Acute Liver Damage Model Research Articles

CHOLERETIC EFFECT OF THE COMPLEX PLANT SUPPLEMENT IN EXPERIMENTAL LIVER DAMAGE

Relevance. The search for supplements with choleretic activity is of great interest due to their detoxicant properties and possible hepatoprotective ef-fect. The aim of our study was to evaluate choleretic effect of the complex plant supplement comprised of Hypecoum erectum L.; Hedysarum dahuri-cum Turcz. ex B.Fedtsch.; Glycyrrhiza uralensis Fisch. ex DC.; Calendula officinalis L.; Scutellaria baicalensis Georgi. dry extracts. Material and methods. The research was conducted on an animal model of acute liver damage induced by CCl4 in 84 albino Wistar rats. The studied complex plant supplement was researched in doses of 100mg/kg, 200 mg/kg and 300 mg/kg in the course of 14 days starting from the 2nd day of the experiment. Choleretic properties were evaluated by both the speed of bile secretion (mg/min) per 100 g of animal weight and the total amount of bile secreted during four hours of observation. Results. It has been established that the use of the dry extract in tetrachloromethane hepatitis in white rats has a choleretic effect characterized by an increase in the rate of bile secretion, an increase in the amount of discharged bile and the growing concentration of bile acids.

Histomorphometric study of rat liver during the treatment of the acute toxic injury

Introduction. There are a few effective therapies are available for acute liver injury at present. The aim of the study was to investigate histological and morphometric changes in the liver using models of toxic damage caused by carbon tetrachloride (CCl4 ) and acetaminophen during correction with Oxymethyluracil (OMU). Material and methods. A total of ninety rats were divided into 18 groups. The treatment of acute liver damage models caused by a single injection of CCl4 or acetaminophen was carried out using “Heptor”, “Mexidol”, and OMU. The correction was carried out twice (sacrificed 24 hours after intoxication) and four times (sacrificed 72 hours after intoxication). Liver tissues were processed using standard histological techniques (H&E). A semi-quantitative assessment was performed using a scale based on the severity of liver cell deaths. Results. Twenty-four hours after administration of CCl4 or 72 hours after administration of acetaminophen, the treatment with OMU led to a decrease in liver cell death compared to the group with administration of only CCl4 or acetaminophen. Seventy-two hours after CCl4 and 24 hours after acetaminophen intoxication, these groups with the OMU treatment did not differ from those of the carbon tetrachloride- or acetaminophen-induced liver injury groups, respectively. Conclusion. Thus, on the model of CCl4 liver injury, the treatment with OMU is more effective for 24 hours. In the case of acetaminophen intoxication, the effectiveness of treatment with OMU is better for 72 hours. The results obtained are possibly associated with a different mechanism of the damaging effect of the studied toxicants.

Effect of Artemisia Capillaris Herba Water Extract on Thioacetamide-Induced Liver Injury Animal Model

This study investigated the hepatoprotective effect of Artemisia Capillaris Herba water extract (AC) in a thioacetamide (TAA) induced acute liver damage model using Sprague-Dawley (SD) rats. The in vitro antioxidant activity of AC was measured by quantitating total polyphenol content, total flavonoid content, and DPPH and ABTS free radical scavenging. Our animal experiment was conducted as follows: AC (100 and 200 mg/kg body weight, PO) and silymarin (Sily 100; 100 mg/kg body weight, PO) were administered for 3 days, concurrent with induction of liver injury (TAA, 200 mg/kg body weight, IP). Serum and liver tissue were collected after 3 days of drug administration. AC treatment significantly reduced serum glutamic oxaloacetic transaminase (GOT), glutamate pyruvate transaminase (GPT), myeloperoxidase (MPO), and ammonia levels. It also effectively decreased protein level expression of NF-ĸBp65, p-IĸBα, COX-2, iNOS, TNF-α, IL-6, and IL-1β in liver tissue, while increasing ZO-1, occludin, claudin-1, claudin-3, and claudin- 4 expression. These results suggest that AC treatment can attenuate inhibition of the NF-ĸB pathway, and enhancement of the tight junction (TJ) pathway in TAA-induced liver injury. Therefore, AC displays potential for use as a natural therapeutic drug.

