Rat Liver Cell Line Research Articles

Efficacy and tolerability of AFPep, a cyclic peptide with anti-breast cancer properties

PurposeThe purpose of this study is to assess the efficacy and safety profile of AFPep, a 9-amino acid cyclic peptide prior to its entry into pre-clinical toxicology analyses en route to clinical trials. MethodsAFPep was assessed for anti-estrogenic activity in a mouse uterine growth assay and for breast cancer therapeutic efficacy in a human tumor xenograft model in mice. AFPep was assessed for tolerability in a variety of in vivo models, notably including assessment for effects on rat liver and human hepatocellular carcinoma cell lines and xenografts. ResultsAFPep arrests the growth of human MCF-7 breast cancer xenografts, inhibits the estrogen-induced growth of mouse uteri, and does not affect liver growth nor stimulate growth of human hepatocellular carcinoma cell lines when growing in vitro or as xenografts in vivo. AFPep is well tolerated in mice, rats, dogs, and primates. ConclusionsAFPep is effective for the treatment of ER-positive breast cancer and exhibits a therapeutic index that is substantially wider than that for drugs currently in clinical use. The data emphasize the importance of pursuing pre-clinical toxicology studies with the intent to enter clinical trials.

Plasmon-activated water effectively relieves hepatic oxidative damage resulting from chronic sleep deprivation.

The role of the hepato-protective agent plasmon-activated water (PAW) as an innovative anti-oxidant during chronic sleep deprivation (SD) is realized in this study. PAW possesses reduced hydrogen-bonded structure, higher chemical potential and significant anti-oxidative properties. In vitro tests using rat liver cell line (Clone-9) have demonstrated that PAW is non-cytotoxic and does not change the cellular migration capacity. The in vivo experiment on SD rats suffering from intense oxidative damage to the liver, an extremely common phenomenon in the present-time with deleterious effects on metabolic function, is performed by feeding PAW to replace deionized (DI) water. Experimental results indicate that PAW markedly reduces oxidative stress with enhanced bioenergetics in hepatocytes. PAW also effectively restores hepatocytic trans-membrane ion homeostasis, preserves membranous structures, and successfully improves liver function and metabolic activity. In addition, the hepato-protective effects of PAW are evidently demonstrated by the reduced values of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) and the recovery of total protein and albumin levels. With clear evidences of PAW for protecting liver from SD-induced injury, delivering PAW as a powerful hepato-protective agent should be worthy of trailblazing new clinical trials in a healthier, more natural, and more convenient way.

Biorefining compounds and organocatalytic upgrading methods

T-2 toxin is a secondary metabolite produced by Fusarium species and commonly contaminates food and animal feed. T-2 toxin can induce hepatotoxicity through apoptosis and oxidative stress; however, the underlying mechanism is not clear. Recent studies indicated that RASSF4, a member of the RASSF family, participates in cell apoptosis and some cancers due to its inactivation via DNA hypermethylation. However, its role in T-2 toxin-induced liver toxicity is poorly understood. Therefore, in this study, female Wistar rats were given a single dose of T-2 toxin at 2 mg/kg b.w. and were sacrificed at 1, 3 and 7 days post-exposure. A normal rat liver cell line (BRL) was exposed to different concentrations of T-2 toxin (10, 20, 40 nM) for 4, 8, 12 h, respectively. Histopathological analysis revealed with apoptosis in some liver cells and clear proliferation under T-2 toxin exposure. Expression analysis by immunohistochemical assays, quantitative real-time PCR (qPCR) and western blot demonstrated that T-2 toxin activated PI3K-Akt/Caspase/NF-κB signaling pathways. Additionally, DNA methylation assays revealed that the expression of RASSF4 was silenced by promoter hypermethylation after exposure to T-2 toxin for 1 and 3 days as compared to the control group. Moreover, joint treatment of 5-Aza-2′-deoxycytidine (DAC) (5 μM) and T-2 toxin (40 nM) increased expression of RASSF4 and PI3K-Akt/caspase/NF-κB signaling pathways-related genes, inducing cell apoptosis. These findings for the first time demonstrated that DNA methylation regulated the RASSF4 expression under T-2 toxin, along with the activation of its downstream pathways, resulting in apoptosis.

The novel protein C9orf116 promotes rat liver cell line BRL-3A proliferation.

