Effects of Zingiber officinale extract supplementation on metabolic and genotoxic parameters in diet-induced obesity in mice.

Obesity is an epidemic associated with many diseases. The nutraceutical Zingiber officinale (ZO) is a potential treatment for obesity; however, the molecular effects are unknown. Swiss male mice were fed a high-fat diet (59 % energy from fat) for 16 weeks to generate a diet-induced obesity (DIO) model and then divided into the following groups: standard diet + vehicle; standard diet + ZO; DIO + vehicle and DIO + ZO. Those in the ZO groups were supplemented with 400 mg/kg per d of ZO extract (oral administration) for 35 d. The animals were euthanised, and blood, quadriceps, epididymal fat pad and hepatic tissue were collected. DIO induced insulin resistance, proinflammatory cytokines, oxidative stress and DNA damage in different tissues. Treatment with ZO improved insulin sensitivity as well as decreased serum TAG, without changes in body weight or adiposity index. TNF-α and IL-1ß levels were lower in the liver and quadriceps in the DIO + ZO group compared with the DIO group. ZO treatment reduced the reactive species and oxidative damage to proteins, lipids and DNA in blood and liver in obese animals. The endogenous antioxidant activity was higher in the quadriceps of DIO + ZO. These results in the rat model of DIO may indicate ZO as an adjuvant on obesity treatment.

Prior Exercise Training Prevent Hyperglycemia in STZ Mice by Increasing Hepatic Glycogen and Mitochondrial Function on Skeletal Muscle.

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia. We investigated the effect of a prior 30 days voluntary exercise protocol on STZ-diabetic CF1 mice. Glycemia, and the liver and skeletal muscle glycogen, mitochondrial function, and redox status were analyzed up to 5 days after STZ injection. Animals were engaged in the following groups: Sedentary vehicle (Sed Veh), Sedentary STZ (Sed STZ), Exercise Vehicle (Ex Veh), and Exercise STZ (Ex STZ). Exercise prevented fasting hyperglycemia in the Ex STZ group. In the liver, there was decreased on glycogen level in Sed STZ group but not in EX STZ group. STZ groups showed decreased mitochondrial oxygen consumption compared to vehicle groups, whereas mitochondrial H2 O2 production was not different between groups. Addition of ADP to the medium did not decrease H2 O2 production in Sed STZ mice. Exercise increased GSH level. Sed STZ group increased nitrite levels compared to other groups. In quadriceps muscle, glycogen level was similar between groups. The Sed STZ group displayed decreased O2 consumption, and exercise prevented this reduction. The H2 O2 production was higher in Ex STZ when compared to other groups. Also, GSH level decreased whereas nitrite levels increased in the Sed STZ compared to other groups. The PGC1 α levels increased in Sed STZ, Ex Veh, and Ex STZ groups. In summary, prior exercise training prevents hyperglycemia in STZ-mice diabetic associated with increased liver glycogen storage, and oxygen consumption by the mitochondria of skeletal muscle implying in increased oxidative/biogenesis capacity, and improved redox status of both tissues. J. Cell. Biochem. 118: 678-685, 2017. © 2016 Wiley Periodicals, Inc.

Intracerebroventricular metformin decreases body weight but has pro-oxidant effects and decreases survival.

Metformin (Met), which is an insulin-sensitizer, decreases insulin resistance and fasting insulin levels. The precise molecular target of Met is unknown; however, several reports have shown an inhibitory effect on mitochondrial complex I of the electron transport chain (ETC), which is a related site for reactive oxygen species production. In addition to peripheral effects, Met is capable of crossing the blood-brain barrier, thus regulating the central mechanism involved in appetite control. The present study explores the effects of intracerebroventricular (i.c.v.) infusion of Met on ROS production on brain, insulin sensitivity and metabolic and oxidative stress outcomes in CF1 mice. Metformin (Met 50 and 100 µg) was injected i.c.v. in mice daily for 7 days; the brain mitochondrial H2O2 production, food intake, body weight and fat pads were evaluated. The basal production of H2O2 of isolated mitochondria from the hippocampus and hypothalamus was significantly increased by Met (100 µg). There was increased peripheral sensitivity to insulin (Met 100 µg) and glucose tolerance tests (Met 50 and 100 µg). Moreover, Met decreased food intake, body weight, body temperature, fat pads and survival rates. Additionally, Met (1, 4 or 10 mM) decreased mitochondrial viability and increased the production of H2O2 in neuronal cell cultures. In summary, our data indicate that a high dose of Met injected directly into the brain has remarkable neurotoxic effects, as evidenced by hypothermia, hypoglycemia, disrupted mitochondrial ETC flux and decreased survival rate.

