Antioxidant activities of anastatin A & B derivatives and compound 38c's protective effect in a mouse model of CCl4-induced acute liver injury

Anastatins A and B, two flavonoid compounds isolated from desert plant Anastatica hierochuntica, have protective activities for primary rat hepatocytes. Anastatins A and B, and their derivatives, were synthesized by our group previously. In this study, the antioxidant activity and cytotoxicity of these compounds were studied using chemical assessment methods, cell proliferation inhibition experiments, and cell oxidative damage models. The best compound, 38c, was used to study the hepatoprotection activity and mechanism by using a CCl₄-induced liver injury model in mice. The results show that most of these flavonoid compounds have good antioxidant activity and low cytotoxicity in vitro. Among them, the most potent compound was 38c, which exhibited a protective effect on CCl₄-induced hepatic injury by suppressing the amount of CYP2E1. These findings indicate that anastatin flavonoid derivatives have potential therapeutic utility against oxidative hepatic injury.

Anastatins B derivative 38c both had good antioxidant activity in vitro and in vivo.     

Antioxidant properties of flavonoid derivatives and their hepatoprotective effects on CCl4 induced acute liver injury in mice

Excessive accumulation of free radicals in the body can cause liver damage, aging, cancer, stroke, and myocardial infarction. Anastatin B, a skeletal flavonoid, was reported to have antioxidant and hepatoprotective effects. Anastatin B derivatives, compound 1 and 2, were synthesized by our group previously. In this study, their antioxidant activity and hepatoprotective mechanism were studied using chemical evaluation methods, a cellular model of hydrogen peroxide (H₂O₂)-induced oxidative damage, and a mouse model of carbon tetrachloride (CCl₄)-induced liver injury. Results from the chemical evaluation suggested that both compounds had good antioxidant power and radical scavenging ability in vitro. MTT assay showed that both compounds had cytoprotective activity in H₂O₂-treated PC12 cells. Moreover, their hepatoprotective activities evaluated using a mouse model of CCl₄-induced liver injury that compared with the model group, pretreatment with compound 1 and 2 significantly decreased alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH), and malondialdehyde (MDA) levels; reduced the liver tissue damage; and increased glutathione content. However, compound 2 was a more effective hepatoprotectant than compound 1 was. Finally, the amount of TNF-α and cytochrome P450 2E1 (CYP2E1) were significantly downregulated in compound 1 and 2 pretreatment groups. Collectively, our findings demonstrate that both compounds have potential antioxidant activity and hepatoprotective effect in vitro and in vivo. Further chemo-biological study and investigation of the compounds'' enzymatic targets are ongoing.

Excessive accumulation of free radicals in the body can cause liver damage, aging, cancer, stroke, and myocardial infarction.     

Significance of aminopyrine breath test as a parameter of hepatic functional reserve in 40% partial hepatectomy of rats with CCl4-induced liver injury

Rats with CCl₄-induced liver injury underwent partial (40%) hepatectomy. The [¹⁴C]aminopyrine breath test (ABT) values in rats with CCl₄-induced liver injury were reduced by 34% compared with those in rats with normal liver. Preoperative ABT values clearly discriminated between survivors and those that died following 40% partial hepatectomy in rats CCl₄-induced liver injury (P<0.05). Hepatic protein synthesis was remarkably enhanced in CCl₄-induced liver injury compared with normal liver (P<0.001), and this was inversely correlated with ABT values (P<0.001). These data show that the enhanced hepatic protein synthesis could induce a decrease of hepatic functional reserve. ABT seems to be a useful preoperative test for predicting surgical mortality following hepatectomy.     