Our previous study has proved that the chromosome 9 open reading frame 116 (C9orf116) (NM_001106564.1) was significantly up-regulated in the proliferation phase of liver regeneration. To study its possible physiological function, we analyzed the effect of C9orf116 on BRL-3A cells via over-expression and interference technique. MTT results showed that the cell viability of the interference group was significantly lower than the control group at 48h after transfection (P<0.05), whereas it was significantly higher in the over-expression group (P<0.05). The flow cytometry results showed that C9orf116 knockdown or over-expression had little effect on BRL-3A cell apoptosis. However, the number of cells in division phase (G2/M) was significantly reduced in the interference group (P<0.05), but significantly increased in the over-expression group (P<0.01). Furthermore, the expressions of cell proliferation-related genes CCNA2, CCND1 and MYC both at mRNA and protein levels were down-regulated in the interference group and up-regulated in the over-expression group. Therefore, we concluded that C9orf116 may promote cell proliferation by modulating cell cycle transition and the expression of key genes CCNA2, CCND1 and MYC in BRL-3A cells.

Genomic characterization and dynamic methylation of promoter facilitates transcriptional regulation of H2A variants, H2A.1 and H2A.2 in various pathophysiological states of hepatocyte

Differential expression of homomorphous variants of H2A family of histone H2A.1 and H2A.2 have been associated with hepatocellular carcinoma and maintenance of undifferentiated state of hepatocyte. However, not much is known about the transcriptional regulation of these H2A variants. The current study revealed the presence of 43bp 5′-regulatory region upstream of translation start site and a 26bp 3′ stem loop conserved region for both the H2A.1 and H2A.2 variants. However, alignment of both H2A.1 and H2A.2 5′-untranslated region (UTR) sequences revealed no significant degree of homology between them despite the coding exon being very similar amongst the variants. Further, transient transfection coupled with dual luciferase assay of cloned 5′ upstream sequences of H2A.1 and H2A.2 of length 1.2 (−1056 to +144) and 1.379kb (−1160 to +219) from experimentally identified 5′UTR in rat liver cell line (CL38) confirmed their promoter activity. Moreover, in silico analysis revealed a presence of multiple CpG sites interspersed in the cloned promoter of H2A.1 and a CpG island near TSS for H2A.2, suggesting that histone variants transcription might be regulated epigenetically. Indeed, treatment with DNMT and HDAC inhibitors increased the expression of H2A.2 with no significant change in H2A.1 levels. Further, methyl DNA immunoprecipitation coupled with quantitative analysis of DNA methylation using real-time PCR revealed hypo-methylation and hyper-methylation of H2A.1 and H2A.2 respectively in embryonic and HCC compared to control adult liver tissue. Collectively, the data suggests that differential DNA methylation on histone promoters is a dynamic player regulating their expression status in different pathophysiological stages of liver.

MEK-ERK-mediated phosphorylation of Mdm2 at Ser-166 in hepatocytes. Mdm2 IS ACTIVATED IN RESPONSE TO INHIBITED Akt SIGNALING.

Mdm2 inactivates the tumor suppressor p53 and Akt has been shown to be a major activator of Mdm2 in many cell types. We have investigated the regulation of Mdm2 in hepatocytes. We found that growth factor-induced Ser-166 phosphorylation of Mdm2 was inhibited by the MEK inhibitors U0126 and PD98059 in HepG2 cells and in a rat liver cell line, TRL 1215. Also, bile acids and oxidative stress induced phosphorylation of Mdm2 at Ser-166 by an apparently MEK-ERK-dependent mechanism. In contrast, Ser-166 phosphorylation of Mdm2 in lung cells was mediated by Akt. Further studies revealed that phosphatidylinositol 3-kinase inhibitors LY294002 and wortmannin induced phosphorylated ERK Tyr-204 and pMdm2 Ser-166 phosphorylations in hepatocytes in culture and in rat hepatocytes in vivo. In HepG2 cells, this effect was inhibited by U0126 and PD98059. LY294002 also reduced the level of pRaf Ser-259. Furthermore, we have shown that myr-Akt-induced overexpression of pAkt suppressed the levels of pMdm2 Ser-166 in hepatocytes. These data indicate a reversed relationship between Akt and Mdm2 in hepatocytes and suggest that Akt is a negative regulator of Raf-MEK-ERK-Mdm2 in this cell type. Ser-166 phosphorylation of Mdm2 has been shown to increase its ubiquitin ligase activity and increase p53 degradation, and our data indicated an attenuated p53 response to DNA damage in hepatocytes exhibiting high levels of pMdm2 Ser-166. Taken together, our data indicate that Mdm2 phosphorylation is regulated via MEK-ERK in hepatocytes. This Mdm2 signaling might be important for the regeneration of hepatocytes after centrilobular cell death.

