Acute liver toxicity by carbon tetrachloride in HSP70 knock out mice

Lobular distribution of enhanced expression levels of heat shock proteins using in-situ hybridization in the mouse liver treated with a single administration of CCl4

This study was conducted to visualize the lobular distribution of enhanced mRNA expression levels of heat shock proteins (HSPs) in liver samples from carbon tetra chloride (CCl4)-treated mice using in-situ hybridization (ISH). Male BALB/c mice given a single oral administration of CCl4 were euthanized 6 hours or 1 day after the administration (6 h or 1 day). Paraffin-embedded liver samples were obtained, ISH for HSPs was conducted, as well as hematoxylin-eosin staining and immunohistochemistry (IHC). At 6 h, centrilobular hepatocellular vacuolization was observed, and increased signals for Hspa1a, Hspa1b, and Grp78, which are HSPs, were noted in the centrilobular area using ISH. At 1 day, zonal hepatocellular necrosis was observed in the centrilobular area, but mRNA signal increases for HSPs were no longer observed there. Some discrepancies between ISH and IHC for HSPs were observed, and they might be partly caused by post-transcriptional gene regulation, including the ribosome quality control mechanisms. It is known that CCl4 damages centrilobular hepatocytes through metabolization by cytochrome P450, mainly located in the centrilobular region, and HSPs are induced under cellular stress. Therefore, our ISH results visualized increased mRNA expression levels of HSPs in the centrilobular hepatocytes of mice 6 hours after a single administration of CCl4 as a response to cellular stress, and it disappeared 1 day after the treatment when remarkable necrosis was observed there.

Characterization of novel mouse models to study the role of necroptosis in aging and age-related diseases

To study the impact of necroptosis-induced chronic inflammation on age-related diseases and aging, two knockin mouse models (Ripk3-KI and Mlkl-KI) were generated that overexpress two genes involved in necroptosis (Ripk3 or Mlkl) when crossed to Cre transgenic mice. Crossing Ripk3-KI or Mlkl-KI mice to albumin-Cre transgenic mice produced hepatocyte specific hRipk3-KI or hMlkl-KI mice, which express the two transgenes only in the liver. Ripk3 and Mlkl proteins were overexpressed 10- and fourfold, respectively, in the livers of the hRipk3-KI or hMlkl-KI mice. Treating young (2-month) hRipk3-KI or hMlkl-KI mice with carbon tetrachloride (CCl4), a chemical inducer of oxidative stress, resulted in increased necroptosis (Mlkl-oligomers) and inflammation in the liver compared to control mice receiving CCl4. Mlkl-oligomerization also was significantly increased in old (18-month) hRipk3-KI and hMlkl-KI mice compared to old control (Cre negative, Ripk3-KI and Mlkl-KI) mice. The increase in necroptosis was associated with an increase in inflammation, e.g., inflammatory cytokines (TNFα, IL-6) and macrophage markers (F4/80, CD68). Importantly, steatosis (triglycerides) and fibrosis (e.g., picrosirius red staining, hydroxyproline levels, and transcripts for TGFβ, Col1α1, and Col3α1) that increase with age were significantly higher in the livers of the old hRipk3-KI or hMlkl-KI mice compared to old control mice. In addition, markers of cellular senescence were significantly increased in the livers of the old hRipk3-KI and hMlkl-KI mice. Thus, the first mouse models have been developed that allow researchers to study the impact of inducing necroptosis in specific cells/tissues on chronic inflammation in aging and age-related diseases.

Heat shock protein 70 protects the lungs from hyperoxic injury in a neonatal rat model of bronchopulmonary dysplasia

