Early cytotoxic and genotoxic effects of atrazine on Wistar rat liver: A morphological, immunohistochemical, biochemical, and molecular study

Risk assessments suggest that intermediate and long-term exposure to triazine herbicides and its metabolites through water can cause severe damage to human health. The objective of this study was to investigate the possible effects of atrazine on Wistar rats submitted to subacute treatment. For this purpose, the activity of catalase and alanine aminotransferase was quantified, and the effect of the herbicide on cell membranes was examined based on the measurement of lipid peroxidation and consequent formation of malondialdehyde and on the mRNA expression of antioxidant enzymes (Mn-superoxide dismutase [SOD] and GSTM1) and connexins. In addition, we evaluated histopathological alterations in the liver, cellular expression of SOD and glutathione (GST), activation of heat shock proteins (HSPs) by immunohistochemistry, and the induction of apoptosis. The genotoxic potential of the herbicide was investigated by the micronucleus test in bone marrow smears. Adult male Wistar rats were treated with an aqueous solution of atrazine at a concentration of 400 mg/kg/day, by gavage, for 14 consecutive days. Control groups were also included. The results showed an increase of catalase levels and maintenance of the expression of antioxidant enzymes (SOD and GST). In addition, lipid peroxidation, hepatic tissue degeneration, activation of HSP90, increased levels of connexin mRNA, and genotoxicity were observed. In conclusion, atrazine induced early hepatic oxidative stress that triggered defense mechanisms to maintain the morphophysiological integrity of the liver. Further studies are needed to better understand the effects of this herbicide on human health. (C) 2011 Elsevier B.V. All rights reserved.

Biodisponibilidade de fontes orgânicas e inorgânicas de zinco em ovinos

This research was done to compare the effects of different zinc sources and doses in the Santa Ines sheep diet. Forty lambs at weaning, with 18,4kg BW were randomly allotted and fed 10 treatments: 1- base diet without zinc supplementation; 2- base diet + 200mg Zn/kg of DM as zinc oxide; 3- base diet + 400mg Zn/kg of DM as zinc oxide; 4- base diet + 600mg Zn/kg of DM as zinc oxide; 5- base diet + 200mg Zn/kg of DM as amino acid zinc; 6- base diet + 400mg Zn/kg of DM as amino acid zinc; 7- base diet + 600mg Zn/kg of DM as amino acid zinc; 8- base diet + 200mg Zn/kg of DM as proteinato zinc; 9- base diet + 400mg Zn/kg of DM as proteinato zinc; 10- base diet + 600mg Zn/kg of DM as proteinato zinc. The animals were weighed and sampled for blood zinc analysis, phosphatase alkaline analysis and immunoglobulins G and M analysis. At the end of the experiment liver samples were collected to study the zinc hepatic levels. There was no difference in phosphatase alkaline levels, hepatic zinc levels and weight gain (P>0,05) but differences (P<0,05) in plasmatic zinc levels and in IgG and IgM levels were observed. Based on liver tissue uptake, estimates of the zinc bioavailability, through the regression equations showed that the organic and inorganic sources of zinc did not differ.

Dehydromonocrotaline induces cyclosporine A-insensitive mitochondrial permeability transition/cytochrome c release

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aromatic antiepileptic drugs and mitochondrial toxicity: Effects on mitochondria isolated from rat liver

Idiosyncratic hepatotoxicity is a well-known complication associated with aromatic antiepileptic drugs (AAED), and it has been suggested to occur due to the accumulation of toxic arene oxide metabolites. Although there is clear evidence of the participation of an immune process, a direct toxic effect involving mitochondria dysfunction is also possible. The effects of AAED on mitochondrial function have not been studied yet. Therefore, we investigated, in vitro, the cytotoxic mechanism of carbamazepine (CB), phenytoin (PT) and phenobarbital (PB), unaltered and bioactivated, in the hepatic mitochondrial function. The murine hepatic microsomal system was used to produce the anticonvulsant metabolites. All the bioactivated drugs (CB-B, PB-B, PT-B) affected mitochondrial function causing decrease in state three respiration, RCR, ATP synthesis and membrane potential, increase in state four respiration as well as impairment of Ca(2+) uptake/release and inhibition of calcium-induced swelling. As an unaltered drug, only PB, was able to affect mitochondrial respiration (except state four respiration) ATP synthesis and membrane potential; however, Ca(2+) uptake/release as well as swelling induction were not affected. The potential to induce mitochondrial dysfunction was PT-B > PB-B > CB-B > PB. Results suggest the involvement of mitochondrial toxicity in the pathogenesis of AAED-induced hepatotoxicity. (C) 2008 Elsevier Ltd. All rights reserved.

