Diethylnitrosamine causes pituitary damage, disturbs hormone levels, and reduces sexual dimorphism of certain liver functions in the rat

A systematic review on multipotent carcinogenic agent, N-nitrosodiethylamine (NDEA), its major risk assessment, and precautions

The International Agency for Research on Cancer has classified N-nitrosodiethylamine (NDEA) as a possible carcinogen and mutagenic substances, placing it in category 2A of compounds that are probably harmful to humans. It is found in nature and tobacco smoke, along with its precursors, and is also synthesized endogenously in the human body. The oral or parenteral administration of a minimal quantity of NDEA results in severe liver and kidney organ damage. The NDEA required bioactivation by CYP450 enzyme to form DNA adduct in the alkylation mechanism. Thus, this bioactivation directs oxidative stress and injury to cells due to the higher formation of reactive oxygen species and alters antioxidant system in tissues, whereas free radical scavengers guard the membranes from NDEA-directed injury in many enzymes. This might be one of the reasons in the etiology of cancer that is not limited to a certain target organ but can affect various organs and organ systems. Although there are various possible approaches for the treatment of NDEA-induced cancer, their therapeutic outcomes are still very dismal. However, several precautions were considered to be taken during handling or working with NDEA, as it considered being the best way to lower down the occurrence of NDEA-directed cancers. The present review was designed to enlighten the general guidelines for working with NDEA, possible mechanism, to alter the antioxidant line to cause malignancy in different parts of animal body along with its protective agents. Thus, revelation to constant, unpredictable stress situations even in common life may remarkably augment the toxic potential through the rise in the oxidative stress and damage of DNA.

Traditional uses, phytochemistry, pharmacology, and pharmacokinetics of the root bark of Paeonia x suffruticosa andrews: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Moutan Cortex (MC), commonly known as "Mu dan pi", refers to the dried root bark of Paeonia x suffruticosa Andrews and is broadly used as a traditional herbal medication in China, Japan, and Korea. For thousands of years, it has been utilized to treat female genital, extravasated blood, cardiovascular, and stagnant blood disorders.

AIM OF THE REVIEW

The purpose of this review article was to summarize information on the traditional uses, phytochemistry, pharmacology and pharmacokinetics of MC, as well as to outline the further research directions for the development of new drugs and the associations between traditional uses and pharmacological effects.

MATERIALS AND METHODS

The information involved in the study was gathered from a variety of electronic resources, including PubMed, Web of Science, ScienceDirect, SciFinder, China Knowledge Resource Integrated Database, and Google Scholar. The date was from 1992 to 2022.

RESULTS

Approximately 163 chemical compounds have been extracted and identified from MC, including monoterpenes, monoterpene glycosides, triterpenes, phenolics, flavonoids, volatile oils, alkaloids, and others. In these categories, the monoterpene glycosides and phenols being the most common. A wide variety of pharmacological effects have been described for MC crude extracts and active molecules, such as antioxidant, anti-inflammatory, antibacterial and antiviral, antitumor, antidiabetic, organ protection, and neuroprotective activities, as well as treating cardiovascular diseases. Pharmacokinetics has been also used in the study of MC, including its crude extracts or chemical constituents, in order to explore the therapeutic mechanism, direct clinically appropriate application and provide new ideas for the exploitation of innovative medicines.

CONCLUSION

Modern pharmacological research has demonstrated that MC, as a significant therapeutic resource, has the ability to heal a wide range of diseases, particularly female genital and cardiovascular problems. These researches propose therapeutic ideas for the development of novel MC medicines. Furthermore, preclinical and clinical study have verified several observed pharmacological properties related with the traditional usages of MC.

Curcumin and vitamin C improve immunity of kidney via gene expression against diethyl nitrosamine induced nephrotoxicity in rats:In vivo and molecular docking studies

Kidney has a crucial role in immunity, so any toxicity occurs for the kidney will result in reduced immunity. The aim of this study is to improve the immune response of insufficient kidneys through immune-related genes. Diethyl Nitrosamine has been used to cause kidney damage in animal models, vitamin C and curcumin have been used to treat impaired kidney. Renal function (urea, uric acid and creatinine) and oxidative stress parameters (superoxide dismutase, malondialdehyde and glutathione peroxidase) will be evaluated in this research work. Molecular docking also will be performed to investigate the role of vitamin C and curcumin in targeting immune response proteins. Also, Complementary component 3, Lipocalin-2, Toll-like receptor 2,Toll-like receptor 4, Kidney injury molecule-1, Interleukin 6, Interleukin-10, Tumor necrosis factor and p38 mitogen-activated protein kinases will be investigated. The obtained results showed that vitamin C and curcumin have good effects in the treatment of impaired kidneys, this was also observed in renal function and oxidative stress parameters, expression levels of proteins and histopathological examinations.

Attenuation of diethylnitrosamine-induced hepatocellular carcinoma in a rat model by combination therapy of diacerein and gold nanoparticles: a histopathological and immunohistochemical study