Nandrolone-induced aggressive behavior is associated with alterations in extracellular glutamate homeostasis in mice.

Nandrolone decanoate (ND), an anabolic androgenic steroid (AAS), induces an aggressive phenotype by mechanisms involving glutamate-induced N-methyl-d-aspartate receptor (NMDAr) hyperexcitability. The astrocytic glutamate transporters remove excessive glutamate surrounding the synapse. However, the impact of supraphysiological doses of ND on glutamate transporters activity remains elusive. We investigated whether ND-induced aggressive behavior is interconnected with GLT-1 activity, glutamate levels and abnormal NMDAr responses. Two-month-old untreated male mice (CF1, n=20) were tested for baseline aggressive behavior in the resident-intruder test. Another group of mice (n=188) was injected with ND (15mg/kg) or vehicle for 4, 11 and 19days (short-, mid- and long-term endpoints, respectively) and was evaluated in the resident-intruder test. Each endpoint was assessed for GLT-1 expression and glutamate uptake activity in the frontoparietal cortex and hippocampal tissues. Only the long-term ND endpoint significantly decreased the latency to first attack and increased the number of attacks, which was associated with decreased GLT-1 expression and glutamate uptake activity in both brain areas. These alterations may affect extracellular glutamate levels and receptor excitability. Resident males were assessed for hippocampal glutamate levels via microdialysis both prior to, and following, the introduction of intruders. Long-term ND mice displayed significant increases in the microdialysate glutamate levels only after exposure to intruders. A single intraperitoneal dose of the NMDAr antagonists, memantine or MK-801, shortly before the intruder test decreased aggressive behavior. In summary, long-term ND-induced aggressive behavior is associated with decreased extracellular glutamate clearance and NMDAr hyperexcitability, emphasizing the role of this receptor in mediating aggression mechanisms.

Reduced brain insulin-like growth factor I function during aging.

Peripheral insulin-like growth factor I (IGF-I) function progressively deteriorates with age. However, whereas deterioration of IGF-I function in the aged brain seems probable, it has not been directly addressed yet. Because serum IGF-I can enter into the brain through the cerebrospinal fluid (CSF), we examined this route of entrance in aged mice. To distinguish endogenous murine IGF-I from exogenously applied IGF-I, we used human IGF-I. We found that after intraperitoneous injection, CSF levels of human IGF-I were significantly higher in old mice (2 year-old) as compared to young ones (4-month-old). In spite of this increase capacity to take IGF-I from the circulation, brain and plasma IGF-I levels were reduced in naive old mice. Moreover, IGF-I signaling was deteriorated in the brain of aged animals. Basal as well as IGF-I-induced activation of the brain IGF-I receptor/Akt/GSK3 pathway was markedly reduced even though old mice have higher levels of brain IGF-I receptors. These data suggest that increases in brain IGF-I receptors and in the capacity to take up serum IGF-I result ineffective because IGF-I function is reduced and aged mice are cognitively impaired, a trait dependant on preserved serum IGF-I input to the brain.

Serum Biomarkers to Mild Cognitive Deficits in Children and Adolescents.

Intellectual disability (ID) is a condition characterized by significant limitations in both cognitive development and adaptive behavior. The diagnosis is made through clinical assessment, standardized tests, and intelligence quotient (IQ). Genetic, inflammation, oxidative stress, and diet have been suggested to contribute to ID, and biomarkers could potentially aid in diagnosis and treatment. Study included children and adolescents aged 6-16 years. The ID group (n = 16) and the control group (n = 18) underwent the Wechsler Intelligence Scale for Children (WISC-IV) test, and blood samples were collected. Correlations between biomarker levels and WISC-IV test scores were analyzed. The ID group had an IQ score below 75, and the values of four domains (IQ, IOP, IMO, and IVP) were lower compared to the control group. Serum levels of FKN, NGF-ß, and vitamin B12 were decreased in the ID group, while DCFH and nitrite levels were increased. Positive correlations were found between FKN and the QIT and IOP domains, NGF and the QIT and IMO domains, and vitamin B12 and the ICV domain. TNF-α showed a negative correlation with the ICV domain. Our study identified FKN, NGF-ß, and vitamin B12 as potential biomarkers specific to ID, which could aid in the diagnosis and treatment of ID. TNF-α and oxidative stress biomarkers suggest that ID has a complex etiology, and further research is needed to better understand this condition and develop effective treatments. Future studies could explore the potential implications of these biomarkers and develop targeted interventions based on their findings.

