Cyclooxygenase-2 inhibitors alleviated depressive and anxious-like behaviors in mice exposed to lipopolysaccharide: Involvement of oxidative stress and neuroinflammation.

Depression and anxiety disorders have their pathophysiologies linked to inflammation and oxidative stress. In this context, celecoxib (CLX) and etoricoxib (ETR) inhibit cyclooxygenase 2 (COX-2), an enzyme expressed by cells involved in the inflammatory process and found in the brain. Studies have been using CLX as a possible drug in the treatment of depression, although its mechanisms at the central nervous system level are not fully elucidated. In this study, the effects of CLX and ETR on behavioral, oxidative, and inflammatory changes induced by systemic exposure to Escherichia coli lipopolysaccharide (LPS) were evaluated in adult male swiss mice. For ten days, the animals received intraperitoneal injections of LPS at 0.5 mg/kg. From the sixth to the tenth day, one hour after LPS exposure, they were treated orally with CLX (15 mg/kg), ETR (10 mg/kg), or fluoxetine (FLU) (20 mg/kg). Twenty-four hours after the last oral administration, the animals underwent evaluation of locomotor activity (open field test), predictive tests for depressive-like behavior (forced swim and tail suspension tests), and anxiolytic-like effect (elevated plus maze and hole board tests). Subsequently, the hippocampus, prefrontal cortex and striatum were dissected for the measurement of oxidative and nitrosative parameters (malondialdehyde, nitrite, and glutathione) and quantification of pro-inflammatory cytokines (IL-1ß and IL-6). LPS induced depressive and anxious-like behavior, and treatment with CLX or ETR was able to reverse most of the behavioral changes. It was evidenced that nitrosative stress and the degree of lipid peroxidation induced by LPS were reduced in different brain areas after treatment with the drugs, as well as the endogenous defense system against free radicals was strengthened. CLX and ETR also significantly reduced LPS-induced cytokine levels. These data are expected to expand information on the role of inflammation in depression and anxiety and provide insights into possible mechanisms of COX-2 inhibitors in psychiatric disorders with a neurobiological basis in inflammation and oxidative stress.

Low-dose candesartan prevents schizophrenia-like behavioral alterations in a neurodevelopmental two-hit model of schizophrenia.

Schizophrenia is a severe mental disorder with complex etiopathogenesis. Based on its neurodevelopmental features, an animal model induced by "two-hit" based on perinatal immune activation followed by peripubertal unpredictable stress was proposed. Sex influences the immune response, and concerning schizophrenia, it impacts the age of onset and symptoms severity. The neurobiological mechanisms underlying the influence of sex in schizophrenia is poorly understood. Our study aimed to evaluate sex influence on proinflammatory and oxidant alterations in male and female mice exposed to the two-hit model of schizophrenia, and its prevention by candesartan, an angiotensin II type 1 receptor (AT1R) blocker with neuroprotective properties. The two-hit model induced schizophrenia-like behavioral changes in animals of both sexes. Hippocampal microglial activation alongside the increased expression of NF-κB, and proinflammatory cytokines, namely interleukin (IL)-1ß and TNF-α, were observed in male animals. Conversely, females presented increased hippocampal and plasma levels of nitrite and plasma lipid peroxidation. Peripubertal administration of low-dose candesartan (0.3 mg/kg PO) prevented behavioral, hippocampal, and systemic changes in male and female mice. While these results indicate the influence of sex on inflammatory and oxidative changes induced by the two-hit model, candesartan was effective in both males and females. The present study advances the neurobiological mechanisms underlying sex influence in schizophrenia and opens new avenues to prevent this devasting mental disorder.

Ethanolic extract of Erythrina velutina Willd ameliorate schizophrenia-like behavior induced by ketamine in mice.

Background Schizophrenia is a chronic mental disorder, characterized by positive, negative and cognitive symptoms. In general, several plants have shown activity in diseases related to the central nervous system (e.g., Erythrina velutina (EEEV), also known as "mulungu"). For this reason, we aimed to investigate the effects of standardized ethanol extract obtained from the stem bark of EEEV on the schizophrenia-like behaviors induced by ketamine (KET) administration. Methods Swiss mice were treated with KET (20 mg/kg, i.p.) or saline for 14 days. In addition, from 8th to 14th days, saline, EEEV (200 or 400 mg/kg, p.o.) or olanzapine (OLAN 2 mg/kg, p.o.) were associated to the protocol. On the 14th day of treatment, schizophrenia-like symptoms were evaluated by the prepulse inhibition of the startle reflex (PPI), locomotor activity evaluated by the open field test (OFT), spatial recognition memory evaluated by the Y-maze task and social interaction test (SIT). Results KET has caused deficits in PPI, and it has also has caused hyperlocomotion in OFT and deficits in SIT as compared to control. EEEV in both doses used, reversed behavioral changes induced by KET, likewise results obtained with the administration of OLAN. Conclusions Taken together, the results demonstrate that the standard extract of EEEV was able to revert schizophrenia-like symptoms, due to the administration in repeated doses of ketamine. Thus, our findings lead to a new perspective for the use of EEEV an interesting alternative for drug discovery in schizophrenia.

Antidepressant, antioxidant and neurotrophic properties of the standardized extract of Cocos nucifera husk fiber in mice.

The plant Cocos nucifera and its derivatives have shown antidepressant-like effects, although its hydroalcoholic extract has not been studied with this end in mind. Therefore, we decided to determine the antidepressant-like effects of the standardized hydroalcoholic extract of Cocos nucifera husk fiber (HECN) as well as oxidative alterations in the prefrontal cortex (PFC), hippocampus (HC) and striatum (ST), and the levels of brain-derived neurotrophic factor (BDNF) in the HC of mice. The extract was characterized based on the content of total polyphenols as well as two phenol compounds-catechin and chlorogenic acid-by HPLC-PDA. Male animals were treated per os (p.o.) for 7 days with distilled water or HECN (50, 100 or 200 mg/kg), or intraperitoneally with vitamin E (Vit E 400 mg/kg). One hour after the last drug administration, the animals were submitted to the open field test, forced swimming test (FST), tail suspension test (TST) and, immediately after the behavioral tests, had their brain removed for neurochemical determinations. The results showed that HECN100 decreased the immobility time in the FST and TST presenting, thus demonstrating an antidepressant-like effect. The administration of HECN decreased malondialdehyde levels in all doses and brain areas studied with the exception of HECN50 in the HC. The administration of HECN also decreased nitrite levels in all doses and brain regions studied. HECN100 also increased the levels of BDNF in HC of mice. In conclusion, we demonstrated that HECN has antidepressant-like properties, probably based on its antioxidant and neurotrophic effects, and is thus relevant for the treatment of depression.