(Z)2-(5-(4-methoxybenzylidene)-2, 4-dioxothiazolidin-3-yl) acetic acid protects rats from CCl(4) -induced liver injury

Background and Aim: (Z)2‐(5‐(4‐methoxybenzylidene)‐2, 4‐dioxothiazolidin‐3‐yl) acetic acid (MDA) is an aldose reductase (AR) inhibitor. Recent studies suggest that AR contributes to the pathogenesis of inflammation by affecting the nuclear factor κB (NF‐κB)‐dependent expression of cytokines and chemokines and therefore could be a novel therapeutic target for inflammatory pathology. The current study evaluated the in vivo role of MDA in protecting the liver against injury and fibrogenesis caused by CCl₄ in rats, and the underlying mechanisms. Methods: A single injection of CCl₄ induced acute hepatitis, and repeated injections were used to induce hepatic fibrosis in rats. Therapeutic efficacy was assessed by comparison of the severity of hepatic injury and fibrosis in MDA ‐ treated rats versus untreated controls. Results: MDA significantly protected the liver from injury by reducing the activity of serum alanine aminotransferase, and improving the histological architecture of the liver. MDA modulated NF‐κB‐dependent activation of inflammatory cytokines by reducing hepatic mRNA levels of tumor necrosis factor‐α, interleukin‐1β, inducible nitric oxide (NO) synthase and transforming growth factor‐β. In addition, MDA attenuated oxidative stress by increasing the content of hepatic glutathione. These favorable changes were associated with suppressed hepatic NF‐κB activation by MDA. MDA treatment improved liver fibrosis in rats that received repeated CCl₄ injections. In vitro, MDA attenuated phosphorylation of IκB and activation of NF‐κB, and thus prevented biosynthesis of NO in lipopolysaccharide‐activated RAW264.7 cells. Conclusions: The present study suggests that AR is a novel therapeutic anti‐inflammatory target for the treatment of hepatitis and liver fibrosis.     

Melatonin overcomes gemcitabine resistance in pancreatic ductal adenocarcinoma by abrogating nuclear factor‐κB activation

Constitutive activation and gemcitabine induction of nuclear factor‐κB (NF‐κB) contribute to the aggressive behavior and chemotherapeutic resistance of pancreatic ductal adenocarcinoma (PDAC). Thus, targeting the NF‐κB pathway has proven an insurmountable challenge for PDAC therapy. In this study, we investigated whether the inhibition of NF‐κB signaling pathway by melatonin might lead to tumor suppression and overcome gemcitabine resistance in pancreatic tumors. Our results showed that melatonin inhibited activities of NF‐κB by suppressing IκBα phosphorylation and decreased the expression of NF‐κB response genes in MiaPaCa‐2, AsPc‐1, Panc‐28 cells and gemcitabine resistance MiaPaCa‐2/GR cells. Moreover, melatonin not only inhibited cell proliferation and invasion in a receptor‐independent manner, but also enhanced gemcitabine cytotoxicity at pharmacologic concentrations in these PDAC cells. In vivo, the mice treated with both agents experienced a larger reduction in tumor burden than the single drug‐treated groups in an orthotopic xenograft mouse model. Taken together, these results indicate that melatonin inhibits proliferation and invasion of PDAC cells and overcomes gemcitabine resistance of pancreatic tumors through NF‐κB inhibition. Our findings therefore provide novel preclinical knowledge about melatonin inhibition of NF‐κB in PDAC and suggest that melatonin should be investigated clinically, alone or in combination with gemcitabine for PDAC treatment.     

N-methyl-4-isoleucine cyclosporine attenuates CCl -induced liver fibrosis in rats by interacting with cyclophilin B and D