Hyperoxia plays a significant role in the pathogenesis of lung injury, such as bronchopulmonary dysplasia (BPD), in premature infants or newborns. BPD management aims to minimize further injury, provide an optimal environment to support growth and recovery. In clinic neonatal care, we need a new therapy for BPD. Heat shock protein 70 (Hsp70) inhibit cell apoptosis and promote cell repair allowing cells to survive lethal injury. We hypothesized that Hsp70 could be used to prevent hyperoxia related BPD in the neonatal rat model through its anti-apoptotic and anti-inflammatory effects. In this study, we explored the effect of Hsp70 on hyperoxia-induced lung injury using neonatal rats. Neonatal Wistar rats were delivered naturally at full term of gestation and were then pooled and randomly assigned to several groups to receive heat stimulation (41°C for 20 min) or room temperature conditions. The Hsp70 group received recombinant Hsp70 intraperitoneally (200 μg/kg, daily). All newborn rats were placed under hyperoxic conditions (85% oxygen) for 21 days. Survival rates in both heat-hyperoxia and Hsp70-hyperoxia groups were higher than those in the hyperoxia group (p < 0.05). Both endogenous and exogenous Hsp70 could reduce early apoptosis of alveolar cells under hyperoxia. Additionally, there were less macrophage infiltration in the lung of the Hsp70 groups (p < 0.05). Heat stress, heat shock proteins, and exogenous recombinant Hsp70 significantly increased the survival rate and reduced pathological hyperoxia induced lung injuries in the development of BPD. These results suggest that treating hyperoxia-induced lung injury with Hsp70 may reduce the risk of developing BPD.

The expression of Catsup in escort cells affects Drosophila ovarian stem cell niche establishment and germline stem cells self-renewal via Notch signaling

Stem cell niche provides extrinsic signals to maintain stem cell renewal or initiate cell differentiation. Drosophila niche is composed of somatic terminal filament cells, cap cells and escort cells. However, the underlying mechanism for the development of stem cell niche remains largely unclear. Here we found that the expression of a zinc transporter Catsup is essential for ovary morphogenesis. Catsup knockdown in escort cells results in defects of niche establishment and germline stem cells self-renewal. These defects could be modified by altered expression of genes involved in zinc metabolism or intervention of dietary zinc levels. Further studies indicated that Catsup RNAi affected adult ovary morphogenesis by suppressing Notch signaling. Lastly, we demonstrated that the defects of Catsup RNAi could be restored by overexpression of heat shock cognate protein 70 (Hsc70). These findings expand our understanding of the mechanisms controlling adult oogenesis and niche establishment in Drosophila.

Investigation of hepatoprotective effect of some algae species on carbon tetrachloride-induced liver injury in rats

The aim of this study was to investigate hepatoprotective effect of some algae species such as Spirulina platensis, Chlorella vulgaris, Laminaria japonica, Sargassum sp. on experimental acute hepatotoxicity model that induced with carbon tetrachloride (CCl₄) in rats. Algaes at a dose of 200 mg/kg and Silymarin at a dose of 25 mg/kg were orally administered for 7 days followed by CCl₄ at a single dose (0.5 ml/kg), at the 8th day to cause experimental acute hepatotoxicity. Levels of biochemical (AST, ALT etc.), lipid peroxidation (MDA), antioxidant (GSH, CAT, GPx) parameters and histopathological examination were carried out to investigate the hepatoprotective effects of algae. In Sp group ALT and ALP levels were significantly decreased compared with CCl₄ (p < .05). Histological liver structures of Sp group were similar to the control group. MDA, GPx and CAT levels of Sp and La groups were significantly different compared with CCl₄ (p < .05). Based on these results, algae species able to minimise the toxic effects of CCl₄ and especially S. platensis could be used in the purpose of protection against chemical-induced hepatotoxicity.

Fabrication, characterization and biological evaluation of silymarin nanoparticles against carbon tetrachloride-induced oxidative stress and genotoxicity in rats

This study aimed to synthesize silymarin nanoparticles (SILNPs) using chitosan nanoparticles as a delivery system and to evaluate their protective effects against CCl4 in rats. Eight groups of male Sprague-Dawley rats were treated for three weeks included the control group, CCl4-treated group (100 mg/kg b.w twice a week); SIL-treated group (50 mg/lg b.w); the groups treated daily with low dose (LD) or high dose (HD) of SILNPs (25, 50 mg/kg b.w) and the groups treated with CCl4 plus SIL, SILNPs (LD) or SILNPs (HD). Blood and tissue samples were collected for different assays. The synthesized SILNPs showed a smooth rounded shape with average particle size of 100 ± 2.8 nm. SILNPs contain the same compounds found in raw SIL and the in vitro release of SILNPs continues till 24 h. The in vivo study revealed that SIL and SILNPs at the low or high dose induced a significant improvement in the hematological parameters, liver and kidney function, lipid profile, serum cytokines, gene expression DNA fragmentation and histology of liver and kidney tissue resulted from CCl4. It could be concluded that SILNPs can be applied in oral delivery formulations with a potential application value for liver disease therapy.