Effects of S-adenosyl methionine and essential phospholipids on serum biochemical parameters in simulated acute liver disease in late pregnancy

AIM: Liver diseases, developing in late pregnancy, remains a very important problem in obstetrics. In present study, the aim was to evaluate the effectiveness of monotherapy by essential phospholipids and by S-adenosyl methionine for simulated acute liver pathology during pregnancy using the biochemical parameters of blood serum.
 STUDY DESIGN AND METHODS: Acute liver injury was simulated in rats from 15th to 18th day of pregnancy using tyloxapol (300 mg / kg daily). As drugs for monotherapy, Essentiale (Sanofi-Aventis, France) and Heptral (Abbott srl, Italy) were used separately and were administered to rats daily from the 16th to the 18th day of pregnancy (50 mg / kg and 35 mg / kg, respectively). On the 19th day of pregnancy, blood serum biochemical parameters were analyzed.
 RESULTS: In the model, the concentrations of triglycerides and cholesterol were sharply increased, which can be caused not only by the inhibitory effect of tyloxapol on the lipoprotein lipase of the lumen of blood vessels, but also by damage to liver cells with the accumulation of lipids in them. The activities of aminotransferases (ALT, AST), glutamate dehydrogenase and lactate dehydrogenase were statistically significantly increased. In healthy pregnant rats, the activity of alkaline phosphatase (ALP) decreased from 15th to 19th day of gestation, but under the treatment by tyloxapol in some cases the increase of ALP activity was observed. After using essential phospholipids in the model of acute liver injury, normal values of ALT and ALP activities were observed, and a significant decrease in triglycerides was revealed, which did not reach the normal values. After using S-adenosyl methionine in this model, the significant changes in blood serum parameters were not observed. By themselves, the drugs change several biochemical parameters in the serum of healthy pregnant rats. Heptral increases urea levels and Essentiale appears to increase AST activity.
 CONCLUSION: The use of essential phospholipids or S-adenosyl methionine as monotherapy in a model of acute liver damage in late pregnancy has demonstrated their low efficiency. It is possible that the combined use of drugs is necessary to increase the effectiveness. The use of S-adenosyl methionine should be carried out under the control of the urea level and glutamate dehydrogenase activity in serum. While using essential phospholipids, it is advisable to control the AST activity.

Suppressive effects of mead acid supplementation on acute liver damage model in rats

Suppressive effects of mead acid supplementation on acute liver damage model in rats

Change in hepatic iron metabolism in a rat model of acute liver damage and recovery: a role for iron storage proteins

Change in hepatic iron metabolism in a rat model of acute liver damage and recovery: a role for iron storage proteins

Anti-inflammatory and hepatoprotective effects of glycyrrhetinic acid on CCl4-induced damage in precision-cut liver slices from Jian carp (Cyprinus carpio var. jian) through inhibition of the nf-kƁ pathway

In order to evaluate the antioxidant and anti-inflammatory effects of glycyrrhetinic acid (GA) on carbon tetrachloride (CCl4)-induced damage in precision-cut liver slices (PCLS) from Jian carp (Cyprinus carpio. Jian), an acute liver damage model was established in this study. The viability of PCLS, levels of anti-oxidases in liver homogenates, expression of inflammation-related genes including nuclear factor-κB (nf-κB)/c-rel, inducible nitric oxide synthase (inos), interleukin-1β (il-1β), interleukin-6 (il-6) and interleukin-8 (il-8), and protein levels of (nf-κB)/c-rel in liver tissues were measured. The results showed that pretreatment of PCLS with GA at 5 and 10 μg/mL for 6 h significantly inhibited the cytotoxicity of CCl4. GA attenuated CCl4-induced oxidative stress in PCLS through promoting the recovery of superoxide dismutase (SOD) and glutathione (GSH) levels, and inhibiting malondialdehyde (MDA) synthesis. In inflammatory response, GA at both 5 and 10 μg/mL significantly inhibited the increase in mRNA levels of inflammatory cytokines including nf-kƁ/c-rel, inos, il-1β, il-6 and il-8, and the protein level of Nf-kƁ/C-rel induced by CCl4. Furthermore, treatment with pyrrolyl dithiocarbamate (PDTC, 4 μg/mL), an inhibitor of nuclear transcription factor nf-kB, significantly inhibited nf-kB levels, and transcription of downstream cytokines inos, il-1β, il-6 and il-8, also the viability of PCLS was significantly increased. These results indicated that GA suppressed inflammation and reduced cytotoxicity by inhibiting the nf-kƁ signaling pathway, and plays a role in liver protection.

