Different sub-anesthetic doses of ketamine increase oxidative stress in the brain of rats

Evaluation of the potential efficacy of the nitric oxide donor molsidomine for the treatment of schizophrenia

Schizophrenia is a chronic devastating psychiatric disease characterized by a high recurrence rate. Pharmacological management of this disorder appears disappointing since it is associated with a lack of efficacy for negative symptoms and cognitive deficits, typical features of schizophrenia, and the presence of severe undesired side effects. Thus, novel molecules with high efficacy and low toxicity for the treatment of schizophrenia are urgently needed. The involvement of the gaseous molecule nitric oxide in the pathogenesis of schizophrenia is well documented since low concentrations of nitric oxide are associated with this psychiatric disease. Therefore, chemicals able to normalize nitric oxide levels, such as nitric oxide donors, might be useful for the management of this type of schizophrenia. Molsidomine is a nitric oxide donor and is under investigation as a novel antischizophrenia agent. The aim of this review is to critically evaluate the potential efficacy of this molecule for the treatment of schizophrenia.

The relationship between alcohol bingeing in the gestational period of wistar rats and the development of schizophrenia in the offspring adult life

The incidence of schizophrenia in young adulthood may be associated with intrauterine factors, such as gestational alcohol consumption. This study investigated the relationship between a single high dose of alcohol during pregnancy in Wistar rats and the development of schizophrenia in the adult life of the offspring. On the 11th day of gestation, pregnant rats received either water or alcohol via intragastric gavage. Male and female offspring were subjected to behavioral tests at 30 days of age according to the maternal group. At 60 days of age, offspring received intraperitoneal injections of ketamine (ket) or saline (SAL). After the final ketamine administration, the adult offspring underwent behavioral tests, and their brain structures were removed for biochemical analysis. Alcohol binge drinking during pregnancy induces hyperlocomotion in both young female and male offspring, with males of alcohol-exposed mothers showing reduced social interactions. In adult offspring, ketamine induced hyperlocomotion; however, only females in the alcohol + ket group exhibited increased locomotor activity, and a decrease in the time to first contact was observed in the alcohol group. Cognitive impairment was exclusively observed in male animals in the alcohol group. Increased serotonin and dopamine levels were observed in male rats in the alcohol + ket group. Biochemical alterations indicate the effects of intrauterine alcohol exposure associated with ketamine in adult animals. These behavioral and biochemical changes suggest that the impact of prenatal stressors such as alcohol persists throughout the animals' lives and may be exacerbated by a second stressor in adulthood, such as ketamine.

Co-administration of sub-effective doses of the constituents of Crocus sativus L. crocins with those of the antipsychotics clozapine and risperidone counteract memory deficits caused by blockade of the NMDA receptor in rats

Experimental evidence indicates that the noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonists ketamine and MK-801 induce schizophrenia-like symptoms in rodents, including cognitive deficits. Crocins are among the active components of the plant Crocus sativus L. and were found to be effective in different models of psychiatric disorders comprising schizophrenia. The present study was designed to evaluate the efficacy of the joint administration of sub-effective doses of crocins with those of the atypical antipsychotics clozapine and risperidone in alleviating nonspatial recognition and emotional memory deficits induced either by ketamine (3 mg/kg) or MK-801 (0.1 mg/kg) in the rat. To this end, the object recognition and the step-through passive avoidance tests were used. Co-administration of sub-effective doses of crocins (5 mg/kg) with those of clozapine (0.1 mg/kg) or risperidone (0.03 mg/kg) counteracted nonspatial recognition and emotional memory deficits induced by NMDA receptor antagonists. The current findings suggest that this combinatorial treatment was efficacious in attenuating cognitive impairments related to the blockade of the NMDA receptor. In addition, the present results support the potential of crocins as an adjunctive drug for the therapy of schizophrenia.

Towards a natural treatment for mania: red onion husk extract modulates neuronal resilience, redox signalling, and glial activation

BACKGROUND

Red onion husk, a readily available agricultural waste material, contains diverse bioactive compounds with potential health benefits. This study aimed to assess the safety and therapeutic potential of red onion husk extract in managing manic-like symptoms and associated neurochemical dysfunctions.

METHODS

Acute and repeated oral dose studies were conducted in mice and rats to evaluate the safety profile of the extract. FT-IR analysis identified functional groups in the extract, while GC-MS analysis identified specific bioactive compounds in the flavonoid-rich fraction. A ketamine-induced manic behaviour model in Wistar rats was employed to assess the extract's efficacy in attenuating manic-like symptoms. Behavioural and neurochemical analyses were performed to further investigate the extract's effects.

RESULTS

The extract demonstrated a favourable safety profile in both acute and repeated dose studies. FT-IR analysis revealed a complex mixture of organic compounds, including hydroxyl groups, alkynes/nitriles, aromatic and non-aromatic C = C bonds, amines, and polysaccharides. GC-MS analysis identified 17 bioactive compounds, including five-methyl-2-phenylindolizine, methadone N-oxide, and 3-phenylthiane, S-oxide. Ketamine administration significantly increased oxidative stress markers, TBARS, and suppressed antioxidant enzyme activities (SOD, GPx, CAT) in both the cerebral cortex and hippocampus, alongside elevated acetylcholinesterase (AchE) activity, indicating enhanced neuronal excitability. Pre-treatment with FRF (25 mg/kg) effectively mitigated ketamine-induced oxidative stress, as evidenced by reduced TBARS levels and partially restored SOD and GPx activities. Interestingly, FRF significantly increased CAT activity (p < 0.001), potentially suggesting an additional compensatory mechanism. Notably, FRF pre-treatment also counteracted ketamine-upregulated AchE activity, offering neuroprotection against heightened neuronal excitability.

CONCLUSION

Red onion husk extract exhibits a favourable safety profile and exerts potent antioxidant and neuroprotective effects, possibly through modulating Nrf2 signalling pathways. Its ability to counteract ketamine-induced oxidative stress and neuronal hyperactivity highlights its potential as a complementary therapeutic strategy for managing manic episodes in bipolar disorder. Further research is warranted to elucidate the precise molecular mechanisms underlying FRF's action and explore its clinical efficacy in human studies.

Haloperidol alters neurotrophic factors and epigenetic parameters in an animal model of schizophrenia induced by ketamine

This study aimed to evaluate Haloperidol's (Hal) effects on the behavioral, neurotrophic factors, and epigenetic parameters in an animal model of schizophrenia (SCZ) induced by ketamine (Ket). Injections of Ket or saline were administered intraperitoneal (once a day) between the 1st and 14th days of the experiment. Water or Hal was administered via gavage between the 8th and 14th experimental days. Thirty minutes after the last injection, the animals were subjected to behavioral analysis. The activity of DNA methyltransferase (DNMT), histone deacetylase (HDAC), and histone acetyltransferase and levels of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neurotrophin-3 (NT-3), and glial-derived neurotrophic factor (GDNF) were evaluated in the frontal cortex, hippocampus, and striatum. Ket increased the covered distance and time spent in the central area of the open field, and Hal did not reverse these behavioral alterations. Significant increases in the DNMT and HDAC activities were detected in the frontal cortex and striatum from rats that received Ket, Hal, or a combination thereof. Besides, Hal per se increased the activity of DNMT and HDAC in the hippocampus of rats. Hal per se or the association of Ket plus Hal decreased BDNF, NGF, NT-3, and GDNF, depending on the brain region and treatment regimen. The administration of Hal can alter the levels of neurotrophic factors and the activity of epigenetic enzymes, which can be a factor in the development of effect collateral in SCZ patients. However, the precise mechanisms involved in these alterations are still unclear.

L-Carnitine Prevents Behavioural Alterations in Ketamine-Induced Schizophrenia in Mice: Possible Involvement of Oxidative Stress and Inflammation Pathways

Schizophrenia is a chronic mental complaint known as cognitive impairment. There has been evidence that inflammation and oxidative stress play a main role in schizophrenia pathophysiology. This study aimed to investigate the effects of l-carnitine, as a potent antioxidant, on the treatment of behavioural and biochemical disturbances in mice with ketamine-induced schizophrenia. In this study, schizophrenia was induced in mice by ketamine (25 mg/kg/day, i.p). Before induction of schizophrenia, mice were treated with l-carnitine (100, 200, and 400 mg/kg/day, i.p). Then, behavioural impairments were evaluated by open field (OF) assessment and social interaction test (SIT). After brain tissue isolation, reactive oxygen species (ROS), glutathione concentration (GSH), lipid peroxidation (LPO), protein carbonyl oxidation, superoxide dismutase activity (SOD), and glutathione peroxidase activity (GPx) were assessed as oxidative stress markers. Furthermore, inflammatory biomarkers such as tumour necrosis factor alpha (TNF-α) and nitric oxide (NO) were evaluated in brain tissue. Our results showed ketamine increased inflammation and oxidative damage in brain tissue that was similar to behaviour disorders in mice. Interestingly, l-carnitine significantly decreased oxidative stress and inflammatory markers compared with ketamine-treated mice. In addition, l-carnitine prevented and reversed ketamine-induced alterations in the activities of SOD and GPx enzymes in mice's brains. Also, improved performance in OFT (locomotor activity test) and SIT was observed in l-carnitine-treated mice. These data provided evidence that, due to the antioxidant and anti-inflammatory effects of l-carnitine, it has a neuroprotective effect on mice model of schizophrenia.

