Lipopolysaccharide Exacerbates Ketamine-Induced Psychotic-Like Behavior, Oxidative Stress, and Neuroinflammation in Mice: Ameliorative Effect of Diosmin.

Schizophrenia, a neuropsychiatric disorder has been associated with aberrant neurotransmission affecting behaviors, social preference, and cognition. Limitations in understanding its pathogenesis via the dopamine hypothesis have engendered other hypotheses such as the glutamate hypothesis. That antagonism of the N-methyl-D-aspartate receptor (NMDAR) elicits schizophrenia-like behaviors indistinguishable from the disorder in animal and human models. There are growing concerns that redox imbalance and neuro-immuno dysfunction may play role in aggravating the symptomologies of this disorder. This 14-day treatment study was designed to investigate the effect of diosmin on lipopolysaccharide (LPS) plus ketamine (NMDAR antagonist). Mice were divided into 4 groups (n = 6). Group 1 was administered 5% DMSO (10 mL/kg, i.p) while group 2-4 received LPS (0.1 mg/kg, i.p) daily for 14 days. Diosmin (50 mg/kg, i.p) and risperidone (0.5 mg/kg, i.p) were given to groups 3 and 4 respectively. Groups 2-4 were given KET (20 mg/kg, i.p.) daily from days 8-14. Behavioral tests were done 30 min after the last dose, and oxidative stress and neuroinflammatory maker were assayed. LPS plus ketamine-induced hyperlocomotion, stereotypy, decreased social preference, and memory impairment. Furthermore, LPS plus-ketamine-induced oxidative stress (reduced GSH, CAT, SOD, and increased MDA and nitrite levels) and marked pro-inflammatory cytokines TNF-α and IL-6 suggesting neuroinflammation. However, diosmin attenuated behavioral deficits and improved memory. Additionally, diosmin potentiated antioxidant level via increased GSH, CAT, and SOD while reducing MDA and nitrite levels. Finally, diosmin reduced TNF-α and IL-6 suggesting anti-neuro-immuno activity. Conclusively, diosmin attenuated LPS plus ketamine-induced behavioral deficits, oxidative stress, neuroinflammation, and improved memory.

Monosodium glutamate induces memory and hepatic dysfunctions in mice: ameliorative role of Jobelyn® through the augmentation of cellular antioxidant defense machineries.

This study investigated the effect of high doses of monosodium glutamate (MSG), a known food additive on hepatic, memory and locomotor functions in mice, and the ameliorative potentials of Jobelyn® (JB), a unique dietary supplement. Twenty four  male Swiss mice  divided into 4 groups (n = 6) were given MSG (2, 4 and 8 g/kg) or normal saline (10 mL/kg) orally for 14 days. In the intervention study, another set of 30 male Swiss mice distributed into 5 groups (n = 6) received normal saline, MSG (8 g/kg) alone or in combination with JB (5, 10 and 20 mg/kg) orally, for 14 days. Memory and locomotor functions as well as brain oxido-nitrergic stress biomarkers were then assessed in both studies. The hepatic oxido-nitrergic stress biomarkers, liver enzymes functions and histomorphology of the liver were also assessed. MSG (2, 4 and 8 g/kg) produced memory dysfunction, hyperlocomotion, increased malondialdehyde and nitrite levels accompanied by decreased antioxidant status in the brain and hepatic tissues. MSG-treated mice had increased hepatic enzyme activities (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) and distorted cyto-architectural integrity of the liver. These findings further suggest that MSG compromised hepatic functioning, which might also contribute to its neurotoxicity. However, JB (5, 10 and 20 mg/kg, p.o) attenuated the memory deficit, hyperlocomotion, increased oxido-nitrergic stress responses in the brain and hepatic tissues induced by MSG (8 g/kg, p.o). JB also normalized hepatic enzymes activities and histomorphological changes in MSG-treated mice. Taken together, JB mitigated MSG-induced toxicity through mechanisms relating to enhancement of cellular antioxidant-machineries and normalization of hepatic enzymatic functions.

Naringin Confers Protection against Psychosocial Defeat Stress-Induced Neurobehavioral Deficits in Mice: Involvement of Glutamic Acid Decarboxylase Isoform-67, Oxido-Nitrergic Stress, and Neuroinflammatory Mechanisms.

