Subchronic exposure to Tamoxifen modulates the hippocampal BDNF/ERK/Akt/CREB pathway and impairs memory in intact female rats.

Tamoxifen (TAM), a Selective Estrogen Receptor Modulator (SERM), is commonly used to treat and prevent breast cancer. Memory impairment has been noticed in patients who experience hormone therapy in the case of TAM and other SERMs. Animal studies that mimic the TAM longer exposure effects are needed to better elucidate the adverse effects of continuous treatment in humans. This study evaluated the effects of TAM subchronic administration on the memory performance and hippocampal neural plasticity of intact female Wistar rats. Animals were treated intragastrically with TAM (0.25 and 2.5 mg/kg) for 59 days. The rats were subjected to the Object Location Test (OLT) and Object Recognition Test (ORT) to evaluate memory performance. After euthanasia, the hippocampus samples were excised and the protein levels of the BDNF/ERK/Akt/CREB pathway were evaluated. The rat's locomotor activity and hippocampal TrkB levels were similar among the experimental groups. TAM at both doses reduced the memory performance of female rats in the OLT and short-term memory of ORT, and impaired hippocampal levels of mBDNF, proBDNF, and pCREB/CREB. TAM only at the dose of 2.5 mg/kg reduced the memory performance of rats in the long-term memory of ORT and hippocampal pERK/ERK and pAkt/Akt ratios. TAM subchronic administration induced amnesic effects and modulated the hippocampal BDNF/ERK/Akt/CREB pathway in intact young adult female Wistar rats.

Social-single prolonged stress as an ether-free candidate animal model of post-traumatic stress disorder: Female and male outcomings.

BACKGROUND: Single Prolonged Stress (SPS) is a valid animal model that reflects the core of post-traumatic stress disorder (PTSD) phenotypes. Although SPS has been a pivotal tool, it can bring ethics approval difficulties due to the use of ether as a stressor. The present study evaluated if changing a chemical (ether) with a social stressor resembles the PTSD hallmark symptoms. METHODS: Female and male young adult rats were distributed in Sham and Social-SPS groups. Rats in Social-SPS groups were subjected to stress, whereas those in Sham groups remained undisturbed. One set of animals performed the behavioral tests, elevated plus-maze (EPM) and Y-maze. Plasma corticosterone levels and cortical and hippocampal molecular protein contents were analyzed. Another set of animals performed the dexamethasone suppression test. RESULTS: A significant decrease in the percentage of time spent and the number of entries in open arms and an increase in anxiety index in the EPM were observed in rats of the social-SPS groups. In the Social-SPS groups, rats reduced the spontaneous alternations in Y-maze. The Social-SPS exposure enhanced the HPA-axis feedback and increased glucocorticoid receptor contents in the cerebral cortex and hippocampus of rats. A decrease in the content of synaptic integrity-related proteins, synaptophysin, and PSD-95, were found in the cortex and hippocampus of rats subjected to social-SPS. There were no statistical differences between males and females in any parameter analyzed. LIMITATIONS: The absence of a task to recap criterion E 'arousal' and predictive validity experiments. CONCLUSIONS: This study reveals that social-SPS recapitulated the main clusters required for a candidate animal model of PTSD.

m-CF3-substituted diphenyl diselenide attenuates all phases of morphine-induced behavioral locomotor sensitization in mice.

