Plinia trunciflora Extract Administration Prevents HI-Induced Oxidative Stress, Inflammatory Response, Behavioral Impairments, and Tissue Damage in Rats.

The disruption of redox homeostasis and neuroinflammation are key mechanisms in the pathogenesis of brain hypoxia-ischemia (HI); medicinal plants have been studied as a therapeutic strategy, generally associated with the prevention of oxidative stress and inflammatory response. This study evaluates the neuroprotective role of the Plinia trunciflora fruit extract (PTE) in neonatal rats submitted to experimental HI. The HI insult provoked a marked increase in the lipoperoxidation levels and glutathione peroxidase (GPx) activity, accompanied by a decrease in the brain concentration of glutathione (GSH). Interestingly, PTE was able to prevent most of the HI-induced pro-oxidant effects. It was also observed that HI increased the levels of interleukin-1ß in the hippocampus, and that PTE-treatment prevented this effect. Furthermore, PTE was able to prevent neuronal loss and astrocyte reactivity induced by HI, as demonstrated by NeuN and GFAP staining, respectively. PTE also attenuated the anxiety-like behavior and prevented the spatial memory impairment caused by HI. Finally, PTE prevented neural tissue loss in the brain hemisphere, the hippocampus, cerebral cortex, and the striatum ipsilateral to the HI. Taken together our results provide good evidence that the PTE extract has the potential to be investigated as an adjunctive therapy in the treatment of brain insult caused by neonatal hypoxia-ischemia.

Phytoestrogen coumestrol attenuates brain mitochondrial dysfunction and long-term cognitive deficits following neonatal hypoxia-ischemia.

INTRODUCTION: Neonatal Hypoxia-Ischemia (HI) is a major cause of morbidity and mortality, and is frequently associated with short and long-term neurologic and cognitive impairments. The HI injury causes mitochondrial damage leading to increased production of reactive oxygen species (ROS). Phytoestrogens are non-steroidal plant substances structurally and functionally similar to estrogen. Coumestrol is a potent isoflavonoid with a protective effect against ischemic brain damage in adult rats. Our aim was to determine if coumestrol treatment following neonatal HI attenuates the long-term cognitive deficits induced by neonatal HI, as well as to investigate one possible mechanism underlying its potential effect. METHODS: On the 7th postnatal day, male Wistar rats were submitted to the Levine-Rice HI model. Intraperitoneal injections of 20 mg/kg of coumestrol, or vehicle, were administered immediately pre-hypoxia or 3 h post-hypoxia. At 12 h after HI the mitochondrial status and ROS levels were determined. At 60th postnatal day the cognitive deficits were revealed in the Morris water maze reference and working spatial memories. Following behavioral analysis, histological assessment was performed and reactive astrogliosis was measured by GFAP expression. RESULTS: Results demonstrate that both pre- and post-HI administration of coumestrol were able to counteract the long-term cognitive and morphological impairments caused by HI, as well as to block the late reactive astrogliosis. The pre-HI administration of coumestrol was able to prevent the early mitochondrial dysfunction in the hippocampus of injured rat pups. CONCLUSION: Present data suggest that coumestrol exerts protection against experimental neonatal brain hypoxia-ischemia through, at least in part, early modulation of mitochondrial function.

Plantar stimulation in parkinsonians: From biomarkers to mobility - randomized-controlled trial.

BACKGROUND: The decrease of Brain-Derived Neurotrophic Factor (BDNF) serum levels has been related to the pathophysiology of several neurodegenerative diseases as well as to neural plasticity and rehabilitation. Automated Mechanical Peripheral Stimulation (AMPS) has been investigated as a complementary therapy for Parkinson Disease (PD). OBJECTIVES: (1) to investigate the effects of AMPS on BDNF and Cortisol serum levels of subjects with PD; (2) to evidence the interplay between BDNF and Cortisol serum levels and the functional mobility improvement after AMPS treatment. METHODS: Thirty-three subjects with PD were randomized into two groups: effective stimulation (AMPS, n = 16) or placebo stimulation (AMPS SHAM, n = 17). Fourteen healthy aged-matched subjects were included as a reference group. Each AMPS group received eight sessions of treatment using a commercial medical device (Gondola™). BDNF and Cortisol serum levels, spatiotemporal gait parameters and TUG test were assessed at baseline and after eight sessions of treatment. RESULTS: After the treatment, AMPS group showed significantly higher levels of BDNF and lower levels of Cortisol compared to AMPS SHAM. AMPS group also showed a positive effect on gait pattern as a higher improvement on gait velocity, stride length, and TUG performance was shown. CONCLUSION: Effective AMPS treatment increased BDNF and decreased Cortisol serum levels and produced improvements in functional mobility.

Synergistic Toxicity of the Neurometabolites Quinolinic Acid and Homocysteine in Cortical Neurons and Astrocytes: Implications in Alzheimer's Disease.

