Diethylnitrosamine-induced Hepatocarcinogenesis In Rats Research Articles

Potential Chemopreventive Role of Boldine Against Hepatocellular Carcinoma via Modulation of Cell Cycle Proteins in Rat Model.

To evaluate the chemopreventive potential of boldine against diethylnitrosamine (DEN) induced hepatocellular carcinoma (HCC) in Wistar albino rats. Boldine is an alkaloid isolated from Peumus boldus. The primary active constituents of boldine exhibited several potential medicinal properties. The present study was evaluated to explore the chemopreventive agent of boldine on anti-proliferative efficacy against diethylnitrosamine (DEN) induced hepatocellular carcinoma (HCC) in Wistar albino rats. The effect of boldine on cellular proliferative markers, i.e., PCNA and Ki67on hepatocellular carcinoma rats was determined by immuno expression study. Liver marker enzymes, tumor biomarker, oxidative stress markers, antioxidant status, and xenobiotic phase I and II enzymes in HCC rats were analyzed. Moreover, cell cycle proteins, i.e., p21Cip1/Kip1and p27 Cip1/Kip1, Cyclin D1, CDK 4, Cyclin E1, and CDK 2 were investigated using immuno expression analysis. Treatment of boldine protected the liver against reactive oxygen species such as hydrogen peroxide, superoxide, protein carbonyl, and lipid peroxide during hepatocarcinogenesis by boosted antioxidants-superoxide dismutase (SOD), catalase (CAT). Boldine caused a substantial enhanced detoxification process by moderating phase I and II xenobiotic-metabolizing enzymes. Besides, the study found that boldine significantly inhibited the cellular proliferative markers like PCNA and Ki67 and regulated the specific cell cycle-associated proteins by up-regulated expression of p21Cip1/Kip1and p27 Cip1/Kip1 and down-regulated expression of Cyclin D1, CDK 4, Cyclin E1, and CDK 2. Our data manifests the anti-proliferative effect of boldine, which negatively modulates cellular proliferation and regulates cell cycle by protecting the cell from reactive oxygen species (ROS), suggesting that boldine establishes it as a chemopreventive agent in diethylnitrosamine-induced hepatocarcinogenesis in rats.

Inhibitory effect of Biejiajian pills against diethylnitrosamine-induced hepatocarcinogenesis in rats

To study the inhibitory effect of Biejiajian pills (BJJ) agaisnt diethylnitrosamine (DEN)-induced hepatocarcinogenesis and explore the relation between this effect and the inflammasome signaling pathway. Sixty-five male SD rats were randomly divided into control group, DEN model group, and 3 BJJ treatment groups at low, medium and high dose (with daily dose of 0.55, 1.1 and 2.2 g/kg, respectively, for 12 consecutive weeks starting from the 5th week after modeling). The pathological changes of the liver tissue were observed with HE and Masson staining, and serum levels of alanine transaminase (ALT), glutamic oxaloacetic transaminase (AST), alkaline phosphatase (ALP) and total bilirubin (TBIL) of the rats were detected using ELISA. Oxidation stress in the liver tissue was assessed with ELISA, and Western blotting and ELISA were used to detect the molecular expressions of inflammasome-related pathway. BJJ significantly inhibited tumor growth in the liver of the rats. HE and Masson staining showed that BJJ treatment obviously ameliorated liver fibrosis and reduced cancer cell and inflammatory cell infiltration in the liver. BJJ significantly reduced elevations of serum ALT, AST, ALP and TBIL levels, increased the contents of superoxide dismutase, catalase and glutathione peroxidase in the liver and suppressed malondialdehyde in Den-treated rats. BJJ also dose-dependently decreased the expressions of NLRP3, apoptosis-associated speck-like protein (ASC), caspase-1, pro-IL-1β, pro-IL-18, IL-1β and IL-18 in the liver of Den-treated rats. BJJ treatment can dose-dependently inhibit DEN-induced hepatocarcinogenesis by enhancing antioxidant capacity and down-regulating inflammatory-related pathways in rats.

Regulation of PKB/Akt-pathway in the chemopreventive effect of lactoferrin against diethylnitrosamine-induced hepatocarcinogenesis in rats.