Capsicum baccatum Red Pepper Prevents Cardiometabolic Risk in Rats Fed with an Ultra-Processed Diet.

Metabolic syndrome is a serious health condition reaching epidemic proportions worldwide and is closely linked to an increased risk of cardiovascular problems. The lack of appropriate treatment paves the way for developing new therapeutic agents as a high priority in the current research. In this study, we evaluated the protective effects of Capsicum baccatum red pepper on metabolic syndrome scenarios induced by an ultra-processed diet in rats. After four months, the ultra-processed diet increased central obesity, triglycerides, total cholesterol, LDL-cholesterol plasma levels, and impaired glucose tolerance. The oral administration of C. baccatum concomitantly with the ultra-processed diet avoided the accumulation of adipose tissue in the visceral region, reduced the total cholesterol and LDL fraction, and improved glucose homeostasis, factors commonly associated with metabolic syndrome. The data presented herein reveal an important preventive action of C. baccatum in developing metabolic disorders among animals fed a hypercaloric diet, significantly reducing their cardiometabolic risk. Allied with the absence of toxic effects after chronic use, our study suggests C. baccatum red pepper as a secure and enriched source of bioactive compounds promising to protect against pathological processes associated with metabolic syndrome.

Effects of Avocado Oil Supplementation on Insulin Sensitivity, Cognition, and Inflammatory and Oxidative Stress Markers in Different Tissues of Diet-Induced Obese Mice.

Obesity induces insulin resistance, chronic inflammation, oxidative stress, and neurocognitive impairment. Avocado oil (AO) has antioxidants and anti-inflammatory effects. This study evaluated the effect of AO supplementation on obese mice in the adipose tissue, muscle, liver, and hippocampus. Male C57BL/6J mice received a standard and high-fat diet (20 weeks) and then were supplemented with AO (4 mL/kg of body weight, 90 days) and divided into the following groups: control (control), control + avocado oil (control + AO), diet-induced obesity (DIO), and diet-induced obesity + avocado oil (DIO + AO) (n = 10/group). AO supplementation was found to improve insulin sensitivity and decrease hepatic fat accumulation and serum triglyceride levels in DIO mice. AO improved cognitive performance and did not affect mood parameters. Oxidative marker levels were decreased in DIO + AO mice in all the tissues and were concomitant with increased catalase and superoxide dismutase activities in the epididymal adipose tissue and quadriceps, as well as increased catalase activity in the liver. AO in obese animals further induced reductions in TNF-α and IL-1ß expressions in the epididymal adipose tissue and quadriceps. These results suggest that AO supplementation has the potential to be an effective strategy for combating the effects of obesity in rats, and human studies are needed to confirm these findings.

Behavioral, genetic and biochemical changes in the brain of the offspring of female mice treated with caffeine during pregnancy and lactation.

The intrauterine environment is a critical location for exposure to exogenous and endogenous factors that trigger metabolic changes through fetal programming. Among the external factors, chemical compounds stand out, which include caffeine, since its consumption is common among women, including during pregnancy. Thereby, the aim of the present study was to evaluate the behavioral, genetic, and biochemical parameters in the offspring of female mice treated with caffeine during pregnancy and lactation. Swiss female mice (60 days old) received tap water or caffeine at 0.3 or 1.0 mg/mL during copulation (7 days), pregnancy (21 days) and lactation (21 days). After the end of the lactation period, the offspring were divided into groups (water, caffeine 0.3 or 1.0 mg/mL) with 20 animals (10 animals aged 30 days and 10 animals aged 60 days per group per sex). Initially, the offspring were submitted to behavioral tasks and then euthanized for genetic and biochemical analysis in the brain (cortex, striatum, and hippocampus). Behavioral changes in memory, depression, and anxiety were observed in the offspring: 30-day-old female offspring at 1.0 mg /mL dose presented anxiogenic behavior and male offspring the 0.3 mg/mL dose at 30 days of age did not alter long-term memory. Furthermore, an increase in DNA damage and oxidative stress in the brain were observed in the offspring of both sexes. Furthermore, there were changes in Ape-1, BAX, and Bcl-2 in the female offspring hippocampus at 30 days of life. Thus, with this study, we can suggest genotoxicity, oxidative stress, and behavioral changes caused by caffeine during pregnancy and lactation in the offspring that were not treated directly, but received through their mothers; thus, it is important to raise awareness regarding caffeine consumption among pregnant and lactating females.

