Emotional-Single Prolonged Stress: A promising model to illustrate the gut-brain interaction.

Excessive stress can precipitate depression and anxiety diseases, and damage gastrointestinal functionality and microbiota changes, favoring the development of functional gastrointestinal disorders (FGIDs) - defined by dysregulation in the brain-gut interaction. Therefore, the present study investigated if Emotional-Single Prolonged Stress (E-SPS) induces depressive/anxiety-like phenotype and gut dysfunction in adult Swiss male mice. For this, mice of the E-SPS group were subjected to three stressors sequential exposure: immobilization, swimming, and odor of the predator for 7 days (incubation period). Next, animals performed behavior tests and 24 h later, samples of feces, blood, and colon tissue were collected. E-SPS increased the plasma corticosterone levels, immobility time in the tail suspension and forced swim test, decreased the grooming time in the splash test, OAT%, and OAE% in the elevated plus-maze test, as well as increased anxiety index. Mice of E-SPS had increased % of intestinal transit rate, % of fecal moisture content, and fecal pellets number, and decreased Claudin1 content in the colon. E-SPS decreased the relative abundance of Bacteroidetes phylum, Bacteroidia class, Bacteroidales order, Muribaculaceae and Porphyromonadaceae family, Muribaculum, and Duncaniella genus. However, E-SPS increased Firmicutes and Actinobacteria phylum, Coriobacteriales order, and the ratio of Firmicutes/Bacteroidetes, and demonstrated Mucispirillum genus presence. The present study showed that E-SPS induced depressive/anxiety-like phenotype, predominant diarrhea gut dysfunction, and modulated the gut bacterial microbiota profile in male adult Swiss mice. E-SPS might be a promising model for future studies on the brain-gut interaction and the development of FGIDs with psychological comorbidities.

p-Chloro-diphenyl diselenide modulates Nrf2/Keap1 signaling and counteracts renal oxidative stress in mice exposed to repeated dexamethasone administrations.

Dexamethasone is a synthetic glucocorticoid that has been associated with oxidative stress in central and peripheral tissues. p-Chloro-diphenyl diselenide ((p-ClPhSe)2) is an antioxidant organoselenium compound. The present study evaluated whether nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap-1) signaling contributes to the (p-ClPhSe)2 antioxidant effects in the kidney of mice exposed to dexamethasone. Adult Swiss mice received dexamethasone (intraperitoneal) at a dose of 2 mg/kg or its vehicle for 21 days. After that, mice were treated with (p-ClPhSe)2 (intragastric) (1, 5, or 10 mg/kg) for 7 days. Samples of kidneys were collected for biochemical assays. (p-ClPhSe)2 at a dose of 1 mg/kg reversed the renal reactive oxygen species (ROS) and carbonyl protein (CP) levels increased by dexamethasone. (p-ClPhSe)2 at doses of 5 and 10 mg/kg was effective against the increase of thiobarbituric acid reactive substances, ROS, and CP, as well as the decrease of δ-aminolevulinic acid dehydratase activity and nonprotein sulfhydryl levels induced by dexamethasone. At 5 mg/kg, (p-ClPhSe)2 reduced the renal levels of 4-OH-2-HNE and heme oxygenase (HO-1), as well as modulated the Nrf2/Keap-1 signaling in mice exposed to dexamethasone. The present findings revealed that (p-ClPhSe)2 antioxidant effects were associated with the modulation of Nrf2/Keap-1 signaling pathway in the kidney of mice exposed to dexamethasone.