The Nitric Oxide (NO) Donor Molsidomine Counteract Social Withdrawal and Cognition Deficits Induced by Blockade of the NMDA Receptor in the Rat

The deficiency of the gaseous molecule nitric oxide (NO) seems to be critically involved in the pathogenesis of schizophrenia. Thus, molecules that can normalize NO levels, as are NO donors, might be of utility for the medication of this psychiatric disease. The aim of the present study was to detect the ability of the NO donor molsidomine to reduce schizophrenia-like impairments produced by the blockade of the N-methyl-D-aspartate (NMDA) receptor in rats. Molsidomine's ability to attenuate social withdrawal and spatial recognition memory deficits induced by the NMDA receptor antagonist ketamine were assessed using the social interaction and the object location test, respectively. Further, the efficacy of the combination of sub-effective doses of molsidomine with sub-effective doses of the atypical antipsychotic clozapine in alleviating non-spatial recognition memory deficits was evaluated utilizing the object recognition task. Molsidomine (2 and 4 mg/kg) attenuated social withdrawal and spatial recognition memory deficits induced by ketamine. Co-administration of inactive doses of molsidomine (1 mg/kg) and clozapine (0.1 mg/kg) counteracted delay-dependent and ketamine-induced non-spatial recognition memory deficits. The current findings suggest that molsidomine is sensitive to glutamate hypofunction since it attenuated behavioral impairments in animal models mimicking the negative symptoms and cognitive deficits of schizophrenia. Additionally, the present results support the potential of molsidomine as an adjunctive drug for the therapy of schizophrenia.

Combined Intake of Fish Oil and D-Fagomine Prevents High-Fat High-Sucrose Diet-Induced Prediabetes by Modulating Lipotoxicity and Protein Carbonylation in the Kidney

Obesity has been recognized as a major risk factor for chronic kidney disease, insulin resistance being an early common metabolic feature in patients suffering from this syndrome. This study aims to investigate the mechanism underlying the induction of kidney dysfunction and the concomitant onset of insulin resistance by long-term high-fat and sucrose diet feeding in Sprague Dawley rats. To achieve this goal, our study analyzed renal carbonylated protein patterns, ectopic lipid accumulation and fatty acid profiles and correlated them with biometrical and biochemical measurements and other body redox status parameters. Rats fed the obesogenic diet developed a prediabetic state and incipient kidney dysfunction manifested in increased plasma urea concentration and superior levels of renal fat deposition and protein carbonylation. An obesogenic diet increased renal fat by preferentially promoting the accumulation of saturated fat, arachidonic, and docosahexaenoic fatty acids while decreasing oleic acid. Renal lipotoxicity was accompanied by selectively higher carbonylation of proteins involved in the blood pH regulation, i.e., bicarbonate reclamation and synthesis, amino acid, and glucose metabolisms, directly related to the onset of insulin resistance. This study also tested the combination of antioxidant properties of fish oil with the anti-diabetic properties of buckwheat D-Fagomine to counteract diet-induced renal alterations. Results demonstrated that bioactive compounds combined attenuated lipotoxicity, induced more favorable lipid profiles and counteracted the excessive carbonylation of proteins associated with pH regulation in the kidneys, resulting in an inhibition of the progression of the prediabetes state and kidney disease.

Curcumin alleviates ketamine-induced oxidative stress and apoptosis via Nrf2 signaling pathway in rats' cerebral cortex and hippocampus

AIMS

To investigate curcumin's protective effect on nerve damage caused by ketamine anesthesia via the Nrf2 signaling pathway. Rats and PC12 cells were used in this experiment to investigate the mechanism of nerve injury caused by ketamine anesthesia. Furthermore, our findings suggest that curcumin may affect oxidative stress and apoptosis by targeting the Nrf2 pathway, thereby alleviating the nerve injury caused by ketamine.

METHODS

The rat cerebral cortex and hippocampus were stained with Nissl and immunohistochemistry to determine the number of neurons and the expression of Caspase-3, Bcl-2, and Bax. CCK-8 assay was used to determine the optimal concentration of ketamine, curcumin, and H₂ O₂ in PC12 cells. Flow cytometry was used to detect changes in reactive oxygen species and the rate of apoptosis in each group. To determine whether Nrf2 entered the nucleus, immunofluorescence was used. Both tissues and cells were subjected to RT-PCR and Western blotting detection at the same time. The levels of oxidative stress were determined using a malondialdehyde (MDA) and superoxide dismutase (SOD) assay kit.

RESULTS

Ketamine reduced the number of neurons in the cortex and hippocampus of rats. The proteins Bax and Caspase-3 were upregulated, while Bcl-2 was down-regulated in the cortex and hippocampus. The viability of PC12 cells has decreased. MDA content increased while SOD activity decreased in cortex, hippocampus, and PC12 cells. Ketamine had an effect on the expression of some genes in the Nrf2 signaling pathway as well as apoptosis. Curcumin pretreatment may be able to prevent ketamine-induced damage.

CONCLUSIONS

The oxidative stress and apoptosis caused by ketamine during growth of the cerebral cortex, hippocampus, and PC12 cells may be decreased by curcumin's activation of the Nrf2 signaling pathway. Our research provides a potential strategy for the secure administration of anesthetics in medical settings.

Reversal of oxidative stress, cytokine toxicity and DNA fragmentation by quercetin in dizocilpine-induced animal model of Schizophrenia

Quercetin, a polyphenolic compound found in a variety of plant products possesses various biological activities and beneficial effects on human health. Schizophrenia (SZ) is one of the neuropsychiatric disorders in human beings with rapid mortality and intense morbidity which can be treated with antipsychotics, but these commercial drugs exert adverse effects and have less efficacy to treat the full spectrum of SZ. The present study was conducted to evaluate neuroprotective effects of quercetin in the preventive and therapeutic treatment of SZ. Quercetin was administered as pre- and post-regimens at the dose of 50 mg/kg in dizocilpine-induced SZ rat model for two weeks. Rats were then subjected for the assessment of different behaviors followed by biochemical, neurochemical, and inflammatory marker analyses. The present findings revealed that quercetin significantly reverses the effects of dizocilpine-induced psychosis-like symptoms in all behavioral assessments as well as it also combats oxidative stress. This flavonoid also regulates dopaminergic, serotonergic, and glutamatergic neurotransmission. A profound effect on inflammatory cytokines and decreased %DNA fragmentation was also observed following the administration of quercetin. The findings suggest that quercetin can be considered as a preventive as well as therapeutic strategy to attenuate oxidative stress and cytokine toxicity, regulate neurotransmission, and prevent enhanced DNA fragmentation that can lead to the amelioration of psychosis-like symptoms in SZ.

Role of the NRG1/ErbB4 and PI3K/AKT/mTOR signaling pathways in the anti-psychotic effects of aripiprazole and sertindole in ketamine-induced schizophrenia-like behaviors in rats

Schizophrenia is a common mental disorder affecting patients' thoughts, behavior, and cognition. Recently, the NRG1/ErbB4 signaling pathway emerged as a candidate therapeutic target for schizophrenia. This study investigates the effects of aripiprazole and sertindole on the NRG1/ErbB4 and PI3K/AKT/mTOR signaling pathways in ketamine-induced schizophrenia in rats. Young male Wistar rats received ketamine (30 mg/kg, intraperitoneally) for 5 consecutive days and aripiprazole (3 mg/kg, orally) or sertindole (2.5 mg/kg, orally) for 14 days. The proposed pathway was investigated by injecting LY294002 (a selective PI3K inhibitor) (25 μg/kg, intrahippocampal injection) 30 min before the drugs. Twenty-four hours after the last injection, animals were subjected to behavioral tests: the open field test, sucrose preference test, novel object recognition task, and social interaction test. Both aripiprazole and sertindole significantly ameliorated ketamine-induced schizophrenic-like behavior, as expected, because of their previously demonstrated antipsychotic activity. Besides, both drugs alleviated ketamine-induced oxidative stress and neurotransmitter level changes in the hippocampus. They also increased the gamma-aminobutyric acid and glutamate levels and glutamate decarboxylase 67 and parvalbumin mRNA expression in the hippocampus. Moreover, aripiprazole and sertindole increased the NRG1 and ErbB4 mRNA expression levels and PI3K, p-Akt, and mTOR protein expression levels. Interestingly, pre-injecting LY294002 abolished all the effects of the drugs. This study reveals that the antipsychotic effects of aripiprazole and sertindole are partly due to oxidative stress reduction as well as NRG1/ErbB4 and PI3K/AKT/mTOR signaling pathways activation. The NRG1/ErbB4 and PI3K signaling pathways may offer a new therapeutic approach for treating schizophrenia in humans.