The purpose of this study was to investigate the effect of combined therapy of diacerein and gold nanoparticles (AuNP) on diethylnitrosamine (DEN) induced hepatocellular carcinoma (HCC) in a rat model. Normal healthy and DEN-induced (HCC) rats were divided into five groups. Group I healthy rats served as normal control, Group II untreated HCC rats, Group III HCC rats administered diacerein, Group IV HCC rats administered AuNP, and Group V HCC rats administered diacerein and AuNP. All treatments were given once daily for 4 weeks. Liver morphology and necroinflammation in all groups were evaluated using hematoxylin and eosin (H&E), Masson's trichrome for fibrosis, and immunohistochemistry assays for expression of TNF-α, IL-6, β-catenin, and caspase-3. Liver sections from Group II HCC rats showed loss of lobular architecture, thick fibrous tissue deposition, leukocyte infiltration, degenerated hepatocytes and HCC neoplastic nodules surrounded by extensive fibrosis. Group II had high expression of TNF-α, IL-6, and β-catenin, and low caspase-3 expression as compared to Group I. HCC rats treated with the combined therapy of diacerein and AuNP (Group V) showed markedly decreased HCC lesions, significant necroinflammation reduction (p ˂ 0.05) and 90% reduction in fibrosis as compared to Group II HCC + diacerein. This combined therapy also reduced (p ˂ 0.05) TNF-α, IL-6, β-catenin expression and increased caspase-3 expression. In conclusion, diacerein combined with AuNP synergistically attenuated the severity of HCC lesions by reducing necroinflammation and fibrosis, decreased TNF-α, IL-6, β-catenin expression, and increased caspase-3 expression for apoptosis.

A novel mechanistic approach for the anti-fibrotic potential of rupatadine in rat liver via amendment of PAF/NF-ĸB p65/TGF-β1 and hedgehog/HIF-1α/VEGF trajectories

Hepatic fibrosis is one of the major worldwide health concerns which requires tremendous research due to the limited outcomes of the current therapies. The present study was designed to assess, for the first time, the potential therapeutic effect of rupatadine (RUP) in diethylnitrosamine (DEN)-induced liver fibrosis and to explore its possible mechanistic actions. For the induction of hepatic fibrosis, rats were treated with DEN (100 mg/kg, i.p.) once weekly for 6 consecutive weeks, and on the 6th week, RUP (4 mg/kg/day, p.o.) was administered for 4 weeks. Treatment with RUP ameliorated changes in body weights, liver indices, liver function enzymes, and histopathological alterations induced by DEN. Besides, RUP amended oxidative stress, which led to the inhibition of PAF/NF-κB p65-induced inflammation, and, subsequently, prevention of TGF-β1 elevation and HSCs activation as indicated by reduced α-SMA expression and collagen deposition. Moreover, RUP exerted significant anti-fibrotic and anti-angiogenic effects by suppressing Hh and HIF-1α/VEGF signaling pathways. Our results highlight, for the first time, a promising anti-fibrotic potential of RUP in rat liver. The molecular mechanisms underlying this effect involve the attenuation of PAF/NF-κB p65/TGF-β1 and Hh pathways and, subsequently, the pathological angiogenesis (HIF-1α/VEGF).

Artichoke (Cynara Scolymus) Methanolic Leaf Extract Alleviates Diethylnitrosamine-Induced Toxicity in BALB/c Mouse Brain: Involvement of Oxidative Stress and Apoptotically Related Klotho/PPARγ Signaling

(1) Background: Various epidemiological studies suggest that oxidative stress and disrupted neuronal function are mechanistically linked to neurodegenerative diseases (NDs), including Parkinson's disease (PD) and Alzheimer's disease (AD). DNA damage, oxidative stress, lipid peroxidation, and eventually, cell death such as NDs can be induced by nitrosamine-related compounds, leading to neurodegeneration. A limited number of studies have reported that exposure to diethylnitrosamine (DEN), which is commonly found in processed/preserved foods, causes biochemical abnormalities in the brain. Artichoke leaves have been used in traditional medicine as a beneficial source of bioactive components such as hydroxycinnamic acids, cynarine, chlorogenic acid, and flavonoids (luteolin and apigenin). The aim of this study is to investigate the favorable effects of exogenous artichoke (Cynara scolymus) methanolic leaf extract supplementation in ameliorating DEN-induced deleterious effects in BALB/c mouse brains. (2) Methods: This study was designed to evaluate DEN (toxicity induction by 100 mg/kg) and artichoke (protective effects of 0.8 and 1.6 g/kg treatment) for 14 days. All groups underwent a locomotor activity test to evaluate motor activity. In brain tissue, oxidative stress indicators (TAC, TOS, and MDA), Klotho and PPARγ levels, and apoptotic markers (Bax, Bcl-2, and caspase-3) were measured. Brain slices were also examined histopathologically. (3) Results: Artichoke effectively ameliorated DEN-induced toxicity with increasing artichoke dose. Impaired motor function and elevated oxidative stress markers (decreasing MDA and TOS levels and increasing TAC level) induced by DEN intoxication were markedly restored by high-dose artichoke treatment. Artichoke significantly improved the levels of Klotho and PPARγ, which are neuroprotective factors, in mouse brain tissue exposed to DEN. In addition, caspase-3 and Bax levels were reduced, whereas the Bcl-2 level was elevated with artichoke treatment. Furthermore, recovery was confirmed by histopathological analysis. (4) Conclusions: Artichoke exerted neuroprotective effects against DEN-induced brain toxicity by mitigating oxidant parameters and exerting antioxidant and antiapoptotic effects. Further research is needed to fully identify the favorable impact of artichoke supplementation on all aspects of DEN brain intoxication.

Biomimetic synthesis of silver nanoparticles for treatment of N-Nitrosodiethylamine-induced hepatotoxicity

The development of bioengineered nanoparticles has attracted considerable universal attention in the field of medical science and disease treatment. Current studies were executed to evaluate the hepatoprotective activity of biosynthesized silver nanoparticles (AgNPs). Their characterization was performed by UV-Visible analysis, fourier transform infrared spectroscopy, transmission electron microscopy (TEM), scanning electron microscope (SEM), and Zeta analyses. In in vivo studies, albino rats (180 ± 10 g) were persuaded with model hepatic toxicant N-nitrosodiethylamine (NDEA) and subsequently cotreated with Morus multicaulis at 100 mg/kg and AgNPs at 100 µg/kg dose. NDEA administration elevates the levels of liver function test biomarkers, which were reinstated to normal by cotreatment of test drugs. The oxidative stress and concentration of drug-metabolizing enzyme increase after induction of toxicant (NDEA), these markers are restored toward normal after cotreatment of nano-drug. Treatments of M. multicaulis extract did not show such significant protection. The NDEA-treated groups showed a significant rise in the level of cytokines (interleukin [IL-6] and IL-10) and reached normal with subsequent treatment with AgNPs. Histopathological studies also exhibited the curative effect of AgNPs in the same manner. Thus current results strongly suggest that biomimetic AgNPs could be used as an effective drug against hepatic alteration.

