipidic nanocarrier system for sesamol improved its efficiency to control hepatic injury. Enhanced effect is probably due to: a) improved oral bioavailability, b) controlled and prolonged effect of entrapped sesamol and iii) reduction in irritation and toxicity, if any, upon oral administration. S-SLNs may be considered as a therapeutic option for hepatic ailments as effectiveness post induction of liver injury, is demonstrated presently.

Carbon tetrachloride-induced liver injury in mice is tissue factor dependent

Tissue factor (TF) is a membranous glycoprotein that activates the coagulation system when blood vessels or tissues are damaged. TF was up-regulated in monocrotaline (MCT)/lipopolysaccharide (LPS) hepatotoxicity model. The present study aimed to test the hypothesis that TF-dependent fibrin deposition occurs in liver toxicity induced by CCl4 in mice. Pericentral deposition of TF and fibrin is induced after CCl4-induced liver toxicity. The toxicity was evaluated by determination of serum activities of ALT, AST and ALP as well as GSH content and histopathological changes. The results showed that injection of mice with TF-antisense deoxyoligonucleotide (TF-AS) prevented the accumulation of TF and fibrin in the hepatic tissues. Furthermore, it significantly restored blood biochemical parameters, GSH content and distorted histopathological features caused by CCl4. The current study demonstrates that TF activation is associated with CCl4-induced liver injury. Furthermore, administration of TF-AS successfully prevented this type of liver injury.

The protective effect of Phoenix dactylifera L. seeds against CCl4-induced hepatotoxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Egyptian medicine, Phoenix dactylifera L. (date palm) seeds are listed in folk remedies for the management of diabetes, liver diseases and gastrointestinal disorders. The present study was conducted to investigate the protective effect of Phoenix dactylifera L. seeds aqueous suspension against the chemically-induced hepatic injury in rats.

METHODS

Liver injury was achieved by exposing Wistar rats to CCl4 (10% in olive oil; 0.5 mL/rat; IP) twice a week for 4 weeks. Along with CCl4, aqueous suspensions of raw or roasted Phoenix dactylifera seeds (1.0 g/kg) were administered orally in a daily manner.

RESULTS

Our results demonstrated that Phoenix dactylifera seeds significantly improved the CCl4-induced alterations in liver function parameters (AST, ALT, ALP and albumin). Moreover, the CCl4-induced oxidative stress, represented by elevated thiobarbituric acid reactive substance (TBARS), nitric oxide and oxidative DNA damage, was ameliorated by Phoenix dactylifera seeds treatment. In addition, Phoenix dactylifera seeds restored the activities of hepatic antioxidant enzymes (superoxide dismutase and glutathione S-transferase) that were declined after CCl4 treatment. Examination of liver histopathology revealed that Phoenix dactylifera seeds attenuate the incidence of liver lesions (including vacuolization and fibroblast proliferation) triggered by CCl4 intoxication.

CONCLUSION

The Phoenix dactylifera seeds could be a promising candidate for protection against the CCl4-induced liver intoxication, and this hepatoprotective effect might be attributed to the antioxidant and free radical scavenging activities.

Haghi M, Panahi F. Protective Effect of Cornus mas Fruits Extract on Serum Biomarkers in CCl4-Induced Hepatotoxicity in Male Rats

BACKGROUND

Nowadays attention to use herbs such as cornelian cherry (Cornus mas) is increasing, which contains high levels of antioxidants and anthocyanins. Cornus mas fruits have been used for gastrointestinal and excretory disorders for many years in traditional medicine, also may improve liver and kidney functions, and have protective effects such as anti-allergic, antidiabetic, antibacterial, antimicrobial, antihistamine and antimalarial properties.

OBJECTIVES

The aim of this study was to investigate protective effects of Cornus mas fruits extract on serum biomarkers in CCl4-induced hepatotoxicity in male rats.