Background and Aim: N‐methyl‐4‐isoleucine cyclosporine (NIM811), a new analogue of cyclosporine A, can inhibit collagen deposition in vitro and reduce liver necrosis in a bile‐duct‐ligation animal model. However, whether NIM811 effects on CCl₄‐induced rat liver fibrosis, and the related mechanism has not been determined. Methods: A liver fibrosis model was induced in Wistar rats using CCl₄ for 6 weeks. Meanwhile, two different doses of NIM811 (low‐dose 10 mg/kg and high‐dose 20 mg/kg) were given to the CCl₄‐treated rats. Liver fibrosis was then evaluated according to histopathological scoring and liver hydroxyproline content. Serum alanine aminotransferase, aspartate aminotransferase and albumin levels, expression of matrix metalloproteinase‐13, tissue inhibitor of metalloproteinase‐1, α‐smooth muscle actin and cyclophilin B and D in liver tissue were determined. Cyclophilin B and D were also studied in an hepatic stellate cell line. Results: Hydroxyproline content was decreased in both NIM811 groups compared with the model (P < 0.05). Liver necrosis and fibrosis were also attenuated in the NIM811 groups. NIM811 suppressed the expression of tissue inhibitor of metalloproteinase‐1, transforming growth factor beta mRNA and α‐smooth muscle actin protein in liver tissue. Expression of cyclophilin B in the fibrosis model was increased compared with the normal group (P < 0.05), and was decreased significantly in the low‐dose NIM811 treatment group (P < 0.05), which indicated that cyclophilin B might have a profibrotic effect. In vitro studies revealed that cyclophilin B and/or D knockout were associated with collagen inhibition. Conclusions: NIM811 attenuates liver fibrosis in a CCl₄‐induced rat liver fibrosis model, which may be related to binding with cyclophilin B and D.     

Overexpression of NK2 promotes liver fibrosis in carbon tetrachloride‐induced chronic liver injury

Background/Aims: Hepatocyte growth factor (HGF) inhibits liver fibrosis induced by carbon tetrachloride (CCl₄) in animal models. NK2 is a natural splice variant of HGF, but its in vivo function remains to be elucidated. We investigated the in vivo effects of NK2 on CCl₄‐induced liver fibrosis. Methods: NK2 transgenic mice and wild‐type (WT) mice were injected intraperitoneally with CCl₄ twice a week. The extent of hepatic fibrosis was evaluated by Azan–Mallory staining. Expression levels of mRNAs of transforming growth factor‐β1 (TGF‐β1) and matrix metalloproteinase‐13 (MMP‐13) were examined by real‐time polymerase chain reaction. The protein levels of α‐smooth muscle actin (α‐SMA), c‐Met and its phosphorylation were determined by Western blot analysis. Results: Liver fibrosis was significantly more severe in NK2 transgenic mice than in WT mice. CCl₄ administration increased the expression levels of TGF‐β1 mRNA and α‐SMA protein, and decreased the expression of MMP‐13 mRNA in livers of NK2 transgenic mice compared with those of WT mice. c‐Met protein expression in the liver was compatible with the degree of fibrosis. As for c‐Met activation, no difference was found between NK2 and WT livers. Conclusion: Overexpression of NK2 acts as an antagonist of HGF and promotes liver fibrosis in CCl₄‐induced chronic liver injury.     

In vivo hepatic oxidative stress because of carbon tetrachloride toxicity: protection by melatonin and pinoline

Abstract: The protective in vivo effects of melatonin or pinoline on carbon tetrachloride (CCl₄)‐induced oxidative damage were investigated in liver of rats and compared to rats injected only with CCl₄ (5 mL/kg body weight). Hepatic cell membrane fluidity, monitored using fluorescence spectroscopy, exhibited a significant decrease in animals exposed to CCl₄ compared to control rats. Increases in lipid and protein oxidation, as assessed by concentrations of malondialdehyde (MDA) and 4‐hydroxyalkenals (4‐HDA), and protein carbonylation, respectively, were also seen in hepatic homogenates of animals exposed to CCl₄. The administration of melatonin (10 mg/kg body weight) or pinoline injected 30 min before and 1 hr after CCl₄, fully prevented membrane rigidity and protein oxidation. However, treatment with melatonin was more effective in terms of reducing lipid peroxidation than pinoline, as the increases in MDA+4‐HDA levels because of CCl₄ were reduced by 93.4% and 34.4% for melatonin or pinoline, respectively. Livers from CCl₄‐injected rats showed several histopathological alterations; above all, there were signs of necrosis and ballooning degeneration. The concurrent administration of melatonin or pinoline reduced the severity of these morphological changes. On the basis of the biochemical and histopathological findings, we conclude that both melatonin and pinoline were highly effective in protecting the liver against oxidative damage and membrane rigidity because of CCl₄. Therefore, these indoles may be useful as cotreatments for patients with hepatic intoxication induced by CCl₄.     