Lactobacillus fermentum HFY06 reduced CCl4-induced hepatic damage in Kunming mice

This study was conducted to investigate the preventative effect of Lactobacillus fermentum HFY06 on carbon tetrachloride (CCl₄)-induced liver injury in Kunming mice. Mice were treated with HFY06, then liver damage was induced using CCl₄. Evaluation indicators included the activities of aspartate aminotransferase (AST), triglycerides (TG), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) in serum; cytokines levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in serum; and related gene expressions of nuclear factor-κB (NF-κB), TNF-α, cyclooxygenase-2 (COX-2), copper/zinc superoxide dismutase (Cu/Zn-SOD), manganese superoxide dismutase (Mn-SOD), and catalase (CAT). Liver tissue was stained with hematoxylin and eosin for pathological analysis. Compared with the model group, HFY06 reduced the liver index, increased the serum SOD and GSH-Px activities, and reduced the AST, TG, and MDA activities in the mice. Inflammation-related IL-6, TNF-α and IFN-γ levels were also reduced after treatment with a high dose of HFY06. Pathological observation showed that CCl₄ damaged the mouse livers, which were significantly improved after treatment with silymarin and HFY06. qPCR also confirmed that the high dose of HFY06 (10⁹ colony-forming units [CFU] per kg per day) upregulated the mRNA expression of the antioxidant genes, Cu/Zn-SOD, Mn-SOD, and CAT, in the liver tissue and downregulated the mRNA expression of the inflammatory factors, NF-κB, TNF-α and COX-2, but HFY06 was less effective than silymarin. These findings indicate that HFY06 prevented CCl₄-induced liver damage in vivo but was less effective than silymarin. Thus, HFY06 may have a potential role in treating liver diseases.

This study was conducted to investigate the preventative effect of Lactobacillus fermentum HFY06 on carbon tetrachloride (CCl₄)-induced liver injury in Kunming mice.     

Chemical composition and hepatoprotective effect of essential oil from Myrtus communis L. flowers against CCL4-induced acute hepatotoxicity in rats

Myrtus communis L. (Myrtle) is one of the most important aromatic and medicinal species from the Myrtaceae family. It is traditionally used as antiseptic, disinfectant drug and hypoglycemic agent. The aim of our study was to evaluate the protective effect of Myrtus communis essential oil (McEO) on CCl₄-induced hepatotoxicity in rat. Thirty two adult Wistar rats were divided into 4 groups of 8 each: (1) a control group; (2) was given a single dose of CCl₄ (1 mL kg⁻¹ in 1% olive oil. ip) on the 14^th day (3) were given during 15 days a daily i.p. injection of McEO at 250 mL kg⁻¹ b.w (4) a group was pretreated with McEO and intoxicated with CCl₄ on the 14^th day. The major components of McEO are α-pinene (35.20%), 1,8-cineole (17%), linalool (6.17%) and limonene (8.94%) which accounted for 67.31% of the whole oil. The antioxidant activity of McEO was evaluated using DPPH scavenging ability, β-carotene bleaching inhibition and hydroxyl radical-scavenging activity. Moreover, the effect of McEO (250 mg kg⁻¹ body weight BW) administrated for 14 consecutive days was evaluated in wistar rat. Administration of a single dose of CCl₄ caused hepatotoxicity as monitored by an increase in lipid peroxidation (thiobarbituric acid reactive substances) as well in protein carbonyl level but decreased in antioxidant markers in the liver tissue. The McEO pre-treatment significantly prevented the increased plasma levels of hepatic markers and lipid levels induced by CCl₄ in rats. Furthermore, this fraction improved biochemical and histological parameters as compared to CCl₄-treated group. Our results suggest that M. communis contains promising substances to counteract the CCl₄ intoxication and which may be efficient in the prevention of hepatotoxicity complications.

Myrtus communis L. (Myrtle) is one of the most important aromatic and medicinal species from the Myrtaceae family.     

