N-acetylcysteine modulates redox imbalance and inflammation in macrophages and mice exposed to formaldehyde.

This study aimed to evaluate the protective role of N-acetylcysteine (NAC) in cells and mice exposed to formaldehyde. For the in vitro study, J774A.1 macrophages cells were incubated for 8, 16 and 24 h with formaldehyde or NAC to assess cell viability and reactive oxygen species (ROS). In the in vivo study, C57BL/6 mice (n = 48) were divided into 6 groups: control (CG), vehicle (VG) that received saline by orogastric gavage, a group exposed to formaldehyde 1% (FG) and formaldehyde exposed groups that received NAC at doses of 100, 150 and 200 mg/Kg (FN100, FN150 and FN200) for a period of 5 days. In vitro, formaldehyde promoted a decrease in cell viability and increased ROS, while NAC reduced formaldehyde-induced ROS production. Animals exposed to formaldehyde presented higher leukocyte counts in the blood and in the bronchoalveolar lavage fluid, and promoted secretion of inflammatory markers IL-6, IL-15, and IL-10. The exposure to formaldehyde also promoted redox imbalance and oxidative damage characterized by increased activities of superoxide dismutase, catalase, decreased GSH/GSSG ratio, as well as it increased levels of protein carbonyls and lipid peroxidation. NAC administration after formaldehyde exposure attenuated oxidative stress markers, secretion of inflammatory mediators and lung inflammation. In conclusion, both in in vitro and in vivo models, NAC administration exerted protective effects, which modulated the inflammatory response and redox imbalance, thus preventing the development airway injury induced by formaldehyde exposure.

Effects of a lycopene-layered double hydroxide composite administration in cells and lungs of adult mice.

Lycopene is a natural compound with one of the highest antioxidant activities. Its consumption is associated with lower risks in lung cancer and chronic obstructive pulmonary disease, for example. Experimentally, a murine model demonstrated the ingestion of lycopene, which reduced the damage in lungs caused by cigarette smoke. Since lycopene is highly hydrophobic, its formulations in supplements and preparations for laboratory assays are based on oils, additionally, bioavailavility is low. We developed a lycopene layered double hydroxide (Lyc-LDH) composite, which is capable of transporting lycopene aqueous media. Our objective was to evaluate the cytotoxicity of Lyc-LDH and the intra-cellular production of reactive oxygen species (ROS) in J774A.1 cells. Also, in vivo assays were conducted with 50 male C57BL/6 mice intranasally treated with Lyc-LDH 10 mg/kg (LG10), Lyc-LDH 25 mg/kg (LG25) and Lyc-LDH 50 mg/kg (LG50) during five days compared against a vehicle (VG) and control (CG) group. The blood, bronchoalveolar lavage fluid (BALF) and lung tissue were analyzed. The results revealed that Lyc-LDH composite attenuated intracellular ROS production stimulated with lipopolysacharide. In BALF, the highest doses of Lyc-LDH (LG25 and LG50) promoted influx of macrophages, lymphocytes, neutrophils and eosinophils compared to CG and VG. Also, LG50 increased the levels of IL-6 and IL-13, and promoted the redox imbalance in the pulmonary tissue. On the contrary, low concentrations did not produce significative effects. In conclusion, our results suggest that intranasal administration of high concentrations of Lyc-LDH induces inflammation as well as redox status changes in the lungs of healthy mice, however, results with low concentrations open a promising way to study LDH composites as vehicles for intranasal administration of antioxidant coadjuvants.

Effects in vitro and in vivo of hesperidin administration in an experimental model of acute lung inflammation.

Mechanical ventilation (MV) is a tool used in critical patient care. However, it can trigger inflammatory and oxidative processes capable of causing or aggravating lung injuries, which is known as ventilator-induced lung injury (VILI). Hesperidin is a flavonoid with antioxidant and anti-inflammatory properties in various diseases. The role of hesperidin in the process triggered by MV is poorly studied. Thus, we hypothesize hesperidin could protect the lung of mice submitted to mechanical ventilation. For that, we evaluated cell viability and reactive oxygen species (ROS) formation in macrophages using different hesperidin concentrations. We observed hesperidin did not reduce cell viability, however; it attenuated the production of intracellular ROS in cells stimulated with lipopolysaccharide (LPS). We further evaluated the effects of hesperidin in vivo in animals submitted to MV. In the bronchoalveolar lavage fluid, there were higher levels of macrophage, lymphocyte and neutrophil counts in animals submitted to MV, indicating an inflammatory process. In the lung tissue, MV induced oxidative damage and increased myeloperoxidase activity, though the antioxidant enzyme activity decreased. MV also induced the production of the inflammatory mediators CCL-2, TNF-α and IL-12. Pretreatment with hesperidin resulted in less recruitment of inflammatory cells to the airways and less oxidative damage. Also, it reduced the formation of CCL-2 and IL-12. Our results show pretreatment with hesperidin can protect the lungs of mice submitted to mechanical ventilation by modulating the inflammatory response and redox imbalance and may act to prevent MV injury.