Melatonin inhibits matrix metalloproteinase-9 (MMP-9) activation in the lipopolysaccharide (LPS)-stimulated RAW 264.7 and BV2 cells and a mouse model of meningitis

Abstract: We explored anti‐inflammatory potential of melatonin against the lipopolysaccharide (LPS)‐induced inflammation in vivo and in vitro. RAW 264.7 and BV2 cells were stimulated by LPS, followed by the treatment with melatonin or vehicle at various time intervals. In a mouse model of meningitis induced by LPS, melatonin (5 mg/kg) or vehicle was intravenously injected at 30 min postinsult. The activity of matrix metalloproteinase‐2 (MMP‐2) and metalloproteinase‐9 (MMP‐9) was determined by gelatin zymography. Nuclear factor‐kappa B (NFκB) translocation and binding activity were determined by immunocytochemistry and electrophoretic mobility shift assay (EMSA). Our results showed that either pretreatment or cotreatment with melatonin at 50–500 μm effectively inhibited the LPS‐induced proMMP‐9 activation in the RAW 264.7 and BV2 cells, respectively (P < 0.05). This melatonin‐induced proMMP‐9 inhibition remained effective when treatment was delayed up to 2 and 6 hr postinsult for RAW 264.7 and BV2 cells, respectively (P < 0.05 for both groups). Additionally, melatonin significantly attenuated the rises of circulatory and cerebral MMP‐9 activity, respectively (P < 0.05) and reduced the loss of body weight (P < 0.05) in mice with meningitis. Moreover, melatonin (50 μm ) effectively inhibited nuclear factor‐kappa B (NFκB) translocation and binding activity in the LPS‐treated RAW 264.7 and BV2 cells, respectively (P < 0.05). These results demonstrate direct inhibitory actions of melatonin against postinflammatory NFκB translocation and MMP‐9 activation and highlight its ability to inhibit systemic and cerebral MMP‐9 activation following brain inflammation.     

All‐trans‐retinoic acid ameliorates carbon tetrachloride‐induced liver fibrosis in mice through modulating cytokine production

Background/Aims: Liver fibrosis with any aetiology, induced by the transdifferentiation and proliferation of hepatic stellate cells (HSCs) to produce collagen, is characterized by progressive worsening in liver function, leading to a high incidence of death. We have recently reported that all‐trans‐retinoic acid (ATRA) suppresses the transdifferentiation and proliferation of lung fibroblasts and prevents radiation‐ or bleomycin‐induced lung fibrosis. Methods: We examined the impact of ATRA on carbon tetrachloride (CCl₄)‐induced liver fibrosis. We performed histological examinations and quantitative measurements of transforming growth factor (TGF)‐β1 and interleukin (IL)‐6 in CCl₄‐treated mouse liver tissues with or without the administration of ATRA, and investigated the effect of ATRA on the production of the cytokines in quiescent and activated HSCs. Results: CCl₄‐induced liver fibrosis was attenuated in histology by intraperitoneal administration of ATRA, and the overall survival rate at 12 weeks was 26.5% without ATRA (n=25), whereas it was 75.0% (n=24) in the treatment group (P=0.0187). In vitro studies disclosed that the administration of ATRA reduced (i) the production of TGF‐β1, IL‐6 and collagen from HSCs, (ii) TGF‐β‐dependent transdifferentiation of the cells and IL‐6‐dependent cell proliferation and (iii) the activities of nuclear factor‐κB p65 and p38mitogen‐activated protein kinase, which stimulate the production of TGF‐β1 and IL‐6, which could be the mechanism underlying the preventive effect of ATRA on liver fibrosis. Conclusions: Our findings indicate that ATRA ameliorates liver fibrosis. As the oral administration of the drug results in good compliance, ATRA could be a novel approach in the treatment of liver fibrosis.     

Attenuated liver fibrosis after bile duct ligation and defective hepatic stellate cell activation in neural cell adhesion molecule knockout mice

