Pre-exposure to a novel nutritional mixture containing a series of phytochemicals prevents acetaminophen-induced programmed and unprogrammed cell deaths by enhancing BCL-XL expression and minimizing oxidative stress in the liver

Bisphenol-A induced cyto-genotoxicity on retinal pigment epithelial cells is differentially modulated by a multi-supplement containing guarana, selenium, and L-carnitine

Bisphenol A (BPA) may adversely affect human health by inducing oxidative stress and irreversible damage to cells. Bioactive compounds found in some functional foods, individually or in combination, can attenuate the negative effects of BPA exposure; an example is the multi-supplement containing guarana (Gua), selenium (Se), and L-carnitine (LC) -GSC- which has already demonstrated antioxidant, genoprotective, and immunomodulatory activities. This study aimed to determine the effect of GSC and its constituents on oxidative and genotoxic alterations triggered by BPA exposure in the retinal epithelial cell line. The cells exposed to BPA (0.001, 0.01, 0.1, 1, 3, and 10 µM) to determine the lowest concentration required to induce cyto-genotoxicity. ARPE-19 cells were then concomitantly exposed to the selected BPA concentration, GSC, and its components (Gua, 1.07 mg/mL; Se, 0.178 µg/mL; and LC, 1.43 mg/mL). Flow cytometry, biochemical assays, qRT-PCR, genotoxicity, apoptosis, and cellular proliferation. Based on our results, 10 µM of BPA could induce cyto-genotoxic and oxidative alterations. BPA did not alter the Bcl-2/BAX expression ratio but induced Casp3 and Casp8 overexpression, suggesting that apoptosis was induced mainly via the extrinsic pathway. GSC partially reversed the alterations triggered by BPA in ARPE-19 cells. However, Se had unexpected negative effects on ARPE-19 cells. The multi-supplement GSC may attenuate changes in oxidative and genotoxic markers related to exposure of ARPE-19 cells to BPA. our results revealed that the antioxidant, anti-apoptotic, and genoprotective properties of GSC were not universally shared by its individual, once Se did not exhibit any positive impact.

Effect of the joint fermentation of pyracantha powder and glutinous rice on the physicochemical characterization and functional evaluation of rice wine

Pyracantha fortuneana, as a kind of wild plant resource for both medicine and food, has high nutrition and health-care value. This study was to explore the effect of the joint fermentation of pyracantha powder and glutinous rice on the physicochemical and functional characterization of rice wine, aiming to improve the rice wine functional quality. As a result, a light dry rice wine fermented with P. fortuneana (PRW) was obtained using the fermentation technology of the Chinese rice wine. Although the contents of alcohol and protein in PRW were lower compared with the rice wine (RW) without adding pyracantha powder, the contents of sugar, ascorbic acid, total phenols, total flavonoids, and anthocyanins were higher in PRW. The analysis of volatile compounds by GC-IMS showed that the contents of most aldehydes, alcohols, and esters increased in PRW. The quantification of organic acids and phenolic monomers indicated that most of the monomers determined were more abundant in PRW. Besides, the antioxidant capacity of PRW, including the scavenging rate of DPPH• and ABTS+•, was significantly stronger than that of RW. The bacteriostatic effect of the phenolic extracts from PRW was also observed obviously. It was expected to provide an effective way for the comprehensive utilization of P. fortuneana resource by producing a kind of nutritious and healthy pyracantha rice wine.

The role of apoptosis in acetaminophen hepatotoxicity

Although necrosis is recognized as the main mode of cell death induced by acetaminophen (APAP) overdose in animals and humans, more recently an increasing number of publications, especially in the herbal medicine and dietary supplement field, claim an important contribution of apoptotic cell death in the pathophysiology. However, most of these conclusions are based on parameters that are not specific for apoptosis. Therefore, the objective of this review was to re-visit the key signaling events of receptor-mediated apoptosis and APAP-induced programmed necrosis and critically analyze the parameters that are being used as evidence for apoptotic cell death. Both qualitative and quantitative comparisons of parameters such as Bax, Bcl-2, caspase processing and DNA fragmentation in both modes of cell death clearly show fundamental differences between apoptosis and cell death induced by APAP. These observations together with the lack of efficacy of pan-caspase inhibitors in the APAP model strongly supports the conclusion that APAP hepatotoxicity is dominated by necrosis or programmed necrosis and does not involve relevant apoptosis. In order not to create a new controversy, it is important to understand how to use these "apoptosis" parameters and properly interpret the data. These issues are discussed in this review.