Heat-shock preconditioning reduces oxidative protein denaturation and ameliorates liver injury by carbon tetrachloride in rats

Membrane lipids and cytosolic proteins are major targets of oxidative injury. This study examined the effect of heat-shock preconditioning associated with the induction of heat-shock protein 72 on liver injury, from the aspect of lipid peroxidation and protein denaturation after carbon tetrachloride (CCl4) administration in rats — one of the representative oxidative injuries. Male Wistar rats were divided into two groups, group HS (preconditioned by heat exposure) and group C (not preconditioned). Expression of HSP72 in the liver tissue was confirmed by Western blot analysis. After a 48-h recovery period, all rats were given CCl₄ intragastrically. Liver damage was assessed by measuring serum liver-related enzyme levels and adenine nucleotide concentration in the liver tissue. Lipid peroxidation and protein denaturation were evaluated by measuring tiobarbituric acid reactive substances (TBARS) and by immunohistochemical staining of 4-hydroxy-2-nonenal(HNE)-modified proteins in the liver. Survival rates of the rats after CCl₄ administration were also compared. Expression of HSP72 was clearly detected in group HS, but not in group C. Heat-shock preconditioning significantly improved the survival rate, suppressed the increase in liver-related enzyme levels and maintained adenosine triphosphate levels (P<0.01 each). HNE-modified proteins — denatured proteins by free radical attack — were significantly less stained in group HS than in group C (P<0.05). However, TBARS levels did not differ between groups. Because heat-shock preconditioning did not alter TBARS levels but reduced HNE-modified proteins in association with the expression of HSP72, it is suggested that HSP72 did not prevent lipid peroxidation but decreased the lipid peroxidation-induced denaturation of proteins. This seemed to be a mechanism of heat-shock preconditioning to ameliorate oxidative liver injury.     

Essential oil from halophyte Lobularia maritima: protective effects against CCl4-induced hepatic oxidative damage in rats and inhibition of the production of proinflammatory gene expression by lipopolysaccharide-stimulated RAW 264.7 macrophages

The present study evaluates the chemical profiling of the essential oil of a halophyte, L. maritima (LmEO), and its protective potential against CCl₄-induced oxidative stress in rats. Forty compounds have been identified in LmEO. The major components are α-pinene (3.51%), benzyl alcohol (8.65%), linalool (22.43%), pulegone (3.33%), 1-phenyl butanone (7.33%), globulol (4.32%), γ-terpinene (6.15%), terpinen-4-ol (4.31%), α-terpineol (3.9%), ledol (3.59%), epi-α-cadinol (3.05%) and α-cadinol (4.91%). In comparison with the CCl₄-intoxicated group, LmEO treatment resulted in decreased liver serum marker enzymes, decreased lipid peroxidation and increased antioxidant enzyme levels, with overall further amelioration of oxidative stress. The administration of LmEO to CCl₄-treated rats at a dose of 250 mg kg⁻¹ body weight significantly reduced the toxic effects and the oxidative stress on the liver, thus validating the traditional medicinal claim of this plant. Moreover, the anti-inflammatory activity of LmEO was evaluated in lipopolysaccharide-stimulated murine RAW 264.7 cells. Our oil could modulate the inflammatory mode of the macrophages by causing reduction in iNOS and COX₂ enzymes as well as in IL-1β, IL-6, and TNF-α cytokine levels. These findings suggest that LmEO exerts anti-inflammatory effects by regulating the expression of inflammatory cytokines.

The present study evaluates the chemical profiling of the essential oil of a halophyte, L. maritima (LmEO), and its protective potential against CCl₄-induced oxidative stress in rats.     

Exploring the Effect of Asclepias curassavica on Markers of Oxidative Stress in Rats

Objective

Extract of the aerial part of Asclepias curassavica L. (Asclepiadaceae family) was screened for both in vitro and in vivo antioxidant activity.

Methods

Different concentrations of different extracts (chloroform, ethyl acetate, methanol and hydroalcohol) of A. curassavica were investigated for in vitro antioxidant activity using the thiocyanate method. The hydroalcoholic extract exhibited the highest inhibitory activity on peroxidation, over the other organic extracts, and was subjected to further in vivo antioxidant activity. Hydroalcoholic extract was administered to rats at two different doses of 250 and 500 mg/kg for 14 days to evaluate oxidative stress parameters such as ferric reducing ability of plasma (FRAP), thiobarbituric acid reactive substance (TBARS) and reduced glutathione (GSH) and to evaluate antioxidant enzyme levels of Superoxide dismutase (SOD) and catalase (CAT).