Aim: Neural cell adhesion molecule (N‐CAM) is expressed by activated hepatic stellate cells (HSC), portal fibroblasts, cholangiocytes and hepatic progenitor cells during liver injury. Its functional role in liver disease and fibrogenesis is unknown. The aim of this study was to investigate the role of N‐CAM in liver fibrogenesis. Methods: To induce fibrosis, N‐CAM knockout mice and wild‐type controls were subjected to bile duct ligation (BDL) or repeated carbon tetrachloride (CCl₄) injections. Fibrosis was quantified by hydroxyproline, immunhistochemistry staining and image analysis. Protein levels were determined with immunoblotting. HSCs were isolated by ultracentrifugation in a Larcoll gradient and thereafter in vitro stimulated with recombinant transforming growth factor (TGF)‐β1. Results: Two weeks after BDL, wild‐type mice had developed pronounced liver fibrosis while N‐CAM?/? mice had less such alterations. N‐CAM?/? mice had less deposition of collagen and fibronectin seen in immunhistochemistry. The protein levels of fibronectin were higher in the liver from the wild type, while laminin were unaltered. CCl₄‐treated N‐CAM?/? and wild‐type mice showed no significant difference in the extent of liver fibrosis or the expression levels of the above‐mentioned genes. HSC isolated from N‐CAM?/? mice showed declined levels of smooth muscle actin and desmin after stimulation in vitro with TGF‐β1. Conclusions: Loss of N‐CAM results in decreased hepatic collagen and fibronectin deposition in mice subjected to BDL, but not in animals exposed to repeated CCl₄ injections. HSC isolated from N‐CAM null mice show impaired activation in vitro. This indicates a role of N‐CAM in cholestatic liver disease and HSC activation.     

Protective effect of melatonin against Opisthorchis viverrini‐induced oxidative and nitrosative DNA damage and liver injury in hamsters

Abstract: The liver fluke, Opisthorchis viverrini, is the risk factor of cholangiocarcinoma, which is a major health problem in northeastern Thailand. Production of reactive oxygen and nitrogen species during the host’s response leads to oxidative and nitrosative stress contributing to carcinogenesis. We investigated the protective effect of melatonin against O. viverrini‐induced oxidative and nitrosative stress and liver injury. Hamsters were infected with O. viverrini followed by oral administration of various doses of melatonin (5, 10, and 20 mg/kg body weight) for 30 days. Uninfected hamsters served as controls. Compared to the levels in O. viverrini‐infected hamsters without melatonin treatment, the indoleamine decreased the formation of oxidative and nitrosative DNA lesions, 8‐oxo‐7,8‐dihydro‐2′‐deoxyguanosine and 8‐nitroguanine, in the nucleus of bile duct epithelium and inflammatory cells, in parallel with a reduction in 3‐nitrotyrosine. Melatonin also reduced the expression of heme oxygenase‐1 and cytokeratin 19, nitrate/nitrite levels, and bile duct proliferation in the liver. Alanine transaminase activity and the levels of 8‐isoprostane and vitamin E were also dose dependently decreased in the plasma of melatonin‐treated hamsters. Melatonin reduced the mRNA expression of oxidant‐generating genes [inducible nitric oxide synthase, nuclear factor‐kappa B (NF‐κB), and cyclooxygenase‐2] and proinflammatory cytokines (TNF‐α and IL‐1β), accompanied by an increase in the expression of antioxidant genes [nuclear erythroid 2‐related factor 2 (Nrf2) and manganese superoxide dismutase]. Thus, melatonin may be an effective chemopreventive agent against O. viverrini‐induced cholangiocarcinoma by reducing oxidative and nitrosative DNA damage via induction of Nrf2 and inhibition of NF‐κB‐mediated pathways.     

Melatonin attenuates hypoxic pulmonary hypertension by inhibiting the inflammation and the proliferation of pulmonary arterial smooth muscle cells

Hypoxia‐induced inflammation and excessive proliferation of pulmonary artery smooth muscle cells (PASMCs) play important roles in the pathological process of hypoxic pulmonary hypertension (HPH). Melatonin possesses anti‐inflammatory and antiproliferative properties. However, the effect of melatonin on HPH remains unclear. In this study, adult Sprague–Dawley rats were exposed to intermittent chronic hypoxia for 4 wk to mimic a severe HPH condition. Hemodynamic and pulmonary pathomorphology data showed that chronic hypoxia significantly increased right ventricular systolic pressures (RVSP), weight of the right ventricle/left ventricle plus septum (RV/LV+S) ratio, and median width of pulmonary arterioles. Melatonin attenuated the elevation of RVSP, RV/LV+S, and mitigated the pulmonary vascular structure remodeling. Melatonin also suppressed the hypoxia‐induced high expression of proliferating cell nuclear antigen (PCNA), hypoxia‐inducible factor‐1α (HIF‐1α), and nuclear factor‐κB (NF‐κB). In vitro, melatonin concentration‐dependently inhibited the proliferation of PASMCs and the levels of phosphorylation of Akt and extracellular signal‐regulated kinases1/2 (ERK1/2) caused by hypoxia. These results suggested that melatonin might potentially prevent HPH via anti‐inflammatory and antiproliferative mechanisms.     