The brain of patients affected by Alzheimer's disease (AD) develops progressive neurodegeneration linked to the formation of proteins aggregates. However, their single actions cannot explain the extent of brain damage observed in this disorder, and the characterization of co-adjuvant involved in the early toxic processes evoked in AD is essential. In this line, quinolinic acid (QUIN) and homocysteine (Hcy) appear to be involved in the AD neuropathogenesis. Herein, we investigate the effects of QUIN and Hcy on early toxic events in cortical neurons and astrocytes. Exposure of primary cortical cultures to these neurometabolites for 24 h induced concentration-dependent neurotoxicity. In addition, QUIN (25 µM) and Hcy (30 µM) triggered ROS production, lipid peroxidation, diminished of Na+,K+-ATPase activity, and morphologic alterations, culminating in reduced neuronal viability by necrotic cell death. In astrocytes, QUIN (100 µM) and Hcy (30 µM) induced caspase-3-dependent apoptosis and morphologic alterations through oxidative status imbalance. To establish specific mechanisms, we preincubated cell cultures with different protective agents. The combined toxicity of QUIN and Hcy was attenuated by melatonin and Trolox in neurons and by NMDA antagonists and glutathione in astrocytes. Cellular death and morphologic alterations were prevented when co-culture was treated with metabolites, suggesting the activation of protector mechanisms dependent on soluble factors and astrocyte and neuron communication through gap junctions. These findings suggest that early damaging events involved in AD can be magnified by synergistic toxicity of the QUIN and Hcy. Therefore, this study opens new possibilities to elucidate the molecular mechanisms of neuron-astrocyte interactions and their role in neuroprotection against QUIN and Hcy.

Vitamin D3 Reverses the Hippocampal Cytoskeleton Imbalance But Not Memory Deficits Caused by Ovariectomy in Adult Wistar Rats.

The objective of study was to investigate changes caused by ovariectomy (OVX) on aversive and non-aversive memories, as well as on cytoskeleton phosphorylating system and on vitamin D receptor (VDR) immunocontent in hippocampus. The neuroprotective role of vitamin D was also investigated. Ninety-day-old female Wistar rats were divided into four groups: SHAM, OVX, VITAMIN D and OVX + VITAMIN D; 30 days after the OVX, vitamin D supplementation (500 IU/kg), by gavage, for 30 days was started. Results showed that OVX impaired short-term and long-term recognition, and long-term aversive memories. OVX altered hippocampal cytoskeleton phosphorylating system, evidenced by the hyperphosphorylation of glial fibrillary acidic protein (GFAP), low molecular weight neurofilament subunit (NFL), medium molecular weight neurofilament subunit (NFM) and high molecular weight neurofilament subunit (NFH), and increased the immunocontent of c-Jun N-terminal protein kinases (JNK), Ca2+/calmodulin-dependent protein kinase II (PKCaMII) and of the sites phosphorylated lysine-serine-proline (KSP) repeats, Ser55 and Ser57. Vitamin D reversed the effects caused by OVX on cytoskeleton in hippocampus, but it was not able to reverse the effects on memory.

Folic Acid Can Contribute to Memory Deficit and Na+, K+- ATPase Failure in the Hippocampus of Adolescent Rats Submitted to Hypoxia- Ischemia.

Recent findings have demonstrated a dual effect of the folic acid (FA) supplementation on the nervous system of rats. We found that FA treatment prevented memory impairment and Na(+), K(+)- ATPase inhibition in the striatum and cortex in adult rats that suffered neonatal hypoxia-ischemia (HI). However, spatial memory deficit has been associated with FA supplementation. In the present study we investigated the role of FA supplementation on spatial memory and Na(+), K(+)-ATPase activity in the hippocampus, as well as on morphologic alterations in adolescent rats submitted to neonatal HI. Wistar rats of both sexes at postnatal day (PND) 7 were submitted to Levine-Rice HI procedure. Intraperitoneal doses of FA were administered immediately before HI and repeated daily until the maximum PND 40. Hippocampal volume and striatum area were estimated and Na(+), K(+)-ATPase activity in the hippocampus was measured at PND 31. Also, the performance of the animals in the water maze was assessed and Na(+), K(+)-ATPase activity measured again at PND 52. Interestingly, HI and FA resulted in spatial memory deficits in the Morris water maze and the Na(+), K(+)-ATPase activity was impaired at PND 31 in HI rats which received FA. Additionally, Na(+), K(+)-ATPase activity in adulthood showed a decrease after HI and a recovery in supplemented animals. Hippocampal and striatal atrophy were partially reversed by FA. To conclude, the present results support the hypothesis that FA supplementation during development contributes to memory deficits caused by HI and Na(+), K(+)-ATPase failure in adolescent rats, although, in adulthood, FA has been effective in reversing enzymatic activity in the hippocampus.

Folic acid prevents behavioral impairment and Na(+), K(+) -ATPase inhibition caused by neonatal hypoxia-ischemia.