Lasting effects of ketamine and isoflurane administration on anxiety- and panic-like behavioral responses in Wistar rats.

In clinical and laboratory practice, the use of anesthetics is essential in order to perform surgeries. Anesthetics, besides causing sedation and muscle relaxation, promote several physiological outcomes, such as psychotomimetic alterations, increased heart rate, and blood pressure. However, studies depicting the behavioral effect induced by ketamine and isoflurane are conflicting. In the present study, we assessed the behavioral effects precipitated by ketamine and isoflurane administration. We have also evaluated the ketamine effect on cell cytotoxicity and viability in an amygdalar neuronal primary cell culture. Ketamine (80 mg/kg) caused an anxiogenic effect in rats exposed to the elevated T-maze test (ETM) 2 and 7 days after ketamine administration. Ketamine (40 and 80 mg/kg) administration also decreased panic-like behavior in the ETM. In the light/dark test, ketamine had an anxiogenic effect. Isoflurane did not change animal behavior on the ETM. Neither ketamine nor isoflurane changed the spontaneous locomotor activity in the open field test. However, isoflurane-treated animals explored less frequently the OF central area seven days after treatment. Neither anesthetic caused oxidative damage in the liver. Ketamine also reduced cellular metabolism and led to neuronal death in amygdalar primary cell cultures. Thus, our work provides evidence that ketamine and isoflurane induce pronounced long lasting anxiety-related behaviors in male rats.

Association of electroanalytical and spectrophotometric methods to evaluate the antioxidant activity of isobenzofuranone in primary cultures of hippocampal neurons.

The isobenzofuran-1(3H)-ones (phthalides) exhibit various biological activities, including antioxidant activity on reactive oxygen species (ROS). An excess of ROS that cannot be naturally contained by cellular enzymatic systems is called redox imbalance, which damage cell membranes, proteins, and DNA, thereby possibly triggering neuronal death in several neurodegenerative diseases. Considering our ongoing efforts to find useful compounds to control redox imbalance, herein we evaluated the antioxidant activity of two phtalides (compounds 3 and 4), using primary cultures of hippocampal neurons. Spectrophotometric assays showed that compound 3 significantly reduced (p ≤ 0.05) ROS levels and lipid peroxidation compared to the control treatment, while compound 4 was unable at any of the tested concentrations. Despite their structural similarity, these compounds behave differently in the intracellular environment, which was reliably corroborated by the determination of oxidation potentials via cyclic voltammetry. It was demonstrated that compound 3 presents a lower oxidation potential. The combination of the mentioned methods allowed us to find a strong correlation between the chemical structure of compounds and their biological effects. Taking together, the results indicate that compound 3 presents desirable characteristics to act as a candidate pharmacological agent for use in the prevention and treatment of neurodegenerative diseases.

Neuroprotective Effect of Isobenzofuranones on Hydrogen Peroxide-Mediated Redox Imbalance in Primary Cultures of Hippocampal Neurons

Abstract In live organisms, there is a balance between the production of reactive oxygen species (ROS) and their neutralization. The increased level of these species leads to a condition called redox imbalance. The aim of this study was to evaluate the protective action of isobenzofuranones in primary cultures of hippocampal neurons subjected to redox imbalance. To accomplish this, MTT and LIVE/DEAD assays were initially performed. In the cultures pretreated with isobenzofuranones 1 and 2, there was a higher number of live cells when compared to that in the untreated ones. Regarding redox imbalance, there was a significant increase in the intracellular levels of ROS. The cultures pretreated with isobenzofuranones showed a reduction in ROS levels. Lipid peroxidation caused by oxidative damage was significantly reduced in the cultures pretreated with isobenzofuranones 1 and 2. Taken together, these data show the ability of isobenzofuranones 1 and 2 to significantly minimize cytotoxicity, cell death, intracellular levels of ROS and lipid peroxidation induced by redox imbalance. These results suggest that isobenzofuranones 1 and 2 represent a possible alternative therapy for the neurodegenerative disturbances that are triggered by ROS production increases.

Cloxacillin benzathine-loaded polymeric nanocapsules: Physicochemical characterization, cell uptake, and intramammary antimicrobial effect.