Amphipathic silica nanoparticles induce cytotoxicity through oxidative stress mediated and p53 dependent apoptosis pathway in human liver cell line HL-7702 and rat liver cell line BRL-3A

The aim of this study was to evaluate the potential cytotoxicity and the underlying mechanism of amphipathic silica nanoparticles (SiO2 NPs) exposure to human normal liver HL-7702 cells and rat normal liver BRL-3A cells. Prior to the cellular studies, transmission electron microscopy (TEM), dynamic light scattering (DLS), and X ray diffraction (XRD) were used to characterize SiO2 NPs, which proved the amorphous nature of SiO2 NPs with TEM diameter of 19.8±2.7nm. Further studies proved that exposure to SiO2 NPs dose-dependently induced cytotoxicity as revealed by cell counting kit (CCK-8) and lactate dehydrogenase (LDH) assays, with more severe cytotoxicity in HL-7702 cells than BRL-3A cells. Reactive oxygen species (ROS) and glutathione (GSH) assays showed elevated oxidative stress in both cells. Morphological studies by microscopic observation, Hochest 33258 and AO/EB staining indicated significant apoptotic changes after the cells being exposed to SiO2 NPs. Further studies by western blot indicated that SiO2 NPs exposure to both cells up-regulated p53, Bax and cleaved caspase-3 expression and down-regulated Bcl-2 and caspase-3 levels. Activated caspase-3 activity detected by colorimetric assay kit and caspase-3/7 activity detected by fluorescent real-time detection kit were significantly increased by SiO2 NPs exposure. In addition, antioxidant vitamin C significantly attenuated SiO2 NPs-induced caspase-3 activation, which indicated that SiO2 NPs-induced oxidative stress was involved in the process of HL-7702 and BRL-3A cell apoptosis. Taken together, these results suggested that SiO2 NPs-induced cytotoxicity in HL-7702 and BRL-3A cells was through oxidative stress mediated and p53, caspase-3 and Bax/Bcl-2 dependent pathway and HL-7702 cells were more sensitive to SiO2 NPs-induced cytotoxicity than BRL-3A cells.

MiR-200a regulates Rheb-mediated amelioration of insulin resistance after duodenal-jejunal bypass.

Objectives:Duodenal–jejunal bypass (DJB) surgery can induce the rapid and durable remission of diabetes. Recent studies indicate that ameliorated hepatic insulin resistance and improved insulin signaling might contribute to the diabetic control observed after DJB. Ras homolog enriched in brain (Rheb) is reported to have an important role in insulin pathway, and some microRNAs (miRNAs) have been found to regulate Rheb. This study was conducted to investigate the effects of DJB on hepatic insulin resistance and the effects of miRNA-200a, a Rheb-targeting miRNA, on the development of DJB-induced amelioration in hepatic insulin resistance.Subjects:We investigated hepatic insulin signaling change and mapped the hepatic miRNAome involved in a rat model of DJB. We studied the effects of miR-200a on Rheb signaling pathway in buffalo rat liver cell lines. Liver tissues were studied and glucose tolerance tests were conducted in DJB rats injected with lentivirus encoding miR-200a inhibitor and diabetic rats injected with miR-200a mimic.Results:Rheb is a potential target of miR-200a. Transfection with an miR-200a inhibitor increased Rheb protein levels and enhanced the feedback action on insulin receptor substrate-dependent insulin signaling, whereas transfection with an miR-200a mimic produced the opposite effects. A luciferase assay confirmed that miR-200a bind to the 3′UTR (untranslated regions) of Rheb. Global downregulation of miR-200a in DJB rats showed impaired insulin sensitivity whereas upregulation of miR-200a in diabetic rats showed amelioration of diabetes.Conclusions:A novel mechanism was identified, in which miR-200a regulates the Rheb-mediated amelioration of insulin resistance in DJB. The findings suggest miR-200a should be further explored as a potential target for the treatment of diabetes.

