Changes in hepatic cytosolic glutathione S-transferase activity and expression of its class-P during prenatal and postnatal period in rats treated with aflatoxin B1

Feed contaminated by fumonisin (Fusarium spp.) in chicks has a negative influence on oxidative stress and performance, and the inclusion of curcumin-loaded nanocapsules minimizes these effects

The aim of this study was to determine whether the addition of curcumin (free and encapsulated) to chick feed would minimize the negative effects on health and performance caused by daily intake of fumonisin. We used 50 birds, divided into five treatments: CP, basal diet with 600 mg/kg of fumonisin, with antibiotic and coccidiostatic agent; CU, 600 mg/kg of fumonisin and 50 mg/kg of curcumin; NC5, feed with 600 mg/kg of fumonisin and 5 mg of nano-curcumin/kg of feed; NC10, feed with 600 mg/kg of fumonisin and 10 mg of nano-curcumin/kg of feed; and CN, fumonisin-free diet, with antibiotic and coccidiostatic. We measured weights, weight gain, and serum biochemistry, as well as antioxidant and oxidant activities. Lower body weight and weight gain were observed in chicks that received feed with fumonisin; curcumin did not minimize this negative effect. Lower glucose and triglyceride levels were also observed in the NC10 group, while the highest cholesterol levels were observed in all groups of birds that consumed fumonisin compared to the CN group. Uric acid levels were significantly lower in CP than in CN. Levels of liver enzymes were higher in CP than in CN. The highest levels of thiobarbituric acid reactive substances were found in CP and CU, whereas ROS was higher in CU compared to CN. Superoxide dismutase activity was significantly lower in CP, while glutathione S-transferase activity was higher in the CP group. Catalase activity was lower in groups of birds that consumed fumonisin compared to CN. Taken together, these findings suggest that intake of curcumin-loaded nanocapsules (10 mg/kg) had hepaprotective and antioxidant effects in chicks artificially intoxicated with fumonisin, minimizing the negative effects caused by this mycotoxin.

Epigenetic alterations caused by aflatoxin b1: a public health risk in the induction of hepatocellular carcinoma

Aflatoxin B1 (AFB1) is currently the most commonly studied mycotoxin due to its great toxicity, its distribution in a wide variety of foods such as grains and cereals and its involvement in the development of + (hepatocellular carcinoma; HCC). HCC is one of the main types of liver cancer, and has become a serious public health problem, due to its high incidence mainly in Southeast Asia and Africa. Studies show that AFB1 acts in synergy with other risk factors such as hepatitis B and C virus leading to the development of HCC through genetic and epigenetic modifications. The genetic modifications begin in the liver through the biomorphic AFB1, the AFB1-exo-8.9-Epoxy active, which interacts with DNA to form adducts of AFB1-DNA. These adducts induce mutation in codon 249, mediated by a transversion of G-T in the p53 tumor suppressor gene, causing HCC. Thus, this review provides an overview of the evidence for AFB1-induced epigenetic alterations and the potential mechanisms involved in the development of HCC, focusing on a critical analysis of the importance of severe legislation in the detection of aflatoxins.

Evaluation of turmeric (Curcuma longa) effect on biochemical and pathological parameters of liver and kidney in chicken aflatoxicosis

CONTEXT

Aflatoxins as potent mycotoxins can influence vital parameters in chickens. Turmeric was used in decreasing toxic effect of mycotoxins on vital organs, traditionally.

OBJECTIVE

The study compared the protective effect of turmeric and Mycoad(TR) in broilers exposed to aflatoxin.

MATERIALS AND METHODS

Chickens (270) were divided into six groups. The chickens were fed a basal diet, turmeric extract (5 mg/kg diet), Mycoad(TR) (25 mg/kg diet), productive aflatoxin (3 mg/kg diet), aflatoxin plus turmeric extract (3 versus 5 mg/kg diet), and aflatoxin plus Mycoad(TR) (3 versus 25 mg/kg diet) in basal diet. At 28 d old, we determined plasma concentration of total protein, albumin, triglyceride, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), calcium, potassium, phosphorous, uric acid, aspartate transferase (AST), and alanine aminotransferase (ALT). Furthermore, liver and kidney were sampled for pathological examination.

RESULTS

Chickens fed turmeric with aflatoxin had significant lower ALT, AST, and uric acid than chickens fed aflatoxin (11.4 ± 0.79, 228 ± 9, and 6 ± 0.4 versus 17.2 ± 1.7, 283 ± 5, and 7.7 ± 0.1) whereas, total protein, calcium, and HDL values in chickens fed aflatoxin plus turmeric increased significantly (2.66 ± 0.16, 8.4 ± 0.2, and 920 ± 4.1 versus 1.7 ± 0.17, 7 ± 0.2, and 690 ± 4.8). Pathological examination revealed severe congestion, degeneration, and necrosis in liver and kidney in chickens that received aflatoxin.