Utilisation of bacterial (Rubrivivax gelatinosus) biomass for egg yolk pigmentation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of monocrotaline on energy metabolism in the rat liver

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In Vitro Evaluation of the Genotoxic Activity and Apoptosis Induction of the Extracts of Roots and Leaves from the Medicinal Plant Coccoloba mollis (Polygonaceae)

Coccoloba mollis (Family Polygonaceae) is a medicinal plant popularly used in cases of memory loss, stress, insomnia, anemia, impaired vision, and sexual impotence, but the scientific literature, to date, lacks studies on the biological effects of this species, particularly with regard to cytotoxicity and induction of DNA damage. The aim of the present study was to assess in vitro (in hepatic HTC cells) ethanolic extracts of the roots and leaves of C. mollis for cytotoxicity, genotoxicity, and induction of apoptosis. For these evaluations the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay, comet assay, micronucleus test with cytokinesis block, and an in situ test for detection of apoptotic cells with acridine orange staining were used. The results showed that the extract obtained from the roots of C. mollis is more cytotoxic than that obtained from the leaves and that the reduction in cell viability observed in the MTT assay was a result, at least in part, from the induction of apoptosis. Both extracts induced DNA damage at a concentration of 20 mu g/mL in the comet assay, but no genotoxicity was detected with any of the treatments carried out in the micronucleus test.

Functional and Structural Adaptations in the Pancreatic alpha-Cell and Changes in Glucagon Signaling During Protein Malnutrition

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morfologia do figado da paca (Cuniculus Paca, Linnaeus 1766)

The elements related to the morphology of the liver of paca (Cuniculus paca), the second largest rodent of the Brazilian fauna, were observed; this species present zootechnical potential. Eight animals from the animals sector of Faculdade de Ciencias Agrarias e Veterinarias - Campus of Jaboticabal - UNESP, which is duly certified by IBAMA as an experimental breeding institute, were used. Through a dissection procedure, it was found that the liver of the paca is located in the cranial portion of the abdomen, immediately after the diaphragm, to which it is connected by the triangular, coronary, and falciform ligaments, having its bigger part located right to the medium plan. The liver of this rodent presents the following lobation: right lateral lobe, right medial lobe, quadrate lobe, left medial lobe, and left lateral lobe, besides the caudate lobe formed by the papillary process of caudate lobe and the caudate process of caudate lobe. Gallbladder is located between the quadrate and right medial lobes. Fragments of this organ were collected, fixed, and histologically prepared, being the samples analyzed through light microscopy. It was microscopically observed that intralobular connective tissue is scarce, basically it consists polyhedral hepatocytes organized into cords interposed between sinusoids and the portal triads are found in the lobe, consisting of the portal vein, hepatic artery, and biliary duct.

Efeitos do pentobarbital sódico e do enfluorano sobre a circulação sanguínea hepática: fluxometria eletromagnética e manometria (estudo experimental no cão)