MATERIALS AND METHODS

Hepatotoxicity was induced by administration of carbon tetrachloride (1 mL/kg i.p.) in 1:1 dilution with olive oil. To evaluate the effect of Cornus mas fruits extract on disease progression, serum marker enzymes, serum total protein and albumin and liver lipid peroxidation were determined in CCl4-induced hepatotoxicity.

RESULTS

Oral administration of Cornus mas fruits extract to rats for 14 days provided a significant (P < 0.05) hepatoprotection by decreasing elevated serum level of enzymes, total serum protein, albumin and liver lipid peroxidation content.

CONCLUSIONS

Cornus mas fruit extract effect may be due to including some antioxidant components, which caused membrane stabilizing and normalization of fluctuated biochemical profiles induced by CCl4 exposure. Our results validated the traditional use of Cornus mas in the treatment of liver disorders.

Hautriwaic acid as one of the hepatoprotective constituent of Dodonaea viscosa

It is widely known that hepatitis and its complications such as cirrhosis or hepatocellular carcinoma are one of the major health problems of the world especially since no specific treatment is available. In the present study we investigated the hepatoprotective potential of the methanolic extract of the whole plant of Dodonaea viscosa and its ethyl acetate, aqueous, butanol and n-hexane fractions against carbon tetrachloride (CCl₄) induced hepatoxicity in rats. Hepatoprotection was assessed in terms of reduction in serum enzymes (ALT, AST, and ALP) that occur after CCl₄ injury, and by histopathology and immunohistochemistry. The methanolic extract reduced the serum enzyme level (ALT, AST, and ALP) down to control levels despite CCl₄ treatment. It also reduced the CCl₄-induced damaged area to 0% as assessed by histopathology. The CD68+ macrophages were also reduced in number around the central vein area by the methanolic extract. These hepatoprotective effects were better than the positive control silymarin. Similar hepatoprotective activities were found with the ethyl acetate, and aqueous fractions of the methanolic extract. The butanol and n-hexane fractions showed elevated levels of ALT, AST and ALP as compared to the positive control silymarin. Histopathology showed ∼30% damage to the liver cells with the butanol and n-hexane fractions which still showed some protective activity compared to the CCl₄ treated control. HPLC fingerprinting suggested that hautriwaic acid present in the methanolic extract and its ethyl acetate, and aqueous fractions may be responsible for this hepatoprotective activity of Dodonaea viscosa which was confirmed by in vivo experiments.

Ex vivo assessment of carbon tetrachloride (CCl(4))-induced chronic injury using polarized light spectroscopy

The liver performs various functions, such as the production and detoxification of chemicals; therefore, it is susceptible to hepatotoxins such as carbon tetrachloride (CCl4), which causes chronic injury. Thus, assessment of injury and its status of severity are of prime importance. Current work reports an ex vivo study for probing the severance of hepatic injury induced by CCl4 with polarized light over the spectral range 400-800 nm. Different concentrations of CCl4 were used to induce varying severity of hepatic injury in a rat model. Linear retardance, depolarization rates, and diagonal Mueller matrix elements (m22, m33, and m44), were successfully used as the distinguishing criterion for normal and different liver injuries. Our results show that linear retardance for injured liver samples with lower doses of CCl4 tends to increase when compared with normal liver samples, while samples injured at higher doses of CCl4 offer almost no retardance. Total, linear, and circular depolarizations follow decreasing trends with increased liver injury severity over the entire investigated wavelength range. Linear polarization states were observed to be better maintained as compared to circular polarization states for all samples. Furthermore, numerical values of diagonal elements of the experimentally measured Mueller matrix also increase with increasing doses of CCl4. Liver fibroses, change in transport albedo, and the relative refractive index of the extracellular matrix caused by CCl4 are responsible for the observed differences. These results will provide a pathway to gauge the severity of injury caused by toxic chemicals.