Pancreatic Transdifferentiation and Glucose-Regulated Production of Human Insulin in the H4IIE Rat Liver Cell Line.

Due to the limitations of current treatment regimes, gene therapy is a promising strategy being explored to correct blood glucose concentrations in diabetic patients. In the current study, we used a retroviral vector to deliver either the human insulin gene alone, the rat NeuroD1 gene alone, or the human insulin gene and rat NeuroD1 genes together, to the rat liver cell line, H4IIE, to determine if storage of insulin and pancreatic transdifferentiation occurred. Stable clones were selected and expanded into cell lines: H4IIEins (insulin gene alone), H4IIE/ND (NeuroD1 gene alone), and H4IIEins/ND (insulin and NeuroD1 genes). The H4IIEins cells did not store insulin; however, H4IIE/ND and H4IIEins/ND cells stored 65.5 ± 5.6 and 1475.4 ± 171.8 pmol/insulin/5 × 106 cells, respectively. Additionally, several β cell transcription factors and pancreatic hormones were expressed in both H4IIE/ND and H4IIEins/ND cells. Electron microscopy revealed insulin storage vesicles in the H4IIE/ND and H4IIEins/ND cell lines. Regulated secretion of insulin to glucose (0–20 mmol/L) was seen in the H4IIEins/ND cell line. The H4IIEins/ND cells were transplanted into diabetic immunoincompetent mice, resulting in normalization of blood glucose. This data shows that the expression of NeuroD1 and insulin in liver cells may be a useful strategy for inducing islet neogenesis and reversing diabetes.

SPINK3: A novel growth factor that promotes rat liver regeneration

Serine peptidase inhibitor, Kazal type 3 (SPINK3) is a trypsin inhibitor, and also a growth factor that has an identical structure to epidermal growth factor (EGF), which could combine with epidermal growth factor receptor (EGFR) to promote cell proliferation. To shed light on the role and regulation mechanism of SPINK3 in rat liver regeneration (LR), Rat Genome 230 2.0 assay was used to detect the expression profiles of LR genes after partial hepatectomy (PH). The results showed that Spink3 was significantly up-regulated at 2-24 h and 72-168 h after PH. In the present study, RT-PCR and immunoblotting were used to validate the assay results. Ingenuity Pathway Analysis 9.0 (IPA) software was used to build the SPINK3 signaling regulating LR and analyze the possible mechanism. And then the expression of cell proliferation-associated gene Ccna2 was examined by RT-PCR in normal rat liver cell line BRL-3A in which Spink3 was overexpressed. The results showed that Ccna2 was significantly up-regulated in BRL-3A in which Spink3 was over-expressed. SPINK3 combining with EGFR accelerated cell proliferation during rat liver regeneration via P38, PKC, JAK-STAT and AKT pathways. Thus, SPINK3 was likely to promote hepatocytes proliferation in LR through P38, PKC, JAK-STAT and AKT.

P53-dependent apoptosis contributes to di-(2-ethylhexyl) phthalate-induced hepatotoxicity

Di-(2-ethylhexyl) phthalate (DEHP) is used extensively in many personal care and consumer products, resulting in widespread non-occupational human exposure through multiple routes and media. DEHP has various deleterious effects including hepatotoxicity. p53 protein is a central sensor in cell apoptosis. In order to clarify the roles of p53 in DEHP-induced hepatotoxicity, Sprague–Dawley (SD) rats were dosed daily with DEHP by gavage for 30 days; BRL cells (rat liver cell line) were treated with DEHP for 24 h after pretreatment with NAC or small interfering RNA (siRNA). Results indicated that after exposure to DEHP, hepatic histological changes such as hepatocyte edema, vacuolation and hepatic sinusoidal dilation, and increased apoptosis index were observed. In the liver, DEHP induced oxidative stress and DNA damage, which activated p53 in vivo and in vitro. Pretreatment with NAC significantly reduced ROS level and p53 expression in BRL cells. The suppressed Mdm2 also contributed to p53 accumulation. Activated p53 mediated hepatocyte apoptosis via the intrinsic mitochondrial pathway, inhibiting anti-apoptotic Bcl-2 and Bcl-xL and inducing pro-apoptotic Bax, cytochrome c and caspases. In p53-silenced BRL cells, hepatocyte apoptosis mediated by p53 was attenuated. PCNA protein level was upregulated after p53 gene silencing. However, the Fas/FasL apoptotic pathway did not exhibit activated signs in DEHP-caused hepatotoxicity. Taken together, DEHP-caused oxidative stress and Mdm2 downregulation contribute to p53 activation. The p53-dependent apoptotic pathway plays critical and indispensable roles in DEHP-induced hepatotoxicity, while the Fas/FasL pathway does not involve in this molecular event.