The present work shows the development and evaluation of the veterinary antibiotic cloxacillin benzathine (CLOXB) loaded into poly-ε-caprolactone (PCL) nanocapsules (NC), as a potential new treatment strategy to manage bovine intramammary infections, such as mastitis. Staphylococcus aureus-induced mastitis is often a recurrent disease due to the persistence of bacteria within infected cells. CLOXB-PCL NC were prepared by interfacial deposition of preformed biodegradable polymer followed by solvent displacement method. The mean diameter of NC varied from 241 to 428 nm and from 326 to 375 nm, when determined by dynamic light scattering and by atomic force microscopy, respectively. The zeta potential of NC was negative and varied from -28 to -51 mV. In vitro release studies from the NC were performed in two media under sink conditions: PBS with 1% polyethylene glycol or milk. A reversed-phase HPLC method was developed to determine the NC entrapment efficiency and kinetics of CLOXB release from the NC. Free CLOXB dissolution occurred very fast in both media, while drug release from the NC was slower and incomplete (below 50%) after 9 h. CLOXB release kinetics from polymeric NC was fitted with the Korsmeyer-Peppas model indicating that CLOXB release is governed by diffusion following Fick's law. The fluorescence confocal microscopy images of macrophage-like J774A.1 cells reveal NC uptake and internalization in vitro. In addition, antimicrobial effect of the intramammary administration of CLOXB-PCL NC in cows with mastitis resulted in no clinical signs of toxicity and allowed complete pathogen elimination after treatment. The in vivo results obtained in this work suggest that CLOXB-PCL NC could be a promising formulation for the treatment of intramammary infections in cattle, considering their physicochemical properties, release profiles and effects on bovine mastitis control.

Lycopene mitigates pulmonary emphysema induced by cigarette smoke in a murine model.

Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disease characterized by a non-fully reversible airflow limitation comprising chronic bronchitis and pulmonary emphysema both being induced by cigarette smoke (CS) exposure. Lycopene has shown antioxidant and anti-inflammatory properties that can prevent acute lung inflammation and emphysema. We hypothesized that administration with lycopene would repair lung damage in emphysema caused by CS exposure. Mice were administered with two different doses of lycopene (25 or 50 mg/kg/day, diluted in sunflower oil by orogastric gavage) and then exposed to 60 days of CS or not (CG). Lycopene promoted a reduction in the number of total leukocytes and it improved pulmonary emphysema. Lycopene was able to minimize redox processes by decreasing lipid peroxidation and DNA damage, and by having an increase in the activities of SOD, CAT and GSH content. Furthermore, it decreased levels of TNF-α, IFN-γ and IL-10. In addition, it was able to decrease MPO activity and nitrite content. In conclusion, our data elucidated the role of lycopene as an antioxidant and anti-inflammatory agent in mice exposed to CS.

Double immunofluorescence labeling for CD31 and CD105 as a marker for polyether polyurethane-induced angiogenesis in mice.

A crucial component of the integration between foreign implants and the host is angiogenesis. However, to date, none of the available techniques and/or endothelial markers employed to assess angiogenesis in the implant/host interface seems to be able to highlight vascular structures convincingly. In the present study we investigated and compared the expression of two endothelial cell markers: platelet endothelial cell adhesion molecule (PECAM-1) (CD31) and endoglin (CD105) using immunohistochemistry (IHC) and immunofluorescence (IF) to identify and quantify newly formed blood vessels in subcutaneous implants of polyether-polyurethane sponge of formalin-fixed paraffin-embedded tissue. At day 14 post implantation the discs of the synthetic matrix were removed and processed for histological and morphometric analysis. In IHC staining for CD31 antibody the number of vessels was 2.27±0.69 and 5.25±0.46 for CD105. In IF for CD31 the number of vessels was 15.36±1.295 and 10.54±0.8213 for CD105. The level of cross-reaction was lesser in IF images compared with IHC images. Co-localization of CD31/CD105 using confocal images showed positive correlation (Pearson's co-relation and Manders' equation). The double labeling for blood vessels using the IF technique for CD31/CD105 may be an important tool for evaluation of angiogenesis in biomaterial/host integration.

Mechanisms of interaction of biodegradable polyester nanocapsules with non-phagocytic cells.

The interaction of polymer nanocapsules (NC) prepared from four biodegradable polyesters with variable polymer hydrophobicity (PCL, PLA, PLGA and PLA-PEG) was investigated in the non-phagocytic Vero, Caco-2 and HepG2 cell lines. The NC, labeled with the highly lipophilic fluorescent indocarbocyanine dye DIL, had very similar sizes (approx. 140 nm) and negative zeta-potentials. Asymmetric flow field-flow fractionation evidenced NC colloidal stability and negligible transfer of the dye to serum proteins in the incubation medium. The cytotoxicity of the NC was evaluated via MTT assay over a large polymer concentration range (1-1000 µg/mL) and time of exposure (2, 24 and 48 h). The NC were safe in vitro up to a concentration of approx. 100 µg/mL or higher, depending on the cell line and nature of the polymer. Vero cells were more sensitive to the NC, in particular NC of the more hydrophobic polymer. The cells were exposed to endocytosis inhibitors, incubated with NC, and the cell-associated fluorescence was quantified by spectrofluorometry. HepG2 cells presented a 1.5-2-fold higher endocytic capacity than Caco-2 and Vero cells. The main mechanism of NC uptake was caveolin-mediated endocytosis in HepG2 and Vero cells, and macropinocytosis in Caco-2 cells. Polymer hydrophobicity had an effect on the level of NC associated to HepG2 cells and to a lesser extent on the endocytosis mechanisms in Vero and Caco-2 cells. The NC uptake levels and endocytosis mechanisms differed significantly between cell lines tested.