DISCUSSION AND CONCLUSION

The study showed that turmeric may provide protection against the toxic effects of aflatoxin on liver and kidney.

Sub-emetic toxicity of Bacillus cereus toxin cereulide on cultured human enterocyte-like Caco-2 cells

Cereulide (CER) intoxication occurs at relatively high doses of 8 µg/kg body weight. Recent research demonstrated a wide prevalence of low concentrations of CER in rice and pasta dishes. However, the impact of exposure to low doses of CER has not been studied before. In this research, we investigated the effect of low concentrations of CER on the behavior of intestinal cells using the Caco-2 cell line. The MTT (mitochondrial 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and the SRB (sulforhodamine B) reactions were used to measure the mitochondrial activity and cellular protein content, respectively. Both assays showed that differentiated Caco-2 cells were sensitive to low concentrations of CER (in a MTT reaction of 1 ng/mL after three days of treatment; in an SRB reaction of 0.125 ng/mL after three days of treatment). Cell counts revealed that cells were released from the differentiated monolayer at 0.5 ng/mL of CER. Additionally, 0.5 and 2 ng/mL of CER increased the lactate presence in the cell culture medium. Proteomic data showed that CER at a concentration of 1 ng/mL led to a significant decrease in energy managing and H2O2 detoxification proteins and to an increase in cell death markers. This is amongst the first reports to describe the influence of sub-emetic concentrations of CER on a differentiated intestinal monolayer model showing that low doses may induce an altered enterocyte metabolism and membrane integrity.

Meta-analytical study of productive and nutritional interactions of mycotoxins in growing pigs

A meta-analysis was carried out in order to study the association of mycotoxins with performance and organ weights in growing pigs. A total of 85 articles published between 1968 and 2010 were used, totaling 1012 treatments and 13 196 animals. The meta-analysis followed three sequential analyses: graphical, correlation and variance-covariance. The presence of mycotoxins in diets was seen to reduce the feed intake by 18% and the weight gain in 21% compared with the control group. Deoxynivalenol and aflatoxins were the mycotoxins with the greatest impact on the feed intake and growth of pigs, reducing by 26% and 16% in the feed intake and by 26% and 22% in the weight gain. The mycotoxin concentration in diets and the animal age at challenge were the variables that more improved the coefficient of determination in equations for estimating the effect of mycotoxins on weight gain. The mycotoxin effect on growth proved to be greater in younger animals. In addition, the residual analysis showed that the greater part of the variation in weight gain was explained by the variation in feed intake (87%). The protein and methionine levels in diets could influence the feed intake and the weight gain in challenged animals. The weight gain in challenged pigs showed a positive correlation with the methionine level in diets (0.68). The mycotoxin effect on growth was greater in males compared with the effect on females. The reduction in weight gain was of 15% in the female group and 19% in the male group. Mycotoxin presence in pig diets has interfered in the relative weight of the liver, the kidneys and the heart. Mycotoxins have an influence on performance and organ weight in pigs. However, the magnitude of the effects varies with the type and concentration of mycotoxin, sex and the animal age, as well as nutritional factors.

Safety evaluation of stem cells used for clinical cell therapy in chronic liver diseases; with emphasize on biochemical markers

There are several issues to be considered to reduce the risk of rejection and minimize side effects associated with liver cell transplantation in chronic liver diseases. The source and the condition of stem cell proliferation and differentiation ex vivo and the transplantation protocols are important safety considerations for cell based therapy. The biochemical and molecular markers are important tools for safety evaluation of different processes of cell expansion and transplantation. Studies show that hepatocytes differentiated from adult and embryonic stem cells exhibit biochemical and metabolic properties resembling mature hepatocytes. Therefore these assays can help to assess the biological and metabolic performance of hepatocytes and progenitor stem cells. The assays also help in testing the contribution of transplanted hepatocytes in improving the repair and function of damaged liver in the recipient. Here we review the biochemical and metabolic markers, which are implicated in evaluation of safety issues of stem cells used for therapeutic purposes in chronic liver diseases and regeneration of damaged liver. We also highlight application of biochemical tests for assessment of liver cell transplantation.