Quercetin ameliorates liver injury induced with Tripterygium glycosides by reducing oxidative stress and inflammation

Quercetin (Que) is one of main compounds in Lysimachia christinae Hance (Christina loosestrife), and has both medicinal and nutritional value. Glycosides from Tripterygium wilfordii Hook.f. (léi gōng téng [the thunder duke vine]; TG) have diverse and broad bioactivities but with a high incidence of liver injury. Our previous study reported on the hepatoprotective properties of an ethanol extract from L. christinae against TG-induced liver injury in mice. This research is designed to observe, for the first time, the possible protective properties of the compound Que against TG-induced liver injury, and the underlying mechanisms that are involved in oxidative stress and anti-inflammation. The results indicated that TG caused excessive elevation in serum levels of alanine/aspartate transaminase (ALT/AST), alkaline phosphatase (ALP), gamma glutamyl transferase (γ-GT), and pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α), as well as hepatic lipid peroxidation (all P < 0.01). On the other hand, following TG exposure, we observed significantly reduced levels of biomarkers, including hepatic glutathione (GSH), glutathione-S-transferase (GST), glutathione peroxidase (GPx), and the anti-inflammatory cytokine interleukin (IL)-10, as well as the enzyme activity and mRNA expression of copper- and zinc-containing superoxide dismutase (CuZn-SOD) and catalase (CAT) (all P < 0.01). Nevertheless, all of these alterations were reversed by the pre-administration of Que or the drug bifendate (positive control) for 7 consecutive days. Therefore, this study suggests that Que ameliorates TG-induced acute liver injury, probably through its ability to reduce oxidative stress and its anti-inflammatory properties.

Protective effect of Baccharis trimera extract on acute hepatic injury in a model of inflammation induced by acetaminophen

BACKGROUND

Acetaminophen (APAP) is a commonly used analgesic and antipyretic. When administered in high doses, APAP is a clinical problem in the US and Europe, often resulting in severe liver injury and potentially acute liver failure. Studies have demonstrated that antioxidants and anti-inflammatory agents effectively protect against the acute hepatotoxicity induced by APAP overdose.

METHODS

The present study attempted to investigate the protective effect of B. trimera against APAP-induced hepatic damage in rats. The liver-function markers ALT and AST, biomarkers of oxidative stress, antioxidant parameters, and histopathological changes were examined.

RESULTS

The pretreatment with B. trimera attenuated serum activities of ALT and AST that were enhanced by administration of APAP. Furthermore, pretreatment with the extract decreases the activity of the enzyme SOD and increases the activity of catalase and the concentration of total glutathione. Histopathological analysis confirmed the alleviation of liver damage and reduced lesions caused by APAP.

CONCLUSIONS

The hepatoprotective action of B. trimera extract may rely on its effect on reducing the oxidative stress caused by APAP-induced hepatic damage in a rat model. General Significance. These results make the extract of B. trimera a potential candidate drug capable of protecting the liver against damage caused by APAP overdose.

Matrix metalloproteinase-9, -10, and -12, MDM2 and p53 expression in mouse liver during dimethylnitrosamine-induced oxidative stress and genomic injury

