Tebuconazole-induced toxicity and the protective effect of Ficus carica extract in Neotropical fruit-eating bats.

Tebuconazole (TEB) is a triazole fungicide widely used in agriculture known to cause metabolic and endocrine disorders in mammals. Several plant extracts have shown to be beneficial against pesticide effects due to their hepatoprotective, antioxidant and anti-inflammatory properties. As fruit bats play a critical role in rainforest regeneration and are constantly exposed to pesticides, we aimed at evaluating TEB-induced toxicity and the possible protective effect of the Ficus carica plant extract in Neotropical fruit-eating bats (Artibeus lituratus). Bats were captured and assigned to 4 experimental groups, offered: 1) CTL (n = 6): papaya; 2) DMSO (n = 6): papaya treated with 1.25% dimethyl sulfoxide (DMSO); 3) TEB (n = 6): papaya treated with tebuconazole (commercial formulation) 0.1%; and 4) TEBFC (n = 6): papaya treated with tebuconazole 0.1% and Ficus carica extract (20%) in DMSO (1.25%). After seven days of exposure, TEB bats showed increased lipid peroxidation, increased superoxide dismutase (SOD) and catalase (CAT) activities, vascular congestion and inflammatory infiltrate in the liver, and increased serum transaminase enzyme activities. We found the same alterations in oxidative stress parameters in the breast muscles of TEB-exposed bats. In the testes, all oxidative stress markers were increased in TEB bats and corroborate findings of histopathological and increased serum testosterone levels observed following TEB exposure. The co-administration of the fungicide with the F. carica plant extract attenuated most oxidative stress markers in exposed bats' liver and testes and decreased liver damage, but failed to revert the steroid imbalance caused by the fungicide exposure.

Effects of subchronic exposure to environmentally relevant concentrations of the herbicide atrazine in the Neotropical fish Astyanax altiparanae.

Atrazine (ATZ) is among the most widely used herbicides in the world, and yet it has a potential to contaminate aquatic environments due to pesticide leaching from agricultural areas. In the Neotropical region, studies about the effects of this herbicide in native aquatic wildlife is scarce.Our study aimed at investigating the effects of a 30-day exposure to a commercial atrazine formulation on oxidative stress parameters, histopathology in testis and liver, and hormone levels in males and female of yellow-tailed tetra fish (Astyanax altiparanae). Adults were exposed to low but environmentally relevant concentrations of atrazine as follows: 0 (CTL-control), 0.5 (ATZ0.5), 1 (ATZ1), 2 (ATZ2) and 10 (ATZ10) µg/L. Our results showed decreased GST activity in gills in all groups of exposed animals and increased CAT activity in gills from the ATZ10 group. In the liver, there was an increase in lipid peroxidation in fish from ATZ1 and ATZ2 groups. Histological analysis of the liver showed increased percentage of sinusoid capillaries in ATZ2 fish, increased vascular congestion in ATZ1 and increased leukocyte infiltration in the ATZ10 group. Hepatocyte diameter analysis revealed a decrease in cell size in all groups exposed to ATZ, and a decrease in hepatocyte nucleus diameter in ATZ1, ATZ2 and ATZ10 groups. Endocrine parameters did not show significant changes following ATZ exposure, although an increase of triiodothyronine/thyroxine (T3/T4) ratio was observed in ATZ2 fish. Our results provide evidence that even low, environmentally relevant concentrations of ATZ produced oxidative damage and histological alterations in adult yellow-tailed tetra.

"Fearing the enemy": Growth and stress biomarker responses of sexually reversed Oreochromis niloticus in the presence of aquatic predatory insects.

Fishes can change their physiological responses when threatened by the presence of predators. Such physiological plasticity, however, usually implies costs that may impede organismal development and reproduction and reduce the ability to cope with other biotic and abiotic stresses. Here, we evaluated the growth and stress biomarker responses in sexually reversed Nile tilapia, Oreochromis niloticus, fingerlings indirectly threatened by the presence of the aquatic insect predator Belostoma anurum (Hemiptera: Belostomatidae). We also evaluated whether the presence of B. anurum would affect growth in fingerlings that received food containing the masculinizing hormone 17 α-methyltestosterone. The antioxidant responses were evaluated by measuring the activity of enzymes (e.g., superoxide dismutase, catalase, and glutathione-S-transferase). Oxidative stress biomarkers (e.g., malondialdehyde and nitric oxide) and blood glucose and lactate responses were also evaluated. Our results revealed that predator exposure did not affect growth in O. niloticus fingerlings reared in the presence or absence of the masculinizing hormone. However, sexually reversed tilapia fingerlings significantly increased not only the glucose and lactate blood levels, but also exhibited increased activities of superoxide dismutase and glutathione-S-transferases enzymes when threatened by the presence of B. anurum nymphs. Collectively, our findings indicate that despite not exhibiting reduced growth performance, sexually reversed tilapia fingerlings were physiologically stressed by the presence of the predator, which may reduce their ability to face environmental and abiotic stresses.