Sex differences on the response to antidepressants and psychobiotics following early life stress in rats

Major depressive disorder (MDD) is the most prevalent mood disorder globally. Most antidepressants available for the treatment of MDD increase the concentration of monoamines in the synaptic cleft. However, such drugs have a high latency time to obtain benefits. Thus, new antidepressants with fast action and robust efficacy are very important. This study evaluated the effects of escitalopram, ketamine, and probiotic Bifidobacterium infantis in rats submitted to the maternal deprivation (MD). MD rats received saline, escitalopram, ketamine, or probiotic for 10, 30, or 50 days, depending on the postnatal day (PND):21, 41, and 61. Following behavior, this study examined the integrity of the blood-brain barrier (BBB) and oxidative stress markers. MD induced depressive-like behavior in females with PND21 and males with PND61. All treatments reversed depressive-like behavior in females and escitalopram and ketamine in males. MD induced an increase in the permeability of the BBB, an imbalance between oxidative stress and antioxidant defenses. Treatments regulated the oxidative damage and the integrity of the BBB induced by MD. The treatment with escitalopram, ketamine, or probiotics may prevent behavioral and neurochemical changes associated with MDD, depending on the developmental period and gender.

A mini-review of the effects of inhalational and intravenous anesthetics on oxidative stress in dogs

General anesthesia increases the production of reactive oxygen species (ROS), which can exacerbate or increase oxidative stress and thus affect the prognosis of surgical procedures. Oxidative stress has been implicated in the development of cardiovascular, dermatologic, oncologic, and other diseases in dogs, as well as ischemia and reperfusion injury. Some anesthetics, such as halogenated anesthetics, have been shown to stimulate the production of ROS, while others, such as propofol, have antioxidant properties. However, the antioxidant effects of these anesthetics may not be sufficient to counteract oxidative damage at the doses used clinically. Nevertheless, the effects of anesthetics should be considered to minimize oxidative damage during anesthesia in dogs to improve the outcome of procedures requiring general anesthesia. This mini-review addresses the current knowledge on oxidative stress during inhalational and intravenous anesthesia in dogs. There is still a lack of information on the management of anesthesia in dogs with respect to oxidative stress. Further research, including comprehensive clinical studies is needed to better understand oxidative injury mechanisms and improve perioperative protocols during anesthesia in dogs.

Safety of general anaesthetics on the developing brain: are we there yet?

Thirty years ago, neurotoxicity induced by general anaesthetics in the developing brain of rodents was observed. In both laboratory-based and clinical studies, many conflicting results have been published over the years, with initial data confirming both histopathological and neurodevelopmental deleterious effects after exposure to general anaesthetics. In more recent years, animal studies using non-human primates and new human cohorts have identified some specific deleterious effects on neurocognition. A clearer pattern of neurotoxicity seems connected to exposure to repeated general anaesthesia. The biochemistry involved in this neurotoxicity has been explored, showing differential effects of anaesthetic drugs between the developing and developed brains. In this narrative review, we start with a comprehensive description of the initial concerning results that led to recommend that any non-essential surgery should be postponed after the age of 3 yr and that research into this subject should be stepped up. We then focus on the neurophysiology of the developing brain under general anaesthesia, explore the biochemistry of the observed neurotoxicity, before summarising the main scientific and clinical reports investigating this issue. We finally discuss the GAS trial, the importance of its results, and some potential limitations that should not undermine their clinical relevance. We finally suggest some key points that could be shared with parents, and a potential research path to investigate the biochemical effects of general anaesthesia, opening up perspectives to understand the neurocognitive effects of repetitive exposures, especially in at-risk children.

Neonatal Anesthesia and Oxidative Stress

Neonatal anesthesia, while often essential for surgeries or imaging procedures, is accompanied by significant risks to redox balance in the brain due to the relatively weak antioxidant system in children. Oxidative stress is characterized by concentrations of reactive oxygen species (ROS) that are elevated beyond what can be accommodated by the antioxidant defense system. In neonatal anesthesia, this has been proposed to be a contributing factor to some of the negative consequences (e.g., learning deficits and behavioral abnormalities) that are associated with early anesthetic exposure. In order to assess the relationship between neonatal anesthesia and oxidative stress, we first review the mechanisms of action of common anesthetic agents, the key pathways that produce the majority of ROS, and the main antioxidants. We then explore the possible immediate, short-term, and long-term pathways of neonatal-anesthesia-induced oxidative stress. We review a large body of literature describing oxidative stress to be evident during and immediately following neonatal anesthesia. Moreover, our review suggests that the short-term pathway has a temporally limited effect on oxidative stress, while the long-term pathway can manifest years later due to the altered development of neurons and neurovascular interactions.

Combination of electroconvulsive stimulation with ketamine or escitalopram protects the brain against inflammation and oxidative stress induced by maternal deprivation and is critical for associated behaviors in male and female rats

This study aimed at evaluating the treatment effects with ketamine, electroconvulsive stimulation (ECS), escitalopram, alone or in combination in adult rats of both sexes, subjected to the animal model of maternal deprivation (MD). All groups were subjected to the forced swimming test (FST), splash and open field tests. The prefrontal cortex (PFC), hippocampus and serum were collected to analyze oxidative stress and inflammatory parameters. MD induced depressive-like behavior in the FST test in males and reduced grooming time in male and female rats. The treatments alone or combined reversed depressive and anhedonic behavior in females. In males, all treatments increased grooming time, except for ECS + escitalopram + ketamine. MD increased lipid peroxidation and protein carbonylation, nitrite/nitrate concentration and myeloperoxidase activity in the PFC and hippocampus of males and females. However, the treatment's response was sex dependent. Catalase activity decreased in the PFC of males and the PFC and hippocampus of females, and most treatments were not able to reverse it. MD increased the inflammation biomarkers levels in the PFC and hippocampus of males and females, and most treatments were able to reverse this increase. In all groups, a reduction in the interleukin-10 levels in the PFC and hippocampus of female and male rats was observed. Our study shows different responses between the sexes in the patterns evaluated and reinforces the use of the gender variable as a biological factor in MDD related to early stress and in the response of the therapeutic strategies used.

Blood-based oxidation markers in medicated and unmedicated schizophrenia patients: A meta-analysis

Increased reactive species due to the effect of antipsychotics on oxidative stress may be involved in the development of schizophrenia. However, antipsychotics may have different direct antioxidant effects due to their chemical structures. The present meta-analysis aimed to investigate whether the cause increased oxidant status in schizophrenia patients is due to the illness or induction by antipsychotics. Studies published from 1964 to 2021 were selected from Pubmed and Scopus databases. Data were analysed using Comprehensive Meta-Analysis version 2. Effect sizes were calculated and compared between unmedicated and medicated patients and healthy controls. Heterogeneity and publication bias were assessed. Subgroup analyses were conducted on drug-free and drug-naïve patients, and patients treated with atypical and typical antipsychotics. We found that medicated patients had significantly higher malondialdehyde (MDA), thiobarbituric acid reactive substances (TBARS) and total oxidant status (TOS). Meanwhile, significantly increased plasma/serum MDA and nitric oxide (NO) were observed in unmedicated patients only. Higher lipid peroxidation in the drug-naïve group may be associated schizophrenia. However, both atypical and typical antipsychotics may worsen lipid peroxidation. Antipsychotic discontinuation in the drug-free group led to significantly increased plasma/serum NO, with larger effect size than the atypical antipsychotic group. In conclusion, medicated schizophrenia patients were more suffered from increased oxidative stress. Therefore, future study may focus on the mechanism of action of specific antipsychotic on oxidative stress.