Characterization of Polysaccharides with Antioxidant and Hepatoprotective Activities from the Edible Mushroom Oudemansiella radicata.

The preliminary structure, in vitro antioxidant and in vivo hepatoprotective activities of water-soluble polysaccharides (ORWP) and alkali-soluble polysaccharides (ORAP), prepared from the mushroom Oudemansiella radicata, were investigated. Both ORWP and ORAP were heteropolysaccharides with mannose, glucose and galactose being the main monosaccharide components. Regarding the antioxidant activities, ORWP and ORAP showed effective 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, hydrogen peroxide scavenging activity and lipid peroxidation inhibitory effects, as well as moderate reducing power and Fe2+ chelating activity. For the hepatoprotective activity, administration of ORWP and ORAP prevented the increase in serum alanine aminotransferase and aspartate aminotransferase activities in a carbon tetrachloride-induced acute liver damage model, suppressed hepatic malondialdehyde formation and stimulated the activities of hepatic superoxide dismutase and glutathione peroxidase. Thus, we speculate that ORWP and ORAP may protect the liver from CCl4-induced hepatic damage via antioxidant mechanisms.

Cell Therapy for Liver Disease Using Bioimaging Rats.

Advances in stem cell research suggest that cell therapy is a potential alternative to liver transplantation. The use of individualized and minimally invasive cell therapy is desirable to avoid rejection and reduce patient burden. While allo-hepatocyte transplantation has been performed for metabolic hepatic disease, auto-bone marrow transplantation (BMT) has shifted toward mesenchymal stem cells (MSCs) transplantation for liver cirrhosis. In this article, an overview of cell transplantation research for liver disease is provided through our recent rat studies. We have developed various kinds of rat imaging models and have evaluated the effect of cell therapy for liver disease. Bone marrow cells (BMCs) of the Alb-DsRed2 rat were transplanted via the portal vein (PV) in acute and chronic liver damage models. The number of Alb-DsRed2+ albumin-producing cells increased, and the size of the cells increased in the chronic liver damage model as well as in the acute liver damage model. Luciferase transgenic (luc-Tg) rat hepatocytes were transplanted into the hepatectomized LEW rat via the PV. Luminescence intensity lasted for 2 months in the hepatectomized rat. BMCs obtained from green fluorescent protein (GFP) Tg rats were transplanted repeatedly via the PV using an implanted catheter with a port. Repeated BMT via the PV reduced the liver fibrosis. Adipocyte-derived MSCs from the luc-Tg rat were transplanted into the hepatectomized rat model via the PV after ischemic reperfusion. MSCs inhibited hepatocyte apoptosis and promoted liver regeneration. Transplanting the optimal number of cells by an effective and safe way is important for clinical application. Bioimaging rats are a powerful tool for cell transplantation research because it makes observation of the in vivo kinetics of transplanted cells possible. Cell transplantation research using bioimaging rats contributes greatly to evaluating effective methods of cell therapy.

Hepatoprotective and proapoptotic effect of Ecballium elaterium on CCl4-induced hepatotoxicity in rats.

To investigate the effects of perorally administered juice on tetrachloromethane (CCl4)-induced hepatotoxicity model in rats. Male Wistar rats were tube-administrated silymarin, Ecballium juice at 0.2mL/kg and 0.7mL/kg daily for 3 consequent days, i.e., 3.28μg and 11.48μg of cucurbitacin B per kg of body weight respectively. On the third day, liver damage was induced by intraperitoneal application of CCl4. On the fourth day, abdominal cavity was macroscopically examined and liver samples were taken for histopathological and immunochemical evaluation. HPLC was used to determine the content of the active substance cucurbitacin B. The experiment revealed that 0.7ml/kg juice concentration expressed the highest pro-apoptotic activity, but with prevailing negative effects. Compared with the lower concentration, there was an observable vasodilatation with consequent interstitial hemorrhages and a larger scope of inflammatory damage, which suppressed the hepatoprotective effect. In the 0.2mL/kg concentration, there was a smaller pro-apoptotic activity but other parameters had better results, and the liver parenchyma damage was reversible. No reactions confirming the potentially allergic effect on laboratory rats were observed; its hepatoprotective and anti-inflammatory effect was confirmed on a model of acute liver damage.

A sexual dimorphism influences bicyclol-induced hepatic heat shock factor 1 activation and hepatoprotection.