The antioxidant and anti-inflammatory properties of lycopene in mice lungs exposed to cigarette smoke.

Lycopene is a carotenoid with known antioxidant and anti-inflammatory properties. We aimed to evaluate the in vitro and in vivo effects of lycopene on reducing the redox imbalance and inflammation induced by cigarette smoke (CS). For the in vitro study, J774A.1 (macrophages) cells were incubated in the presence of 0.5, 1.0, 2.0, 4.0, 8.0, 10.0 and 25 µM of lycopene for 3, 6 and 24 h or in the presence of 0.1%, 0.25%, 0.5%, 0.625%, 1.25%, 2.25%, 5% and 10% cigarette smoke extract (CSE) for 3, 6 and 24 h to assess cell viability and measurement of intracellular reactive oxygen species (ROS). For the in vivo study, 40 mice were divided into 5 groups: a control exposed to ambient air (CG), a vehicle-control group that received 200 µl of sunflower oil by orogastric gavage, a group exposed to CS and two groups administered lycopene (diluted in sunflower oil) at doses of either 25 or 50 mg/kg/day prior to exposure to CS (LY25+CS and LY50+CS). The total treatment time lasted 5 days. A cell viability decrease was observed at 10- and 25-µM concentrations of lycopene in 3, 6 and 24 h compared with CG. There was an increase of ROS production in 24 h in CS compared with CG. Lycopene concentrations of 1 µM and 2 µM were able to reduce the production of ROS in 24 h compared with CS. In the bronchoalveolar lavage fluid, the total number of leukocytes increased in the CS group compared with the control groups (CG). Administration with lycopene at the highest dose suppressed this CS-induced increase in leukocytes. Lipid peroxidation and DNA damage increased in the CS group compared with that in the controls, and this increase was suppressed by lycopene at the highest dose. In contrast, superoxide dismutase activity decreased in the CS group compared with that in the controls. Catalase activity also increased in the CS group compared with that in both control groups, and this increase was suppressed in LY25+CS and LY50+CS. There was an increase in the levels of tumor necrosis factor-α, interferon-γ and interleukin-10 after exposure to CS, and these effects were suppressed by both doses of lycopene. These data elucidate the role of lycopene as an antioxidant and anti-inflammatory agent in these two models of short-term exposure to CS.

Evaluation of change in canine diagnosis protocol adopted by the visceral leishmaniasis control program in Brazil and a new proposal for diagnosis.

The techniques used for diagnosis of canine visceral leishmaniasis (CVL) in Brazil ELISA and IFAT have been extensively questioned because of the accuracy of these tests. A recent change in the diagnosis protocol excluded IFAT and included the Dual-Path Platform (DPP). We evaluated the prevalence and incidence rates of Leishmania spp. before and after the change in the protocol. In addition, based on our results, we propose a new alternative that is less expensive for the screening and confirmation of CVL. Plasma samples were obtained from a serobank from dogs evaluated in a cross-sectional study (1,226 dogs) and in a cohort study of susceptible animals (n = 447), followed for 26 months. Serology testing was performed using ELISA, IFAT, and DPP. The incidence and prevalence of CVL were determined by using the protocol of the Visceral Leishmaniasis Control and Surveillance Program until 2012 (ELISA and IFAT using filter paper) and the protocol used after 2012 (DPP and ELISA using plasma). The prevalence was 6.2% and the incidence was 2.8 per 1,000 dog-months for the protocol used until 2012. For the new diagnosis protocol for CVL resulted in an incidence of 5.4 per 1,000 dog-months and a prevalence of 8.1%. Our results showed that the prevalence and incidence of infection were far greater than suggested by the previously used protocol and that the magnitude of infection in endemic areas has been underestimated. As tests are performed sequentially and euthanasia of dogs is carried out when the serological results are positive in both tests, the sequence does not affect the number of animals to be eliminated by the Control Program. Then we suggest to municipalities with a large demand of exams to use ELISA for screening and DPP for confirmation, since this allows easier performance and reduced cost.