Meta-analytical study of productive and nutritional interactions of mycotoxins in broilers

A meta-analysis was carried out to study the association of mycotoxins with performance, productive indices, and organ weights in broilers. Ninety-eight papers published between 1980 and 2009 were used, totaling 1,401 diets and 37,371 animals. Meta-analysis followed 3 sequential analyses: graphical, correlation, and variance-covariance. The mycotoxin presence in diets reduced (P < 0.05) feed intake by 12% and weight gain by 14% compared with control group. Ochratoxins and aflatoxins were the mycotoxins with the greatest effect on feed intake and bird growth, reducing (P < 0.05) feed ingestion by 17 and 11%, respectively, and weight gain by 20 and 11%, respectively. The mycotoxin concentration in diets and the animal age at challenge were the variables that more improved the coefficient of determination for equations to estimate mycotoxin effect on weight gain. The mycotoxin effect on growth proved to be greater in young poultry. The residual analysis revealed that 65% of the variation in weight gain was explained by feed intake. The variation in weight gain of challenged broilers in relation to nonchallenged broilers was also influenced by ingestion of nutrients such as protein and methionine. Mortality was 8.8 and 2.8 times greater (P < 0.05) in groups that received diets with deoxynivalenol and aflatoxins, respectively. Mycotoxins also increased (P < 0.05) the relative weight of liver by 15%, of kidneys by 11%, of lungs by 9%, and of gizzard by 3%. Mycotoxins influenced broiler performance, productive indices, and organ weights. However, the magnitude of the effects varied with type and concentration of mycotoxin, animal age, and nutritional factors.

Sulforaphane-mediated reduction of aflatoxin B₁-N⁷-guanine in rat liver DNA: impacts of strain and sex

Aflatoxin B₁ (AFB₁) is a DNA-binding toxin that contributes to the burden of liver cancer in tropical areas. AFB₁-DNA adducts are powerful biomarkers that discern individual and population risk from exposure to this carcinogen. The discovery of concordance between the metabolic pathways of the male Fischer rat and humans allowed data from rats to guide the development of chemoprevention strategies employed in clinical trials in high-risk regions. In this study, the variables of strain and sex are studied in the rat model, as a step toward understanding how ethnic differences and sex influence DNA adduct formation and the induction of enzymes by chemoprotective agents. Sulforaphane (SF), which induces phase II enzymes including glutathione S-transferases (GSTs), was evaluated for its ability to induce GST activity and reduce the AFB₁-DNA adducts in livers of both sexes of two rat strains that differ in susceptibility to AFB₁ hepatocarcinogenesis. A dose-dependent relationship was found for SF for both induction of GST and reduction in of AFB₁-N⁷-guanine in both Fischer (sensitive to AFB₁) and Sprague-Dawley rats (relatively resistant). Sprague-Dawley rats exhibited the greatest increase in GST levels and the largest reduction in AFB₁-N⁷-guanine in liver DNA. Males and females of each strain were also compared to determine if the ability of SF to induce GST and reduce AFB₁-N⁷-guanine correlated with gender differences in sensitivity to AFB₁ carcinogenesis. No gender-specific responses to SF were observed. These results support the view that SF induction of liver GST activity may play a role in its chemoprotective activity.

Expression of placental glutathione S-transferase in rat tongue mucosa exposed to cigarette smoke

Glutatione S-transferases (GSTs) are a family of enzymes involved in detoxification of xenobiotics. Placental GST, known as GST-P, has been detected in tissues following exposure to carcinogenic agents being regarded a reliable biomarker of exposure and susceptibility in early phases of carcinogenesis. The aim of this study was to investigate the expressivity of GST-P positive foci in the rat tongue mucosa exposed to cigarette smoke by means of immunohistochemistry. A total of twelve male Wistar rats were distributed into two groups: negative control and experimental group exposed to cigarette smoke during 75 days. After experimental period, no histopathological changes in the tongue mucosa were evidenced in the negative control and the experimental group. However, a total of five GST-P positive foci were detected in two out of six animals exposed to cigarrette smoke. None control animals were noticed GST-P positive foci. These data indicate that expression of GST-P may reflect the carcinogenic effect of cigarette smoke as well as the genetic susceptibility of animals in relation to continuous carcinogens exposure.

Placental glutathione S-transferase correlates with cellular proliferation during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide

Taking into consideration that glutatione S-transferase (GST) and cellular proliferation play a crucial role during carcinogenesis, the goal of this study was to investigate the expression of placental GST, called GST-P, and proliferating cellular nuclear antigen (PCNA) by means of immunohistochemistry during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4NQO). This is a useful model for studying oral squamous cell carcinoma phase by phase. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution by drinking water for 4, 12 or 20 weeks. Ten animals were used as negative control. GST-P positive foci were detected in non-neoplastic oral cells at 4 weeks of 4NQO administration. In the same way, GST-P positive cells were detected in pre-neoplastic lesions and squamous cell carcinomas induced after 12 and 20 weeks-treatment, respectively. None of the control animals expressed GST-P positive cells. Regarding cellular proliferation, PCNA positive nuclei were higher at 12 and 20 weeks following 4NQO exposure (p<0.05) when compared to negative control. These results suggest that the expression of GST-P is correlated with cellular proliferation, in which GST-P is associated with risk and progression of oral cancer, whereas PCNA is closely involved during neoplastic conversion.