Contribution of Opioid and Nitrergic Systems to m-Trifluoromethyl diphenyl Diselenide Attenuates Morphine-Induced Tolerance in Mice.

m-Trifluoromethyl diphenyl diselenide (TFDD) has antinociceptive and antidepressant-like properties and attenuates morphine withdrawal signs in mice. This study investigated if TFDD affects the development of morphine tolerance to its antinociceptive and antidepressant-like effects in mice. We also investigated whether TFDD modulates signaling pathways related to morphine tolerance, including the opioid receptors and some parameters of the nitrergic system. Male adult Swiss mice received morphine alone (5 mg/kg, subcutaneous) and in combination with TFDD (10 mg/kg, intragastric) for 7 days. Mice were subjected to hot plate and forced swim tests on days 1, 3, 5, and 7 of the experimental protocol. Repeated TFDD administrations avoided tolerance development mediated by morphine, including its antinociceptive and antidepressant-like effects. A single morphine dose increased MOR and NOx but decreased iNOS contents in the mouse cerebral cortex. In turn, single morphine and TFDD co-administration restored the MOR and iNOS protein levels. On the other hand, morphine repeated doses enhanced DOR and reduced MOR and NOx contents, whereas the morphine and TFDD association reestablished DOR and NOx levels in the mouse cerebral cortex. In conclusion, some opioid and nitrergic system parameters might contribute to TFDD attenuation of antinociceptive and antidepressant-like tolerance induced by morphine in mice.

4,4'-Dichloro-diphenyl diselenide modulated oxidative stress that differently affected peripheral tissues in streptozotocin-exposed mice.

Streptozotocin (STZ) is a substance used experimentally to induce a diabetes model, a metabolic disease associated with oxidative tissue damage. This study evaluated if 4-4'-dichloro-diphenyl diselenide (p-ClPhSe)2 modulates oxidative stress in peripheral tissues of diabetic mice. Male Swiss mice received a single STZ injection (i.p.) at a dose of 200 mg/kg or its vehicle and were treated with (p-ClPhSe)2 (7 days, 5 mg/kg) or metformin (200 mg/kg, twice per day). After, the mice were euthanized to collect liver, kidney, and skeletal muscle samples. In the liver, (p-ClPhSe)2 reduced thiobarbituric acid reactive substances (TBARS) and protein carbonyl levels and normalized the superoxide dismutase activity in STZ-treated mice. In the kidney, (p-ClPhSe)2 reversed the increase in the reactive species levels but not the catalase (CAT) activity reduction in STZ-treated mice. There was no evidence of oxidative damage in the skeletal muscle of STZ-treated mice, but an increase in the CAT activity and a reduction in non-protein thiol levels were found. (p-ClPhSe)2 did not reverse a decrease in hepatic and renal δ-aminolevulinic acid dehydratase activity in STZ-treated mice. The results show that the liver and kidney of STZ-treated mice were more susceptible to oxidative stress. This study reveals that (p-ClPhSe)2 modulated oxidative stress, which differently affected peripheral tissues of diabetic mice.

Similar hepatoprotective effectiveness of Diphenyl diselenide and Ebselen against cisplatin-induced disruption of metabolic homeostasis and redox balance in juvenile rats.

Cisplatin is an antineoplastic drug well recognized for its success in the battle against several types of cancer in adult, juvenile, and child populations. Meanwhile, this drug is also famous due to its serious side effects, such as hepatotoxicity. This study evaluated the hepatoprotective effectiveness of Diphenyl Diselenide (PhSe)2 and Ebselen in a model of cisplatin-induced toxicity in juvenile rats. Juvenile Wistar rats received a single intraperitoneal (i.p) injection of cisplatin (6 mg/kg) or saline solution, at postnatal day (PND) 21. Ebselen (11 mg/kg) or (PhSe)2 (12 mg/kg) was intragastrically (i.g) administered in rats from PND 21 to PND 25. At PND 26, the blood and liver were collected for the biochemistry assays. A single administration of cisplatin was enough to alter the makers of hepatic function (an increase of AST activity) and the blood lipid profile (an increase of cholesterol and triglycerides, TG). The cisplatin-induced metabolic disruption was demonstrated by the increase of hepatic glycogen and TG contents and hexokinase, glucose-6-phosphatase, and tyrosine aminotransferase activities; a decrease of citrate synthase activity and the levels of GLUT-2. Cisplatin-induced hepatic oxidative stress was characterized by an increase in reactive oxygen species, TBARS, protein carbonyl, and Nox levels as well as the decrease in NPSH levels. Ebselen and (PhSe)2 were effective against all alterations caused by this chemotherapy medication. The present findings highlight the (PhSe)2 and Ebselen similar hepatoprotective effectiveness against cisplatin-induced disruption of metabolic homeostasis and redox balance in juvenile rats.