Bicyclol [4,4'-dimethoxy-5,6,5',6'-bis(methylenedioxy)-2-hydroxy-methyl-2'-methoxycarbonyl biphenyl] is a synthetic hepatoprotectant widely used in clinical practice, but resistance to this treatment is often observed. We found that the hepatoprotective effect of bicyclol was greatly compromised in female and castrated male mice. This study was to dissect the molecular basis behind the sex difference, which might underlie the clinical uncertainty. We compared bicyclol-induced hepatoprotection between male and female mice using acute liver damage models. Inducible knockout by the Cre/loxp system was used to decipher the role of heat shock transcription factor 1 (HSF1). Functional experiments, western blot, and histopathological analysis were used to determine the key causative factors which might antagonize bicyclol in female livers. HSF1 activation and heat shock protein 70 (Hsp70) expression, which were responsible for bicyclol-induced hepatoprotection, were compromised in female and castrated male livers. Compromised HSF1 activation was a result of HSF1 phosphorylation at serine 303, which was catalyzed by glycogen synthase kinase 3β (GSK3β). Testosterone was necessary for bicyclol to inhibit hepatic GSK3β activity. Administration of testosterone or GSK3β inhibitors restored bicyclol-induced protection in females. Bicyclol induces sex-specific hepatoprotection based on a sex-specific HSF1/Hsp70 response, in which testosterone and GSK3β play key roles. Because a lot of patients suffering from liver diseases have very low testosterone levels, our results give a possible explanation for the clinical variation in bicyclol-induced hepatoprotection, as well as practicable solutions to improve the effect of bicyclol.

Inhibition of TGFβ type I receptor activity facilitates liver regeneration upon acute CCl4 intoxication in mice.

Liver exhibits a remarkable maintenance of functional homeostasis in the presence of a variety of damaging toxic factors. Tissue regeneration involves cell replenishment and extracellular matrix remodeling. Key regulator of homeostasis is the transforming growth factor-β (TGFβ) cytokine. To understand the role of TGFβ during liver regeneration, we used the single-dose carbon tetrachloride (CCl4) treatment in mice as a model of acute liver damage. We combined this with in vivo inhibition of the TGFβ pathway by a small molecule inhibitor, LY364947, which targets the TGFβ type I receptor kinase [activin receptor-like kinase 5 (ALK5)] in hepatocytes but not in activated stellate cells. Co-administration of LY364947 inhibitor and CCl4 toxic agent resulted in enhanced liver regeneration; cell proliferation (measured by PCNA, phosphorylated histone 3, p21) levels were increased in CCl4+LY364947 versus CCl4-treated mice. Recovery of CCl4-metabolizing enzyme CYP2E1 expression in hepatocytes is enhanced 7days after CCl4 intoxication in the mice that received also the TGFβ inhibitor. In summary, a small molecule inhibitor that blocks ALK5 downstream signaling and halts the cytostatic role of TGFβ pathway results in increased cell regeneration and improved liver function during acute liver damage. Thus, in vivo ALK5 modulation offers insight into the role of TGFβ, not only in matrix remodeling and fibrosis, but also in cell regeneration.

Effects of Combination of G-CSF and SCF One Week Prior to Liver Injury In Acute liver Damage Model Induced by Thioacetamide Administration

Effects of Combination of G-CSF and SCF One Week Prior to Liver Injury In Acute liver Damage Model Induced by Thioacetamide Administration

Visualization of Acute Liver Damage Induced by Cycloheximide in Rats Using PET with [18F]FEDAC, a Radiotracer for Translocator Protein (18 kDa)

Liver damage induced by drug toxicity is an important concern for both medical doctors and patients. The aim of this study was to noninvasively visualize acute liver damage using positron emission tomography (PET) with N-benzyl-N-methyl-2-[7,8-dihydro-7-(2-[18F]fluoroethyl)-8-oxo-2-phenyl-9H-purin-9-yl]acetamide ([18F]FEDAC), a radiotracer specific for translocator protein (18 kDa, TSPO) as a biomarker for inflammation, and to determine cellular sources enriching TSPO expression in the liver. A mild acute liver damage model was prepared by a single intraperitoneal injection of cycloheximide (CHX) into rats. Treatment with CHX induced apoptosis and necrotic changes in hepatocytes with slight neutrophil infiltration. The uptake of radioactivity in the rat livers was measured with PET after injection of [18F]FEDAC. The uptake of [18F]FEDAC increased in livers damaged from treatment with CHX compared to the controls. Presence of TSPO was examined in the liver tissue using quantitative reverse transcriptase-polymerase chain reaction and immunohistochemical assays. mRNA expression of TSPO was elevated in the damaged livers compared to the controls, and the level was correlated with the [18F]FEDAC uptake and severity of damage. TSPO expression in the damaged liver sections was mainly found in macrophages (Kupffer cells) and neutrophils, but not in hepatocytes. The elevation of TSPO mRNA expression was derived from the increase of the number of macrophages with TSPO and neutrophils with TSPO in damaged livers. From this study we considered that PET imaging with [18F]FEDAC represented the mild liver damage through the enhanced TSPO signal in inflammatory cells. We conclude that this method may be a useful tool for diagnosis in early stage of acute liver damage.