Hepatoprotective effects of Vaccinium arctostaphylos against CCl4-induced acute liver injury in rats

BACKGROUND

This study was carried out to evaluate the antioxidant and hepatoprotective effects of Vaccinium arctostaphylos (V.a) methanolic extract on carbon tetrachloride (CCl4)-induced acute liver injury in Wistar rats.

METHODS

Total phenolic and total flavonoid contents as well as antioxidant activity of V.a were determined. Extracts of V.a at doses of 200 and 400 mg/kg were administered by oral gavage to rats once per day for 7 days and then were given an intraperitoneal injection of 1 mL/kg CCl4 (1:1 in olive oil) for 3 consecutive days. Serum biochemical markers of liver injury, oxidative markers, as well as hydroxyproline (HP) content and histopathology of liver were evaluated.

RESULTS

The obtained results showed that V.a had strong antioxidant activity. Treatment of rats with V.a blocked the CCl4-induced elevation of serum markers of liver function and enhanced albumin and total protein levels. The level of hepatic HP content was also reduced by the administration of V.a treatment. Histological examination of the liver section revealed that V.a prevented the occurrence of pathological changes in CCl4-treated rats.

CONCLUSIONS

These findings suggested that V.a may be useful in the treatment and prevention of hepatic injury induced by CCl4.

Analysis of IL-6, STAT3 and HSPA1L gene polymorphisms in anti-tuberculosis drug-induced hepatitis in a nested case-control study

OBJECTIVES

To investigate the association of IL-6, STAT3 and HSPA1L polymorphisms with the risk of anti-tuberculosis drug-induced hepatitis (ATDH) in Chinese Han population.

METHODS

The study was designed as a nested case-control study within a prospective cohort. Each case was matched with four controls by sex, age at baseline (±5 years), treatment history, disease severity, drug dosage and place of sample collection. Genetic polymorphisms of IL-6, STAT3 and HSPA1L were determined blindly by TaqMan single-nucleotide polymorphism (SNP) genotyping assay. Odds ratio (OR) with 95% confidence intervals (CIs) was estimated by conditional logistic regression model to measure the association between selected SNPs and the risk of ATDH.

RESULTS

A total of 89 incident ATDH cases and 356 ATDH-free controls were genotyped for IL-6 (rs2066992, rs2069837, rs1524107), STAT3 (rs1053004, rs1053023, rs1053005) and HSPA1L (rs2227956). In genotype analysis, no significant difference was observed in genotypes frequencies of the seven selected SNPs between case and control group after Bonferroni correction. In haplotype analysis, carriers with STAT3 GAT and AGC (rs1053023-rs1053005-rs1053004) haplotypes had a significantly higher risk of ATDH compared with wild-type haplotype (P<0.0001).

CONCLUSION

This study suggested that genetic variants of STAT3 might contribute to ATDH susceptibility in Chinese Han population. Studies in larger, varied populations are required to confirm these findings.

Neutralization of ADAM8 ameliorates liver injury and accelerates liver repair in carbon tetrachloride-induced acute liver injury

Although some studies have described the function of ADAM8 (a disintegrin and metalloprotease 8) related with rheumatoid arthritis, cancer and asthma, etc., the concrete role of ADAM8 in acute liver injury is still unknown. So mice respectively received anti-ADAM8 monoclonal antibody (mAb) of 100 μg/100 μl, 200 μg/100 μl or 300 μg/100 μl in PBS or PBS pre-injection. Then acute liver injury was induced in the mice by intraperitoneal (i.p.) injection of carbon tetrachloride (CCl₄). Serum AST and ALT level, Haematoxylin-eosin (H&E) staining, the expression level of vascular endothelial growth factor (VEGF), cytochrome P450 1A2 (CYP1A2) and proliferating cell nuclear antigen (PCNA) were detected in the mice after CCl4 administration. Our results showed that anti-ADAM8 mAb pre-injection could effectively lower AST and ALT levels (P < 0.05 or P < 0.01) and reduce liver injury (P < 0.05 or P <0.01), induce the expression of VEGF, CYP1A2 and PCNA (P <0.05 or P < 0.01) in dose-dependent manner compared with the control mice which received PBS pre-injection. In summary, our study suggested that ADAM8 might promote liver injury by inhibiting the proliferation of hepatocytes, angiogenesis and affecting the metabolism function of liver during acute liver injury induced by CCl₄. Anti-ADAM8 mAb injection might be suitable as a potential method for acute liver injury therapy.