Zoletil promotes apoptosis in BV-2 microglial cells via induction of oxidative stress and neural inflammation

Zoletil® (ZOL) is a combination drug of tiletamine, a dissociative anesthetic and zolazepam, a minor tranquilize, which has been used to induce short-term anesthesia in various animals. Depending on the administered dose, the effects of ZOL can range from sedation to anesthesia. Here, we aimed to determine the neurotoxicity of ZOL and elucidate its mechanism of action using BV-2 microglial cells. The results of MTT reduction assay and TUNEL staining revealed that ZOL induced neuronal toxicity and apoptosis in BV-2 cells. ZOL caused apoptosis via phosphorylation of c-Jun N-terminal kinase, increased ratio of Bax to Bcl-2, disruption of mitochondrial membrane potential, activation of caspase-3, and cleavage of poly (ADP-ribose) polymerase. Furthermore, reactive oxygen species were involved in ZOL-induced neuronal cell death as assessed by 2',7'-dichlorofluorescein diacetate staining. Moreover, BV-2 cells treated with ZOL exhibited increased expression of inflammatory enzymes, such as inducible nitric oxide synthase and cyclooxygenase-2, along with subsequent production of nitric oxide and prostaglandin E₂. ZOL upregulated the expression of interleukin-1β, a proinflammatory cytokine. With respect to its molecular mechanism, ZOL increased the nuclear translocation and DNA binding of redox-sensitive transcription factor NF-κB, which seemed to be mediated by activation of extracellular signal-regulated kinase and p38 mitogen-activated protein kinase. These findings suggest that ZOL leads to apoptosis in BV-2 cells by inducing oxidative stress and inflammatory responses.

Neuroprotective effects of curcumin-loaded nanophytosome on ketamine-induced schizophrenia-like behaviors and oxidative damage in male mice

Curcumin as an antioxidant natural herb has shown numerous pharmacological effects. However, the poor bioavailability of curcumin is a significant pharmacological barrier for its antioxidant activities. The present study was conducted to develop curcumin-loaded nanophytosome (CNP) and explore their therapeutic potential in a ketamine (KET)-induced schizophrenia (SCZ) model. The mice in our experiment were treated orally with curcumin and CNP (20 mg/kg) for 30 consecutive days. In addition, the animals received intraperitoneal injection of KET (30 mg/kg/day) from the 16th to the 30th day. SCZ-like behaviors were evaluated employing forced swimming test (FST), open field test (OFT), and novel object recognition test (NORT), and oxidative stress markers in the brain were estimated. Our results revealed that CNP has a greater neuroprotective effect compared to free curcumin. CNP pretreatment significantly ameliorated KET-induced brain injury evidenced by a marked reduction in the depressive and anxiety-like behaviors, memory deficits, and oxidative stress markers in cortical and subcortical tissues. Therefore, CNP, as a suitable drug delivery system, may improve curcumin bioavailability and confer stronger neuroprotective effects against KET-induced behavioral deficits and oxidative damages.

Andrographolide improves PCP-induced schizophrenia-like behaviors through blocking interaction between NRF2 and KEAP1

Schizophrenia is one of the foremost psychological illness around the world, and recent evidence shows that inflammation and oxidative stress may play a critical role in the etiology of schizophrenia. Andrographolide is a diterpenoid lactone from Andrographis paniculate, which has shown anti-inflammation and anti-oxidative effects. In this study, we explored whether andrographolide can improve schizophrenia-like behaviors through its inhibition of inflammation and oxidative stress in Phencyclidine (PCP)-induced mouse model of schizophrenia. We found that abnormal behavioral including locomotor activity, forced swimming and novel object recognition were ameliorated following andrographolide administration (5 mg/kg and 10 mg/kg). Andrographolide inhibited PCP-induced production of inflammatory cytokines, decreased p-p65, p-IκBα, p-p38 and p-ERK1/2 in the prefrontal cortex. Andrographolide significantly declined the level of MDA and GSH, as well as elevated the activity of SOD, CAT and GCH-px. In addition, andrographolide increased expression of NRF-2, HO-1 and NQO-1, promoted nuclear translocation of NRF-2 through blocking the interaction between NRF-2 and KEAP1, which may be associated with directly binding to NRF-2. Furthermore, antioxidative effects and anti-schizophrenia-like behaviors of andrographolide were compromised by the application of NRF-2 inhibitor ML385. In conclusion, these results suggested that andrographolide improved oxidative stress and schizophrenia-like behaviors induced by PCP through increasing NRF-2 pathway.

The Nitric Oxide (NO) Donor Sodium Nitroprusside (SNP) and Its Potential for the Schizophrenia Therapy: Lights and Shadows

Schizophrenia is a severe psychiatric disorder affecting up to 1% of the worldwide population. Available therapy presents different limits comprising lack of efficiency in attenuating negative symptoms and cognitive deficits, typical features of schizophrenia and severe side effects. There is pressing requirement, therefore, to develop novel neuroleptics with higher efficacy and safety. Nitric oxide (NO), an intra- and inter-cellular messenger in the brain, appears to be implicated in the pathogenesis of schizophrenia. In particular, underproduction of this gaseous molecule is associated to this mental disease. The latter suggests that increment of nitrergic activity might be of utility for the medication of schizophrenia. Based on the above, molecules able to enhance NO production, as are NO donors, might represent a class of compounds candidates. Sodium nitroprusside (SNP) is a NO donor and is proposed as a promising novel compound for the treatment of schizophrenia. In the present review, we intended to critically assess advances in research of SNP for the therapy of schizophrenia and discuss its potential superiority over currently used neuroleptics.

Effects of maternal folic acid supplementation on nuclear methyltransferase activity of adult rats subjected to an animal model of schizophrenia

INTRODUCTION

Schizophrenia is considered one of the most disabling and severe human diseases worldwide. The etiology of schizophrenia is thought to be multifactorial and evidence suggests that DNA methylation can play an important role in underlying pivotal neurobiological alterations of this disorder. Some studies have demonstrated the effects of dietary supplementation as an alternative approach to the prevention of schizophrenia, including folic acid. However, no study has ever investigated the role of such supplementation in altering the DNA methylation system in the context of schizophrenia.

OBJECTIVES

The present study aims to investigate the effects of maternal folic acid supplementation at different doses on nuclear methyltransferase activity of adult rat offspring subjected to an animal model schizophrenia induced by ketamine.

METHODS

Adult female Wistar rats, (60 days old) received folic acid-deficient diet, control diet, or control diet plus folic acid supplementation (at 5, 10, or 50 mg/kg) during pregnancy and lactation. After reaching adulthood (60 days), the male offspring of these dams were subjected to the animal model of schizophrenia induced by 7 days of ketamine intraperitoneal injection (25 mg/kg). After the 7-day protocol, the activity of nuclear methyltransferase was evaluated in the brains of the offspring.

RESULTS

Maternal folic acid supplementation at 50 mg/kg increased methyltransferase activity in the frontal cortex, while 10 mg/kg increased methyltransferase activity in the hippocampus. In the striatum of offspring treated with ketamine, maternal deficient diet, control diet, and folic acid supplementation at 5 mg/kg decreased methyltransferase activity compared to the control group. The folic acid supplementation at 10 and 50 mg/kg reversed this ketamine effect.

CONCLUSIONS

Maternal FA deficiency could be related to schizophrenia pathophysiology, while FA supplementation could present a protective effect since it demonstrated persistent effects in epigenetic parameters in adult offspring.

Crocus sativus L. Extracts and Its Constituents Crocins and Safranal; Potential Candidates for Schizophrenia Treatment?

Schizophrenia is a chronic mental devastating disease. Current therapy suffers from various limitations including low efficacy and serious side effects. Thus, there is an urgent necessity to develop new antipsychotics with higher efficacy and safety. The dried stigma of the plant Crocus sativus L., (CS) commonly known as saffron, are used in traditional medicine for various purposes. It has been demonstrated that saffron and its bioactive components crocins and safranal exert a beneficial action in different pathologies of the central nervous system such as anxiety, depression, epilepsy and memory problems. Recently, their role as potential antipsychotic agents is under investigation. In the present review, I intended to critically assess advances in research of these molecules for the treatment of schizophrenia, comment on their advantages over currently used neuroleptics as well-remaining challenges. Up to our days, few preclinical studies have been conducted to this end. In spite of it, results are encouraging and strongly corroborate that additional research is mandatory aiming to definitively establish a role for saffron and its bioactive components for the treatment of schizophrenia.