Melatonin inhibits the sphingosine kinase 1/sphingosine‐1‐phosphate signaling pathway in rabbits with fulminant hepatitis of viral origin

The sphingosine kinase (SphK)1/sphingosine‐1‐phosphate (S1P) pathway is involved in multiple biological processes, including liver diseases. This study investigate whether modulation of the SphK1/S1P system associates to the beneficial effects of melatonin in an animal model of acute liver failure (ALF) induced by the rabbit hemorrhagic disease virus (RHDV). Rabbits were experimentally infected with 2 × 10⁴ hemagglutination units of a RHDV isolate and received 20 mg/kg of melatonin at 0, 12, and 24 hr postinfection. Liver mRNA levels, protein concentration, and immunohistochemical labeling for SphK1 increased in RHDV‐infected rabbits. S1P production and protein expression of the S1PR1 receptor were significantly elevated following RHDV infection. These effects were significantly reduced by melatonin. Rabbits also exhibited increased expression of toll‐like receptor (TLR)4, tumor necrosis factor alpha (TNF‐α), interleukin (IL)‐6, nuclear factor‐kappa B (NF‐κB) p50 and p65 subunits, and phosphorylated inhibitor of kappa B (IκB)α. Melatonin administration significantly inhibited those changes and induced a decreased immunoreactivity for RHDV viral VP60 antigen in the liver. Results obtained indicate that the SphK1/S1P system activates in parallel to viral replication and the inflammatory process induced by the virus. Inhibition of the lipid signaling pathway by the indole reveals novel molecular pathways that may account for the protective effect of melatonin in this animal model of ALF, and supports the potential of melatonin as an antiviral agent.     

Loss of clock gene mPer2 promotes liver fibrosis induced by carbon tetrachloride

Aim: The clock gene mPer2 controls circadian periods and plays a critical role in clock resetting and responses to drugs of abuse. Mice deficient in mPer2 exhibit a marked susceptibility to acute liver injury. Clinical observations have demonstrated the existence of a relationship between circadian rhythm and liver cirrhosis. Here, we sought direct evidence for clock function to liver fibrosis using mPer2‐deficient mice. Methods: Hepatic fibrosis was induced in wild‐type (WT) and mPer2^?/? mice by repetitive intraperitoneal carbon tetrachloride (CCl₄) injection. Masson trichrome staining and analysis of α‐smooth muscle actin (α‐SMA) immunohistochemistry were performed to show the collagen accumulation and the hepatic stellate cell (HSC) activation, respectively. The mRNA levels of fibrosis‐related genes were monitored by quantitative real‐time polymerase chain reaction. The protein level of TIMP‐1 was determined by immunohistochemistry. Transferase deoxytidyl uridine end labeling, α‐SMA double staining and 4′,6′‐diamidino‐2‐phenylindole dihydrochloride staining were performed to show HSC apoptosis in vivo and in vitro, respectively. Results: CCl₄ caused much more severe liver fibrosis and activated more HSC in mPer2 null mice as compared to WT animals. Meanwhile, mPer2 null mice exhibited less efficiency in fibrosis resolution. Apoptotic HSC were significantly fewer in mPer2 null mice compared with WT mice after CCl₄; transfected Per2 cDNA into cultured HSC resulted in more HSC apoptosis with upregulation of TRAIL‐R2/DR5 expression. Conclusion: Loss of clock gene mPer2 predisposes liver fibrosis by increasing HSC activation and inhibiting HSC apoptosis.     

Curcumin downregulates Smad pathways and reduces hepatic stellate cells activation in experimental fibrosis