Keap1/Nrf2/HO-1 signaling pathway contributes to p-chlorodiphenyl diselenide antidepressant-like action in diabetic mice.

RATIONALE: The association between depression and diabetes has been recognized for many years, but the nature of this relationship remains uncertain. OBJECTIVES: This study investigated the antidepressant-like effect of (p-ClPhSe)2 on mice made diabetic by streptozotocin (STZ) and the contribution of cerebral cortical Keap1/Nrf2/HO-1 signaling pathway for this effect. METHODS: Male adult Swiss mice received streptozotocin (STZ, 200 mg/kg, i.p.) to induce diabetes (glycemia ≥ 200 mg/dl) or citrate buffer (5 ml/kg, control group). The mice were treated with (p-ClPhSe)2 at the dose of 5 mg/kg, i.g., for 7 days. Mice performed behavior tests, tail suspension (TST), and forced swimming tests (FST), to evaluate depressive-like phenotype. RESULTS: Diabetic mice showed an increase in immobility time in the TST and FST when compared to the control group. The protein contents of Keap1/Nrf2/HO-1 pathway were decreased in the cerebral cortex of diabetic mice. Diabetic mice had an increase in the relative adrenal weight and a decrease in the protein content of glucocorticoid receptor. The levels of TBARS and RS and SOD activity were found altered in the cerebral cortex of diabetic mice. The number of FJC-positive cells was increased in the cerebral cortex of diabetic mice. Treatment with (p-ClPhSe)2 was effective against depressive-like phenotype, oxidative stress, and FJC-positive cells of diabetic mice. (p-ClPhSe)2 did not reverse the parameters of HPA axis evaluated in this study. (p-ClPhSe)2 modulated the cerebral cortical Keap1/Nrf2/HO-1 pathway in diabetic mice. CONCLUSIONS: This study demonstrates the contribution of cerebral cortical Keap1/Nrf2/HO-1 pathway in the (p-ClPhSe)2 antidepressant-like action in diabetic mice.

(p-ClPhSe)2 modulates hippocampal BDNF/TrkB signaling and reverses memory impairment induced by diabetes in mice.

Diabetes is a metabolic disease characterized by hyperglycemia because of insulin resistance and/or insufficient insulin release. The most common diabetic brain complications include cognitive decline and depression. The present study investigated whether the 4-4'-dichlorodiphenyl diselenide (p-ClPhSe)2 is effective against memory impairment induced by diabetes in mice and the role of hippocampal BDNF/TrkB signaling in this effect. Male adult Swiss mice received an injection of streptozotocin (STZ) (200 mg/kg, i.p.) to induce diabetes. The results revealed that STZ injection in mice resulted in resilience (glycemia <200 mg/dl) or diabetes (glycemia ≥200 mg/dl). The vehicle-control group received citrate buffer (5 ml/kg). The animals were subchronically treated with (p-ClPhSe)2 (1 or 5 mg/kg, i.g.) for 7 days. Mice performed a battery of well-validated behavior tests designated to evaluate memory, object recognition (ORT), object location (OLT), and Morris water maze (MWM). The hippocampal protein contents of the BDNF/TrkB pathway were determined in the samples of experimental groups. Fluoro Jade C (FJC) was used for staining degenerating neurons. The STZ administration resulted in memory impairment that was demonstrated in the mouse ORT, OLT, and MWM tests. The molecular findings indicate an increase in hippocampal protein levels of proBDNF and TrKB but a decrease in those of mBDNF and pCREB in diabetic mice. The number of FJC-positive cells was increased in the hippocampus of diabetic mice. (p-ClPhSe)2 at the dose of 5 mg/kg modulated the hippocampal BDNF/TrkB pathway, reduced FJC-positive cells and reversed memory impairment induced by STZ in mice. These findings demonstrate the effectiveness of (p-ClPhSe)2 against memory impairment caused by diabetes in mice. (p-ClPhSe)2 modulated the hippocampal BDNF/TrkB signaling pathway in diabetic mice.