Bamboo salt attenuates CCl4-induced hepatic damage in Sprague-Dawley rats

Bamboo salt, a Korean folk medicine, is prepared with solar salt (sea salt) and baked several times at high temperatures in a bamboo case. In this study, we compared the preventive effects of bamboo salt and purified and solar salts on hepatic damage induced by carbon tetrachloride in Sprague-Dawley rats. Compared with purified and solar salts, bamboo salts prevented hepatic damage in rats, as evidenced by significantly reduced serum levels of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase (P < 0.05). Bamboo salt (baked 9×) triggered the greatest reduction in these enzyme levels. In addition, it also reduced the levels of the proinflammatory cytokines interleukin (IL)-6, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α. Histopathological sections of liver tissue demonstrated the protective effect of bamboo salt, whereas sections from animals treated with the other salt groups showed a greater degree of necrosis. We also performed reverse transcription-polymerase chain reaction and western blot analyses of the inflammation-related genes iNOS, COX-2, TNF-α, and IL-1β in rat liver tissues. Bamboo salt induced a significant decrease (~80%) in mRNA and protein expression levels of COX-2, iNOS, TNF-α, and IL-1β, compared with the other salts. Thus, we found that baked bamboo salt preparations could prevent CCl₄-induced hepatic damage in vivo.

Hepatoprotective activity of Calotropis gigantea flowers against carbon-tetrachloride-induced liver damage in mice

Ethanol extract of Calotropis gigantea flowers (CGFE) was evaluated for its antioxidant and hepatoprotective activity to validate its use in traditional therapeutic indications. This CGFE exhibited significant antioxidant activity (at 20, 40, 60, 80 and 100 µg/ml in vitro) as evidenced by its hydroxyl, nitric oxide and hydrogen peroxide anion radical scavenging activities. This in vitro antioxidant activity was reinforced by a significant hepatoprotection (at 250 and 500 mg/kg dose) by decreasing the activity of serum glutamate oxaloacetate transaminase and serum glutamate pyruvate transaminase. The hepatoprotective activity of the CGFE was comparable with standard drug silymarin (100 mg/kg, p.o.).The results obtained from present study indicate the presence of natural antioxidants and hepatoprotective constituents. Hence, the above finding confirms in vitro antioxidant and hepatoprotective potential of CGFE in mice.

Hepatoprotective effects of Juglans regia extract against CCl4-induced oxidative damage in rats

CONTEXT

Different parts of the walnut [Juglans regia L. (Juglandaceae)] have been used in folk medicine for protection against liver injury, although its actual efficacy remains uncertain.

OBJECTIVE

The present study investigated the protective effect of walnut leaf extract against carbon tetrachloride (CCl4)-induced liver damage in rats.

MATERIALS AND METHODS

The rats were randomly divided into seven groups: control, CCl4 (i.p., 0.5 mL/kg b.w., 50% CCl4 in olive oil), walnut extract (at dose level of 0.2 g/kg b.w.) alone, walnut extract (at dose levels of 0.05, 0.1, 0.2 and 0.4 g/kg b.w.) with CCl4, and treatment was carried out accordingly. On the 28th day, rats were sacrificed and blood was withdrawn by cardiac puncture. Liver damage was assessed by serum biochemical parameters (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and albumin), antioxidant enzymes (superoxide dismutase and catalase) and histopathological observation.

RESULTS

Administration of walnut leaf extract (ranging from 0.2 to 0.4 g/kg b.w.) significantly lowered serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase levels in CCl4-treated rats. Walnut leaf extract increased antioxidant enzymes, including superoxide dismutase and catalase. Histopathological examination of livers showed that walnut leaves extract reduced fatty degeneration, cytoplasmic vacuolization and necrosis in CCl4-treated rats.

DISCUSSION AND CONCLUSION

These results suggest that walnut extract has a protective effect over CCl4-induced oxidative damage in rat liver. These results demonstrate that walnut extract acts as a good hepatoprotective and antioxidant agent in attenuating hepatocellular damage.