Treatment during early tumor development has greater success because tissue growth remains largely confined to its original locus. At later stages, malignant cells migrate from their original location, invade surrounding normal areas, and can disseminate widely throughout the body. Remodeling of the extracellular matrix (ECM) serves as a key facilitator of this dissemination. Proteolytic enzymes including plasmin and matrix metalloproteinases (MMPs) play an integral role in degrading the surrounding ECM proteins and clearing a path for tumor cell migration. Specific MMPs are highly expressed late during malignant tumor invasion. It is not understood whether early changes in MMPs influence apoptotic and necrotic cell death, processes known to govern the early stages of carcinogenesis. Similarly, the interaction between MDM2 and p53 is tightly controlled by a complex array of post-translational modifications, which in turn dictates the stability and activity of both p53 and MDM2. The present studies examine the hypothesis that model hepatotoxin dimethylnitrosamine (DMN), which is also a model carcinogen, will induce the MMP family of proteins after administration in hepatotoxic doses. Doses of 25, 50, and 100 mg/kg DMN were administered i.p. to male C3H mice. Changes in parameters associated with apoptotic and necrotic cell death, DNA damage, cell proliferation, and extracellular proteinases were examined in liver at 24 h. Serum ALT activity, oxidative stress [malondialdehyde], and caspase-activated DNAse mediated DNA laddering increased in a dose-dependent manner, as did the level of MDM2 protein. MMP-9, -10 and -12 (gelatinase-B, stromelysin-2, macrophage elastase), and p53 protein levels increased following 25 mg/kg DMN, but were successively decreased after higher DMN doses. The results of this study demonstrate changes in MDM2 and MMPs during DMN-induced acute liver injury and provide a plausible linkage between DMN-induced oxidative stress-mediated genomic injury and its likely involvement in setting the stage for initiating subsequent metastatic disease at later circumstances.

Grape antioxidant dietary fibre prevents mitochondrial apoptotic pathways by enhancing Bcl-2 and Bcl-xL expression and minimising oxidative stress in rat distal colonic mucosa

Grape antioxidant dietary fibre (GADF) is a grape product rich in dietary fibre and natural antioxidants. We reported previously that GADF intake reduced apoptosis and induced a pro-reducing shift in the glutathione (GSH) redox status of the rat proximal colonic mucosa. The aim of the study was to elucidate the molecular mechanisms responsible for the anti-apoptotic effect of GADF and their association with the oxidative environment of the distal colonic mucosa. The ability of GADF to modify colonic crypt cell proliferation was also investigated. Male Wistar rats (n 20) were fed with diets containing either cellulose (control group) or GADF (GADF group) as fibre for 4 weeks. GADF did not modify cell proliferation but induced a significant reduction of colonic apoptosis. The anti-apoptotic proteins Bcl-2 (B-cell lymphoma-2) and Bcl-xL (B-cell lymphoma extra large) were up-regulated in the mitochondria and down-regulated in the cytosol of the GADF mucosa, whereas the opposite was found for the pro-apoptotic protein Bax (Bcl-2-associated X protein), leading to an anti-apoptotic shift in the pattern of expression of the Bcl-2 family. Cytosolic cytochrome c and cleaved caspase-3 levels and caspase-3 activity were reduced by GADF. The modulation of the antioxidant enzyme system and the increase of the cytosolic GSH:glutathione disulfide (GSSG) ratio elicited by GADF helped to reduce oxidative damage. The cytosolic GSH:GSSG ratio was negatively related to apoptosis. These results indicate that GADF acts on the expression of the pro- and anti- apoptotic Bcl-2 proteins, attenuating the mitochondrial apoptotic pathway in the distal colonic mucosa. This effect appears to be associated with the antioxidant properties of GADF.

A novel dietary supplement containing multiple phytochemicals and vitamins elevates hepatorenal and cardiac antioxidant enzymes in the absence of significant serum chemistry and genomic changes