Igf-1 and its isoform expression in hepatic cell tumors and the surrounding tissue in mice liver carcinogenesis induced by diethylnitrozamine

The expression of the Igf-1 gene in mice liver at different stages of development of hepatocellular carcinoma induced by diethylnitrozamine--from the initial diffuse tissue dysplasia and nodular hyperplasia to the development of multiple adenomas and carcinoma--has been analyzed. It was marked that the level of Igf-1 expression in all liver neoplasms decreased; it increased only in the liver tissue surrounding the carcinoma. The dependence of Igf-1 expression on inflammatory processes accompanying tumor growth was analyzed on the model of acute liver damage by diethylnitrozamine. It was established that the level of Igf-1 expression in liver tissue under acute damage in sexually mature mice was the same as in the control group. By the means of semiquantitative evaluation of the products of two Igf-1 splice isoforms--locally active (Mgf) and circulating (Igf- 1v4)--it has been shown that the amount of mRNA of both isoforms in hepatocellular carcinoma was lower, and in tissue surrounding the tumor higher, than in the samples of the control group. At the same time, the proportion of transcripts of isoforms was stable.

Low dose of carbon monoxide intraperitoneal injection provides potent protection against GalN/LPS‐induced acute liver injury in mice

Carbon monoxide (CO) is an important effector-signaling molecule involved in various pathophysiological processes. Here we investigated the protective effects of exogenous CO in a murine model of acute liver damage induced by d-galactosamine (GalN) and lipopolysaccharide (LPS). Exogenous CO gas was administered to mice via intraperitoneal injection (first at a dose of 15 ml kg(-1) and then, 6 h later, 8 ml kg(-1)), which caused a significant elevation of blood carboxyhemoglobin levels of up to 12-14% for more than 12 h. GalN/LPS were given to induce acute liver damage in mice 30 min prior to CO exposure. This showed that GalN/LPS induced severe liver injury in mice, whereas CO injection remarkably improved the survival rate of mice and led to attenuated hepatocellular damage. CO exhibited anti-oxidative capabilities by inhibiting hepatic malondialdehyde contents and restoring superoxide dismutase and glutathione, as well as by reducing inducible NOS/NO production. The anti-apoptotic and anti-inflammatory effects of CO were substantial, characterized by a notable inhibition of hepatocyte apoptosis and a reduction of pro-inflammatory cytokines in mice. Our findings thus supported the hypothesis that exogenous CO provides protective effects against acute liver damage in mice, mainly dependent on its anti-oxidative, anti-inflammatory and anti-apoptotic properties.

Protective Properties of Laggera alata Extract and its Principle Components Against D-Galactosamine-Injured Hepatocytes

Laggera alata extract (LAE) was quantitatively analyzed, and its principle components isochlorogenic acids were isolated and authenticated. Protective properties of LAE were studied using a d-galactosamine (d-GalN)-induced injury model in neonatal rat hepatocytes and a d-GalN-induced acute liver damage model in mice. Meanwhile, the effect of isochlorogenic acids derived from LAE on d-GalN-induced hepatocyte injury were also measured in vitro. LAE at concentrations of 10–100 μg/ml significantly reduced cellular leakage of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and improved cell viability. The isochlorogenic acids (4,5-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic acid and 3,4-O-dicaffeoylquinic acid) at concentrations of 1–100 μg/ml also remarkably improved viability of hepatocytes. The oral treatment of LAE at doses of 50, 100 and 200 mg/kg markedly reduced the serum AST and ALT activity of mice and resulted in significant recovery of hepatocytes in liver sections.