Intestinal and liver morphometry of the Yellow Tail Tetra (Astyanax altiparanae) fed with oregano oil.

This study aimed to evaluate the effect of oregano oil on the intestinal and liver morphometry of yellow tail tetra, Astyanax altiparanae. Fish (1.46 ± 0.09 g) were kept in a 60-L aquaria, at a stocking density of 0.5 fi sh L-1. Six diets containing varying amounts of oregano oil were evaluated (0.0; 0.5; 1.0; 1.5; 2.0 and 2.5 g of oregano oil kg-1). At the end of 90 days, the fi sh were euthanised. Four intestines and four livers were collected per treatment, which were fi xed in Bouin and embedded in resin. For height and width folds, the absorption surface area and thickness of the muscular layer a positive linear effect of oregano oil was observed. A decrescent linear effect on the total number of goblet cells was also observed. For the cytoplasmic percentage of hepatocytes and liver glycogen, a positive linear effect of oregano oil was observed. There was a decreasing linear effect on the percentage of nuclei in the hepatocytes and capillaries. Thus, the oregano essential oil promotes increased absorption areas, modulates the amount of goblet cells involved in protecting the intestinal mucosa and promotes cytoplasmic increase with greater deposition of liver glycogen in yellow tail tetra.

Modulation of oxidative and inflammatory cardiac response by nonselective 1- and 2-cyclooxygenase inhibitor and benznidazole in mice.

OBJECTIVES: This study investigated the combined effects of benznidazole (BZ) and ibuprofen (IB) on the oxidative and inflammatory status of the cardiac tissue in vivo. METHODS: Swiss mice were randomized in groups receiving BZ (100 mg/kg) and IB (400 mg/kg) alone or combined (BZ + IB 200 or 400 mg/kg). Control animals were concurrently treated with 1% carboxymethyl cellulose. All treatments were administered orally for 7 days. KEY FINDINGS: BZ treatment increased cardiac production of nitrogen/oxygen-reactive species, malondialdeyde, carbonyl proteins, prostaglandins as well as the activities of catalase, superoxide dismutase and glutathione peroxidase. These parameters were attenuated by IB, with the best results at higher dose. Individually, BZ and IB significantly reduced the tissue levels of chemokine ligand 2, tumour necrosis factor-α and IL-10, but no reduction was observed when the treatments were combined. CONCLUSIONS: BZ triggers an oxidative and nitrosative route, which is associated with increased prostaglandin synthesis and marked damages to the lipids and proteins of the cardiac tissue. IB treatment attenuated reactive stresses triggered by BZ, which was an independent effects of this drug on the endogenous antioxidant enzymes. Individually, but not together, BZ and IB reduced the cardiac inflammatory status, indicating a beneficial and complex drug interaction.

Trypanosoma cruzi infection and benznidazole therapy independently stimulate oxidative status and structural pathological remodeling of the liver tissue in mice.

This study used a murine model of Chagas disease to investigate the isolated and combined impact of Trypanosoma cruzi infection and benznidazole (BZ) therapy on liver structure and function. Male C57BL/6 mice were challenged with T. cruzi and BZ for 15 days. Serum levels of cytokines and hepatic enzymes, liver oxidative stress, morphology, collagen, and glycogen content were monitored. Separately, T. cruzi infection and BZ treatment resulted in a pro-oxidant status and hepatic reactive damage. Concurrently, both T. cruzi infection and BZ treatment induced upregulation of antioxidant enzymes and pathological reorganization of the liver parenchyma and stroma. T. cruzi infection increased serum levels of Th1 cytokines, which were reduced by BZ in both infected and non-infected animals. BZ also induced functional organ damage, increasing serum levels of liver enzymes. When combined, T. cruzi infection and BZ therapy elicited intense hepatic reactive damage that was not compensated by antioxidant enzymatic reaction, subsequently culminating in more severe morphofunctional hepatic injury. Taken together, these findings indicate that during specific treatment of Chagas disease, hepatic pathology may be a result of an interaction between BZ metabolism and specific mechanisms activated during the natural course of T. cruzi infection, rather than an isolated toxic effect of BZ on liver structure and function.