Results and Discussion

The IC₅₀ value (31.2 µg/mL) of hydroalcoholic extract was found to be less than the standard, α-tocopherol (IC₅₀ value 66.1 µg/mL). The hydroalcoholic extract significantly (p < 0.05) increased the FRAP on days 7 and 14 of treatment. Significant (p < 0.05) reduction of TBARS along with an increase in the SOD enzyme level in the liver and kidney at two different doses was observed. Treatment at a 500 mg/kg bodyweight dose caused a significant increase only in the level of CAT in the liver and kidney. However, there was no significant effect of TBARS, SOD and CAT in the heart, and the GSH level in liver, heart and kidney.

Conclusion

It can be concluded that the hydroalcoholic extract of A. curassavica had significant antioxidant activity, which might be helpful in preventing (or slowing) various oxidative stress-related diseases.     

Branched chain amino acids supplementation modulates TGF‐β1/Smad signaling pathway and interleukins in CCl4‐induced liver fibrosis

The alterations and low levels of circulating branched chain amino acids (BCAAs), leucine, isoleucine, and valine, are associated with liver diseases. The study was designed to evaluate hepatoprotective effect of BCAAs on CCl₄‐induced liver fibrosis and to investigate the molecular mechanisms underlying these effects in rats. In all, 30 male rats were divided into three groups. Control group (n = 10) and CCl₄ group (n = 10), where rats were injected with CCl₄ (1 mL/kg of 0.5 : 1 v/v injected i.p. twice weekly for 12 weeks). In CCl₄ + BCAAs group (n = 10), rats were injected with similar doses of CCl₄ and supplemented with a mixture of 600 mg/kg BCAAs (2 : 1 : 1.2 leucine : isoleucine : valine) by oral gavage, three times/week for 12 weeks. Liver fibrosis was assessed by measuring total bilirubin, total protein, alanine aminotransferase, and aspartate aminotransferase, hydroxyproline content, and serum IL‐6 and IL‐10. Histopathologic studies and α‐smooth muscle actin (α‐SMA) were detected immunohistochemically in liver. Serum insulin level, blood glucose, liver malodialdehyde concentration (MDA), glutathione peroxidase, and superoxide dismutase (SOD) activities were quantified. TGF‐β1, Smad3, and Smad7 gene expressions were estimated by qRT‐PCR. BCAAs suppressed liver fibrosis induced by CCl₄ treatment. BCAAs modulated liver indices and downregulated TGF‐β1, Smad3, and Smad7 expressions in hepatocytes. BCAAs enhanced liver antioxidant enzyme activities (P < 0.001), reduced serum levels of TGF‐β1, IL‐6, and IL‐10 compared to CCL₄ group and ameliorated histopathologic changes in rat liver. BCAAs may have a protective role against liver fibrosis via antioxidant and anti‐inflammatory mechanisms.     

PEGylation improves pharmacokinetic profile, liver uptake and efficacy of Interferon gamma in liver fibrosis

Interferon gamma (IFNγ) is a potent cytokine that displays a variety of anti-viral, anti-proliferative, immunomodulatory, apoptotic and anti-fibrotic functions. However, its clinical use is limited to the treatment of few diseases due to the rapid clearance from the body. PEGylated IFN-alpha formulations are shown to be beneficial in viral hepatitis, but PEGylation of IFNγ to enhance its therapeutic effects in liver fibrosis is not yet explored. Liver fibrosis is characterized by the extensive accumulation of an abnormal extracellular matrix and is the major cause of liver-related morbidity and mortality worldwide. To date, there is no pharmacotherapy available for this disease. We modified IFNγ with different-sized linear PEG molecules (5, 10 and 20 kDa) and assessed the biological activity in vitro and in vivo. All PEGylated IFNγ constructs were biologically active and activated IFNγ signaling in vitro as determined with a nitric oxide release assay and a pGAS-Luc reporter plasmid assay, respectively. Similar to IFNγ, all PEGylated IFNγ induced a significant reduction of fibrotic parameters in mouse NIH3T3 fibroblasts as shown with immunohistochemical staining and quantitative PCR analyses. In vivo, the pharmacokinetic profile of radiolabeled ¹²⁵I-IFNγ-PEG conjugates revealed a decreased renal clearance and an increased plasma half-life with an increase of PEG size. Moreover, the liver accumulation of PEGylated IFNγ constructs was significantly higher than the unmodified IFNγ, which was also confirmed by increased MHC-II expression in the livers. Furthermore, in a CCl₄-induced acute liver injury model in mice, PEGylated constructs reduced the early fibrotic parameters more drastically than unmodified IFNγ. Of note, these effects were stronger with higher PEG-sized IFNγ constructs. These data nicely correlated with the pharmacokinetic data. In conclusion, PEGylation significantly improved the pharmacokinetics, liver uptake and anti-fibrotic effects of IFNγ. This study opens new opportunities to exploit the therapeutic applications of PEGylated IFNγ for the treatment of liver fibrosis and other diseases.     