Hepatoprotection in a Rat Model of Acute Liver Damage Through Inhibition of CY2E1 Activity by Total Alkaloids Extracted From Rubus alceifolius Poir

We aimed to examine the effect of an alkaloid extract of the roots of Rubus alceifolius Poir on liver damage and cytochrome enzymes, and underlying mechanism. Hepatotoxicity was induced in rats by treatment with carbon tetrachloride (CCl(4)). Rats were then treated with the hepatoprotective drug bifendate, or with low, medium, and high doses of an alkaloid extract from the roots of R alceifolius Poir. Both bifendate and alkaloid treatment decreased the increase in liver enzymes and cell damage caused by CCl(4). Carbon tetrachloride treatment alone caused a decrease in total cytochrome P450 content, an increase in CYP2E1 and CYP3A1 messenger RNA (mRNA) levels, and an increase in CYP2E1 and a decrease in CYP3A1 enzymatic activity. Alkaloid treatment brought these concentrations and activities back toward normal. In summary, these results suggest that alkaloids from R alceifolius Poir may act to protect the liver through decreasing CYP2E1 enzymatic activity through decreasing its mRNA.

Single dose intravenous thioacetamide administration as a model of acute liver damage in rats

Thioacetamide (TAA) has been used extensively in the development of animal models of acute liver injury. Frequently, TAA is administered intraperitoneally to induce liver damage under anaesthesia. However, it is rarely administered by intravenous injection in conscious rats. The experiments in this study were designed to induce acute liver damage by single intravenous injection of TAA (0, 70 and 280 mg/kg) in unrestrained rats. Biochemical parameters and cytokines measured during the 60-h period following TAA administration, included white blood cells (WBC), haemoglobulin (Hb), platelet, aspartate transferase (GOT), alanine transferase (GPT), total bilirubin (TBIL), direct bilirubin (DBI), albumin, ammonia (NH3), r-glutamyl transpeptidase (r-GT), tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). Rats were sacrificed by decapitation 60 h after TAA administration and livers were removed immediately for pathology and immunohistochemical (IHC) examination. Another group of rats were sacrificed by decapitation 1, 6 and 24 h after TAA administration and livers were removed immediately for time course change of pathology and IHC examination. TAA significantly increased blood WBC, GOT, GPT, TBIL, DBIL, NH3, r-GT, TNF-alpha and IL-6 levels but decreased the blood Hb, platelet and albumin level. The levels of histopathological damage in the liver after intravenous TAA administration were also increased with a dose-dependent trend and more increased at 60 h after TAA administration. The levels of inducible nitric oxide synthase (iNOS) and nuclear factor-kappaB (NF-kappaB) detected by IHC in the liver after intravenous TAA administration were also increased with a dose-dependent trend and more increased at 1 h after TAA administration. Single intravenous TAA administration without anaesthesia is a restorable animal model which may be used to investigate acute liver damage.

Trans-3-Phenyl-2-Propenoic Acid (Cinnamic Acid) Derivatives: Structure-Activity Relationship as Hepatoprotective Agents

Among various phenolic compounds, caffeic acid (3,4-dihydroxycinnamic acid) exhibited pharmacological antioxidant, anticancer and antimutagenic activities. The antioxidant properties of phenolic compounds depend on their chemical structure, however, the role of the ethylenic side chain in the radical scavenging activity remains controversial. Thus, the aim of this study consisted to test cinnamic acid and 15 cinnamic acid derivatives in the well known CCl(4)-induced acute liver damage model, which is dependent on oxidative stress mechanisms. Cinnamic acid and 15 cinnamic acid derivatives (50 mg/kg, p.o.) were administered to male Wistar rats intoxicated with CCl(4) (4 g/kg, p.o.). The activities of gamma-glutamyl transpeptidase, alkaline phosphatase and alanine aminotransferase were measured in serum. The lipid peroxidation products were determined in liver. Compounds with a methoxy group at position 3 or 4, or a 3,4-methylenedioxy moiety were the most active ones. Also, we observed that the monosubstituted 3 or 4 hydroxy, or the bulky 3,4 dibenzyloxy substituted compounds showed lower activity. The poorest activity was displayed by disubstituted 3,4-dihydroxy, dimethoxy or diacetyl cinnamic acid derivatives, the ester derived from cinnamic acid with an 8 carbon chain and N-dimethyl substituted compound. Thus, the methoxy substituted group at positions 3 or 4 or the 3,4-methylenedioxy moiety in the caffeic acid derivatives; seem to be the main features required for the hepatoprotection in this model.