In 18 dogs, previously anesthetized with sodium pentobarbital for the surgical preparation, catheterism and monitoring, the action of sodium pentobarbital (7.5 mg/kg) and enflurane (1.5 - 2%) in the liver circulation was studied. Measurements of the following parameters were made in four different times, before and 15, 30 and 60 min after the drug administration. By direct determination: hepatic artery flow, portal vein flow, mean pressure of the abdominal aorta, peripheral arterial pressure (mean), pressure in the caudal cava vein, portal pressure; and by indirect determination: total flow, arterial-cava gradient, portal-cava gradient, resistance in the hepatic artery territory, resistance in the territory of the portal vein, and total resistance. Based on the results, it is concluded that in the experiment's conditions: sodium pentobarbital doesn't change significantly the hepatic circulation, and enflurance produces a fall in the total hepatic flow, by reducing the portal flow, without alterations of the hepatic arterial flow. It diminishes the total hepatic resistance by diminishing the arterial resistance without alterations of the portal resistance; it diminishes the arterial-cava gradient in consequence of the reduction of the abdominal aorta pressure and of the portal pressure, but it seems that the caudal cava pressure is not altered. It also occurs a fall in the peripheral mean pressure.

Estudo das alterações eletrocorticográficas na insuficiência hepática aguda experimental.

The aim of this study was to test the application and value of electrocorticography (ECG) in the early diagnosis and characterization of electrocorticograms changes on experimental fulminant hepatic failure (FHF). Our material was composed of two groups of guinea pigs: a) ethanolamine group--42 animals with FHF induced by intrabiliary injection of 2.5 ml of monoethanolamine oleate; b) control group--10 animals submitted to intrabiliary injection of 2.5 ml of saline. Electrocorticograms recordings were taken in both groups with the electrodes implanted on the parieto-occipital regions of the skull. The hepatic failure was characterized by clinical manifestations, serum biochemical tests and histopathological findings. In the early hepatic coma the electrocorticograms could not be unequivocally distinguished from normal pattern, and alpha rhythm was recognizable in most animals. With further deterioration of the clinical condition the tracing showed progressive slowness of the normal rhythm, increased voltage and triphasic waves followed by suppression of electrical activity preceding the animal death. The electrocorticography was not suitable for the early diagnosis of hepatic coma, since the ECG alterations became evident only in overt coma. However the method could be useful for the characterization of cerebral disorders and the study of the pathogenesis of fulminant hepatic failure.

Liver response to low-hexachlorobenzene exposure in protein- or energy-restricted rats

The individual effects of protein deficiency and energy restriction on liver response to low-hexachlorobenzene (HCB) exposure were investigated in adult male Wistar rats. In rats fed either the low-protein or control diet, the only effect caused by HCB was a decrease in paralysis time following an ip injection of zoxazolamine. This decrease was similar for both groups. In the animals subjected to energy restriction, HCB induced a greater decrease in paralysis time, an increase in the size of centrilobular hepatocytes, a lower liver DNA content and an increased concentration of HCB in the adipose tissue, compared with the control and protein-deficient groups. Our data suggest that energy restriction increases liver response to HCB, while protein deficiency does not impair the hepatic reaction to small doses of HCB exposure.

Reação metabólica à infecção no hospedeiro.

At the site of local reaction to infection the interleukin-1 (1L-1) is released signaling to distant tissues the presence of infection and attempting to strengthen the host's defenses and inhibit the bacterial growth. This phenomenon is accompanied by anorexia and fever. The muscle-protein breakdown is sustained and the released amino acids are taken up by the liver and other RE structures where they are used as substrates for energy and for synthesis of defense-related proteins. The metabolic adaptations to sepsis include hyperthermia, increased synthesis of hepatic globulins, development of granulopoiesis and neutrophilia and redistribution of serum iron and trace minerals.

Litíase intrahepática primária. Relato de caso e revisão da literatura.

Primary intrahepatic lithiasis is an entity defined by intrahepatic stones exclusively located in the IH ducts above the emergence of the common bile duct. The disease is classified in two types: Eastern type (stones formed primarily in intrahepatic ducts; frequent in Japan) and Western type (stones formed in the extrahepatic bile system, usually in gallbladder, which migrate up to the intra-hepatic ducts). The mechanisms of lithogenesis in the entity are as yet not fully understood; multiple factors seem to operate synergistically: anatomical changes of the intrahepatic ducts, metabolic disorders, infections, idiopathic alteration. All these factors may facilitate biliary stasis leading ultimately to stone formation. We report on a case of and review the literature on primary intrahepatic lithiasis, which is a rare occurrence in the West and a disease of difficult surgical approach and high mortality.