Psychosocial stress has been widely reported to contribute to psychiatric disturbances. Perturbations in the enzymes of GABAergic and cholinergic systems have been implicated as precursors in different stress-related neuropsychiatric diseases. Targeting glutamic acid decarboxylase-67 kDa (GAD67) and acetylcholinesterase (AChE) via oxidative, nitrergic, and neuroinflammatory mechanisms have been recognized as prospective strategies for the prevention of psychosocial stress-induced behavioral impairments. Naringin, a neuro-active flavonoid compound isolated from citrus fruits, has been shown to produce memory-enhancing, antiepileptic, antidepressant, and anti-inflammatory activities similarly to ginseng, a very potent adaptogen. In this communication, we assessed the effect of naringin on social-defeat stress (SDS)-induced behavioral, GABAergic, cholinergic, oxidative, nitrergic, and neuroinflammatory changes in mice using the resident-intruder paradigm. The intruder male mice were culled into six groups. Groups 1 and 2 (normal- and SDS-controls) received sterile saline, groups 3-5 were given naringin (25-100 mg/kg, i.p.) whereas group 6 had ginseng (50 mg/kg, i.p.) daily for 14 days, but followed by 10 min SDS (physical and psychological) exposure to groups 2-6 with aggressor-resident mice. Behavioral effects using Y-maze, elevated-plus maze, sociability, and tail-suspension tests were assessed on day 14. GAD67, AChE enzymes, and biomarkers of oxidative, nitrergic, and neuroinflammatory changes were assayed in the striatum, prefrontal cortex, and hippocampus. Naringin and ginseng reversed all SDS-induced behavioral impairments. Naringin increased the levels of GAD67 and decreased AChE activities in the striatum, prefrontal cortex, and hippocampus. Furthermore, naringin reduced pro-inflammatory cytokines (TNF-α, IL-6), malondialdehyde, nitrite concentrations, and increased glutathione levels in a region-dependent manner. Our study suggests that naringin attenuated SDS-induced behavioral endophenotypes of neuropsychiatric disease through increased GAD67 synthesis, inhibition of AChE activity, oxidative, nitrergic stress, and neuroinflammatory processes in stress-sensitive brain regions.

Morin decreases cortical pyramidal neuron degeneration via inhibition of neuroinflammation in mouse model of schizophrenia.

Neuroinflammation plays a prominent role in the pathophysiology and progression of schizophrenia. Thus, suppression of neuroinflammation may retard the progression of the disease. This study was designed to investigate whether morin, a bioactive compound with antipsychotic-like activity could reduce biomarkers of neuroinflammation and neurodegeneration in lipopolysaccharide (LPS)- and ketamine (KET)-induced schizophrenic-like behavior in mice. Animals were treated once daily intraperitoneally with morin (100 mg/kg), haloperidol (1 mg/kg), risperidone (0.5 mg/kg), or saline (10 mL/kg) in combination with LPS (0.1 mg/kg) for 14 consecutive days. However, from days 8-14, overt schizophrenia-like episode was produced with i.p. injection of KET (20 mg/kg) once daily. Schizophrenic-like behaviors: positive (open-field test), negative (social-interaction and social-memory tests) and cognitive (Y-maze test) symptoms were assessed on day 14. Thereafter, the levels and expressions of biomarkers of neuroinflammation were estimated in the striatum (ST), prefrontal cortex (PFC) and hippocampus (HC) using spectrophotometry, ELISA and immunohistochemistry. The effects of morin on cortical pyramidal neurons were estimated using Golgi-impregnation staining technique. LPS in combination with KET significantly (p < 0.05) induced schizophrenia-like behaviors, which was attenuated by morin. Morin significantly (p < 0.05) decreased tumor necrosis factor-α, interleukine-6 levels and myeloperoxidase activity in the ST, PFC and HC of mice treated with LPS + KET. Moreover, morin reduced regional brain expressions of cyclooxygenase-2, inducible nitric oxide synthase and nuclear factor kappa-B, and also rescued loss of pyramidal neurons in the PFC. Taken together, these findings suggest that morin reduces schizophrenic-like symptoms induced by LPS + KET via mechanisms related to inhibition of the release of pro-inflammatory mediators and suppression of degeneration of cortical pyramidal neurons in mice.

Morin Attenuates Neurochemical Changes and Increased Oxidative/Nitrergic Stress in Brains of Mice Exposed to Ketamine: Prevention and Reversal of Schizophrenia-Like Symptoms.