Evaluation of the effects of two anaesthetic protocols on oxidative status and DNA damage in red-eared sliders (Trachemys scripta elegans) undergoing endoscopic coeliotomy

The aim of this study was to assess how red-eared sliders (Trachemys scripta elegans) respond to anaesthesia itself and coelioscopy. For that purpose, the turtles were anaesthetised with ketamine-medetomidine or propofol, and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) and the level of malondialdehyde (MDA) were determined by spectrophotometry. The possible genotoxic effects of the anaesthetic agents were estimated by comet assay. A total of 24 turtles were included in this study. The animals were divided into four groups according to the anaesthetic protocol and according to whether endoscopy would be performed. Significantly decreased activities of CAT were found only in the propofol group and in turtles undergoing coelioscopy. Both anaesthetic protocols induced significantly increased MDA levels, while no differences were observed after the intervention. A significant increase in GST activity was detected in turtles after both anaesthetic protocols, but after coelioscopy significant changes in GST activity were found only in the propofol group. However, no differences in SOD activity and no DNA damages were detected in either group. These findings suggest that ketamine-medetomidine may be more suitable anaesthetic agents in red-eared sliders than propofol.

Long Acting Polycaprolactone Based Parenteral Formulation of Aripiprazole Targeting Behavioural and Biochemical Deficit in Schizophrenia

Schizophrenia is a neurodevelopmental disorder which is expressed in the form of disturbed behaviour and abnormal mental functions. Patient's non-adherence to the medicine is the main cause of failure of drug therapy and increases incidence of relapses. Thus, for successful management of disease long acting parenteral formulations were developed. Aripiprazole was encapsulated in biocompatible polycaprolactone microsphere by o/w emulsion solvent-evaporation method in order to achieve sustained release of the drug for several weeks after single subcutaneous administration. They were optimised on the basis of various parameters such as physical appearance, particle size (49.4 μm-387.1 μm), encapsulation efficiency (70%-95%), percentage yield (33%-75%) and drug loading (25.9%-47.5%). The surface topography and sphericity of the microspheres was determined by scanning electron microscopy which revealed that the microspheres formed were spherical and non-porous in nature. The in vitro releases from the selected formulations were found to be 87% and 95% respectively after 45 days of dissolution. In vivo efficacy of optimised formulation showed significantly (p < 0.05) amelioration of various positive, negative and cognitive symptoms associated with schizophrenia and oxidative stress markers in ketamine-induced schizophrenia model in rats for 30 days.

Postnatal Antioxidant and Anti-inflammatory Treatments Prevent Early Ketamine-Induced Cortical Dysfunctions in Adult Mice

Early brain insult, interfering with its maturation, may result in psychotic-like disturbances in adult life. Redox dysfunctions and neuroinflammation contribute to long-term psychiatric consequences due to neurodevelopmental abnormalities. Here, we investigated the effects of early pharmacological modulation of the redox and inflammatory states, through celastrol, and indomethacin administration, on reactive oxygen species (ROS) amount, levels of malondialdehyde (MDA) and antioxidant enzymes (superoxide dismutase 1, SOD1, glutathione, GSH, and catalase, CAT), as well as of pro-inflammatory cytokines (tumor necrosis factor-alpha, TNF-α, interleukin-6, IL-6, and interleukin-1 beta, IL-1β), in the prefrontal cortex of adult mice exposed to a neurotoxic insult, i.e. ketamine administration, in postnatal life. Early celastrol or indomethacin prevented ketamine-induced elevations in cortical ROS production. MDA levels in ketamine-treated mice, also administered with celastrol, were comparable with the control ones. Indomethacin also prevented the increase in lipid peroxidation following early ketamine administration. Whereas no significant differences were detected in SOD1, GSH, and CAT levels between ketamine and saline-administered mice, celastrol elevated the cortical amount of these antioxidant enzymes and the same effect was induced by indomethacin per se. Both celastrol and indomethacin prevented ketamine-induced enhancement in TNF-α and IL-1β levels, however, they had no effects on increased IL-6 amount resulting from ketamine exposure in postnatal life. In conclusion, our data suggest that an early increase in cortical ROS scavenging and reduction of lipid peroxidation, via the enhancement of antioxidant defense, together with inhibition of neuroinflammation, may represent a therapeutic opportunity against psychotic-like disturbances resulting, later in life, from the effects of a neurotoxic insult on the developing brain.

Crocin alleviates schizophrenia-like symptoms in rats by upregulating silent information regulator-1 and brain derived neurotrophic factor

BACKGROUND

In neonatal rats, MK-801 treatments can produce schizophrenia-like symptoms. Crocin is a water soluble carotenoid in Saffron that exerts potent neuroprotective effects. This work aimed to demonstrate the function of crocin in the alleviation of motor and cognitive impairments elicited by MK-801 in a neonatal rodent schizophrenia model, and to illustrate the underlying molecular mechanisms.

METHODS

Rats were treated with vehicle, MK-801 (1 mg/kg), MK-801 + 25 mg/kg crocin, or MK-801 + 50 mg/kg crocin. Motor learning and coordination, locomotion and exploratory activities, as well as spatial memory were assessed using the rotarod test, pen field test, and the Morris water maze test, respectively. Relative mRNA and protein levels of genes of interest were analyzed using qRT-PCR and Western blot assays, respectively.

RESULTS

In the hippocampus of rats with MK-801-elicited schizophrenia, administration of crocin elevated the expression of silent information regulator-1 (SIRT1) and brain derived neurotrophic factor (BDNF), and relieved the oxidative stress. The learning deficits and motor perturbations caused by MK-801 treatments were also alleviated by the crocin administration.

CONCLUSION

Collectively, crocin has exerted neuroprotective effects in the rat model of MK-801-elicited schizophrenia, via regulations of SIRT1 and downstream BDNF expression in the hippocampus.

Ketamine disrupted storage but not retrieval of information in male rats and apomorphine counteracted its impairing effect

Ketamine, a non-competitive NMDA receptor antagonist, has been reported to mimic the cognitive symptoms of schizophrenia in animals. It has been reported to produce learning and memory deficits in rodents. However, there have limited number of reports that investigated the specific components of memory process that are affected with ketamine. In the present study, we investigated the effects of ketamine [8 and 20 mg/kg, intraperitoneally, (i.p.)] on storage and retrieval of information in rats using an object recognition test. We examined also whether a low dose range of the D1/D2 dopamine receptor agonist apomorphine (0.05 and 0.1 mg/kg, i.p.) would counteract the effects of ketamine. The results show that ketamine dose-dependently impaired storage of information while it did not affect rats' retrieval abilities. Administration of apomorphine reversed the ketamine-induced performance deficits in the ORT. The current findings show a differential modulation of post-training memory components (storage and retrieval of information) by ketamine and suggest a functional interaction between dopamine and NMDA receptors in the control of memory storage which may be of relevance to cognitive deficits a core feature of schizophrenia.

Resveratrol, a SIRT1 Activator, Ameliorates MK-801-Induced Cognitive and Motor Impairments in a Neonatal Rat Model of Schizophrenia

BACKGROUND

In neonatal rats, MK-801 treatment generates schizophrenia-like symptoms. Resveratrol (RSV) is a phenolic compound and a potent neuroprotective agent. This research aimed to illustrate the effect of RSV on the amelioration of MK-801-induced cognitive and motor impairments in a neonatal rat schizophrenia model and the related potential molecular changes.

METHODS

Rats were administrated with MK-801, MK-801 + RSV (40 mg/kg), or MK-801 + RSV (80 mg/kg). Motor learning, coordination, locomotor and exploratory activity, and spatial memory were measured by rotarod test, pen field test, and Morris water maze test. Relative protein levels were analyzed by Western blot and ELISA. mRNA levels were shown by qRT-PCR.

RESULTS

In the hippocampus of MK-801-induced schizophrenia rat model, RSV enhanced silent information regulator 1 (SIRT1) and brain derived neurotrophic factor (BDNF) expression and alleviated oxidative stress. Motor perturbations and learning impairments by MK-801 treatment were ameliorated by the administration of RSV.

CONCLUSION

In conclusion, RSV showed neuroprotective effect on MK-801-induced schizophrenia rat model through regulating SIRT1 and downstream BDNF expression in the hippocampus.