Synthesis and evaluation of fatty acid amides on the N-oleoylethanolamide-like activation of peroxisome proliferator activated receptor α.

A series of fatty acid amides were synthesized and their peroxisome proliferator-activated receptor α (PPAR-α) agonistic activities were evaluated in a normal rat liver cell line, clone 9. The mRNAs of the PPAR-α downstream genes, carnitine-palmitoyltransferase-1 and mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase, were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR) as PPAR-α agonistic activities. We prepared nine oleic acid amides. Their PPAR-α agonistic activities were, in decreasing order, N-oleoylhistamine (OLHA), N-oleoylglycine, Oleamide, N-oleoyltyramine, N-oleoylsertonin, and Olvanil. The highest activity was found with OLHA. We prepared and evaluated nine N-acylhistamines (N-acyl-HAs). Of these, OLHA, C16:0-HA, and C18:1Δ(9)-trans-HA showed similar activity. Activity due to the different chain length of the saturated fatty acid peaked at C16:0-HA. The PPAR-α antagonist, GW6471, inhibited the induction of the PPAR-α downstream genes by OLHA and N-oleoylethanolamide (OEA). These data suggest that N-acyl-HAs could be considered new PPAR-α agonists.

Salidroside ameliorates Cd-induced calcium overload and gap junction dysfunction in BRL 3A rat liver cells.

It is known that cadmium (Cd) induces cytotoxicity via Ca(2+) signaling, although the underlying mechanism is unclear. Here, we studied the molecular mechanisms of Cd-induced cytotoxicity in BRL 3A cells, a rat liver cell line. We observed that Cd treatment was associated with a time-dependent decrease in cell index (CI) in BRL 3A cells. Mechanistically, we observed that Cd exposure was associated with decreased expression of Cx43, P-Cx43, and Cx32. Specifically, Cx43 was decreased at the site of cell-cell junctions at the cell membrane, corresponding to a decrease in gap junctional intercellular connections (GJICs). We also found that Cd triggered a rise in the intracellular free Ca(2+) concentration ([Ca(2+)]i), and the intracellular calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis, acetoxymethyl ester (BAPTA-AM), prevented the Cd-induced decrease in CI. On the other hand, the gap junction blocker 18-β-glycyrrhetinic acid (GA) and the endoplasmic reticulum Ca(2+)-ATPase inhibitor thapsigargin exacerbated cytotoxic injury induced by Cd via further elevating [Ca(2+)]i, The extracellular calcium chelator ethylene glycol tetraacetic acid could partly attenuate Cd-induced calcium elevation but had little effect on GA combined Cd. Furthermore, salidroside as a protective agent prevented Cd-induced GJIC inhibition and calcium overload. Our findings suggest that Cd triggers elevation of [Ca(2+)]i via mainly stimulating Ca(2+) release from intracellular Ca(2+) storage organelles and inhibiting GJIC, causing cytotoxic injury, and salidroside could be used to prevent Cd-induced cytotoxicity.

SiO₂ nanoparticle-induced impairment of mitochondrial energy metabolism in hepatocytes directly and through a Kupffer cell-mediated pathway in vitro.