Developmental toxicity in rare minnow (Gobiocypris rarus) embryos exposed to Cu, Zn and Cd

Using rare minnow (Gobiocypris rarus) embryos as experimental model, the developmental toxicity of Cu, Zn and Cd were investigated following exposure to 0.001-1.000mg/L for 72h, and the toxicity effects were evaluated by larval malformation rate, heart rate, pericardial area, spontaneous movements, tail length, enzyme activities and biomarker genes. Our results revealed that increased malformation rate provide a gradual dose-response relationship, and the most pronounced morphological alteration was heart and body malformations. Values of 72h EC50 with their 95 percent confidence intervals on G. rarus embryos were 0.103 (0.072-0.149)mg/L for Cu, 0.531 (0.330-1.060)mg/L for Zn, 0.219 (0.147-0.351)mg/L for Cd. Enzyme activities can be regard as a type of low-dose stimulation and high-dose inhibition. Stress and metabolism-related genes (hsp70, cyp1a and mt) were significantly up-regulated, development-related genes (wnt8a, vezf1 and mstn) were significantly down-regulated after the treatment by Cu, Zn and Cd. Overall, the present study points out Cu, Zn and Cd are highly toxic to G. rarus embryos. The information presented in this study will be helpful in fully understanding the toxicity induced by Cu, Zn and Cd in fish embryos.

Proper heat shock pretreatment reduces acute liver injury induced by carbon tetrachloride and accelerates liver repair in mice

Whether proper heat shock preconditioning can reduce liver injury and accelerate liver repair after acute liver injury is worth study. So mice received heat shock preconditioning at 40°C for 10 minutes (min), 20 min or 30 min and recovered at room temperature for 8 hours (h) under normal feeding conditions. Then acute liver injury was induced in the heat shock-pretreated mice and unheated control mice by intraperitoneal (i.p.) injection of carbon tetrachloride (CCl₄). Hematoxylin and eosin (H&E) staining, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and the expression levels of heat shock protein 70 (HSP70), cytochrome P450 1A2 (CYP1A2) and proliferating cell nuclear antigen (PCNA) were detected in the unheated control mice and heat shock-pretreated mice after CCl₄ administration. Our results showed that heat shock preconditioning at 40°C for 20 min remarkably improved the mice’s survival rate (P<0.05), lowered the levels of serum AST and ALT (P<0.05), induced HSP70 (P<0.01), CYP1A2 (P<0.01) and PCNA (P<0.05) expression, effectively reduced liver injury (P<0.05) and accelerated the liver repair (P<0.05) compared with heat shock preconditioning at 40°C for 10 min or 30 min in the mice after acute liver injury induced by CCl₄ when compared with the control mice. Our results may be helpful in further investigation of heat shock pretreatment as a potential clinical approach to target liver injury

Regulation of wound healing and organ fibrosis by toll-like receptors

Chronic injury often triggers maladaptive wound healing responses leading to the development of tissue fibrosis and subsequent organ malfunction. Inflammation is a key component of the wound healing process and promotes the development of organ fibrosis. Here, we review the contribution of Toll-like receptors (TLRs) to wound healing with a particular focus on their role in liver, lung, kidney, skin and myocardial fibrosis. We discuss the role of TLRs on distinct cell populations that participate in the repair process following tissue injury, and the contribution of exogenous and endogenous TLR ligands to the wound healing response. Systemic review of the literature shows that TLRs promote tissue repair and fibrosis in many settings, albeit with profound differences between organs. In particular, TLRs exert a pronounced effect on fibrosis in organs with higher exposure to bacterial TLR ligands, such as the liver. Targeting TLR signaling at the ligand or receptor level may represent a novel strategy for the prevention of maladaptive wound healing and fibrosis in chronically injured organs. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.