Abnormal activation of protein kinase B (PKB) is associated with many cancers. This makes inhibition of PKB signaling pathway a promising strategy for cancer therapy. Lactoferrin (Lf) has been reported for its inhibition of tumor growth and metastasis, however, the mechanism is not completely understood. Its anti-hepatocarcinogenic activity has not taken the deserved recognition despite the additional advantages of Lf as an antiviral against hepatitis C virus, the main cause of hepatocellular carcinoma (HCC), and as a targeting ligand for delivering chemotherapeutics to hepatoma cells. This study evaluated the anti-hepatocarcinogenic effect of Lf, and the role of PKB in this effect using diethylnitrosamine (DENA)-induced HCC rat model, and a primary cell culture prepared from the induced hepatic lesions (DENA-HCC cell culture). Up-regulation of activated PKB in the hepatocytes of rats with DENA-induced HCC was observed, as measured biochemically in the liver homogenate, and localized immunohistochemically. This was accompanied by increment of hepatocytes proliferation, and expression of vascular endothelial growth factor and endothelial nitric oxide synthase. Involvement of PKB in DENA-induced HCC was confirmed by the observed decrease in cell proliferation in DENA-HCC cell culture that was treated with PKB inhibitor. In Lf-treated rats, a dose-dependent chemopreventive effect was observed, with decreased expression and activation of PKB, amelioration of the other DENA-induced alterations, and stimulation of apoptosis. In vitro, Lf blocked PKB activator-induced cell proliferation. These findings support the chemopreventive activity of Lf against HCC, and suggest regulation of PKB-pathway as a potential mechanism underlying this effect.

Regulation of PKB/Akt-pathway in the chemopreventive effect of lactoferrin against diethylnitrosamine-induced hepatocarcinogenesis in rats

Regulation of PKB/Akt-pathway in the chemopreventive effect of lactoferrin against diethylnitrosamine-induced hepatocarcinogenesis in rats

Potential effect of Nigella sativa against Diethylnitrosamine-induced hepatocarcinogenesis in rats

Objective of the investigation was the study of potential protective effects of the watery extract of Nigella sativa against diethylnitrosamine induced hepatocarcinogenesis in rats. N. sativa was administered to rats for protection against diethylnitrosamine-induced hepatocarcinogenesis. It was administered prior to, simultaneously with or after injection of diethylnitrosamine. Five groups of Wister rats were used. Group A was administered diethylnitrosamine and N. sativa simultaneously, group B was administered only diethylnitrosamine and group C received only N. sativa. These three groups were maintained for up to eight weeks. Group D received N. sativa six weeks after administration ofdiethylnitrosamine,while group E (“protective group”) received N. sativa on day 1 and diethylnitrosamine six weeks later. These two groups were maintained for up to 12 weeks. All rats were subjected to partial hepatectomy to enhance carcinogenesis. P-isoform of glutathione s transferase (GST-P) was detected in the cytoplasm and nuclei of hepatocytes. The number of GST-P positive foci was significantly smaller in test groups (A, D, E), particularly in groups A and E, when compared with to those in group B, indicating that N. sativa has protective effects against diethylnitrosamine induced liver cancer in rats, even in the very early stages of hepatocarcinogenesis.

Biochemical Evaluation of Preventive Effect of blueberries on Diethylnitrosamine-Induced Hepatocarcinogenesis in Rats

Biochemical Evaluation of Preventive Effect of blueberries on Diethylnitrosamine-Induced Hepatocarcinogenesis in Rats

Hesperetin conjugated PEGylated gold nanoparticles exploring the potential role in anti-inflammation and anti-proliferation during diethylnitrosamine-induced hepatocarcinogenesis in rats