Previous studies have revealed that morin (MOR), a neuroactive bioflavonoid, with proven psychotropic and neuroprotective properties reduced schizophrenic-like behaviors in mice. This study further evaluated the ability of MOR to prevent and reverse ketamine-induced schizophrenic-like behaviors and the underlying neurochemical changes and increased oxidative/nitrergic stress in mice. In the preventive protocol, mice received intraperitoneal injection of MOR (100 mg/kg), reference antipsychotic drugs [haloperidol (1 mg/kg), risperidone (0.5 mg/kg)], or saline daily for 14 consecutive days prior to i.p. injection of ketamine (KET) (20 mg/kg/day) from the 8th to the 14th day. In the reversal protocol, the animals received KET or saline for 14 days prior to MOR, haloperidol, risperidone, or saline treatments. Schizophrenic-like behaviors: positive (open-field test), negative (social-interaction test) and cognitive (Y-maze test) symptoms were evaluated. Thereafter, the brain levels of dopamine, glutamate, 5-hydroxytryptamine and acetyl-cholinesterase, as well as biomarkers of oxidative/nitrergic stress were measured in the striatum, prefrontal-cortex (PFC) and hippocampus (HC). Morin prevented and reversed KET-induced hyperlocomotion, social and cognitive deficits. Also, MOR or risperidone attenuated altered dopaminergic, glutamatergic, 5-hydroxytryptaminergic and cholinergic neurotransmissions in brain region-dependent manner. The increased malondialdehyde and nitrite levels accompanied by decreased glutathione concentrations in the striatum, PFC and HC in KET-treated mice were significantly attenuated by MOR or risperidone. Taken together, these findings suggest that the anti-schizophrenic-like activity of MOR may be mediated via mechanisms related to attenuation of neurochemical changes and oxidative/nitrergic alterations in mice.

Involvement of GABAergic, BDNF and Nox-2 mechanisms in the prevention and reversal of ketamine-induced schizophrenia-like behavior by morin in mice.

GABAergic (Gamma-aminobutyric acid) and neurotrophic derangements have important implication in schizophrenia, a neuropsychiatric disease. Previous studies have shown that nicotinamide adenine dinucleotide phosphate oxidase (NADPH-oxidase) alters GABAergic and neurotrophic activities via inflammatory and oxidative pathways. Thus, it has been proposed that agents with anti-oxidant and anti-inflammatory properties might be beneficial for the treatment of the disease. Morin is neuroactive bioflavonoid compound, which has been reported to demonstrate antipsychotic and anti-oxidant/anti-inflammatory activities. In this study, we further evaluated its effects on the brain markers of GABAergic, neurotrophic and oxidative alterations in the preventive and reversal of schizophrenia-like behavior induced by ketamine (KET). In the prevention protocol, adult mice were treated intraperitoneally with morin (100 mg/kg/day), haloperidol (1 mg/kg/day), risperidone (0.5 mg/kg/day), or saline (10 mL/kg/day) for 14 consecutive days. In addition, the animals were administered KET (20 mg/kg/day) from the 8th to the 14th day. In the reversal protocol, the animals received KET or saline for 14 days. From 8th to 14th days mice were additionally treated with morin, haloperidol, risperidone or saline. Schizophrenic-like behaviors consisting of positive (stereotypy test), negative (behavioral despair in forced swim test) and cognitive (novel-object recognition test) symptoms were evaluated. Afterwards, brain levels of biomarkers of GABAergic (Glutamic acid decarboxylase-67, GAD67), neurotrophic (Brain-derived neurotrophic factor, BDNF) and oxidative [NADPH-oxidase, superoxide dismutase, (SOD) and catalase (CAT)] alterations were determined in the striatum, prefrontal cortex (PFC) and hippocampus, respectively. Morin significantly (p < 0.05) prevented and reversed KET-induced increased stereotypy, behavioral despair and deficit in cognitive functions when compared with KET-treated mice respectively. Also, morin and risperidone but not haloperidol, significantly (p < 0.05) prevented and reversed the decreases in expressions of GAD67 and BDNF immunoreactivity in the striatum, PFC and hippocampus caused by KET. Moreover, morin and risperidone significantly (p < 0.05) decreased regional brain expressions of NADPH-oxidase immunopositive cells and increased endogenous anti-oxidant enzymes (SOD and CAT) in the striatum, PFC and hippocampus relative to KET controls respectively. Taken together, these findings further suggest that the antipsychotic-like activity of morin may be mediated via mechanisms related to enhancement of GABAergic neurotransmission and neurotrophic factor, and suppression of NADPH-oxidase induced oxidative damage in mice.