Pain-depression dyad induced by reserpine is relieved by p,p'-methoxyl-diphenyl diselenide in rats.

Depression and pain comorbidity represent a neuropsychiatric condition with substantial socioeconomic impact to society. The commonly used antidepressants and analgesics to treat this comorbidity have shown restricted clinical efficacy. In this way, the aim of this study was to investigate the behavioral, biochemical and neurochemical effects of a p,p'-methoxyl-diphenyl diselenide (OMePhSe)2 supplemented diet on pain-depression dyad induced by reserpine in rats. Adult Wistar rats were fed with 10mg (MeOPhSe)2 per kg of rat chow supplemented diet for 30 days. Pain-depression dyad was induced by daily subcutaneous reserpine injection (0.5mg/kg for three consecutive days) from 22 to 24 day of (MeOPhSe)2 supplementation. The results showed that the reserpine injected rats had behavior phenotypes typical of depression-pain dyad and the (MeOPhSe)2-supplemented diet protected against these modifications. Furthermore, the (MeOPhSe)2 dietary supplementation was effective against the increase in the prefrontal cortical MDA levels caused by reserpine. (MeOPhSe)2-supplemented diet triggered a per se augmentation of Nrf-2 levels. The [3H] serotonin uptake, [3H] glutamate uptake and release and MAO activity were not altered in the prefrontal cortices of rats from any experimental group. Therefore, the results indicate that protective effects of a (MeOPhSe)2-supplemented diet can be mediated, at least in part, by its antioxidant property.

p-Chloro-diphenyl diselenide reverses memory impairment-related to stress caused by corticosterone and modulates hippocampal [(3)H]glutamate uptake in mice.

Chronic stress or chronically high levels of glucocorticoids can result in memory impairment. This study aimed to investigate if 4,4'-dichloro-diphenyl diselenide (p-ClPhSe)2 reverses memory impairment-related to stress caused by corticosterone administration in mice and its possible mechanism of action. Swiss mice received corticosterone (20µg/ml) in their drinking water during four weeks. In the last week, the animals were treated with (p-ClPhSe)2 (1 or 5mg/kg) by the intragastric route (i.g.) once a day for 7days. The cognitive performance of mice was assessed through the object recognition test (ORT), the object location test (OLT) and the step-down passive avoidance test (SDPA), some of predictive tests of memory. Biochemical parameters were determined and locomotor activity of mouse was performed to gain insight in (p-ClPhSe)2 toxicity. The findings demonstrated that treatment with (p-ClPhSe)2 in both doses was effective in reversing memory deficits in the ORT, the OLT and the SDPA caused by corticosterone exposure in mice. Treatment with (p-ClPhSe)2 at both doses reversed the increase in the [(3)H] glutamate uptake by hippocampal slices of mice treated with corticosterone. By contrast, [(3)H] glutamate uptake by brain cortical slices was not altered in mice exposed to corticosterone. The Na(+)K(+)ATPase activity was not altered in hippocampus and cerebral cortices of mice treated with corticosterone. There was no sign of toxicity in mice treated with (p-ClPhSe)2. This organoselenium compound reversed memory impairment-related to stress caused by corticosterone and modulated hippocampal [(3)H]glutamate uptake in mice.

Evidence for the contribution of multiple mechanisms in the feeding pattern of rats exposed to p-chloro-diphenyl diselenide-supplemented diets.