藤梨根拮抗四氯化碳致急性肝损伤作用活性部位的初步筛选

目的:通过建立四氯化碳(CCl4)致急性肝损伤小鼠模型,测定其血清中谷丙转氨酶(ALT)的含量,对藤梨根不同提取部位抑制ALT升高的作用比较,筛选出具有拮抗肝损伤作用的提取部位。方法:取藤梨根原药材,经过乙醇提取、乙酸乙酯萃取,得乙酸乙酯提取部位;过聚酰胺柱洗脱,得不同提取部位,分为X部位、Y部位、Z部位;小鼠预防性给药2 d,以CCl4橄榄油混合物(1%)2 mL/kg腹腔注射造就小鼠化学性肝损伤模型,第3天给药后摘眼球取血,测血清中ALT活力。结果:乙酸乙酯部位、X部位、Y部位均具有拮抗CCl4致急性肝损伤小鼠血清ALT升高的作用,其中X部位在一定剂量范围内具有量效关系。结论:含有黄酮类化合物的藤梨根提取X部位,具有拮抗CCl4致急性肝损伤的作用,且在一定剂量范围内具有量效关系。     

Therapeutic administration of an ingredient of aged-garlic extracts,S-allyl cysteine resolves liver fibrosis established by carbon tetrachloride in rats

S-allyl cysteine (SAC) is the most abundant compound in aged garlic extracts (AGEs). AGE has been reported to ameliorate the oxidative damage implicated in a variety of diseases. However, the effects of SAC have not been established in liver cirrhosis. The aim of this study was to examine the effect of therapeutic administration of SAC in liver cirrhosis by chronic carbon tetrachloride (CCl₄) administration in rats. SAC or other cysteine compounds were administered from 4 weeks when liver fibrosis was confirmed to be in process. CCl₄ administration elevated plasma alanine aminotransferase, plasma lipid peroxidation, liver hydroxyproline, and liver transforming growth factor (TGF)-β at 12 weeks. SAC prevented these changes induced by CCl₄. Furthermore, SAC improved survival in a dose-dependent manner following consecutive CCl₄ administration. The inhibitory mechanisms may be associated with a decrease in the profibrogenic cytokine, TGF-β as well as the antioxidative properties of SAC.     

Individual and synergistic protective properties of Salvia officinalis decoction extract and sulfasalazine against ethanol-induced gastric and small bowel injuries