Serum insulin-like system alterations in patients with spinocerebellar ataxia type 3.

Spinocerebellar ataxias (SCAs) constitute a group of autosomal dominant neurodegenerative disorders with no current treatment. The insulin/insulin-like growth factor 1 (IGF-1) system (IIS) has been shown to play a role in the neurological dysfunction of SCAs and other polyglutamine disorders. We aimed to study the biomarker profile of serum IIS components in SCA3. We performed a case-control study with 46 SCA3 patients and 42 healthy individuals evaluating the peripheral IIS profile (insulin, IGF-1, IGFBP1 and 3) and the correlation with clinical, molecular, and neuroimaging findings. SCA3 patients presented lower insulin and IGFBP3 levels and higher insulin sensitivity (HOMA2), free IGF-I, and IGFBP1 levels when compared with controls. IGFBP-1 levels were directly associated with CAG expanded repeat length; IGF-1 was associated with the volumetries of specific brainstem regions on magnetic resonance imaging (MRI). Insulin levels and sensitivity were related to age at onset of symptoms. Our findings indicate an involvement of IIS components in SCA3 neurobiology and IGFBP-1 as a potential biomarker of the disease.

Effects of Low-Intensity Transcranial Pulsed Ultrasound Treatment in a Model of Alzheimer's Disease.

Alzheimer's disease (AD) is the most common neurodegenerative disease. One of the main pathology markers of AD is the beta-amyloid plaques (ßA1-42) created from residues of the badly processed amyloid precursor protein. The accumulation of these plaques can induce neuroinflammation and oxidative stress and impair antioxidant mechanisms, culminating in cognitive and memory deficits. New therapies are necessary to treat AD as the approved drugs do not treat the progress of the disease. Transcranial low-intensity pulsed ultrasound (LIPUS) affects brain metabolism and could be tested as a treatment for AD. This study was aimed at evaluating the LIPUS treatment in a model of AD induced by ßA1-42 intracerebroventricularly (ICV) and its effects on learning memory, neurotrophins, neuroinflammation and oxidative status. ßA1-42 was administered ICV 24 h before the start of a 5-wk LIPUS treatment. The treatment with LIPUS improved recognition memory, as well as increasing nerve growth factor ß and brain-derived neurotrophic factor levels in the hippocampus and cortex. There was a decrease in protein damage in the hippocampus treated with LIPUS. Neuroinflammation and oxidative stress were not present in the AD model used. The results indicated that LIPUS is a novel and promising adjuvant strategy for treatment of the late stage of AD.

Physical Exercise Training Improves Judgment and Problem-Solving and Modulates Serum Biomarkers in Patients with Alzheimer's Disease.

Alzheimer's disease (AD) is characterized by progressive impairment of memory, with an etiology involving oxidative stress and inflammation. Exercise training is a safe, efficacious, and economic approach to manage neurodegenerative diseases. In AD, the biomarkers of oxidative damage to lipids, proteins, and DNA are elevated. In the present study, we aimed to evaluate whether exercise is effective in patients with AD by assessing the serum biomarkers associated with the redox status, neurotrophin levels, and inflammatory system. This nonrandomized clinical study (n = 15) involved 22 training sessions performed twice a week (60 min/session) in patients diagnosed with AD. The cognitive and self-awareness tests were performed 48 h before and after the physical training session. In patients with AD, physical training significantly improved the judgment and problem-solving domains of the memory score; however, general mental health, memory, orientation, and home/hobby domains were improved slightly, and the neurotrophin levels remained unaltered. Significantly, the markers of protein integrity also increased following exercise. Furthermore, catalase activity and ROS levels decreased, nitrite levels increased, and interleukin-4 level increased following physical training in patients with AD. Although proinflammatory cytokines remained unaltered, the levels of neuron-specific enolase, a marker of neuronal damage, decreased following exercise training in these patients. In conclusion, physical exercise training could be a safe and effective method for blocking the AD progression and improving the antioxidant capacity and anti-inflammatory system, whereas certain assessed biomarkers could be utilized to monitor AD therapy.