Oxidation-reduction mechanisms in psychiatric disorders: A novel target for pharmacological intervention

While neurotransmitter dysfunction represents a key component in mental illnesses, there is now a wide agreement for a central pathophysiological hub that includes hormones, neuroinflammation, redox mechanisms as well as oxidative stress. With respect to oxidation-reduction (redox) mechanisms, preclinical and clinical evidence suggests that an imbalance in the pro/anti-oxidative homeostasis toward the increased production of substances with oxidizing potential may contribute to the etiology and manifestation of different psychiatric disorders. The substantial and continous demand for energy renders the brain highly susceptible to disturbances in its energy supply, especially following exposure to stressful events, which may lead to overproduction of reactive oxygen and nitrogen species under conditions of perturbed antioxidant defenses. This will eventually induce different molecular alterations, including extensive protein and lipid peroxidation, increased blood-brain barrier permeability and neuroinflammation, which may contribute to the changes in brain function and morphology observed in mental illnesses. This view may also reconcile different key concepts for psychiatric disorders, such as the neurodevelopmental origin of these diseases, as well as the vulnerability of selective cellular populations that are critical for specific functional abnormalities. The possibility to pharmacologically modulate the redox system is receiving increasing interest as a novel therapeutic strategy to counteract the detrimental effects of the unbalance in brain oxidative mechanisms. This review will describe the main mechanisms and mediators of the redox system and will examine the alterations of oxidative stress found in animal models of psychiatric disorders as well as in patients suffering from mental illnesses, such as schizophrenia and major depressive disorder. In addition, it will discuss studies that examined the effects of psychotropic drugs, including antipsychotics and antidepressants, on the oxidative balance as well as studies that investigated the effectiveness of a direct modulation of oxidative mechanisms in counteracting the behavioral and functional alterations associated with psychiatric disorders, which supports the promising role of the redox system as a novel therapeutic target for the improved treatment of brain disorders.

Potential therapeutic antipsychotic effects of Naringin against ketamine-induced deficits in rats: Involvement of Akt/GSK-3β and Wnt/β-catenin signaling pathways

AIM

Schizophrenia is a chronic, disabling and one of the major neurological illnesses affecting nearly 1% of the global population. Currently available antipsychotic medications possess limited effects. The current research aimed at investigating potential therapeutic add-on benefit to enhance the effects of clozapine anti-schizophrenic.

MAIN METHODS

To induce schizophrenia, ketamine was administered at a dose of 25 mg/kg i.p. for 14 consecutive days. Naringin was administered to Wistar rats at a dose of 100 mg/kg orally, alone or in combination with clozapine 5 mg/kg i.p from day 8 to day 14. Furthermore, behavioral tests were conducted to evaluate positive, negative and cognitive symptoms of schizophrenia. In addition, neurotransmitters' levels were detected using HPLC. Moreover, oxidative stress markers were assessed using spectrophotometry. Furthermore, apoptotic and wnt/β-catenin pathway markers were determined using western blotting (Akt, GSK-3β and β-catenin), colorimetric methods (Caspase-3) and immunohistochemistry (Bax, Bcl2 and cytochrome c).

KEY FINDINGS

Ketamine induced positive, negative and cognitive schizophrenia symptoms together with neurotransmitters' imbalance. In addition, ketamine treatment caused significant glutathione depletion, lipid peroxidation and reduction in catalase activity. Naringin and/or clozapine treatment significantly attenuated ketamine-induced schizophrenic symptoms and oxidative injury. Additionally, ketamine provoked apoptosis via increasing Bax/Bcl2 expression, caspase-3 activity, and Cytochrome C and Akt protein expression while naringin/clozapine treatment significantly inhibited this apoptotic effect. Moreover, naringin activated the neurodevelopmental wnt/β-catenin signaling pathway evidenced by increasing pGSK-3β and reducing pβ-catenin protein expression.

SIGNIFICANCE

These findings may suggest that naringin possesses a potential therapeutic add-on effect against ketamine-induced schizophrenia.

Ketamine induces immediate and delayed alterations of OCD-like behavior

RATIONALE

Obsessive-compulsive disorder (OCD) is a psychiatric disorder characterized by intrusive obsessive thoughts and/or compulsive behaviors. Currently, serotonin reuptake inhibitors (SRIs) provide the only pharmacological monotherapy for OCD, but response rates are insufficient. Ketamine, a noncompetitive NMDA receptor antagonist, was reported to have rapid, sustained therapeutic effects in OCD patients. However, the mechanisms remain unknown.

OBJECTIVES

Here, we aimed to provide a platform for investigating mechanisms underlying anti-OCD effects of ketamine treatment by assessing whether ketamine pretreatment could alleviate 5-HT1B receptor (5-HT1BR)-induced OCD-like behavior in mice.

METHODS

We assessed whether acute ketamine (0, 3, 10, 30 mg/kg), administered at two pretreatment time points (30 min, 24 h), would modulate 5-HT1BR-induced OCD-like behavior in mice. Behavioral measures were perseverative hyperlocomotion in the open field and deficits in prepulse inhibition (PPI) induced by acute pharmacological 5-HT1BR challenge.

RESULTS

Three milligrams per kilogram of ketamine reduced 5-HT1BR-induced perseverative hyperlocomotion, but not PPI deficits, 24 h postinjection. In contrast, higher doses of ketamine were either ineffective (10 mg/kg) or exacerbated (30 mg/kg) 5-HT1BR-induced perseverative hyperlocomotion 30 min postinjection. At 24 h postinjection, 30 mg/kg ketamine reduced perseverative hyperlocomotion across all groups.

CONCLUSIONS

Our results suggest that the 5-HT1BR-induced model of OCD-like behavior is sensitive to a low dose of ketamine, a potential fast-acting anti-OCD treatment, and may provide a tool for studying mechanisms underlying the rapid therapeutic effects of ketamine in OCD patients.

Energization by multiple substrates and calcium challenge reveal dysfunctions in brain mitochondria in a model related to acute psychosis

Schizophrenia etiology is unknown, nevertheless imbalances occurring in an acute psychotic episode are important to its development, such as alterations in cellular energetic state, REDOX homeostasis and intracellular Ca²⁺ management, all of which are controlled primarily by mitochondria. However, mitochondrial function was always evaluated singularly, in the presence of specific respiratory substrates, without considering the plurality of the electron transport system. In this study, mitochondrial function was analyzed under conditions of isolated or multiple respiratory substrates using brain mitochondria isolated from MK-801-exposed mice. Results showed a high H₂O₂ production in the presence of pyruvate/malate, with no change in oxygen consumption. In the condition of multiple substrates, however, this effect is lost. The analysis of Ca²⁺ retention capacity revealed a significant change in the uptake kinetics of this ion by mitochondria in MK-801-exposed animals. Futhermore, when mitochondria were exposed to calcium, a total loss of oxidative phosphorylation and an impressive increase in H₂O₂ production were observed in the condition of multiple substrates. There was no alteration in the activity of the antioxidant enzymes analyzed. The data demonstrate for the first time, in an animal model of psychosis, two important aspects (1) mitochondria may compensate deficiencies in a single mitochondrial complex when they oxidize several substrates simultaneously, (2) Ca²⁺ handling is compromised in MK-801-exposed mice, resulting in a loss of phosphorylative capacity and an increase in H₂O₂ production. These data favor the hypothesis that disruption of key physiological roles of mitochondria may be a trigger in acute psychosis and, consequently, schizophrenia.

Sub-anesthetic and anesthetic ketamine produce different long-lasting behavioral phenotypes (24 h post-treatment) via inducing different brain-derived neurotrophic factor (BDNF) expression level in the hippocampus

Clinical and preclinical researches have shown that sub-anesthetic ketamine elicits sustained antidepressant effects for up to 1-2 weeks. Pharmacokinetics studies (t1/2 = 23 min) in mice showed no ketamine residue at 24 h after sub-anesthetic or anesthetic ketamine administration. Therefore, this study aims to reveal the mechanism underlying these different biological functions at 24 h after sub-anesthetic and anesthetic ketamine treatment. First, at the animal behavioral level, we found that sub-anesthetic ketamine induced antidepressant and anxiolytic effects while anesthetic ketamine induced depressive-like phenotypes and cognitive impairment. Second, we examined the correlation between behavior phenotype and protein expression, and found that the Brain-derived neurotrophic factor (BDNF) level is oppositely regulated by sub-anesthetic and anesthetic ketamine. Sub-anesthetic ketamine significantly increased the BDNF level, correlating to antidepressant effects; whereas anesthetic dose reduced BDNF expression in the hippocampus, correlating to depressive-like behaviors, anxiety-like behaviors and cognitive impairment. Third, the antidepressant effects of sub-anesthetic ketamine were prevented by pre-treatment of ANA-12, a Tropomyosin receptor kinase B (TrkB) inhibitor. Thus, we conclude that BDNF may be the key factor underlying antidepressant and anxiolytic effects of sub-anesthetic ketamine at 24 h after treatment. These results may shed light on future studies and the development of long-lasting anti-depressant drugs and therapies.