The present study was carried out to determine the phytochemical composition of Salvia officinalis flowers decoction extract (SOFDE) as well as its individual and/or synergistic actions with sulfasalazine against ethanol (EtOH)-induced peptic ulcer in Wistar rats. In this respect, rats were divided into six groups of eight animals each: control, EtOH, EtOH + sulfasalazine (SULF, 100 mg kg⁻¹, b.w., p.o.), mixture: MIX (SOFDE, 50 mg kg⁻¹ b.w., p.o. + SULF, 50 mg kg⁻¹, b.w., p.o.) and EtOH + two doses of SOFDE (100 and 200 mg kg⁻¹ b.w., p.o.). In vitro, the phytochemical and the antioxidant properties were determined using colorimetric analysis. HPLC-PDA/ESI-MS assay was used to identify the distinctive qualitative profile of phenolic compounds. Our results firstly indicated that SOFDE is rich in total tannins, flavonols, anthocyanins and a moderate concentration of total carotenoids. Chromatographic techniques allowed the identification of 13 phenolic compounds and the major ones are quinic acid, protocatechuic acid, gallic acid and salviolinic acid. SOFDE also exhibited an important in vitro antioxidant activity using the β-carotene bleaching method. In vivo, SOFDE and the mixture provide significant protection against ethanol-induced gastric and duodenal macroscopic and histological alterations. Also, SOFDE alone or in combination with SULF, showed a significant protection against the secretory profile disturbances, lipid peroxidation, antioxidant enzyme activities and non-enzymatic antioxidant level depletion induced by alcohol administration. Importantly, we showed that EtOH acute intoxication increased gastric and intestinal calcium, free iron, magnesium and hydrogen peroxide (H₂O₂) levels, while SOFDE/MIX treatment protected against all these intracellular mediators'' deregulation. We also showed that alcohol treatment significantly increased the C-reactive protein (CRP) and alkaline phosphatase (ALP) activities in plasma. The SOFDE and MIX treatment significantly protected against alcohol-induced inflammation. More importantly, we showed in the present work that the mixture exerted a more important effect than SOFDE and SULF each alone indicating a possible synergism between these two molecules. In conclusion, our data suggests that SOFDE and SULF exerted a potential synergistic protective effect against all the macroscopic, histological and biochemical disturbances induced by EtOH intoxication. This protection might be related in part to its antioxidant and anti-inflammatory properties as well as by negatively regulating Fenton reaction components such as H₂O₂ and free iron.

The present study was carried out to determine the phytochemical composition of Salvia officinalis flowers decoction extract (SOFDE) as well as its individual and/or synergistic actions with sulfasalazine against ethanol (EtOH)-induced peptic ulcer in Wistar rats.     

Se@SiO2 nanocomposites suppress microglia-mediated reactive oxygen species during spinal cord injury in rats

Selenium (Se) is an essential trace element with strong antioxidant activity, showing a great prospect in the treatment of spinal cord injury (SCI). However, the narrow gap between the beneficial and toxic effects has limited its further clinical application. In this experiment, we used porous Se@SiO₂ nanocomposites (Se@SiO₂) modified by nanotechnology as a new means of release control to investigate the anti-oxidative effect in SCI. In vitro Se@SiO₂ toxicity, anti-oxidative and anti-inflammatory effects on microglia were assayed. In vivo we investigated the protective effect of Se@SiO₂ to SCI rats. Neurological function was evaluated by Basso, Beattie and Bresnahan (BBB). The histopathological analysis, microglia activation, oxidative stress, inflammatory factors (TNF-α, IL-1β and IL-6) and apoptosis were detected at 3 and 14 days after SCI. The favorable biocompatibility of Se@SiO₂ suppressed microglia activation, which is known to be associated with oxidative stress and inflammation in vivo and in vitro. In addition, Se@SiO₂ improved the rat neurological function and reduced apoptosis via caspase-3, Bax and Bcl-2 pathways in SCI. Se@SiO₂ was able to treat SCI and reduce oxidative stress, inflammation and apoptosis induced by microglia activation, which may provide a novel and safe strategy for clinical application.

Selenium (Se) is an essential trace element with strong antioxidant activity, showing a great prospect in the treatment of spinal cord injury (SCI).     

Hepatoprotective effects of misoprostol and silymarin on carbon tetrachloride-induced hepatic damage in rats