BACKGROUND: Behavioral sensitization, thought to underlie some aspects of drug dependence, is typically measured as increased locomotion in response to repeated administration of a drug. The study aimed to investigate the (m-CF3-PhSe)2 effects on the acquisition, withdrawal, and re-exposure phases of morphine-induced behavioral locomotor sensitization. METHODS: Swiss male mice were treated with saline or morphine at 10 mg/kg twice a day for 3 days; those of the morphine group were kept in the morphine withdrawal period (5 days). On day 9, mice were re-exposed to morphine. (m-CF3-PhSe)2 (10 mg/kg) or vehicle was administered at all phases of morphine protocol, and mice performed locomotor activity test. Oxidative stress markers and the levels of opioid, dopamine, and glutamate receptors were determined in samples of the cerebral cortex. (m-CF3-PhSe)2 administered at all phases of protocol attenuated morphine-induced locomotor sensitization. RESULTS: Mice exposed to morphine showed reduced weight gain and increased locomotor activity, but (m-CF3-PhSe)2 treatment attenuates the weight gain and behavioral hyperlocomotion effects. (m-CF3-PhSe)2, independent of the administration phase, modulated the increase of opioidergic (MOR, DOR, KOR) and glutamatergic (NMDA 2A and 2B) protein contents and attenuated redox imbalance in the cerebral cortex of mice exposed to morphine. However, (m-CF3-PhSe)2 did not modulate cortical protein levels of dopaminergic (D1 and D2) receptors in the acquisition phase of morphine-induced locomotor sensitization protocol. CONCLUSION: (m-CF3-PhSe)2 was effective against the behavioral and molecular alterations caused by morphine at all phases of locomotor sensitization.

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.

Bis(phenylimidazoselenazolyl) diselenide elicits antinociceptive effect by modulating myeloperoxidase activity, NOx and NFkB levels in the collagen-induced arthritis mouse model.

Bis(phenylimidazoselenazolyl) diselenide (BPIS) is an organoselenium with acute antinociceptive and antioxidant properties. OBJECTIVES: The aim of this study was to investigate BPIS effect on a collagen-induced arthritis (CIA) model in mice. METHODS: Protocol of exposure consisted in arthritis induction by chicken collagen type II on day 0 with booster injection on day 21. On day 60 after collagen injection, incidence of mechanic allodynia (Von Frey test) or thermal hyperalgesia (hot plate test) was evaluated. During following 5 days, mice were treated with BPIS (0.1-1 mg/kg; p.o.; daily) or vehicle. On day 65, mice were killed, and paws and spinal cord were removed for analyses. KEY FINDINGS: Mice submitted to CIA model developed both mechanical allodynia and thermal hyperalgesia, which were reversed by BPIS at the highest dose. In paw, BPIS reversed the increase in myeloperoxidase activity in the CIA group. In the spinal cord, BPIS decreased NOx and NFkB levels increased in the CIA group. BPIS-treated animals had lower cyclooxygenase-2 levels in the spinal cord. CONCLUSIONS: The myeloperoxidase activity in paw and NOx and NFkB levels in spinal cord are related to antinociceptive properties of BPIS in CIA model.

Combined Therapy With Swimming Exercise and a Diet Supplemented With Diphenyl Diselenide Is Effective Against Age-Related Changes in the Hepatic Metabolism of Rats.

Aging is characterized by a widespread loss of homeostasis in biological systems and is accompanied by pathophysiological changes including the liver injury. The aim of the present study was to investigate the effects of the combined therapy with swimming exercise (20 min session, 5 days/week during 4 weeks) and a diet supplemented with 1 ppm of (PhSe)2 on the hepatic metabolic alterations caused by aging in rats. In this study, male old Wistar rats had an increase in the epididymal fat relative weight, disturbances in the activities of hepatic enzymes associated to the glucose homeostasis, higher hepatic triglyceride content and higher activity of the plasma alanine aminotransferase (ALT), and aspartate aminotransferase (AST). The combined therapy normalized the activities of glucose-6-Pase and tyrosine aminotransferase, gluconeogenic enzymes, increased the hepatic glycogen content and was effective against the increase in the hepatic triglycerides content, without altering the activities of hexoquinase, and citrate synthase. Moreover, the combined therapy normalized the activities of AST and ALT, indicating a hepatoprotective effect. The combined therapy with swimming exercise and a diet supplemented with 1 ppm of (PhSe)2 contributed to the hepatic glucose homeostasis in old rats. Nevertheless, more studies are needed to investigate the possible mechanisms of action behind these effects. J. Cell. Biochem. 118: 1574-1582, 2017. © 2016 Wiley Periodicals, Inc.