Metformin Improves Biochemical and Pathophysiological Changes in Hepatocellular Carcinoma with Pre-Existed Diabetes Mellitus Rats

Hepatocellular carcinoma (HCC) is one of the world’s most widely recognized malignant tumors that accounts for 90% of all the primary liver cancers and is a major cause of death from cancer, representing half a million deaths per year. Obesity and associated metabolic irregularities, particularly diabetes mellitus (DM) and insulin resistance, are important risk factors for the advancement of HCC. Recently, retrospective studies showed that metformin (MET) could protect the hepatic tissues in pre-existing diabetes mellitus from HCC. The purpose of this study was to assess the role of MET treatment in the pre-existing diabetic rats before and after HCC induction by diethylnitrosamine (DEN). Thirty-five male Sprague Dawley albino rats were partitioned into the following groups: Group 1 (Gp1) was the control. Gp2 was injected intraperitoneally (i.p) with streptozotocin (STZ) (80 mg/kg) and DEN (50 mg/kg/7 weeks). Gp3, Gp4, and Gp5 were injected as in Gp2 and treated with MET (150 mg/kg) before and/or after HCC induction. Biochemical parameters including liver functions, lipid profile, and oxidative stress biomarkers were determined. Furthermore, histological and immunohistochemical changes were assessed in all groups. Our results illustrated that the group of rats that were treated with STZ and DEN had significant changes in both liver functions and were associated with alterations in the liver histopathological architectures. Treatment with MET before or after HCC induction ameliorated the cellular changes in the liver tissues; however, the utmost protection was found in a group of rats, which were treated with MET before and after HCC induction.

Nuclear receptor AHR-mediated xenobiotic detoxification pathway involves in atrazine-induced nephrotoxicity in quail (Coturnix C. coturnix)

Atrazine (ATR), one of the most widely used pesticides in agricultural production, are gradually concerned due to potential ecosystem and health risks. Further, the induction of ATR nephrotoxicity and detoxification response is still unknown. To evaluate ATR-induced nephrotoxicity, quails were treated with 0, 50, 250 or 500 mg/kg ATR by gavage administration for 45 days. Histopathology indicated that ATR exposure caused renal tubular epithelial cell swelling and endoplasmic reticulum degeneration, suggesting that ATR exposure causes renal impairment even renal diseases. Notably, ATR interfered cytochrome P450 system (CYP450s) homeostasis by enhancing contents or activities of CYP450s (total CYP450, Cyt b5, AH, APND, NCR and ERND) and the expression of CYP450 isoforms (CYP1A, CYP1B, CYP2C and CYP3A). ATR triggered phase II detoxifying reaction, reflected by the elevated GSH level, GST activity and the up-regulation of GST isoforms (GSTa, GSTa3 and GSTt1) and GSH synthetase (GCLC). Moreover, ABC transporters were activated to expel ATR from the body by increasing expression of MRP1 and P-GP gene. Accompanying these alterations, the nuclear receptors (AHR, CAR and PXR) were activated by ATR in a dose-dependent manner. Analysis results of present study demonstrated that the induction of phase II detoxifying enzyme system and ABC transporters could be modulated by nuclear receptors response and CYP450s disturbance in low-dose ATR-treated quail. In conclusion, all data suggested that nuclear receptors AHR-mediated detoxification pathway was involved in ATR-induced nephrotoxicity. These results provided new evidence about the nephrotoxic effects of ATR on the response of biotransformation and detoxification system.

Opium Consumption and the Incidence of Cancer: Does Opium Account as an Emerging Risk Factor for Gastrointestinal Cancer?

PURPOSE

Some epidemiological studies have shown an association between opium consumption and the incidence of gastrointestinal (GI) cancer. The present study was designed to investigate the effects of opium on the initiation of GI cancer in rats.

METHODS

Forty-five rats were randomly divided into three groups; each received different treatment for 40 weeks. The rats in group 1 received purified water, while animals in group 2 were treated with 5 mg/kg diethylnitrosamine (DEN) orally for 8 weeks and continued with purified water by the end of the experiment. The third experimental group received 300 mg/kg opium for 16 weeks and then continued with 50 mg/kg phenobarbital by the end of the 40th week. The growth of tumors in the treated groups was assessed by histological changes and the up/down expression of p53, cdkn1, cdk2, e-cdh, and n-cdh genes in different parts of GI tract.

RESULTS

Histological examinations revealed that DEN was able to induce the growth of tumor in GI tract as shown by active mitotic figure in different regions of GI system and hyperplasia of hepatocytes associated with infiltration of inflammatory cells, intestinal villous hypertrophy, and colorectal adenoma. There was also significant (p < 0.05) overexpression of p53, cdk2, and n-Cdh genes in different parts of digestive system in DEN-treated group. However, these pathological changes and the degradation of gene expression were not observed in the opium-treated group.

CONCLUSION

The results of this study suggest that the opium does not promote the initiation of cancer in GI tract.