The aim of this study was to investigate the effect of misoprostol, silymarin or the co‐administration of misoprostol + silymarin on the carbon tetrachloride (CCl₄)‐induced hepatic injury in rats. Misoprostol (10, 100, 1000 μg/kg), silymarin (25 mg/kg) or misoprostol (100 μg/kg) + silymarin (25 mg/kg) was given once daily orally simultaneously with CCl₄ and for 15 days thereafter. The results showed that misoprostol (10, 100 or 1000 μg/kg) conferred significant protection against the hepatotoxic actions of CCl₄ in rats, reducing serum alanine aminotransferase (ALT) levels by 24.7%, 42.6% and 49.4%, respectively compared with controls. Misoprostol, given at 100 or 1000 μg/kg, decreased aspartate aminotransferase (AST) by 28 and 43.6% and alkaline phosphatase (ALP) by 19.3% and 53.4% respectively. Meanwhile, silymarin reduced ALT, AST and ALP levels by 62.7%, 66.1% and 65.1% respectively. The co‐administration of misoprostol (100 μg/kg) and silymarin (25 mg/kg) resulted in 61.4%, 66.1% and 57.5% reduction in ALT, AST and ALP levels respectively. Histopathological alterations and depletion of hepatocyte glycogen and DNA content by CCl₄ were markedly reduced after treatment with misoprostol, silymarin or misoprostol + silymarin. Image analysis of liver specimens revealed a marked reduction in liver necrosis; area of damage: 32.4%, 24% and 10.2% after misoprostol (10, 100 or 1000 μg/kg), 7.2% after silymarin and 10.9% after treatment with misoprostol 100 μg/kg + silymarin, compared with CCl₄ control group (46.7%). These results indicate that treatment with misoprostol protects against hepatocellular necrosis induced by CCl₄. This study suggests a potential therapeutic use for misoprostol in liver injury.     

Heat-shock preconditioning reduces oxidative protein denaturation and ameliorates liver injury by carbon tetrachloride in rats

Membrane lipids and cytosolic proteins are major targets of oxidative injury. This study examined the effect of heat-shock preconditioning associated with the induction of heat-shock protein 72 on liver injury, from the aspect of lipid peroxidation and protein denaturation after carbon tetrachloride (CCl₄) administration in rats - one of the representative oxidative injuries. Male Wistar rats were divided into two groups, group HS (preconditioned by heat exposure) and group C (not preconditioned). Expression of HSP72 in the liver tissue was confirmed by Western blot analysis. After a 48-h recovery period, all rats were given CCl₄ intragastrically. Liver dam-age was assessed by measuring serum liver-related enzyme levels and adenine nucleotide concentration in the liver tissue. Lipid peroxidation and protein denaturation were evaluated by measuring tiobarbituric acid reactive substances (TBARS) and by immunohistochemical staining of 4-hydroxy-2-nonenal(HNE)-modified proteins in the liver. Survival rates of the rats after CCl₄ administration were also compared. Expression of HSP72 was clearly detected in group HS, but not in group C. Heat-shock preconditioning significantly improved the survival rate, suppressed the increase in liver-related enzyme levels and maintained adenosine triphosphate levels (P<0.01 each). HNE-modified proteins - denatured proteins by free radical attack - were significantly less stained in group HS than in group C (P<0.05). However, TBARS levels did not differ between groups. Because heat-shock preconditioning did not alter TBARS levels but reduced HNE-modified proteins in association with the expression of HSP72, it is suggested that HSP72 did not prevent lipid peroxidation but decreased the lipid peroxidation-induced denaturation of proteins. This seemed to be a mechanism of heat-shock preconditioning to ameliorate oxidative liver injury.     

Hepatoprotective effects of Liv-52 and its indirect influence on the regulation of thyroid hormones in rat liver toxicity induced by carbon tetrachloride

This study was undertaken to investigate the protective effect of Liv-52, a herbal formulation, on various serum and liver marker enzymes, lipid peroxidation and histological changes in the liver of male albino rats suffering long-term carbon tetrachloride (CCl₄) poisoning. It was observed that the activities of serum marker enzymes, hepatic enzymes and NADPH-dependent lipid peroxidation were significantly elevated after treatment with CCl₄. However, in rats given Liv-52 at the same time as CCl₄, the levels of all the marker enzymes were closer to those found in control animals. A similar trend was seen in the case of lipid peroxidation after Liv-52 treatment. CCl₄ alone caused severe liver damage, but when Liv-52 was simultaneously given, there was much less effect on the structure of the organ. Circulating T₃ and T₄ concentrations were also determined after 6 weeks of simultaneous treatment with Liv-52 and CCl₄. Concentrations of T₃ were significantly lowered after CCl₄ treatment alone, but Liv-52 administration together with CCl₄ resulted in maintenance of the T₃ activity within normal limits, thus suggesting indirect beneficial effects of Liv-52 on the regulation of thyroid hormone concentrations.     