The liver has been shown to be a primary target organ for SiO2 nanoparticles in vivo, and may be highly susceptible to damage by these nanoparticles. However, until now, research focusing on the potential toxic effects of SiO2 nanoparticles on mitochondria-associated energy metabolism in hepatocytes has been lacking. In this work, SiO2 nanoparticles 20 nm in diameter were evaluated for their ability to induce dysfunction of mitochondrial energy metabolism. First, a buffalo rat liver (BRL) cell line was directly exposed to SiO2 nanoparticles, which induced cytotoxicity and mitochondrial damage accompanied by decreases in mitochondrial dehydrogenase activity, mitochondrial membrane potential, enzymatic expression in the Krebs cycle, and activity of the mitochondrial respiratory chain complexes I, III and IV. Second, the role of rat-derived Kupffer cells was evaluated. The supernatants from Kupffer cells treated with SiO2 nanoparticles were transferred to stimulate BRL cells. We observed that SiO2 nanoparticles had the ability to activate Kupffer cells, leading to release of tumor necrosis factor-α, nitric oxide, and reactive oxygen species from these cells and subsequently to inhibition of mitochondrial respiratory chain complex I activity in BRL cells.

In Vitro Hepatoprotective Activity of Isolated Fractions of Cressa Cretica

Coastal flora has unique potential for bioactive compounds and now many commercially available drugs originating from marine environment are used. In our present study, in vitro hepatoprotective effects of four fractions isolated from coastal sand dune species of Cressa cretica L. have been studied and their liver toxicity was determined in freshly isolated rat liver and normal human HepG2 cell line. All the four isolated fractions showed very good results, but the n-butanol fraction exhibited most pronounced effects. It is concluded that C. cretica contains very good hepatoprotective compounds and in the following studies we will try to determine these compounds.

Coactivation of the PI3K/Akt and ERK signaling pathways in PCB153-induced NF-κB activation and caspase inhibition

Polychlorinated biphenyls (PCBs) are a group of persistent and widely distributed environmental pollutants that have various deleterious effects, e.g., neurotoxicity, endocrine disruption and reproductive abnormalities. In order to verify the hypothesis that the PI3K/Akt and MAPK pathways play important roles in hepatotoxicity induced by PCBs, Sprague–Dawley (SD) rats were dosed with PCB153 intraperitoneally at 0, 4, 16 and 32mg/kg for five consecutive days; BRL cells (rat liver cell line) were treated with PCB153 (0, 1, 5, and 10μM) for 24h. Results indicated that the PI3K/Akt and ERK pathways were activated in vivo and in vitro after exposure to PCB153, and protein levels of phospho-Akt and phospho-ERK were significantly increased. Nuclear factor-κB (NF-κB) activation and caspase-3, -8 and -9 inhibition caused by PCB153 were also observed. Inhibiting the ERK pathway significantly attenuated PCB153-induced NF-κB activation, whereas inhibiting the PI3K/Akt pathway hardly influenced phospho-NF-κB level. However, inhibiting the PI3K/Akt pathway significantly elevated caspase-3, -8 and -9 activities, while the ERK pathway only synergistically regulated caspase-9. Proliferating cell nuclear antigen (PCNA), a reliable indicator of cell proliferation, was also induced. Moreover, PCB153 led to hepatocellular hypertrophy and elevated liver weight. Taken together, PCB153 leads to aberrant proliferation and apoptosis of hepatocytes through NF-κB activation and caspase inhibition, and coactivated PI3K/Akt and ERK pathways play critical roles in PCB153-induced hepatotoxicity.

The Effect of Copper on the mRNA Expression Profile of Xenobiotic-Metabolizing Enzymes in Cultured Rat H4-II-E Cells

Copper (Cu(2+)) is an essential element that plays important roles in physiological functions of the body. However, high Cu(2+) levels can have toxic implications. This study aims to investigate the constitutive response to Cu(2+) exposure of xenobiotic-metabolizing enzymes in cultured rat liver (H4-II-E) cell lines. Rat cells were exposed to copper sulfate (0-500 μM) for 24 h. The effects of Cu(2+) on the messenger RNA (mRNA) expressions of phase I and II enzymes and regulatory elements were examined using real-time PCR. Metallothionein mRNA expression was induced in a dose-dependent manner after treatment with Cu(2+). mRNA expressions of phase I enzymes such as cytochrome P450 1A1 and 1A2 (CYP1A1 and CYP1A2) were slightly induced after exposure to low concentrations of Cu(2+); however, CYP1A1 and CYP1A2 mRNA expressions were significantly downregulated at higher Cu(2+) concentrations. These effects corresponded with expression of aryl hydrocarbon receptor mRNA. The mRNA expressions of phase II enzymes were reduced upon exposure to Cu(2+). In conclusion, phase I and II enzyme expressions were significantly modulated upon Cu(2+) exposure. These results indicated that Cu(2+) exposure had toxicological implications for cultured H4-II-E cells.