Reduction of liver tumerogenic effect of N-nitrosodiethylamine by treatment with ɣ-oryzanol in Balb/C mice

In recent years, naturally occurring phytochemicals with antioxidant capacity have generated surmount interest in their therapeutic usage against a wide range of pathological and toxicological conditions. The present study was designed to evaluate potential of ɣ-oryzanol (OZ), a bio-active natural antioxidant against hepatocellular carcinoma effect of the carcinogen N-nitrosodiethylamine in Balb/c mice. OZ inhibited the proliferation of Hep-3B cell line in concentration dependent manner. Administration of OZ to N-nitrosodiethylamine induced Balb/c mice for 16 and 32 weeks showed reduction in levels of liver injury markers, restored the levels of liver tumor markers, suppressed the hepatic nodular incidence and multiplicity, and favorably modulated the liver antioxidant status in a time dependent manner. Histologically, no obvious signs of neoplasia in the liver tissues were observed in OZ supplemented rats with N-nitrosodiethylamine induced liver tumerogenesis. OZ was found to be effective for reduction of N-nitrosodiethylamine induced hepatocellular carcinoma.

In vitro, In silico and In vivo Antitumor Activity of Crude Methanolic Extract of Tetilla dactyloidea (Carter, 1869) on DEN Induced HCC in a Rat Model

Tetilla dactyloidea (Carter, 1869) is a marine sponge classified under Demospongia and recent studies have demonstrated that active constituents of Demospongia class have exhibited several potential medical applications. However, no preliminary pharmacological studies have been reported so far. The present investigation was carried out to evaluate the zoo-chemical status, antioxidant potential and anticancer activity of Crude Methanolic Extract of Tetilla dactyloidea (CMETD). Hepatocellular Carcinoma (HCC) was induced in the liver of male Sprague Dawley (SD) rats by treating with diethylnitrosamine (DEN). Nodule incidence, body weight, liver marker enzymes, enzymatic and non-enzymatic antioxidant, phase I metabolizing and liver macromolecular damaging enzymes and immuno-histopathological changes were assessed in DEN and DEN+CMETD treated rats. Oral administration of CMETD at a dose of 400mg/kg body weight to DEN treated rats restored the above parameters to near normal levels compared to control. The biochemical results were consistent with histopathological observations suggesting marked hepatoprotective effect of CMETD in a dose dependent manner. The GCMS of CMETD analysis showed the presence of six compounds. In in silico analysis 9-Octadecenoic acid (Z)-, 2-hydroxy-1-(hydroxymethyl) ethyl ester ligand showed an effective binding energy of -7.1kcal/mol against Cox-2 receptor. The compounds showed desirable pharmacokinetic properties and significant molecular interactions with the HCC receptors. To conclude, our results clearly suggested that CMETD treatment prevented liver damage, protected the antioxidant defense system and possessed anti-carcinogenic potential in DEN induced hepatic carcinoma.

A new in vivo analysis model to detect sexually dimorphic rat liver cytochrome P450 gene expression dependent on growth hormone secretory patterns

Several drug-metabolizing cytochrome P450 (CYP) enzymes exhibit sexual dimorphism depending on the pituitary growth hormone (GH) secretory patterns. However, the mechanism underlying CYP sexual dimorphism remains unclear. We previously established a transgenic (Alb-DsRed2 Tg) rat that expressed red fluorescent DsRed2 protein, particularly in hepatocytes, to visualize cell differentiation and multiplication and found that hepatic DsRed2 expression exhibited sexual dimorphism that was limited to adult males. In this study, we compared the expression patterns between sexual dimorphic Cyps and DsRed2 in Tg rats after experimentally reversing the GH secretory patterns in males and females. Postnatal day 1 male and female Tg rats were gonadectomized and then testosterone propionate (0.25 mg/rat) was subcutaneously administered to ovariectomized females immediately after surgery. Cyp mRNA and DsRed2 expression levels were quantified using RT-PCR and an in vivo imaging system, respectively. GH-dependent Cyps and hepatic DsRed2 expression patterns were reversed in males and females at 9 weeks after birth and were significantly correlated (P<0.05). This suggested that DsRed2 expression in these Tg rats depended on GH secretory patterns. Based on DsRed2 fluorescence, this Tg rat model could become a tool to readily and effectively evaluate changes in GH-dependent Cyp expression.

Significance of Rumex vesicarius as anticancer remedy against hepatocellular carcinoma: a proposal-based on experimental animal studies

Rumex vesicarius is an edible herb distributed in Egypt and Saudi Arabia. The whole plant has significant value in folk medicine and it has been used to alleviate several diseases. Hepatocellular carcinoma (HCC), the major primary malignant tumor of the liver, is one of the most life-threatening human cancers. The goal of the current study was to explore the potent role of Rumex vesicarius extract against HCC induced in rats. Thirty adult male albino rats were divided into 3 groups: (I): Healthy animals received orally 0.9% normal saline and served as negative control group, (II): HCC group in which rats were orally administered N-nitrosodiethylamine NDEA, (III): HCC group treated orally with R. vesicarius extract in a dose of 400 mg/kg b.wt daily for two months. ALT and AST, ALP and γ-GT activities were estimated. CEA, AFP, AFU, GPC-3, Gp-73 and VEGF levels were quantified. Histopathological examination of liver tissue sections was also carried out. The results of the current study showed that the treatment of the HCC group with R. vesicarius extract reversed the significant increase in liver enzymes activity, CEA, AFP, AFU, glypican 3, golgi 73 and VEGF levels in serum as compared to HCC-untreated counterparts. In addition, the favorable impact of R. vesicarius treatment was evidenced by the marked improvement in the histopathological features of the liver of the treated group. In conclusion, the present experimental setting provided evidence for the significance of R. vesicarius as anticancer candidate with a promising anticancer potential against HCC. The powerful hepatoprotective properties, the potent antiangiogenic activity and the effective antiproliferative capacity are responsible for the anticancer effect of this plant.