Effect of ketogenic diet on nucleotide hydrolysis and hepatic enzymes in blood serum of rats in a lithium-pilocarpine-induced status epilepticus.

The ketogenic diet (KD) is a high-fat and low-carbohydrate diet, used for treating refractory epilepsy in children. We have previously shown alterations in nucleotidase activities from the central nervous system and blood serum of rats submitted to different models of epilepsy. In this study we investigated the effect of KD on nucleotidase activities in the blood serum, as well if KD has any influence in the activity of liver enzymes such as alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase activities in Wistar rats submitted to the lithium-pilocarpine model of epilepsy. At 21 days of age, rats received an injection of lithium chloride and, 18-19 h later, they received an injection of pilocarpine hydrochloride for status epilepticus induction. The results reported herein show that seizures induced by lithium-pilocarpine elicit a significant increase in ATP hydrolysis and alkaline phosphatase activity, as well as a decrease in ADP hydrolysis and aspartate aminotransferase activity. The KD is a rigorous regimen that can be associated with hepatic damage, as shown herein by the elevated activities of liver enzymes and 5'-nucleotidase in blood serum. Further studies are necessary to investigate the mechanism of inhibition of lithium on nucleotidases in blood serum.

Insulin activates microglia and increases COX-2/IL-1ß expression in young but not in aged hippocampus.

Brain insulin resistance and neuroinflammation are known to increase with age. Insulin exerts metabolic roles on neurons and astrocytes, but its effects on microglia is unclear. In this study we investigated whether insulin affected microglia in the hippocampus of young and aged rats. We injected intracerebroventricular (i.c.v.) insulin (20 mU) or vehicle for five days and evaluated microglial inflammatory markers in the hippocampus of young (3 months) Wistar rats. Increased microglial activation (Iba-1+CD68+cells) and COX-2/IL-1ß levels in the hippocampus were found. Since the aged brain is an experimental model for brain insulin resistance and chronic neuroinflammation we submitted aged rats (22 months) to i.c.v. insulin/vehicle administration and found no significant increase in Iba-1+CD68+ microglia or COX-2/IL-1ß levels. To further investigate whether insulin triggered transient or persistent proinflammatory responses, young rats were evaluated eight-days after the last insulin injection. Microglia were persistently activated, and COX-2 levels remained elevated in the hippocampus, which paralleled increased spatial memory performance in the Morris Water Maze behavioral task. To determine if microglia were directly responsive to insulin, primary microglia were challenged with insulin and increased Akt Ser473 phosphorylation, a protein activated by the insulin receptor, was detected. These data suggest that microglia in the hippocampus integrate insulin signaling and neuroinflammatory responses and that this signal is disrupted during chronic inflammation. In our concept, the disruption between microglia activation by insulin signaling is a new pathological mechanism behind insulin resistance in the aging brain.

Intranasal insulin treatment modulates the neurotropic, inflammatory, and oxidant mechanisms in the cortex and hippocampus in a low-grade inflammation model.

The inflammatory process plays a critical role in the development of neurodegenerative diseases. Insulin is used in preclinical and clinical studies of neurological disorders. Its intranasal (IN) administration directly in the brain allows for its peripheral metabolic effects to be avoided. Swiss male mice were injected with lipopolysaccharide (LPS) (0.1 mg/kg) to induce low-grade inflammation. IN insulin treatment was initiated 4 h later at a dose of 1.7 IU once daily for 5 days. LPS induced cognitive deficits, which the IN insulin treatment reversed. LPS significantly decreased, whereas IN insulin significantly increased the levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor-ß in the cortex. In the hippocampus, IN insulin significantly decreased the BDNF level. LPS significantly increased the interleukin (IL)-6 levels in the cortex, while IN Insulin significantly decreased its levels in the hippocampus. The tumor necrosis factor-α levels were significantly decreased by IN insulin both in the cortex and hippocampus. Moreover, IN insulin significantly increased the IL-10 levels in the cortex. The levels of oxidative and nitrosative stress were significantly higher in the LPS-treated mice; however, IN insulin had a modulatory effect on both. LPS significantly increased the antioxidant enzyme activity both in the cortex and hippocampus, whereas IN insulin significantly increased the activity of both superoxide dismutase and catalase in the hippocampus and that of catalase in the cortex. The hydrogen peroxide levels revealed that LPS significantly affected the electron transport chain. Therefore, IN insulin could be useful in the treatment of neuroinflammatory diseases.