A novel dietary supplement composed of three well-known phytochemicals, namely, Salvia officinalis (sage) extract, Camellia sinensis (oolong tea) extract, and Paullinia cupana (guarana) extract, and two prominent vitamins (thiamine and niacin) was designed to provide nutritional support by enhancing metabolism and maintaining healthy weight and energy. The present study evaluated the safety of this dietary supplement (STG; S=sage; T=tea; G=guarana) and assessed changes in target organ antioxidant enzymes (liver, kidneys and heart), serum chemistry profiles and organ histopathology in Fisher 344 rats. Adult male and female Fisher 344 rats were fed control (no STG) or STG containing (1X and 7X, 1X=daily human dose) diets and sacrificed after 2 and 4 months. Serum chemistry analysis and histopathological examination of three vital target organs disclosed no adverse influence on protein, lipid and carbohydrate profiles, genomic integrity of the liver and/or the tissue architecture. However, analysis of the most important antioxidant components in the liver, kidney and heart homogenates revealed a dramatic increase in total glutathione concentrations, glutathione peroxidase and superoxide dismutase enzyme activities. Concomitantly, oxidative stress levels (malondialdehyde accumulation) in these three organs were less than control. Organ specific serum markers (ALT/AST for the liver; CPK/AST for the heart; BUN/creatinine for kidneys) and the genomic integrity disclosed no STG-induced alteration. Some of the serum components (lipid and protein) showed insignificant changes. Overall, STG-exposed rats were more active, and the results suggest that STG exposure produces normal serum chemistry coupled with elevated antioxidant capacity in rats fed up to seven times the normal human dose and does not adversely influence any of the vital target organs. Additionally, this study reiterates the potential benefits of exposure to a pharmacologically relevant combination of phytochemicals compared to a single phytochemical entity.

Silymarin modulates doxorubicin-induced oxidative stress, Bcl-xL and p53 expression while preventing apoptotic and necrotic cell death in the liver

The emergence of silymarin (SMN) as a natural remedy for liver diseases, coupled with its entry into NIH clinical trial, signifies its hepatoprotective potential. SMN is noted for its ability to interfere with apoptotic signaling while acting as an antioxidant. This in vivo study was designed to explore the hepatotoxic potential of Doxorubicin (Dox), the well-known cardiotoxin, and in particular whether pre-exposures to SMN can prevent hepatotoxicity by reducing Dox-induced free radical mediated oxidative stress, by modulating expression of apoptotic signaling proteins like Bcl-xL, and by minimizing liver cell death occurring by apoptosis or necrosis. Groups of male ICR mice included Control, Dox alone, SMN alone, and Dox with SMN pre/co-treatment. Control and Dox groups received saline i.p. for 14 days. SMN was administered p.o. for 14 days at 16 mg/kg/day. An approximate LD(50) dose of Dox, 60 mg/kg, was administered i.p. on day 12 to animals receiving saline or SMN. Animals were euthanized 48 h later. Dox alone induced frank liver injury (>50-fold increase in serum ALT) and oxidative stress (>20-fold increase in malondialdehyde [MDA]), as well as direct damage to DNA (>15-fold increase in DNA fragmentation). Coincident genomic damage and oxidative stress influenced genomic stability, reflected in increased PARP activity and p53 expression. Decreases in Bcl-xL protein coupled with enhanced accumulation of cytochrome c in the cytosol accompanied elevated indexes of apoptotic and necrotic cell death. Significantly, SMN exposure reduced Dox hepatotoxicity and associated apoptotic and necrotic cell death. The effects of SMN on Dox were broad, including the ability to modulate changes in both Bcl-xL and p53 expression. In animals treated with SMN, tissue Bcl-xL expression exceeded control values after Dox treatment. Taken together, these results demonstrated that SMN (i) reduced, delayed onset, or prevented toxic effects of Dox which are typically associated with hydroxyl radical production, (ii) performed as an antioxidant limiting oxidative stress, (iii) protected the integrity of the genome, and (iv) antagonized apoptotic and necrotic cell death while increasing antiapoptotic Bcl-xL protein levels and minimizing the leakage of proapoptotic cytochrome c from liver mitochondria. These observations demonstrate the protective actions of SMN in liver, and raise the possibility that such protection may extend to other organs during Dox treatment including the heart.

Aqueous extract of Hibiscus sabdariffa L. decelerates acetaminophen-induced acute liver damage by reducing cell death and oxidative stress in mouse experimental models

BACKGROUND

Acetaminophen (AAP)-induced oxidative stress can cause cell death to induce liver damage. The antioxidant effect of Hibiscus sabdariffa L. (HS) was shown in previous studies. In this study the effect of HS extract (HSE) on AAP-induced liver injury in BALB/c mice was investigated.