The antibacterial effect of the co-administration of poly(propylene imine) dendrimers and ciprofloxacin

Fluoroquinolones, including ciprofloxacin, are often used to treat bacterial diseases. Due to the spread of drug resistance among microorganisms, alternative treatments are being sought. We report here on the antimicrobial activity of generation 4 (G4) PPI dendrimers in the presence of ciprofloxacin against the reference strains of Gram-positive bacterium Staphylococcus aureus ATCC 6538 and Gram-negative bacterium Escherichia coli ATCC 25922. Cytotoxicity of these compounds was investigated in the eukaryotic B14 Chinese hamster fibroblast cell line, HepG2 human liver hepatocellular carcinoma cell line, mouse neuroblastoma N2a cell line and BRL-3A rat liver cell line. For both strains, the administration of PPI dendrimers along with ciprofloxacin significantly improved its antibacterial effect compared to the cultures given the drug alone. The simultaneous application of dendrimers and ciprofloxacin shows the opportunity of using it at lower doses. Ciprofloxacin and PPI dendrimers are harmful to bacterial strains at the concentrations non-toxic to the eukaryotic cells.

Cytotoxicity evaluation and antioxidant enzyme expression related to heavy metals found in tuna by-products meal: An in vitro study in human and rat liver cell lines

Heavy metals can accumulate in organisms via various pathways, including respiration, adsorption and ingestion. They are known to generate free radicals and induce oxidative and/or nitrosative stress with depletion of anti-oxidants. Tuna by-product meal (TBM) is rich in proteins and can, therefore, offer an attractive protein source for animals. This study was undertaken to assess the effects of metals present in TBM, namely cadmium (Cd), lead (Pb), and mercury (Hg), separately or in combination with oxidative stress, on cell viability. Three cell models: rat liver FTO2B, human hepatoma HepG2, and human hepatic WRL-68, were used. Cell viability was determined following exposure to various concentrations of the metals. Two antioxidant genes, catalase (CAT) and superoxide dismutase (SOD), were measured to obtain a better understanding of oxidative stress-associated gene expression. Among the metals present in TBM, only Cd at a concentration of 30μM was noted to exhibit cytotoxic effects. This cytotoxicity was even more pronounced after co-stimulation with H2O2, used to mimic systemic oxidative stress. At non-toxic concentrations, Hg and Pb were noted to aggravate oxidative stress toxicity. The results further revealed that exposure to Cd, Pb, and a co-stimulation of H2O2 with Hg resulted in the increased expression of antioxidant gene SOD. A risk assessment of toxic contaminants in TBM indicated that food safety objectives should consider the human health impacts of foods derived from animals fed on contaminated meal and that much care should be taken when TBM is used in animal diet.

Protective role of litchi (Litchi chinensis Sonn.) flower extract against cadmium- and lead-induced cytotoxicity and transforming growth factor β1-stimulated expression of smooth muscle α-actin estimated with rat liver cell lines

The protective potential of litchi flower acetone extract (LFAE) against cadmium (Cd)- and lead (Pb)-induced hepatocytotoxicity, and transforming growth factor β1 (TGF-β1)-mediated activation of hepatic stellate cells (HSCs) were evaluated. Phenolic compounds were plentiful in LFAE (429mg/g of dried extract); epicatechin (122.1mg/g of dried extract), gentisic acid (60.2mg/g of dried extract) and proanthocyanidin A2 (163.3mg/g of dried extract) were the major flavanoid, phenolic acid and proanthocyanidin, respectively. Cd and Pb treatments significantly promoted lipid peroxidation and DNA damage in rat liver cells (Clone 9), and caused viabilities of the cells down. However, LFAE addition could dose-dependently decrease the Cd- and Pb-induced lipid peroxidation and DNA fragmentation, and increase the cell viabilities. LFAE could also suppress TGF-β1-induced activation of HSCs concluded from down-regulating expression of smooth muscle α-actin (αSMA). These effects should be attributed to the antioxidant action of phenolic compounds in LFAE.