Mouse hepatic neoplasm formation induced by trace level and low frequency exposure to diethylnitrosamine through β-catenin signaling pathway

It has been reported that massive levels or/and high frequency exposure of diethylnitrosamine could induce hepatic neoplasm. However, it would be more interesting to figure out the hepatotoxic effects of diethylnitrosamine exposure at trace level and low frequency, which could be more common in our daily life. We found that both the mRNA and protein expression levels of β-catenin were aberrant in all liver tissues, accompanied by inflammation, steatosis, fibrosis and hepatic neoplasm after 10-week exposure of diethylnitrosamine (dissolved in sesame oil, 0.16 mmol per kg body weight) to mice. In addition, gradual increase in the mRNA expression of several pivotal risk factors (TNF-α, COX-2, PPAR-γ, AP-2, Smad-2, TGF-β1, and C-myc), as well as their protein expression levels, were associated with the aberrant expression or/and nucleus localization of β-catenin. Altogether, our results show that long-term diethylnitrosamine exposure at trace amounts and low frequency can also induce hepatotoxicity (including inflammation, steatosis and fibrosis) and consequently aberrant activation of β-catenin which in turn plays an important role in the initiation and promotion of liver tumors.

Antioxidant activity of ethanolic extract of Tinospora cordifolia on N-nitrosodiethylamine (diethylnitrosamine) induced liver cancer in male Wister albino rats

BACKGROUND

Cancer is a disease that evokes wide spread fear among people and is one of the leading causes of deaths in the world. Diethylnitrosamine (DEN) is a known carcinogen in rodent liver. DENs reported to undergo metabolic activation by cytochrome P450 enzymes to form reactive electrophiles that cause oxidative stress leading to cytotoxicity, mutagenicity and carcinogenicity.

OBJECTIVE

The present study was carried out to evaluate the antioxidant activity of ethanolic extract of Tinospora cordifolia (EETC) in N-nitrosodiethylamine (DEN) induced liver cancer in male Wister albino rats.

MATERIALS AND METHODS

The antioxidant activity was assessed by the levels of lipid peroxidation (LPO), enzymic and nonenzymic antioxidants.

RESULT

A significant levels of LPO was increased as the enzymic and nonenzymic antioxidants values were decreased in liver cancer bearing animals.

CONCLUSIONS

The administration of EETC to cancer bearing animals reverted the LPO levels, enzymic and nonenzymic antioxidants to near normal.

Anticancer effect of rosiglitazone in rats treated with N-nitrosodiethylamine via inhibition of DNA synthesis: an implication for hepatocellular carcinoma

Rosiglitazone, peroxisome proliferator-activated receptor-γ (PPARγ) ligand, is a clinically tested drug used in the treatment of diabetes.

Prophylactic Role of Averrhoa carambola (Star Fruit) Extract against Chemically Induced Hepatocellular Carcinoma in Swiss Albino Mice

Liver cancer remains one of the severe lethal malignancies worldwide and hepatocellular carcinoma (HCC) is the most common form. The current study was designed to evaluate the prophylactic role of the fruit of Averrhoa carambola (star fruit or Kamrak) on diethylnitrosamine- (DENA-) induced (15 mg/kg b.wt.; single i.p. injection) and CCl4-promoted (1.6 g/kg b.wt. in corn oil thrice a week for 24 weeks) liver cancer in Swiss albino mice. Administration of ACE was made orally at a dose of 25 mg/kg b.wt/day for 5 consecutive days and it was withdrawn 48 hrs before the first administration of DENA (preinitiational stage). CCl4 was given after 2 weeks of DENA administration. A cent percent tumor incidence was noted in carcinogen treated animals while ACE administration resulted in a considerable reduction in tumor incidence, tumor yield, and tumor burden. Further, ACE treatment brings out a significant reduction in lipid peroxidation (P < 0.001) along with an elevation in the activities of enzymatic antioxidants (superoxide dismutase, P < 0.001, and catalase, P < 0.001), nonenzymatic antioxidant (reduced glutathione, P < 0.001), and total proteins (P < 0.001) when compared to the carcinogen treated control. These results demonstrate that ACE prevents the DENA/CCl4 induced adverse physical and biochemical alterations during hepatic carcinogenesis in mice. This study suggests the prophylactic role of Averrhoa carambola against hepatocellular carcinoma in mice; therefore, it could be employed for the further screening as a good chemopreventive natural supplement against cancer.

Effects of Echinacea purpurea on Hepatic and Renal Toxicity Induced by Diethylnitrosamine in Rats

BACKGROUND

Nitrites are mainly used in food preservation. These materials could change to nitrosamine due to the effect of heat and gastric acid. Nitrosamine is absorbed in intestine and enters the liver and hepatocytes by portal venous system, and hampers the detoxification system of liver by interfering in cytochrome P450 enzymes, so, the liver gently proceeds to cirrhosis and cancer.

OBJECTIVES

The current study aimed to investigate the hepatic and renal protective effects of aerial parts of Echinacea purpurea extract (EPE) on injury induced by diethylnitrosamine (DEN).

MATERIALS AND METHODS

Twenty Wistar rats were divided into 4 groups. Groups were as follow: Control group (normal saline), DEN (200 mg/kg, IP, a single dose), EPE (100 mg/kg, orally, daily) and DEN + EPE which received as group DEN and EPE. After 30 days, Blood samples, and liver and kidney tissues were taken for further examination. Aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), BUN, Creatinine and total and direct bilirubin were estimated in serum.