Liver cancer is the fifth most common cancer and one of the leading causes of death in the world, and second most common cause of death in men. Natural products emerge as the most enduring approaches in the development of anticancer targeting drug. Hesperetin (HP), one of the abundant flavonoids found naturally in citrus fruits, has received considerable attention in anti-cancer promotion and progression. The present study was conducted to decipher the role of 0.5 ml hesperetin conjugated gold nanoparticles (Au-mPEG(5000)-S-HP NPs) during diethylnitrosamine (DEN)-induced hepatocarcinogenesis in male Wistar albino rats and shows the better antioxidant that possesses anti-inflammatory, anti-proliferation and anticarcinogenic properties and may modulate signaling pathways. The confirmation of polymer functionalized gold nanoparticles and drug loaded polymer gold nanoparticles were characterized by HR-TEM with EDAX, and DLS with Zeta potential techniques. The drug encapsulation efficiency and release properties were carried out in PBS at pH 7.4 for Au- mPEG(5000)-S-HP and compared with the control pure hesperetin (HP). Here, we review the role of mast cell counts, tumor necrosis factor alpha (TNF-α), transcription factor nuclear factor-κB (NF-κB), levels of glycoconjugates, proliferating cell nuclear antigen (PCNA) and argyrophilic nucleolar organizing regions, are the master regulator of inflammation and proliferation, in the development of hepatocellular injury, liver fibrosis and HCC. DEN-administered animals showed increased mast cell counts, tumor necrosis factor alpha, transcription factor nuclear factor-κB, glycoconjugates, proliferating cell nuclear antigen, and argyrophilic nucleolar organizing regions. Whereas Au-mPEG(5000)-S-HP NPs supplementation considerably suppressed all the above abnormalities. These results suggest that the Au-mPEG(5000)-S-HP NPs exhibited the better potential anticancer activity by inhibiting cell inflammation and proliferation in DEN-induced hepatocellular carcinogenesis.

Preventive Effect of blueberries on Diethylnitrosamine-Induced Hepatocarcinogenesis in Rats

Nitrosamine compounds are known hepatic carcinogens. This study was designed to study the efficacy of dietary supplementation with blueberries (BB) on diethylnitrosamine (DEN)-initiated hepatocarcinogenesis in male wistar rats. Rats were divided into three groups. The first group served as normal control group, the second group received DEN at a dose of 10 mg/kg body weight five times a week for 15 weeks. The third one received DEN as in DEN-treated group simultaneously with 4% BB-supplemented diet. The results showed that BB caused significant decrease in the elevated serum levels of α-fetoprotein (AFP), homocysteine (Hcy) along with levels of glutathione(GSH), deoxyribonucleic acid (DNA), ribonucleic acid (RNA)and activity of glutathione reductase (GR) in liver. Normalization of elevated 2-macroglobulin (2M) and total antioxidant capacity (TAC) levels in serum, hepatic Glutathione-S-transferase (GST), glutathione peroxidase (GPx) activities and liver weight was achieved whereas body weight was significantly decreased. Moreover, no significant change was observed in elevated relative liver weight, hepatic glucose-6-P-dehydrogenase (G6PD), lactate dehydrogenase (LDH) along with serum aminotransferases, alkaline phosphatase (ALP) and ɤ -glutamyltransferase (ɤ-GT) activities. Significant increase in reduced hepatic activity of xanthine oxidase (XO) was achieved and histopathological damage was minimized in BB-treated group. It is suggested that BB suppress DEN-induced hepatocarcinogenesis and could be developed as a promising chemoprotective natural supplement for liver cancer.

Metformin inhibits early stage diethylnitrosamine‑induced hepatocarcinogenesis in rats.

Antitumor effects of metformin have recently emerged despite its original use for type II diabetes. In the present study, the effects of metformin on the development and recurrence of hepatocellular carcinoma (HCC) were investigated using the diethylnitrosamine (DEN)-induced rat model of HCC. Tumor foci were characterized by gross examination and by histopathological characteristics, including proliferation, hepatic progenitor cell content and the expression of hepatocarcinoma-specific molecular markers. Potential target molecules of metformin were investigated to determine the molecular mechanism underlying the inhibitory effects of metformin on chemically induced liver tumorigenesis. The antitumor effects of metformin were increased by the reduction of surface nodules and decreased the incidence of altered hepatocellular foci, hepatocellular adenoma and carcinoma. Also, decreased expression levels of glutathione S-transferase placental form, proliferating cell nuclear antigen and cytokeratin 8 described the inhibitory effects of metformin on HCC. In the present study, Wistar rats receiving treatment with DEN were administered metformin for 16 weeks. In addition, metformin suppressed liver tumorigenesis via an AMPK-dependent pathway. These results suggested that metformin has promising effects on the early stage of HCC in rats. Therefore, metformin may be used for the prevention of HCC recurrence following primary chemotherapy for HCC and/or for high-risk patients, including chronic hepatitis and cirrhosis.