Perioperative Oxidative Stress: The Unseen Enemy

Reactive oxygen species (ROS) are essential for cellular signaling and physiological function. An imbalance between ROS production and antioxidant protection results in a state of oxidative stress (OS), which is associated with perturbations in reduction/oxidation (redox) regulation, cellular dysfunction, organ failure, and disease. The pathophysiology of OS is closely interlinked with inflammation, mitochondrial dysfunction, and, in the case of surgery, ischemia/reperfusion injury (IRI). Perioperative OS is a complex response that involves patient, surgical, and anesthetic factors. The magnitude of tissue injury inflicted by the surgery affects the degree of OS, and both duration and nature of the anesthetic procedure applied can modify this. Moreover, the interindividual susceptibility to the impact of OS is likely to be highly variable and potentially linked to underlying comorbidities. The pathological link between OS and postoperative complications remains unclear, in part due to the complexities of measuring ROS- and OS-mediated damage. Exogenous antioxidant use and exercise have been shown to modulate OS and may have potential as countermeasures to improve postoperative recovery. A better understanding of the underlying mechanisms of OS, redox signaling, and regulation can provide an opportunity for patient-specific phenotyping and development of targeted interventions to reduce the disruption that surgery can cause to our physiology. Anesthesiologists are in a unique position to deliver countermeasures to OS and improve physiological resilience. To shy away from a process so fundamental to the welfare of these patients would be foolhardy and negligent, thus calling for an improved understanding of this complex facet of human biology.

Gallic acid prevents ketamine-induced oxidative damages in brain regions and liver of rats

INTRODUCTION

Ketamine (KET) is an anesthetic agent widely used in human and veterinary medicine. According to studies, KET is associated to direct neutorotoxic damages due to its capacity to induce oxidative stress. Because of the free radical generation in the organism and its relation with diseases' development, there is a growing interest to study antioxidant molecules, such as gallic acid (GA), a natural phenolic compound.

AIM

Evaluate the GA antioxidant potential for the prevention of oxidative damage in the brain and liver tissue of rats exposed to acute KET administration.

MATERIAL AND METHODS

32 Wistar male rats received GA (by gavage, 13.5 mg/kg) for three consecutive days, 24 h after the last GA dose, animals were anesthetized with KET (50 mg/kg, i.m.). All animals were euthanized by decapitation 60 min after KET administration. The liver, brain cortex and hippocampus were removed and homogenized for biochemical analysis.

RESULTS

In brain cortex, KET increased reactive species (RS) generation, protein carbonyls (PC) levels and reduced non-protein thiols (NPSH) levels, while GA pre-treatment reduced PC and increased NPSH levels. KET increased PC and decreased NPSH levels in the hippocampus, and GA reduced PC and NPSH levels. In the liver, no difference was observed in the RS generation, while KET induced and increase of PC levels and decreased NPSH levels, while GA pre-treatment prevented it.

CONCLUSION

GA administration can prevent oxidative damage caused by acute KET administration and minimize its noxious effects. Further studies are needed to evidence GA antioxidant properties regarding KET chronic use.

Subchronic ketamine alters behaviour, metabolic indices and brain morphology in adolescent rats: Involvement of oxidative stress, glutamate toxicity and caspase-3-mediated apoptosis

Ketamine is a dissociative anaesthetic agent whose recreational use amongst adolescents and young adults is reaching epidemic proportions in a number of countries. While animal studies have examined the long-term detrimental effects of early-life ketamine exposure, there is a paucity of information on the immediate effects of ketamine following subchronic administration in the adolescence period. Adolescent rats were assigned into four groups of 10 animals each, administered intraperitoneal (i.p) injections of vehicle or one of three doses of ketamine (7.5, 15 or 30 mg/kg daily) for 8 weeks, and then exposed to behavioural paradigms. Rats were then euthanised after an overnight fast, and blood taken was used for measurement of metabolic indices. The brains were dissected out and either homogenised for estimation of neurochemical parameters, or processed for histological and immunohistochemical studies. Results showed that subchronic administration of ketamine was associated with a lesser weight gain inspite of an increase in food intake across the treatment groups. There was a dose-dependent increase in open-field novelty-induced behaviours, a decline in spatial working-memory, and an anxiolytic effect in the elevated-plus maze. There was associated derangement of serum triglyceride, and increase in brain glutamate levels, acetylcholinesterase activity, plasma/brain oxidative stress parameters, caspase-3 activity and biochemical indices of hepatic and renal function. Ketamine administration was also associated with neurodegenerative changes in the cerebral cortex, hippocampus, cerebellum and the pons. In conclusion, subchronic administration of ketamine to adolescent rats was associated with dose-related memory loss, oxidative stress and possibly caspase-3 mediated neurodegenerative changes.

Markers of oxidative stress and antioxidant status in the plasma, urine and saliva of healthy mice

Oxidative stress markers are usually measured in plasma, a stable environment for biomarkers. Blood collection is invasive, but the use of alternative biofluids is limited, due to high variability. In this study, we aimed to establish reference values for oxidative stress markers in plasma, urine and saliva of adult, healthy mice and to identify some sources of variability. Samples were obtained from 41 female and 37 male adult, healthy mice of the CD-1 strain, aged 95-480 days, weighing 21-55 grams. Reference ranges of TBARS (thiobarbituric acid reactive substances), AOPP (advanced oxidation protein products), fructosamine, GSH/GSSG (reduced and oxidized glutathione) ratio, TAC (total antioxidant capacity), and FRAP (ferric reducing antioxidant power) were measured in plasma and urine, and TBARS, GSH/GSSG ratio, TAC and FRAP in saliva, using standard spectrophotometric and fluorometric methods. Salivary GSH/GSSG and urinary AOPP were higher in females. Urinary fructosamine, GSH/GSSG and FRAP were higher in males. Urinary TAC and FRAP negatively correlated with age, and urinary GSH/GSSG positively correlated with weight. We determined that urine and saliva can be obtained non-invasively from mice, in sufficient amounts for reliable oxidative status assessment. Further studies are needed to uncover whether these biofluids reflect systemic oxidative status in diseases.

Changes in behavioural parameters, oxidative stress and neurotrophins in the brain of adult offspring induced to an animal model of schizophrenia: The effects of FA deficient or FA supplemented diet during the neurodevelopmental phase

A deficiency of maternal folic acid (FA) can compromise the function and development of the brain, and may produce a susceptibility to diseases such as schizophrenia (SZ) in the later life of offspring. The aim of this study was to evaluate the effects of both FA deficient and FA supplemented diets during gestation and lactation on behavioural parameters, the markers of oxidative stress and neurotrophic factors in adult offspring which had been subjected to an animal model of SZ. Female mother rats (Dam's) were separated into experimental maternal groups, which began receiving a special diet (food) consisting of the AIN-93 diet, a control diet, or an FA deficient diet during the periods of pregnancy and lactation. Dam's receiving the control diet were further subdivided into four groups: one group received only control diet, while three groups to receive supplementation with FA at different doses (5, 10 and 50 mg/kg). Adult offspring bred from the Dam's were divided into ten groups for induction of the animal model of SZ through the administration of ketamine (Ket) (25 mg/kg). After the last administration of the drug, the animals were subjected to the behavioural tests and were then euthanized. The frontal cortex (FC) and hippocampus (Hip) were then dissected for later biochemical analysis. Our data demonstrates that Ket induced the model of SZ by altering the behavioural parameters (e.g. hyperlocomotion, social impairment, deficits in the sensory-motor profile and memory damage in the adult animals); and also caused changes in the parameters of oxidative stress (lipid hydroperoxide - LPO; 8-isoprostane - 8-ISO; 4-hydroxynonenal - 4-HNE; protein carbonyl content; superoxide dismutase - SOD and catalase - CAT) as well as in the levels of neurotrophic factors (brain-derived neurotrophic factor - BDNF and nerve growth factor - NGF) particularly within the FC of adult offspring. A deficiency in maternal FA, alone or in combination with ket, was able to induce hyperlocomotion and social impairment in the offspring with increased levels of lipid and protein damage (LPO, 8-ISO, 4-HNE, carbonylation of protein) within the FC, increased activity of antioxidant enzymes (SOD and CAT) in both of the brain structures studied, and also reduced the levels of neurotrophins (BDNF and NGF), particularly within the Hip of the adult offspring. Supplementation of FA (5, 10 and 50 mg/kg) to the Dam's was mostly able to prevent the cognitive damage which was induced by Ket in the adult animals. FA (10 and 50 mg/kg) attenuated the action of Ket in the animals in relation to the biochemical parameters, proving the possible neuroprotective effect of FA in the adulthood of offspring that were subjected to the animal model of SZ. Our study indicates that the intake of maternal FA during pregnancy and lactation plays an important role, particularly in the regulation of markers of oxidative stress and neurotrophins.