RESULTS

DEN induced hepatotoxicity and nephrotoxicity in all the treated animals by elevated serum ALT, AST, ALP and BUN, creatinin and total and direct bilirubin levels. AST, BUN and total and direct bilirubin significantly decreased in DEN + EPE compared to DEN group. After 30 days of DEN administration, histopathological investigation revealed proliferation of hepatic stellate cells and early fibrosis which were partly improved by EPE administration.

CONCLUSIONS

The current study findings indicated that Echinacea purpurea extract played an important role in the protection against DEN toxicity in rats.

Effect of paeonol on antioxidant and immune regulatory activity in hepatocellular carcinoma rats

The study investigated the immunity and antioxidant potential of paeonol by employing a hepatocellular carcinoma (HCC) rat model. Three doses of paeonol (20, 40, 60 mg/kg b.w. orally) were administrated to diethylnitrosamine (DEN)-induced HCC rats. Results showed that paeonol significantly reduced the serum AST, ALT, ALP, GGT, AFU and liver MDA levels, increased serum WBC, TP, ALB, A/G, TNF-α and IFN-γ and liver antioxidant enzymes activities (SOD, CAT, GSH-Px, GR) in HCC rats. Altogether, these results suggest that the paeonol could effectively decrease oxidative injury and improve immunity function in HCC rats.

Cloudy apple juice protects against chemical-induced oxidative stress in rat

BACKGROUND

Apples abundant in phenolic compounds show a variety of biological activities that may contribute to beneficial effects against some chronic diseases.

PURPOSE

The aim of our study was to assess the protective effect of cloudy apple juice against chemical-induced oxidative stress in rats.

METHODS

Male Wistar rats were treated with apple juice per os, 10 mL/kg/day for 28 days and with a single dose of N-nitrosodiethylamine (NDEA), 150 mg/kg or carbon tetrachloride (CCl(4)), 2 mL/kg, 24 h before killing. Two groups of rats not pretreated with juice were administered each of the xenobiotics alone.

RESULTS

Microsomal lipid peroxidation in the liver was decreased in rats pretreated with juice by 52-87% when compared to animals given NDEA or CCl(4) alone. Pretreatment with juice protected antioxidant enzymes: catalase, glutathione peroxidase and glutathione reductase but not superoxide dismutase. Their activity was recovered by 49-173% when compared to that in rats given either toxicant alone. The plasma activity of paraoxonase 1 was reduced by both toxicants and was increased by 23% in the apple/CCl(4) group. A rise in plasma protein carbonyls caused by the xenobiotics was reduced by 20% only in apple/NDEA-treated rats. Also, in this group of animals, a 9% decrease in DNA damage in blood leukocytes was observed.

CONCLUSION

Phytochemicals in commonly consumed apple juice may protect some macromolecules against oxidative insult induced by xenobiotics.

Protective effect of chokeberry on chemical-induced oxidative stress in rat

Male Wistar rats were treated with chokeberry juice per os, 10 mL/kg/day, for 28 days and a single intraperitoneal (i.p.) dose of N-nitrosodiethylamine (NDEA), 150 mg/kg, or carbon tetrachloride (CCl4), 2 ml/kg. The level of hepatic microsomal lipid peroxidation, expressed as thiobarbituric acid reactive substances (TBARS), was increased in animals dosed with NDEA and CCl4. Juice pretreatment resulted in a significant decrease in TBARS by 53% and 92%, respectively. In rats administered juice alone, 50% decrease in TBARS was noted. The activities of all antioxidant enzymes were decreased in the liver of rats administered either toxicant by 29%—52% as compared to controls. Juice pretreatment resulted in an increase in the activity of catalase, glutathione peroxidase and glutathione reductase by 117%, 56% and 44%, respectively, only in rats challenged with NDEA. Although no response of plasma protein carbonyls to both toxicants was observed, the pretreatment with juice caused a 55% decrease of this parameter in CCl4—dosed rats. DNA damage in blood leukocytes induced by either toxicant was slightly reduced, by 24%, in the rats pretreated with juice and administered NDEA. The results of the study showed that pretreatment with chokeberry juice confers some protection against chemical-induced oxidative stress.

Evaluation of the protective effect of ascorbic acid on nitrite- and nitrosamine-induced cytotoxicity and genotoxicity in human hepatoma line

Nitrites are ubiquitous environmental contaminants present in drinking water and foods. Nitrosamines can be formed endogenously from nitrate and nitrite and secondary amines or may be present in food, tobacco smoke, and drinking water. The major goal of this work was to evaluate the cytotoxic, reactive oxygen species (ROS)-producing and genotoxic effects of nitrite and nitrosamines and the possible protection by ascorbic acid in HepG2 cells. It was found that nitrite, N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), and N-nitrosomorpholine (NMOR) decreased cell viability, increased intracellular ROS production, and caused genotoxicity. Compared to untreated cells as determined by alkaline Comet assay, nitrite, NDMA, NDEA, and NMOR raised the tail intensity up to 1.18-, 3.79-, 4.24-, and 4.16-fold, respectively. Ascorbic acid (AA, 10 microM) increased cell viability and reduced ROS production significantly (p < 0.05). Additionally, AA treatment decreased the tail intensity caused by nitrite, NDMA, NDEA, and NMOR to 33.74%, 58.6%, 44.32%, and 43.97%, respectively. It can be concluded that ascorbic acid was able to reduce both tail intensity and tail moment in all of the nitrosamine treatments, particularly in NDMA. AA protected HepG2 cells against genotoxic effects caused by nitrosamines. This protection might be through different mechanisms, some of which are not still understood in depth. The future interest will be to understand which pathways are influenced by antioxidants, particularly by AA, and the outcomes of this prevention in other cell line types.