RESULTS

In vivo, BALB/c mice were fed orally with 200, 400 or 600 mg kg(-1) HSE for 2 weeks and then injected with 1000 mg kg(-1) AAP. Pretreatment with HSE decreased lipid peroxidation and increased catalase activity and glutathione level. It also decreased AAP-induced liver injury, accompanied by decreased expression of pJNK, Bax and tBid in the liver. Additionally, HSE protected BALB/c normal liver cells from AAP-induced damage in vitro.

CONCLUSION

It has been demonstrated that HSE can protect the mouse liver from AAP-induced injury and that the protective mechanism might involve decreasing oxidative stress and reducing cell death.

Green-tea polyphenols downregulate cyclooxygenase and Bcl-2 activity in acetaminophen-induced hepatotoxicity

Acetaminophen (APAP) elicits hepatotoxicity via multifactorial pathways, including increased apoptosis, cyclooxygenase (Cox-2) generation, reactive metabolite release, and glutathione (GSH) depletion. We previously showed that mice that consumed different antioxidants in their diets were protected against APAP-induced hepatotoxicity. We therefore further investigated the mechanisms by which green-tea polyphenols (GrTP) protect against APAP-induced hepatic damage. Mice were administered a diet supplemented with GrTP or vehicle for 5 consecutive days followed by intraperitoneal (IP) injection of a toxic dose of APAP or sham. APAP administration upregulated Cox-2 and B-cell lymphoma-2 (Bcl-2) production and had an effect, albeit minor, on Cox-1 and Fas expression in hepatic tissue. GrTP supplementation normalized APAP induced Cox-2 expression and Bcl-2 activation (P < 0.01), as evidenced by immunohistochemistry and Western blot analyses. Similarly, APAP administration elicited marked depletion (99%) in hepatic reduced GSH (rGSH) and endogenous S-adenosylmethionine (SAMe) concentrations (twofold) when compared with sham. APAP also caused severe centrilobular apoptosis and necrosis accompanied by leukocyte infiltration and marked elevations in the hepatic enzyme, alanine aminotransferase (ALT) released from damaged hepatocytes, and cytokine tumor necrosis factor alpha (TNF-alpha). GrTP improved hepatic histopathology (P < 0.01) and attenuated ALT activity (P < 0.05) and the depletion of rGSH (P < 0.05). In conclusion, GrTP supplementation attenuated hepatotoxicity by normalizing Cox-2 and Bcl-2 activation, suggesting a potential use for GrTP in treatng APAP toxicity.

Preventing hypoxia/reoxygenation damage to hepatocytes by p66(shc) ablation: up-regulation of anti-oxidant and anti-apoptotic proteins

BACKGROUND/AIMS

Ischemia/reperfusion damage to the liver remains a serious concern in many clinical situations. Major mechanisms for this certainly include oxidative stress.

METHODS

The effects of ablating the p66 isoform of ShcA (p66(shc)) on hypoxia/reoxygenation (H/R)-induced oxidative stress and cell injury in hepatocytes were investigated.

RESULTS

Immediately after reoxygenation, AML12 cells were clearly under oxidative stress; many cells underwent apoptosis. However, knockdown of p66(shc) by specific RNAi markedly decreased cellular oxidative stress and H/R-induced apoptosis, as well as conferring resistance to H(2)O(2) insult. These data suggest that prevention of apoptosis conferred by ablation of p66(shc) results from changed ROS-scavenging, but not inhibition of ROS generation. These data were also confirmed in fibroblasts from p66(shc) knockout mice. Anti-oxidant molecules, such as MnSOD and Ref-1 and the anti-apoptotic molecule Bcl-xL were up-regulated, and pro-apoptotic FLICE was down-regulated, by ablation of p66(shc). Interestingly, catalase expression was not affected in p66(shc)-knockdown-AML12 cells although it is a major target in other cell types.

CONCLUSIONS

Our findings suggest that in hepatocytes, ablation of p66(shc) is cytoprotective against H/R-induced oxidative stress, with MnSOD and Ref-1 playing critical roles, and with up-regulation of Bcl-xL and down-regulation of FLICE contributing jointly to preventing cells from undergoing oxidant-induced apoptosis.