The effects of ketamine and thiopental used alone or in combination on the brain, heart, and bronchial tissues of rats

INTRODUCTION

We compared the side effects of ketamine and thiopental used alone and of a ketamine/thiopental combination dose on the brain,heart, and bronchial tissues of rats.

MATERIAL AND METHODS

Three groups received intraperitoneal injections of 30 mg/kg ketamine (K-30); 15 mg/kg thiopental (T-15); or of both in combination (KTSA). These doses were doubled in another set of study groups (K-60, T-30, and KTA groups, respectively). Optimal anesthesia duration was examined in all groups.

RESULTS

Anesthesia did not occur with 30 mg/kg ketamine or 15 mg/kg thiopental. However, when used alone ketamine and thiopental led to oxidative stress in the striatum, heart, and bronchial tissues. Conversely, combined administration of anesthetics and subanesthetic doses were found not to create oxidative stress in any of these areas. The highest level of adrenaline in blood samples collected from the tail veins was measured in the KTA-60, and the lowest amount in the T-30. Creatine kinase activity was highest in the KTA-60 group (p < 0.001). When we compared for all 5 groups to untreated control group; the creatine kinase-MB activities were significiantly different in K-30, T-15 and T-30 (p < 0.001).

CONCLUSIONS

The studied doses of ketamine led to oxidative stress by increasing the amount of adrenaline. Thiopental increased oxidative stress with decreases in adrenaline. A longer anesthetic effect with minimal adverse events may be achieved by ketamine and thiopental in combination.

Advantages of the Alpha-lipoic Acid Association with Chlorpromazine in a Model of Schizophrenia Induced by Ketamine in Rats: Behavioral and Oxidative Stress evidences

Schizophrenia is a chronic mental disorder reported to compromise about 1% of the world's population. Although its pathophysiological process is not completely elucidated, evidence showing the presence of an oxidative imbalance has been increasingly highlighted in the literature. Thus, the use of antioxidant substances may be of importance for schizophrenia treatment. The objective of this study was to evaluate the behavioral and oxidative alterations by the combination of chlorpromazine (CP) and alpha-lipoic acid (ALA), a potent antioxidant, in the ketamine (KET) model of schizophrenia in rats. Male Wistar rats (200-300 g) were treated for 10 days with saline, CP or ALA alone or in combination with CP previous to KET and the behavioral (open field, Y-maze and PPI tests) and oxidative tests were performed on the last day of treatment. The results showed that KET induced hyperlocomotion, impaired working memory and decreased PPI. CP alone or in combination with ALA prevented KET-induced behavioral effects. In addition, the administration of KET decreased GSH and increased nitrite, lipid peroxidation and myeloperoxidase activity. CP alone or combined with ALA prevented the oxidative alterations induced by KET. In conclusion, the treatment with KET in rats induced behavioral impairments accompanied by hippocampal oxidative alterations, possibly related to NMDA receptors hypofunction. Besides that, CP alone or combined with ALA prevented these effects, showing a beneficial activity as antipsychotic agents.

Clinical significance of interleukin‑6 and inducible nitric oxide synthase in ketamine‑induced cystitis

Ketamine is an ionotropic glutamatergic N-methyl-D-aspartate receptor antagonist, which is widely used among recreational drug abusers. Ketamine abusers exhibit substantially reduced bladder capacity, which can lead to urinary frequency. The molecular pathogenesis of ketamine-induced cystitis has been scarcely reported. Given previous clinical findings, it may be hypothesized that pathological alterations in smooth muscle cells (SMCs) of the urinary bladder serve a crucial role in the mechanism underlying cystitis. In the present study, two lineages of SMCs, one from differentiated foreskin-derived fibroblast-like stromal cells and the other from cultured normal aortic SMCs, were used to study ketamine-induced molecular alterations. Polymerase chain reaction was used to study the effects of ketamine on oxidative stress. The effects of adjuvant chemo-therapy with cyclophosphamide (CTX) were also investigated. The results indicated that the expression levels of interleukin-6 and inducible nitric oxide synthase (iNOS) were decreased, whereas collagen expression and deposition were increased in ketamine-treated SMCs. Conversely, treatment with CTX restored the expression of iNOS, which may prevent or limit oxidative damage. In conclusion, the present study demonstrated that ketamine may induce several molecular alterations in SMCs and these changes may be associated with the clinical symptoms observed in ketamine abusers. In addition, the specific chemotherapeutic agent CTX may reverse these ketamine-induced aberrations.

Antioxidant Treatment in Male Mice Prevents Mitochondrial and Synaptic Changes in an NMDA Receptor Dysfunction Model of Schizophrenia

Glutamate theories of schizophrenia suggest that the disease is associated with a loss of NMDA receptors, specifically on GABAergic parvalbumin-expressing interneurons (PVIs), leading to changes in the excitation-inhibition balance in the prefrontal cortex (PFC). Oxidative stress contributes to the loss of PVI and the development of schizophrenia. Here, we investigated whether the glutathione precursor N-acetyl cysteine (NAC) can prevent changes in synaptic transmission at pyramidal cells and PVIs that result from developmental NMDAR blockade and how these changes are related to mitochondrial dysfunction in the PFCs of mice. Perinatal treatment with ketamine induced persistent changes in the reduced glutathione/oxidized glutathione (glutathione disulfide) ratio in the medial PFC, indicating long-lasting increases in oxidative stress. Perinatal ketamine treatment also reduced parvalbumin expression, and it induced a decline in mitochondrial membrane potential, as well as elevations in mitochondrial superoxide levels. At the level of synaptic function ketamine reduced inhibition onto layer 2/3 pyramidal cells and increased excitatory drive onto PVI, indicating long-lasting disruptions in the excitation-inhibition balance. These changes were accompanied by layer-specific alterations in NMDAR function in PVIs. All of these changes were mitigated by coadministration of NAC. In addition, NAC given only during late adolescence was also able to restore normal mitochondria function and inhibition at pyramidal cells. These results show that ketamine-induced alterations in PFC physiology correlate with cell type-specific changes in mitochondria function. The ability of NAC to prevent or restore these changes supports the usefulness of antioxidant supplementation in the treatment of schizophrenia.

Protective effect of gallic acid in experimental model of ketamine-induced psychosis: possible behaviour, biochemical, neurochemical and cellular alterations

Gallic acid has been reported to possess a number of psychopharmacological activities. These activities are attributed to the antioxidant potential due to the presence of phenolic moeity. The present study was carried out to investigate the protective effects of gallic acid in an experimental model of ketamine-induced psychosis in mice. Ketamine (50 mg/kg, i.p.) was used to induce stereotyped psychotic behavioural symptoms in mice. Behavioural studies (locomotor activity, stereotype behaviour, immobility duration and memory retention) were carried out to investigate the protective of gallic acid on ketamine-induced psychotic symptoms, followed by biochemical and neurochemical changes and cellular alterations in the brain. Chronic treatment with gallic acid for 15 consecutive days significantly attenuated stereotyped behavioural symptoms in mice. Biochemical estimations revealed that gallic acid reduced the lipid peroxidation and restored the total brain proteins. Furthermore, gallic acid remarkably reduced the dopamine levels, AChE activity and inflammatory surge (serum TNF-α), and increased the levels of GABA and increased glutathione in mice. The study revealed that gallic acid could ameliorate psychotic symptoms and biochemical changes in mice, indicating protective effects in psychosis.

The preventive effects of ascorbic acid supplementation on locomotor and acetylcholinesterase activity in an animal model of schizophrenia induced by ketamine

Studies have shown that schizophrenic patients seem to have nutritional deficiencies. Ascorbic acid (AA) has an important antioxidant effect and neuromodulatory properties. The aim of this study was to evaluate the effects of AA on locomotor activity and the acetylcholinesterase activity (AChE) in an animal model of schizophrenia (SZ). Rats were supplemented with AA (0.1, 1, or 10 mg/kg), or water for 14 days (gavage). Between the 9th and 15th days, the animals received Ketamine (Ket) (25 mg/kg) or saline (i.p). After the last administration (30 min) rats were subjected to the behavioral test. Brain structures were dissected for biochemical analysis. There was a significant increase in the locomotor activity in Ket treated. AA prevented the hyperlocomotion induced by ket. Ket also showed an increase of AChE activity within the prefrontal cortex and striatum prevented by AA. Our data indicates an effect for AA in preventing alterations induced by Ket in an animal model of SZ, suggesting that it may be an adjuvant approach for the development of new therapeutic strategies within this psychiatric disorder.