Antioxidant and antimutagenic effect of quercetin against DEN induced hepatotoxicity in rat

Diethylnitrosamine (DEN), a potent hepatocarcinogen, is found in tobacco smoke, processed meat as well as in different food products. Quercetin (QC), a naturally occurring flavonoid has excellent antioxidant properties. The present study was aimed to investigate the chemoprotective potential of QC against DEN induced hepatotoxicity in Sprague-Dawley (SD) rats. Quercetin was administered (10, 30 and 100 mg/kg) for 5 consecutive days after DEN (200 mg/kg) treatment. The animals were killed 24 h after the last dose of QC/saline treatment. The DEN induced hepatotoxicity was evident by elevated malondialdehyde (MDA) and decreased glutathione (GSH) levels in the liver. A significant increase in the levels of plasma aspartate transaminase (AST) and plasma alanine transaminase (ALT) was observed in the DEN treated group. The DEN induced DNA damage was evaluated using a single cell gel electrophoresis (SCGE) assay. A significant increase in the number of TUNEL positive cells was observed in the DEN treated group. Quercetin restored AST, ALT and GSH levels at all the tested doses. Restoration of the MDA level and cellular morphology was observed at doses of 10 and 30 mg/kg of QC. Further, DEN induced DNA damage and apoptosis was ameliorated by QC. The results indicate that QC ameliorates the DEN induced hepatotoxicity in rats and can be a candidate for a good chemoprotectant.

Protective effects of garlic and silymarin on NDEA-induced rats hepatotoxicity

Background ­— The present study was conducted to investigate the chemopreventive effects of garlic extract and silymarin on N-nitrosodiethylamine (NDEA) and carbon tetrachloride (CCl₄)-induced hepatotoxicity in male albino rats. Methods and Results — Animals were pretreated with garlic, silymarin or both for one week prior to the injection of NDEA. Then animals received a single injection of NDEA followed by weekly subcutaneous injections of CCl₄ for 6 weeks. Oral administration was then continued along with the injection of CCl₄ for the duration of the experiment. Serum aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), hepatic lipid peroxidation (LPO), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione-S-transferase (GST) and glutathione reductase (GSR) were measured. Injection of NDEA induced a significant elevation in serum AST, ALT and ALP. In the liver, NDEA increased oxidative stress through the increase in LPO and decrease in SOD, and GSH-dependent enzymes. Although administration of garlic or silymarin significantly reduced the liver toxicity, combined administration was more effective in preventing the development of hepatotoxicity. Conclusion — These novel findings suggest that silymarin and garlic have a synergistic effect, and could be used as hepatoprotective agents against hepatotoxicity.

Characterization of hepatic sexual dimorphism in Alb-DsRed2 transgenic rats

We previously created the Alb-DsRed2 transgenic (Tg) rat that specifically expresses the red fluorescent protein, DsRed2, in the liver. Herein, we demonstrate that the DsRed2 expression is sexually dimorphic and exhibits a male-specific pattern. The profiling of sexual dimorphism in DsRed2 expression during pre-pubertal development was investigated using an in vivo fluorescent imaging analysis. The DsRed2 expression decreased gradually in both sexes until 28days after birth. While DsRed2 expression was not persistent in the female liver, the male hepatic expression increased again at 35days. Sexual dimorphic DsRed2 expression did not change in gonadectomized male and female Tg-rats. However, female hepatic DsRed2 was induced 72h after the hypophysectomy. Hepatocytes isolated from the female Tg-rats also revealed DsRed2 induction by 96h in culture. These results suggest that the pituitary hormone suppresses the female hepatic DsRed2 expression causing the sexual dimorphism of DsRed2 expression.

Reproductive outcome in a cohort of male and female rubber workers: a registry study

PURPOSE

To investigate whether blue-collar employment in the Swedish rubber industry from 1973 onwards had a negative impact on reproductive health.

METHODS

Pairs of mother and child, and triads of father-mother-child were obtained through linkage of a cohort of 18,518 rubber factory employees with the Swedish Population Registry. Birth outcomes were obtained from the Medical Birth Register for 17,918 children. For each child, parental employment as blue-collar rubber worker during the pregnancy and sperm maturation period was obtained from work-place records. Children to female food industry workers, in all 33,256, constituted an external reference group.

RESULTS

The sex ratio was reversed, with odds ratio (OR) for having a girl was 1.15 (95% CI 1.02, 1.31) when the mother was exposed. When both parents were exposed, the OR was even higher, 1.28 (95% CI 1.02, 1.62). An increased risk of multiple births was observed when both parents were exposed, with OR 2.42 (95% CI 1.17, 5.01). Children with both maternal and paternal exposure had a reduced birth weight compared to the external reference cohort. After adjustment for smoking (available for births from 1983 onwards), ethnicity and sex, the difference between children (singletons, live births) with maternal and paternal exposure and external referents was -142 g (95% CI -229, -54). The adjusted OR for having a small-for-gestational-age child was 2.15 (95% CI 1.45, 3.18) when the mother was a rubber worker during the pregnancy.

CONCLUSION

There were clear indications that reproductive outcome was adversely affected in rubber workers. The findings warrant further investigation with refinement of exposure indices and inclusion of other endpoints of reproductive health.

Silymarin downregulates COX-2 expression and attenuates hyperlipidemia during NDEA-induced rat hepatocellular carcinoma

Silymarin is a naturally available bioflavonoid and is a strong antioxidant with a capacity to inhibit the formation of tumors in several cancer models. In the present study, we investigated whether dietary supplementation of silymarin has any role in lipid components, lipid-metabolizing enzymes, free fatty acid profile, and expression of cyclooxygenase-2 (COX-2) in N-nitrosodiethylamine (NDEA)-induced hepatocellular carcinoma in rats. NDEA-induced rats showed severe hyperlipidemia along with upregulated expression of COX-2 as revealed by western blotting and immunohistochemistry. Dietary silymarin supplementation attenuated this hyperlipidemia and downregulated the expression of COX-2. Thus we conclude that compounds like silymarin with potent hypolipidemic effect are strong candidates as chemopreventive agents for the treatment of liver cancer.