Introduction and ObjectivesCurcumin, a polyphenol, is a natural compound that has been widely studied as a hepatoprotector; however, only a few studies have examined its ability to reduce fibrosis in previously established cirrhosis. The objective of this study was to investigate whether curcumin could reduce carbon tetrachloride (CCl₄)-induced fibrosis and if so, to determine the action mechanisms involved in the reduction process.Materials and MethodsCCl₄ was administered to male Wistar rats (400 mg/kg, three times a week, i. p.) for 12 weeks; curcumin (100 mg/kg body weight twice per day, p. o.) was administered from week 9–12 of CCl₄ treatment. Biochemical markers of hepatic injury and oxidative stress were evaluated. Hematoxylin and eosin, Masson’s trichrome stains, transmission electron microscopy; immunohistochemistry, and zymography assays were carried out. Moreover, Smad3 and α-SMA mRNA and protein levels were studied. Western blotting by TGF-β, CTGF, Col-I, MMP-13, NF-κB, IL-1, IL-10, Smad7, pSmad3, and pJNK proteins was developed.Results and ConclusionsCurcumin reduced liver damage, oxidative stress, fibrosis, and restored normal activity of MMP-9 and MMP-2. Besides, curcumin restored NF-κB, IL-1, IL-10, TGF-β, CTGF, Col-I, MMP-13, and Smad7 protein levels. On the other hand, curcumin decreased JNK and Smad3 phosphorylation. Furthermore, curcumin treatment decreased α-SMA and Smad3 protein and mRNA levels. Curcumin normalized GSH, and NF-κB, JNK-Smad3, and TGF-β-Smad3 pathways, leading to a decrement in activated hepatic stellate cells, thereby producing its antifibrotic effects.     

Inhibitory effect of glycyrrhizin on NF-κB binding activity in CC14- plus ethanol-induced liver cirrhosis in rats

ABSTRACT— Aims/Background: Potenlini is an injectable compound whose active component is glycyrrhizin, which is extracted from licorice. Previous studies showed that it could reduce liver injury, improve alanine aminotransferase (ALT) levels and act as an antifibrotic agent. However, the mechanism of its action remains unclear. The aim of this study was to determine the molecular mechanism of its action by investigating the effects of potenlini on nuclear factor-κB(NF-κB) binding activity in an animal model of liver cirrhosis. Methods: Rats were randomly allocated into a normal control group, a model control group, and a potenlini group. Rats in the latter two groups were treated with CCl₄ and ethanol solution in order to induce chronic liver injury. Rats in the potenlini group were given potenlini treatment at the same time. Results: Serum ALT levels were significantly reduced in rats treated with potenlini compared with levels in rats of the model control group, which had dramatically increased ALT levels. Histologically, liver steatosis and fibrosis were severe in the rats of the model group, but were significantly improved in rats of the potenlini group. NF-κB binding activity was markedly increased in the liver specimens taken from the rats of the model control group in comparison with the binding of normal livers, but the binding levels were nearly normal in the livers of the potenlini group. Conclusions: The results suggest that potenlini can inhibit the NF-κB binding activity in CCl₄ and ethanol-induced chronic liver injury, and that effect may be a possible mechanism by which potenlini protects the liver from hepatotoxin-induced liver injury and cirrhosis.     

Effects of salviainolic acid A (SA‐A) on liver injury: SA‐A action on hepatic peroxidation

Abstract: Background/Aims: This study aimed to investigate the actions of salviainolic acid A (SA‐A), an antiperoxidative component of Salvia miltiorrhiza (Sm), on rat liver injury and fibrosis. Methods: Acute and chronic rat liver injury models were established using carbon tetrachloride (CCl₄). After 48 h (acute) or during 6 weeks of CCl₄ injection, rats were further divided and treated with biphenyl dimethyl‐dicarboxylate (BDD) or colchicine, as a control antifibrotic treatment, with Sm, a herbal compound, or SA‐A, a water‐soluble extract of Sm. Liver function was investigated by assessing alanine transaminase (ALT) and aspartate transaminase (AST) activities, histological analysis, hydroxyproline (Hyp) and malondiadehyde (MDA) content. In vitro, isolated cultured hepatocytes were injured with CCl₄ gas for 24 h, followed by treatment with either vitamin E or various concentrations of SA‐A. The extent of hepatocyte injury was monitored by analyzing various lipid peroxidative parameters such as superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), lactase dehydrogenase (LDH), and glutathione peroxidase (GSH‐PX) levels in hepatocyte supernatants. Results: SA‐A significantly decreased abnormal serum ALT activity both in acutely and chronically injured rat livers, decreased abnormal serum AST activity, Hyp and MDA content and attenuated hepatic collagen deposition. After CCl₄ incubation and injury, the activities of AST, ALT CAT, GSH‐PX and LDH and MDA content in hepatocyte supernatants increased significantly, but GSH levels decreased significantly. SA‐A markedly improved these pathological changes in a dose‐dependent manner. 10^?4 mol/l SA‐A had stronger inhibitory action than vitamin E. Conclusions: Our studies suggest that SA‐A has antiperoxidative effects on injured hepatocytes in liver injury and fibrosis induced by CCl₄.