Calligonum comosum extract inhibits diethylnitrosamine-induced hepatocarcinogenesis in rats.

Calligonum comosum (C. comosum) is an Egyptian desert plant that contains polyphenol antioxidants. The present study examined the chemopreventive effect of an extract of C. comosum in a rat model of hepatocarcinogenesis. Male Wistar rats (n=40) were administered 100 mg/kg diethylnitrosamine (DEN) by intraperitoneal (i.p.) injection once a week for 3 weeks. Subsequently, depending on whether the rats received further administration of 0.8 mg/kg carbon tetrachloride (CCl4) i.p. once a week for 7 weeks and 100 mg/kg C. comosum extract in their diet for 7 weeks, the rats were divided into four groups as follows: Group 1, treatment with DEN alone; group 2, treatment with DEN and C. comosum extract; group 3, treatment with DEN and CCl4; and group 4, treatment with DEN, CCl4 and C. comosum extract. The supplementation of C. comosum extract significantly suppressed the elevation in serum liver enzyme levels, including aspartate aminotransferase, alanine transaminase and γ-glutamyl transferase, and reduced the degree of oval cell proliferation induced by DEN and CCl4. In addition, C. comosum extract significantly decreased the number and area of glutathione S-transferase placental form-positive preneoplastic hepatic foci induced by DEN, with or without CCl4 treatment. To the best of our knowledge, the present study is the first to provide definitive evidence of the hepatoprotective and chemopreventive effects of C. comosum.

Carvacrol modulates instability of xenobiotic metabolizing enzymes and downregulates the expressions of PCNA, MMP-2, and MMP-9 during diethylnitrosamine-induced hepatocarcinogenesis in rats.

Hepatocellular carcinoma is the fifth most common malignant tumor in the world, both in terms of incidence and mortality in Asian and Western countries. There are currently limited therapeutic regimens available for effective treatment of this cancer. Carvacrol is a predominant monoterpenoic phenol believed to impede cancer promotion and progression. The present study was conducted to decipher the role of carvacrol during diethylnitrosamine (DEN)-induced hepatocarcinogenesis in male wistar albino rats. Carvacrol (15mg/kg body weight) suppressed the elevation of serum tumor marker enzymes, carcinoembryonic antigen, and α-feto protein induced by DEN. The activities of phase I enzymes increased markedly during DEN induction, but was found to be significantly lowered upon carvacrol treatment. On the contrary, the phase II enzymes decreased in DEN-administered animals, which was improved normalcy upon carvacrol-treated animals. DEN-administered animals showed increased mast cell counts, argyrophilic nucleolar organizing regions, proliferating cell nuclear antigen, and matrix metalloproteinases (MMPs-2/9), whereas carvacrol supplementation considerably suppressed all the above abnormalities. The results suggest that the carvacrol exhibited the potential anticancer activity by inhibiting cell proliferation and preventing metastasis in DEN-induced hepatocellular carcinogenesis.

Orally Administered Lycopene Attenuates Diethylnitrosamine-Induced Hepatocarcinogenesis in Rats by Modulating Nrf-2/HO-1 and Akt/mTOR Pathways

Hepatocarcinogenesis is one of the most prevalent and lethal cancers. We studied the mechanisms underlying the inhibition of diethylnitrosamine (DEN)-induced hepatocarcinogenesis by lycopene in rats. Hepatocarcinogenesis was induced by an intraperitoneal injection of DEN followed by promotion with phenobarbital for 24 successive wk. The rats were given lycopene (20 mg/kg body weight) 3 times a week orally for 4 wk prior to initiation, and the treatment was continued for 24 consecutive wk. Lycopene reduced incidence, number, size, and volume of hepatic nodules. Serum alanine transaminase, aspartate aminotransferase, total bilirubin, and malondialdehyde (MDA) considerably increased and hepatic antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase) and glutathione decreased in DEN-treated rats when compared with the control group. Lycopene significantly reversed these biochemical changes and increased the expression of NF-E-2-related factor-2)/heme oxygenase-1, and it decreased NF-κB/cyclooxygenase-2, inhibiting the inflammatory cascade and activating antioxidant signaling (P < 0.05). Lycopene also decreased DEN-induced increases in phosphorylated mammalian target of rapamycin (p-mTOR), phosphorylated p70 ribosomal protein S6 kinase 1, phosphorylated 4E-binding protein 1, and protein kinase B (P < 0.05). Lycopene is an active chemopreventive agent that offers protection against DEN-induced hepatocarcinogenesis by inhibiting NF-κB and mTOR pathways.