Silymarin modulates the oxidant-antioxidant imbalance during diethylnitrosamine induced oxidative stress in rats

Oxidative stress is a common mechanism contributing to initiation and progression of hepatic damage in a variety of liver disorders. Hence, there is a great demand for the development of agents with potent antioxidant effect. The aim of the present investigation is to evaluate the efficacy of silymarin as a hepatoprotective and an antioxidant against diethylnitrosamine induced hepatocellular damage. Single intraperitoneal administration of diethylnitrosamine (200 mg/kg) to rats resulted in significantly elevated levels of serum aspartate transaminase (AST) and alanine transaminase (ALT), which is indicative of hepatocellular damage. Diethylnitrosamine induced oxidative stress was confirmed by elevated levels of lipid peroxidation and decreased levels of superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase (GR) and glutathione-S-transferase (GST) in the liver tissue. The status of non-enzymic antioxidants like, vitamin-C, vitamin-E and reduced glutathione (GSH) were also found to be decreased in diethylnitrosamine administered rats. Further, the status of membrane bound ATPases was also altered indicating hepatocellular membrane damage. Posttreatment with the silymarin (50 mg/kg) orally for 30 days significantly reversed the diethylnitrosamine induced alterations in the liver tissue and offered almost complete protection. The results from the present study indicate that silymarin exhibits good hepatoprotective and antioxidant potential against diethylnitrosamine induced hepatocellular damage in rats.

Effect of Cassia fistula Linn. leaf extract on diethylnitrosamine induced hepatic injury in rats

The hepatoprotective and antioxidant effect of Cassia fistula Linn. leaf extract on liver injury induced by diethylnitrosamine (DEN) was investigated. Wistar rats weighing 200+/-10g were administered a single dose of DEN (200mg/kg b.w., i.p.) and left for 30 days. For hepatoprotective studies, ethanolic leaf extract (ELE) of C. fistula Linn. (500mg/kg b.w., p.o.) was administered daily for 30 days. AST, ALT, ALP, LDH, gamma-GT and bilirubin were estimated in serum and liver tissue. Lipid peroxidation (LPO), SOD and CAT were also estimated in liver tissue as markers of oxidative stress. DEN induced hepatotoxicity in all the treated animals were evident by elevated serum ALT, AST, ALP and bilirubin levels and a simultaneous fall in their levels in the liver tissue after 30 days. Induction of oxidative stress in the liver was evidenced by increased LPO and fall in the activities of SOD and CAT. ELE administration for 30 days prevented the DEN induced hepatic injury and oxidative stress. In conclusion, it was observed that ELE of C. fistula Linn. protects the liver against DEN induced hepatic injury in rats.

Gene expression profile in the livers of rats orally administered ethinylestradiol for 28 days using a microarray technique

To identify genes showing responses to estrogen exposure in the livers of animals in a repeated oral dose toxicity study, dose-dependent gene expression profiles were analyzed using high-density oligonucleotide microarrays in Sprague-Dawley rats of both sexes administered ethinylestradiol (EE) for 28 days at concentrations of 0, 0.01, 0.1, and 1.0 ppm in the diet. Among 3776 genes examined, examples showing increased expression on EE-treatment were detected predominantly in females. Genes showing dose-dependent up-regulation with greater than five-fold change at 1.0 ppm from the control levels were found to, respectively, number 4 in males, and 24 in females. Most of the latter exhibited relatively high basal expression as well as low variability, and many exhibited clear dose-dependence. Genes showing dose-dependent down-regulation were rather few, and many of those affected exhibited relatively low expression levels with large variation between animals, like genes showing dose-unrelated expression patterns in both sexes or dose-dependent up-regulation in males. Considering that detection of changes in endocrine-linked organs and estrous cyclicity is only possible at the high dose of 1.0 ppm, up-regulation of genes dose-dependently in females provides a sensitive tool to detect estrogenic effects in the rat liver in the framework of the 28-day toxicity study.

Marked inhibition of testosterone biosynthesis by the hepatotoxin nodularin due to apoptosis of Leydig cells

We previously observed that the serum testosterone level was greatly reduced in the course of diethylnitrosamine-nodularin-induced hepatocarcinogenesis in Fischer 344 male rats (Lim et al., Gastroenterological Carcinogenesis, 1999). As an extension of this observation, this study was undertaken to investigate the molecular mechanism of downregulation of testosterone and its effect on target organs in Fischer 344 male rats treated with the hepatotoxin nodularin. After treating the rats with nodularin, a marked reduction of the testosterone level was noted in both serum and testis, with an accompanying accumulation of cholesterol in serum. Reduction of serum testosterone was not due to increased degradation of testosterone in the liver but to impaired biosynthesis in the testes, reduced activities of the cholesterol side chain cleavage enzyme and 17alpha-hydroxylase, and decreased expression of the steroidogenic acute regulatory protein gene, all of which constitute rate-limiting steps for testosterone biosynthesis in the testes. Intraperitoneal injection of nodularin into rats induced cuboidal changes of glandular epithelium in ventral prostates and apoptotic changes of spermatogonium, for example, nuclear chromatin condensation, shrinkage, and detachment from Sertoli cells, which included many lysosomal granules. Leydig cells also showed evidence of chromatin condensation and significant induction of peroxisome proliferation. In conclusion, the potential causes of impaired testosterone biosynthesis might have been apoptosis of Leydig cells induced by direct toxicity of the hepatotoxin on testes or hypothalamopituitary dysfunction.