Extraction optimization of Angelica sinensis polysaccharides and its antioxidant activity in vivo

Extraction of Angelica sinensis polysaccharides (ASP) was optimized by the utilization of response surface methodology, RSM. Through the analysis, extraction time and water/solid were found to be the most significant factors. Based on contour plots and variance analysis, optimum operational conditions for maximizing polysaccharides yield (5.6%) were found to be extraction time 130 min, water/solid 5, and extraction number 5. A. sinensis polysaccharides (150 and 300 mg/kg) were administered for 15 days. The hepatoprotective activity was assessed using various biochemical parameters. Serum aspartate aminotransferase (AST), alanine aminotransfere (ALT) and alkaline phosphatase (ALP) levels were significantly restored toward normalization by the extracts (150 and 300 mg/kg body weight). ASP (150 and 300 mg/kg body weight) significantly increased the levels of antioxidant enzymes. It can be concluded that ASP possesses significant protective effect against hepatotoxicity induced by carbon tetrachloride (CCl4). This protective effect appears due to ASP antioxidant properties.

Dietary honey and ginseng protect against carbon tetrachloride-induced hepatonephrotoxicity in rats

Liver diseases are amongst the most serious health problems in the world today and hepatocellular carcinoma is one of the world's deadliest cancers. The aim of the current study was to evaluate the protective effect of sider honey and/or Korean ginseng extract (KGE) against carbon tetrachloride (CCl(4))-induced hepato-nephrotoxicity in rat. Eighty male Sprague-Dawley (SD) rats were allocated into different groups and over a 4-week period, they orally received honey and/or KGE or were treated either with CCl(4) alone (100 mg/kg b.w) or with CCl(4) after a pretreatment period with honey, KGE or a combination of both. Clinical, clinico-pathological and histopathological evaluations were done and CCl(4)-treated groups were compared with rats receiving no treatment and with rats given honey, KGE or a combination of these substances. The results indicated that oral administration of CCl(4) induced severe hepatic and kidney injury associated with oxidative stress. The combined treatment with CCl(4) plus honey and/or KGE resulted in a significant improvement in all evaluated parameters. This improvement was prominent in the group receiving CCl(4) after combined pretreatment with honey and KGE. Animals receiving honey and/or KGE (without CCl(4)-treatment) were comparable to the control untreated group. It could be concluded that honey and KGE protect SD rats against the severe CCl(4)-induced hepatic and renal toxic effects. Our results suggest that the protective activity of honey and KGE may have been related to their antioxidant properties.

Isoflavones-Enriched Soy Protein Prevents CCL(4)-Induced Hepatotoxicity in Rats

The burden of liver disease in Egypt is exceptionally high due to the highest prevalence of hepatitis C virus (HCV) resulting in rising rates of hepatocellular carcinoma (HCC). The aim of the current study was to determine the isoflavones in soy and to evaluate the protective role of soy against CCl₄-induced liver damage in rats. Four experimental groups were treated for 8 weeks and included the control group, soy-supplemented diet (20% w/w) group, the group treated orally with CCl₄ (100 mg/kg bw) twice a week, and the group fed soy-supplemented diet and treated with CCl₄. Blood and liver tissue samples were collected for biochemical analyses and histological examination. The results indicated that protein content was 45.8% and the total isoflavones recorded 167.3 mg/100 g soy. Treatment with CCl₄ resulted in a significant biochemical changes in serum liver tissue accompanied with severe oxidative stress and histological changes. Supplementation with soy succeeded to restore the elevation of liver enzymes activities and improved serum biochemical parameters. Moreover, soy supplementation improved the antioxidant enzymes, decreased lipid peroxidation, and improved the histological picture of the liver tissue. It could be concluded that soy-protein-enriched isoflavones may be a promising agent against liver diseases.

Antioxidant activity and hepatoprotective effects of whey protein and Spirulina in rats

OBJECTIVES

The aims of the present study were to evaluate the antioxidant, radical scavenging, and metal-chelating activity of whey protein concentrate (WPC) and Spirulina alone or in combination in vitro and to evaluate their hepatoprotective effects against CCl(4) in vivo.