Cancer Chemopreventive Effect of Spirogyra Neglecta (Hassall) Kützing on Diethylnitrosamine-Induced Hepatocarcinogenesis in Rats

Spirogyra neglecta, a freshwater green alga, is a local food in the northern and northeastern parts of Thailand. This investigation explored the anticarcinogenicity of S neglecta and its possible cancer chemopreventive mechanisms in rats divided into 14 groups. Groups 1 and 10 served as positive and negative control groups, respectively. Groups 1-9 were intraperitoneally injected with diethylnitrosamine (DEN) once a week for 3 weeks. Groups 10-14 received normal saline instead. One week after the last DEN injection, groups 2-5 were administered for 9 consecutive weeks various doses of S neglecta extract (SNE) and dried S neglecta (SND), mixed with basal diet. Groups 6-9 and 11-14 similarly were administered various doses of SNE and SND starting from the first week of the experiment. Administration of SNE and SND was not associated with formation of glutathione-S- transferase placental form (GST-P) positive foci in rat liver. SNE and SND during initiation phase significantly reduced the number of GST-P positive foci in rats injected with DEN. The number of GST-P also diminished in groups treated with SNE and SND after injection with DEN, except for the low dose extract group. SNE showed stronger anticarcinogenic potency than SND. Furthermore, SNE also decreased the number of Ki-67 positive cells. However, the numbers of TUNEL-positive cells in the liver of the SNE-treated groups were not statistically different from the controls. The GST activity in 50 mg/kg bw of SNE and 1% of SND groups was significantly increased as compared to the positive control. In conclusion, Spirogyra neglecta (Hassall) Kutzing showed cancer chemopreventive properties at the early stages of diethylnitrosamine-induced hepatocarcinogenesis in rats. Possible inhibitory mechanisms include enhancement of the activities of some detoxifying enzymes and/or suppression of precancerous cells.

Sequential study of liver collagen fibers in diethylnitrosamine-induced hepatocarcinogenesis in rats

Objective To observe the sequential changes of collagen fibers in rats with diethylnitrosamine(DEN)-induced hepatocellular carcinoma(HCC),so as to provide a reference for pathogenesis research of HCC.Methods Fifty male Wistar rats,weighing 100-120g,were randomly divided into normal group and HCC model group.The model group was intraperitoneally administered with 50mg/kg DEN(0.1mL),twice a week for 4weeks,then once a week for another 10weeks.The control group was given normal saline(0.1mL)in the same manner.Finally the rats were sacrificed;the normal and diseased liver tissues were observed by H-E,Masson and argyrophilic fiber staining.The expression of collagen typeⅠand typeⅢ mRNA was detected by fluorogenic quantitative PCR;the expression of matrix metalloproteinase(MMP)was examined by gelatinases spectrometry.Results Cirrhosis was found in rats 5weeks after treatment with DEN and HCC was induced 14weeks after DEN treatment;collagen deposition in liver tissues increased in a progressive manner,and the collagen contents in the HCC tissues was greatly less than that in the adjacent tissues,showing a decreasing trend.The contents of MMP-2and MMP-9in the HCC and adjacent tissues had opposite changes compared with collagen.Conclusion Collagen deposition in cirrhosis liver tissue is increased during the process of DEN-induced HCC,but it is decreased in HCC tissues in aprogressive manner,which indicates that collagen might be degraded during the progression from cirrhosis to HCC.