Bioactive properties: enhancement of hepatoprotective,antioxidant and DNA damage protective effects of golden grey mullet protein hydrolysates against paracetamol toxicity

This study was undertaken to examine the hepatoprotective, antioxidant, and DNA damage protective effects of protein hydrolysates from Liza aurata, against paracetamol overdose induced liver injury in Wistar rats. L. aurata protein hydrolysates (LAPHs) were mainly constituted by glutamic acid (Glu) and glutamine (Gln) and lysine (Lys). In addition, they contained high amounts of proline (Pro), leucine (Leu) and glycine (Gly). The molecular weight distribution of the hydrolysates was determined by size exclusion chromatography, which analyzed a representative hydrolysate type with a weight range of 3–20 kDa. The hepatoprotective effect of LAPHs against paracetamol liver toxicity was investigated by in vivo assay. Rats received LAPHs daily by gavage, for 45 days. Paracetamol was administrated to rats during the last five days of treatment by intraperitoneal injection. Paracetamol overdose induced marked liver damage in rats was noted by a significant increase in the activities of serum aspartate amino transferase (AST) and alanine amino transferase (ALT), and oxidative stress which was evident from decreased activity of the enzymatic antioxidants (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)), and level of glutathione (GSH), and increased concentration of lipid peroxidation products (MDA). Furthermore, paracetamol increased the DNA damage with liver histopathological changes. LAPH pretreatment significantly attenuated paracetamol-induced hepatotoxic effects, including oxidative damage, histopathological lesions, and apoptotic changes in the liver tissue. Interestingly, LAPHs restored the activities of antioxidant enzymes and the level of GSH, ameliorated histological and molecular aspects of liver cells. The present data suggest that paracetamol high-dose plays a crucial role in the oxidative damage and genotoxicity of the liver and therefore, some antioxidants such us LAPHs might be safe as hepatoprotectors. Altogether, our studies provide consistent evidence of the beneficial effect of LAPHs on animals treated with a toxic dose of paracetamol and might encourage clinical trials.

This study was undertaken to examine the hepatoprotective, antioxidant, and DNA damage protective effects of protein hydrolysates from Liza aurata, against paracetamol overdose induced liver injury in Wistar rats.     

Protective Effects of Vitamin E Analogs against Carbon Tetrachloride-Induced Fatty Liver in Rats

Recently, it has been reported that α-tocopherol (α-Toc) is effective for amelioration of liver damage. However, it is unknown whether other vitamin E analogs are effective. In this study, we investigated the effects of γ-tocopherol (γ-Toc) and tocotrienols (T3) in rats with fatty liver. Rats fed a vitamin E-deficient diet for four weeks were divided into eight groups: Control, carbon tetrachloride (CCl₄), α-Toc, α-Toc + CCl₄, γ-Toc, γ-Toc + CCl₄, T3 mix, T3 mix + CCl₄. After a 24 h fast, the rats were administered 20 mg of each of the vitamin E analogs, respectively. Moreover, the CCl₄ group were given 0.5 ml/kg body weight corn oil preparation containing CCl₄ 6 h after vitamin E administration. We measured the activities of aspartate aminotransferase and alanine aminotransferase (ALT) in plasma, and the contents of triglyceride (TG), total cholesterol (T-Chol) and vitamin E analogs in the liver. Also, we determined the hepatic expression of mRNA for inflammatory cytokines. The liver TG content in the γ-Toc + CCl₄ and T3 mix + CCl₄ groups was decreased in comparison with the CCl₄ group. Moreover, ALT activity in the T3 mix + CCl₄ group was significantly lower than CCl₄ group. These findings suggest that γ-Toc and T3 are effective for amelioration of fatty liver.