Gold Nanoparticles Treatment Reverses Brain Damage in Alzheimer's Disease Model.

Alzheimer's disease (AD) is characterized by amyloid (A)ß peptide accumulation and intracellular neurofibrillary tangles. New hypotheses have suggested that AD involves neuroinflammation and oxidative stress. Gold nanoparticles (AuNP) presents anti-inflammatory and antioxidant characteristics. The present study evaluated the AuNP treatment on an AD model (okadaic acid, OA). Male Wistar rats were injected intracerebroventricularly with OA (100 µg); 24 h later they were treated with 20-nm AuNP (at a dose 2.5 mg/kg) every 48 h for 21 days. The following groups were separated (n = 12/group): Sham, AuNP, OA, and OA + AuNP. OA increases Tau phosphorylation in the cortex and hippocampus, while AuNP treatment maintained it as normal. Spatial memory was impaired by OA, and AuNP treatment prevented this deficit. Neurotrophic factors (BDNF and NGF- ß) in the cortex and hippocampus were decreased by OA. The OA and OA + AuNP groups showed increased interleukin (IL)-1 ß in the hippocampus and cortex, and the AuNP group showed increased IL-1 ß in the hippocampus. In both groups, S100 levels in the cortex and hippocampus were increased by OA. IL-4 was increased in OA + AuNP animals. AuNPs prevented oxidative stress (sulfhydryl and nitrite levels) in brain structures induced by OA. Moreover, OA modulated ATP synthase activity, and AuNP maintained normal brain mitochondrial function. The antioxidant capacities were reduced by OA, and AuNP restored antioxidant status (SOD, catalase activities and GSH levels) on brain. OA-induced damage on brain tissues, and long-term AuNP treatment prevented the neuroinflammation, modulation of mitochondrial function, and impaired cognition induced by AD model, showing that AuNPs may be a promising treatment for neurodisease caused by these elements.

Therapeutic effects of iontophoresis with gold nanoparticles in the repair of traumatic muscle injury.

Studies have shown the benefits of gold nanoparticles (GNPs) in muscle and epithelial injury models. In physiotherapy, the use of the microcurrent apparatus is associated with certain drugs (Iontophoresis) to increase the topical penetration and to associate the effects of both therapies. Therefore, the objective of this study was to investigate the effects of iontophoresis along with GNPs in the skeletal muscle of rats exposed to a traumatic muscle injury. We utilised 50 Wistar rats randomly divided in to five experimental groups (n = 10): Control group (CG); Muscle injury group (MI); MI + GNPs (20 nm, 30 mg kg-1); MI + Microcurrent (300 µA); and MI + Microcurrent + GNPs. The treatment was performed daily for 7 days, with the first session starting at 24 h after the muscle injury. The animals were sacrificed and the gastrocnemius muscle was surgically removedand stored for the proper evaluations. The group that received iontophoresis with GNPs showed significant differences in inflammation and oxidative stress parameters and in the histopathological evaluation showed preserved morphology. In addition, we observed an improvement in the locomotor response and pain symptoms of these animals. These results suggest that the association of boththerapies accelerates the inflammatory response of the injured limb.

Insulin treatment protects the brain against neuroinflammation by reducing cerebral cytokines and modulating mitochondrial function.