Preliminary findings suggest that food intake reduction induced by p-chloro-diphenyl diselenide [(p-ClPhSe)2] in rats is mediated by a satiating action; however, additional experiments are necessary to clarify its actions. The purpose of this study was to investigate the effects of diets supplemented with (p-ClPhSe)2 on feeding behavior of rats as well as the (p-ClPhSe)2 effectiveness in producing aversive reactions or specific flavor. The results demonstrated that behavioral satiety sequence (BSS) was preserved in animals exposed to (p-ClPhSe)2-supplemented diets (0.01 and 0.1%) and associated with a shift of the onset of resting to the left indicating a satiating action at the first contact. In addition, the frequency, the mean duration and the mean size of meals were decreased in rats exposed to a 0.1% (p-ClPhSe)2 diet. Alternatively, a second contact with a 0.01% (p-ClPhSe)2 diet caused disruption of BSS and pronounced changes in the meal pattern, suggesting that it produces aversiveness. In fact, rats developed a significant taste aversion to the saccharin solution after receiving the administration of (p-ClPhSe)2 (1 and 10mg/kg; i.p.). Lastly, a diet containing 0.1% of (p-ClPhSe)2 seems to alter the palatability of food given that rats had a preference for the control diet. The findings of the present study suggest that (p-ClPhSe)2 reduced the food intake of rats by inducing a satiating action at the first contact, but it also produced aversive reactions when rats were re-exposed to it. A specific flavor seems also to contribute to (p-ClPhSe)2 suppressant effects on feeding.

Ketoprofen-loaded pomegranate seed oil nanoemulsion stabilized by pullulan: Selective antiglioma formulation for intravenous administration.

This study aimed to prepare pomegranate seed oil nanoemulsions containing ketoprofen using pullulan as a polymeric stabilizer, and to evaluate antitumor activity against in vitro glioma cells. Formulations were prepared by the spontaneous emulsification method and different concentrations of pullulan were tested. Nanoemulsions presented adequate droplet size, polydispersity index, zeta potential, pH, ketoprofen content and encapsulation efficiency. Nanoemulsions were able to delay the photodegradation profile of ketoprofen under UVC radiation, regardless of the concentration of pullulan. In vitro release study indicates that nanoemulsions were able to release approximately 95.0% of ketoprofen in 5h. Free ketoprofen and formulations were considered hemocompatible at 1 µg/mL, in a hemolysis study, for intravenous administration. In addition, a formulation containing the highest concentration of pullulan was tested against C6 cell line and demonstrated significant activity, and did not reduce fibroblasts viability. Thus, pullulan can be considered an interesting excipient to prepare nanostructured systems and nanoemulsion formulations can be considered promising alternatives for the treatment of glioma.

Effects of diphenyl and p-chloro-diphenyl diselenides on feeding behavior of rats.

RATIONALE: The searching for safe and effective antiobesity drugs has been the subject of intense research. Previous studies have shown several pharmacological applications of organoselenium compounds; however, their possible anorectic-like actions have not been investigated. OBJECTIVE: This study aims to investigate the effects of (PhSe)2 and (p-ClPhSe)2 on feeding behavior of rats and their potential as weight-reducing agents. METHODS: The effects of intraperitoneal administration of diselenides were investigated through the microstructural pattern of feeding behavior, behavioral satiety sequence (BSS), hypothalamic serotonin (5-HT) uptake, body weight, and epididymal fat content of male rats. RESULTS: Our findings demonstrated that food intake of fasted rats was reduced by both diselenides (1 and 10 mg/kg). Diphenyl diselenide [(PhSe)2] (1 mg/kg) and p-chloro-diphenyl diselenide [(p-ClPhSe)2] (10 mg/kg) decreased the frequency, mean duration, and mean size of meals compared with the control treatment. The BSS structure was preserved when organoselenium compounds (1 mg/kg) were administered, and it was associated to a displacement to the left when the resting period started indicating a satiating action. Inhibition of 5-HT uptake in the hypothalamus (∼20 %) was also found in rats treated with low doses of (PhSe)2 and (p-ClPhSe)2 (1 mg/kg). Treatments with a high dose of both diselenides (10 mg/kg) carried out for 7 days induced weight loss and epididymal fat reduction in sated rats. CONCLUSION: This study suggests that diselenides caused a satiating action in rats that could be partially explained by the inhibition of hypothalamic 5-HT uptake. These organoselenium compounds were potential weight-reducing agents when repeatedly administered.