Null anticarcinogenic effect of silymarin on diethylnitrosamine-induced hepatocarcinogenesis in rats

The aim of this study was to investigate the anticarcinogenic effects of silymarin in diethylnitrosamine (DEN)-induced hepatocarcinogenic rat models. Severe and mild models of hepatocellular carcinoma (HCC) were generated by the intraperitoneal administration of 40 mg/kg DEN once a week for 18 weeks and 100 mg/kg DEN every 2 weeks for 6 weeks in male Wistar rats, respectively. In the severe and mild models of HCC, the rats were treated with 0.1 and 0.5% silymarin for 18 weeks and with 0.1% silymarin for 5 weeks, respectively. Serum transaminase levels were not significantly decreased by the silymarin treatment in either model. Macroscopic and microscopic features indicated that the silymarin-containing formulations did not significantly inhibit the hepatic tumor formation induced by DEN. Furthermore, immunohistochemical and western blot analyses demonstrated that the expression levels of proliferating cell nuclear antigen and glutathione S-transferase P, which are hepatocarcinogenic markers, were not significantly modified by the silymarin treatment. These results indicate that silymarin may not be considered as a candidate agent against hepatocarcinogenesis.

Sequential analysis of diethylnitrosamine-induced hepatocarcinogenesis in rats

In the present study, we examined the sequential changes of diethylnitrosamine (DEN)-induced hepatocarcinogenesis in Wistar rats. After 14 weeks of DEN treatment, hyperplastic nodules developed as a consequence of the appearance of renewed hepatocytes, degenerated hepatocytes, oval cells and fibrotic changes. Total bilirubin and alanine aminotransferase levels were significantly higher in the DEN group compared to the control group throughout the experimental period. Our data may prove beneficial to future analyses of chemopreventive compounds during various stages of hepatocarcinogenesis in rats.

POSSIBLE INVOLVEMENT OF OXIDATIVE STRESS IN DIETHYLNITROSAMINE-INDUCED HEPATOCARCINOGENESIS: CHEMOPREVENTIVE EFFECT OF CURCUMIN

ABSTRACT This study investigated the effect of curcumin against diethylnitrosamine (DEN)-induced hepatocarcinogenesis. Rats were divided into three groups. The first group served as a control. The second group received DEN (orally, 20 mg/kg) five times a week for 8 weeks, followed by 10 mg/kg for another 7 weeks. The third group was supplemented with 2% curcumin diet simultaneously with DEN. The results showed normalization of serum level of total antioxidant capacity, γ-glutamyl transferase and aminotransferase activities along with deoxyribonucleic acid, ribonucleic acid and malondialdehyde levels, glutathione reductase and glutathione peroxidase activities in the liver of curcumin group. Significant decreases in the elevated level of glutathione, glutathione-S-transferase and glucose-6-P dehydrogenase activities were observed. Serum alkaline phosphatase activity and the relative liver weight were not significantly altered. Concomitantly, the histopathological damage was attenuated by curcumin. In conclusion, curcumin exerted a potential chemopreventive effect in DEN-induced hepatocarcinogenesis. PRACTICAL APPLICATIONS Various therapeutic effects, such as anti-inflammatory, anti-cancer, anti-angiogenic and wound-healing effects, have been described for curcumin. The present study is an endeavor in the direction of determining its possible mechanism of protection in diethylnitrosamine-induced hepatocarcinogenesis in rats. Our study proved that curcumin exhibits a hepatoprotective potential, and hence, it can be used as value-added agents to limit both exposure to and the adverse health effects from dietary hepatocarcinogens.

Potential chemoprevention of diethylnitrosamine-induced hepatocarcinogenesis in rats: Myrrh (Commiphora molmol) vs. turmeric (Curcuma longa)

The aim of the present study was to assess the potential chemopreventive effects of myrrh (Commiphora molmol) vs. turmeric (Curcuma longa) in hepatocarcinogenic rats induced by a single intraperitoneal injection of diethylnitrosamine (DENA) (200mg/kg body weight). Ninety male Wistar rats used in this study were randomly divided into six equal groups (n=15). Group 1 rats served as negative controls; group 2 received a single i.p. injection of DENA and served as positive controls. Rats in both groups were fed on basal diet. Group 3 rats were fed a diet containing 5% turmeric, whereas group 4 rats were fed a diet containing 2% myrrh. Rats in groups 5 and 6 received a single i.p. injection of DENA and were fed diets containing 5% turmeric and 2% myrrh, respectively. The study demonstrated that DENA caused a significant increase in serum indices of liver enzymes and also severe histological and immunohistochemical changes in hepatic tissues. These included disorganized hepatic parenchyma, appearance of pseudoacinar and trabecular arrays of hepatocytes and alterations in CD10-immunoreactivity. Dietary supplementation of turmeric relatively improved the biochemical parameters to values approximating those of the negative controls and delayed the initiation of carcinogenesis. In contrast, myrrh did not improve the biochemical parameters or delay the hepatocarcinogenesis. Both turmeric and myrrh induced significant biochemical and histological changes in non-treated rats. In conclusion, DENA significantly changes the biological enzymatic activities in serum and the integrity of hepatic tissues. Phytochemicals with potential hepatoprotective effects must be applied cautiously owing to their potential hepatotoxicity.