METHODS

Five concentrations (20, 40, 60, 80, and 100 mg/100 mL) of WPC, Spirulina, and their combination were tested in vitro. In the in vivo study, eight groups of male rats comprised the control group and the groups treated with WPC, Spirulina alone, or in combination with or without CCl(4) were used.

RESULTS

The in vitro study showed that WPC and Spirulina showed antioxidant, radical scavenging, and metal-chelating activities in dose-dependent manner. The in vivo study showed that both agents succeeded in preventing liver damage induced by CCl(4). This prevention was more pronounced in rats receiving the combination of WPC and Spirulina.

CONCLUSION

Whey protein concentrate and Spirulina have free radical scavenging properties and antioxidant activity.

Changes in hepatic gene expression in response to hepatoprotective levels of zinc

BACKGROUND

Zinc (Zn) administration at non-toxic doses protects against the hepatotoxicity produced by many agents, but the underlying mechanisms remain elusive.

AIM

To examine the basis of Zn-induced generalised hepatoprotective effects.

METHODS

Rats and mice were given Zn at known hepatoprotective levels (100 mumol ZnCl2/kg/day, s.c., for 4 days) and molecular responses were assessed.

RESULTS

Zn treatment produced changes in 5% of the genes on custom-designed mouse liver array and Rat Toxicology-II array. Changes in gene expression were further confirmed and extended by real-time reverse transcriptase-polymerase chain reaction. Zn treatment dramatically increased the expression of the metallothionein (Mt), and modestly increased the expression of acute-phase protein genes (ceruloplasmin, Stat3, egr1, Cxc chemokines and heat-shock proteins). For genes encoding for antioxidant enzymes, some were increased (Nrf2 and Nqo1), while others remained unaltered (Cu, Zn SOD and glutathione S-transferases). Expressions of cytokine and pro-inflammatory genes were not affected, while genes related to cell proliferation (cyclin D1) were modestly upregulated. Some metabolic enzyme genes, including cytochrome P450s and UDP-glucuronosyltransferase, were modestly suppressed, perhaps to switch cellular metabolic energy to acute-phase responses. Liver Zn content was increased between 1.6- and 2.1-fold, while hepatic MT protein was increased between 50 and 200-fold. Mice typically showed greater responses than rats.

CONCLUSION

Such gene expression changes, particularly the dramatic induction of MT and Nrf2 antioxidant pathway, occur in the absence of overt liver injury, and are probably important in the hepatoprotective effects of Zn against toxic insults.

New insights into generalized hepatoprotective effects of oleanolic acid: key roles of metallothionein and Nrf2 induction

Oleanolic acid (OA) is a natural triperpenoid that protects against a variety of hepatotoxicants such as carbon tetrachloride, cadmium, acetaminophen, and bromobenzene. To gain insight into the molecular mechanisms of this generalized hepatoprotection, genomic analysis was performed on mouse and rat livers after OA treatment. Mice and rats were given OA at a hepatoprotective dose (50 micromol/kg, s.c., daily for 4 days) and hepatic RNA was isolated, purified, and subjected to gene expression analysis. OA treatment produced changes in 5% of the genes on custom-designed mouse liver array and rat toxicology-II array. Changes in key gene expressions were further analyzed by real-time RT-PCR. OA treatment dramatically increased expression of hepatic metallothionein (Mt), and increased the expression of the nuclear factor E2-related factor 2 (Nrf2), NAD(P)H:quinone oxidoreductase 1 (Nqo1), heme oxygenase-1 (Hmox1), and glutamate-cysteine ligases (Gclc and Gclm). OA treatment also increased the expression of genes related to cell proliferation and suppressed the expression of several cytochrome P450 genes possibly to switch cellular metabolic energy to an acute-phase response. Hepatic MT protein was increased 60- and 15-fold in mice and rats, respectively, together with a 30% increase in mouse liver zinc. These gene expression changes, particularly the dramatic induction of MT and the Nrf2 signaling, occur with hepatoprotection doses of OA, and likely are important in the generalized protective effects of OA against hepatotoxicants.