In the central nervous system, glial cells protect the brain against neuronal stress by inducing inflammatory responses; namely, intracellular signaling and cytokine production. However, chronic inflammation is often associated with degenerative diseases that can damage hormone signaling and mitochondrial function. Lipopolysaccharide (LPS) induces neuroinflammation by stimulating the production of interleukin-1beta (IL-1ß) and tumor necrosis factor-alpha (TNF-α); moreover, it generates oxidative stress and impairs cognitive functions. The aim of the present study was to assess the therapeutic efficacy of intracerebroventricular (i.c.v.) injections of insulin against neuroinflammation. Inflammation was first induced in male Wistar rats (60 days old, n = 12/group) through an intraperitoneal injection of 0.1 mg/kg LPS. The i.c.v. insulin treatment at a 0.5 mU dose was initiated 4 h later and administered once a day for 5 days. Thereafter, the spatial memory of the rats was assessed, and the hippocampus and cortex were later dissected for biochemical analyses. Our results showed that LPS induced cognitive function impairments, but the insulin treatment reversed these effects. Whereas the levels of brain-derived neurotrophic factor and beta-nerve growth factor in the hippocampus were not altered by LPS, they were decreased in the cortex by insulin. The IL-1ß and TNF-α levels were increased in the cortex and hippocampus following exposure to LPS, but insulin reversed these effects. Evaluation of the H2O2levels and mitochondrial membrane potential revealed that LPS modulated mitochondrial function, an effect that was also reversed by insulin. Moreover, LPS induced oxidative stress by decreasing the superoxide dismutase and catalase activities and glutathione and sulfhydryl levels. Furthermore, the levels of oxidative stress probes/markers (i.e.,2',7'-dichlorodihydrofluoresceindiacetateand nitrite) were higher in the LPS-treated rats. These effects were all reversed in the cortex and hippocampus by insulin treatment. Our results suggest a potential role for insulin as a therapeutic drug against inflammatory diseases associated with mitochondrial dysfunction in the brain.

Memantine mediates astrocytic activity in response to excitotoxicity induced by PP2A inhibition.

Reduced activity of protein phosphatase 2 A (PP2A) is a common feature in Alzheimer's disease (AD) and non-AD tauopathies. The administration of okadaic acid (OKA), a potent PP2A and PP1 inhibitor, is a common research tool for inducing AD-like alterations such as tau hyperphosphorylation and cognitive decline. Recently, we showed that OKA increases cerebrospinal fluid (CSF) glutamate levels, which was strongly correlated with cognitive decline. Also, we demonstrated that memantine (MN), a glutamatergic NMDAR channel blocker, was capable of preventing the increase in CSF glutamate levels and cognitive decline. Here, we aimed to analyze whether the protective effects of MN involve intrinsic astrocytic properties, particularly related to glutamate uptake and astrocytic reactivity - indexed by the expression of S100B and glial fibrillary acidic protein (GFAP). Rats received intraperitoneal injections of MN or saline over 3 consecutive days before receiving intrahippocampal infusion of OKA or saline. Afterward, they were submitted to behavioral tasks and then, euthanatized for neurochemical analysis. Here, we showed that the neuroprotective effects of MN in response to OKA neurotoxicity involve astrocytic activation. MN decreased glutamate uptake in the hippocampus and increased the release of S100B protein in the CSF in response to OKA neurotoxicity, which indicates a possible neurons-astrocyte coupling protective mechanism. These findings shed light on astrocytes as potential targets for treating neurological disorders associated with decreased PP2A activity.

Sustained elevation of cerebrospinal fluid glucose and lactate after a single seizure does not parallel with mitochondria energy production.

Generalized seizures trigger excessive neuronal firing that imposes large demands on the brain glucose/lactate availability and utilization, which synchronization requires an integral mitochondrial oxidative capability. We investigated whether a single convulsive crisis affects brain glucose/lactate availability and mitochondrial energy production. Adult male Wistar rats received a single injection of pentylentetrazol (PTZ, 60 mg/kg, i.p.) or saline. The cerebrospinal fluid (CSF) levels of glucose and lactate, mitochondrial respirometry, [14C]-2-deoxy-D-glucose uptake, glycogen content and cell viability in hippocampus were measured. CSF levels of glucose and lactate (mean ± SD) in control animals were 68.08 ± 11.62 mg/dL and 1.17 ± 0.32 mmol/L, respectively. Tonic-clonic seizures increased glucose levels at 10 min (96.25 ± 13.19) peaking at 60 min (113.03 ± 16.34) returning to control levels at 24 h (50.12 ± 12.81), while lactate increased at 10 min (3.23 ± 1.57) but returned to control levels at 360 min after seizures (1.58 ± 0.21). The hippocampal [14C]-2-deoxy-D-glucose uptake, glycogen content, and cell viability decreased up to 60 min after the seizures onset. Also, an uncoupling between mitochondrial oxygen consumption and ATP synthesis via FoF1-ATP synthase was observed at 10 min, 60 min and 24 h after seizures. In summary, after a convulsive seizure glucose and lactate levels immediately rise within the brain, however, considering the acute impact of this metabolic crisis, mitochondria are not able to increase energy production thereby affecting cell viability.