Diethylnitrosamine-induced hepatocarcinogenesis in rats: possible chemoprevention by blueberries

Nitrosamine compounds are known hepatic carcinogens. This study was designed to study the efficacy of dietary supplementation with blueberries (BB) on diethylnitrosamine (DEN)-initiated hepatocarcinogenesis in male wistar rats. Rats were divided into three groups. The first group served as normal control group, the second group received DEN at a dose of 10 mg/kg body weight five times a week for 15 weeks. The third one received DEN as in DEN-treated group simultaneously with 4% BB-supplemented diet. The results showed that BB caused significant decrease in the elevated serum levels of α-fetoprotein (AFP), homocysteine (Hcy) along with levels of glutathione(GSH), deoxyribonucleic acid (DNA), ribonucleic acid (RNA)and activity of glutathione reductase (GR) in liver. Normalization of elevated α2-macroglobulin (α2M) and total antioxidant capacity (TAC) levels in serum, hepatic glutathione-S-transferase (GST), glutathione peroxidase (GPx) activities and liver weight was achieved whereas body weight was significantly decreased. Moreover, no significant change was observed in elevated relative liver weight, hepatic glucose-6-P-dehydrogenase (G6PD), lactate dehydrogenase (LDH) along with serum aminotransferases, alkaline phosphatase (ALP) and γ-glutamyltransferase (γ-GT) activities. Significant increase in reduced hepatic activity of xanthine oxidase (XO) was achieved and histopathological damage was minimized in BB-treated group. It is suggested that BB suppress DEN- induced hepatocarcinogenesis and could be developed as a promising chemopreventive natural supplement for liver cancer. Key words: Blueberries, diethylnitrosamine, hepatocarcinogenesis, α2-macroglobulin, α-fetoprotein, homocysteine, glutathione, rats.

Molecular basis of anticlastogenic potential of vanadium in vivo during the early stages of diethylnitrosamine-induced hepatocarcinogenesis in rats

Carcinogen-induced DNA base modification and subsequent DNA lesions are the critical events for the expression of premalignant phenotype of the cell. We have therefore investigated the chemopreventive efficacy of a vanadium salt against diethylnitrosamine (DEN)-induced early DNA and chromosomal damages in rat liver. Hepatocarcinogenesis was induced in male Sprague–Dawley rats with a single, necrogenic, intraperitoneal injection of DEN (200 mg/kg body weight). 8-Hydroxy-2′-deoxyguanosines (8-OHdGs), strand-breaks and DNA–protein crosslinks (DPCs) were measured by HPLC, comet assay and spectrofluorimetry, respectively. There was a significant and steady elevation of modified bases 8-OHdGs along with substantial increments of the extent of single-strand-breaks (SSBs), DPCs and chromosomal aberrations (CAs) following DEN exposure. Supplementation of vanadium as ammonium metavanadate (NH 4VO 3, +V oxidation state) at a dose of 0.5 ppm in terms of the salt weight throughout the experiment abated the formations of 8-OHdGs ( P < 0.0001; 79.54%), tailed DNA ( P < 0.05; 31.55%) and length:width of DNA mass ( P < 0.02; 61.25%) in preneoplastic rat liver. Vanadium treatment also inhibited DPCs ( P < 0.0001; 58.47%) and CAs ( P < 0.001; 45.17%) studied at various time points. The results indicate that the anticlastogenic potential of vanadium in vivo might be due to the observed reductions in liver-specific 8-OHdGs, SSBs and/or DPCs by this trace metal. We conclude that, vanadium plays a significant role in limiting DEN-induced genotoxicity and clastogenicity during the early stages of hepatocarcinogenesis in rats.