Folic acid plays an important role in neuroplasticity and acts as a neuroprotective agent, as observed in experimental brain ischemia studies. The aim of this study was to investigate the effects of folic acid on locomotor activity, aversive memory and Na(+),K(+)-ATPase activity in the frontal cortex and striatum in animals subjected to neonatal hypoxia-ischemia (HI). Wistar rats of both sexes at postnatal day 7 underwent HI procedure and were treated with intraperitoneal injections of folic acid (0.011 µmol/g body weight) once a day, until the 30th postnatal day. Starting on the day after, behavioral assessment was run in the open field and in the inhibitory avoidance task. Animals were sacrificed by decapitation 24 h after testing and striatum and frontal cortex were dissected out for Na(+),K(+)-ATPase activity analysis. Results show anxiogenic effect in the open field and an impairment of aversive memory in the inhibitory avoidance test in HI rats; folic acid treatment prevented both behavioral effects. A decreased Na(+),K(+)-ATPase activity in striatum, both ipsilateral and contralateral to ischemia, was identified after HI; a total recovery was observed in animals treated with folic acid. A partial recovery of Na(+),K(+)-ATPase activity was yet seen in frontal cortex of HI animals receiving folic acid supplementation. Presented results support that folic acid treatment prevents memory deficit and anxiety-like behavior, as well as prevents Na(+),K(+)-ATPase inhibition in the striatum and frontal cortex caused by neonatal hypoxia-ischemia.

Behavioral and neurochemical effects of proline.

Proline is an amino acid with an essential role for primary metabolism and physiologic functions. Hyperprolinemia results from the deficiency of specific enzymes for proline catabolism, leading to tissue accumulation of this amino acid. Hyperprolinemic patients can present neurological symptoms and brain abnormalities, whose aetiopathogenesis is poorly understood. This review addresses some of the findings obtained, mainly from animal studies, indicating that high proline levels may be associated to neuropathophysiology of some disorders. In this context, it has been suggested that energy metabolism deficit, Na(+),K(+)-ATPase, kinase creatine, oxidative stress, excitotoxicity, lipid content, as well as purinergic and cholinergic systems are involved in the effect of proline on brain damage and spatial memory deficit. The discussion focuses on the relatively low antioxidant defenses of the brain and the vulnerability of neural tissue to reactive species. This offers new perspectives for potential therapeutic strategies for this condition, which may include the early use of appropriate antioxidants as a novel adjuvant therapy, besides the usual treatment based on special diets poor in proline.

Ascorbate uptake is decreased in the hippocampus of ageing rats.

Ascorbate, an intracellular antioxidant, has been considered critical for neuronal protection against oxidant stress, which is supported especially by in vitro studies. Besides, it has been demonstrated an age-related decrease in brain ascorbate levels. The aims of the present study were to investigate ascorbate uptake in hippocampal slices from old Wistar rats, as well as its neuroprotective effects in in vitro and in vivo assays. Hippocampal slices from male Wistar rats aged 4, 11 and 24 months were incubated with radiolabeled ascorbate and incorporated radioactivity was measured. Hippocampal slices from rats were incubated with different concentrations of ascorbate and submitted to H(2)O(2)-induced injury, cellular damage and S100B protein levels were evaluated. The effect of chronic administration of ascorbate on cellular oxidative state and astrocyte biochemical parameters in the hippocampus from 18-months-old Wistar rats was also studied. The ascorbate uptake was decreased in hippocampal slices from old-aged rats, while supplementation with ascorbate (2 weeks) did not modify any tested oxidative status in the hippocampus and the incubation was unable to protect hippocampal slices submitted to oxidative damage (H(2)O(2)) from old rats. Our data suggest that the decline of ascorbate uptake might be involved in the brain greater susceptibility to oxidative damage with advancing age and both in vitro and vivo assays suggest that ascorbate supplementation did not protect hippocampal cells.

Long-term effects of environmental stimulation following hypoxia-ischemia on the oxidative state and BDNF levels in rat hippocampus and frontal cortex.

Environmental enrichment recovers memory deficits without affecting atrophy of the hippocampus adult rats submitted to neonatal hypoxia-ischemia (HI). The present study was designed to investigate whether the modulation of brain oxidative status and/or BDNF content, as assessed in adulthood, are involved with the functional neuroprotection caused by environmental enrichment in animals receiving neonatal HI. Male Wistar rats, in the 7th postnatal day, were submitted to the Levine-Rice model of neonatal hypoxia-ischemia, comprising permanent occlusion of the right common carotid artery and a 90 min period of hypoxia (8% O(2)-92% N(2)). Starting 2 weeks after the HI event, animals were stimulated by the enriched environment (1 h/day for 9 weeks). Rats were sacrificed approximately 24 h after the end of enrichment period and some oxidative stress parameters, specifically the free radical levels, macromolecules damage and superoxide dismutase activity, in hippocampus and frontal cortex samples were determined. BDNF levels were also measured in the same encephalic structures. Indexes of macromolecules damage, TBARS levels and total cellular thiols, as well as free radical levels were unchanged in both studied structures. An increased SOD activity in the right hippocampus of HI group maintained in standard environment was found, this effect was reversed in HI enriched group. Moreover, BDNF levels were increased only in the hippocampus of non-stimulated HI group. These results suggest that the environmental enrichment protocol bearing cognitive protection is not associated to increases in BDNF expression nor SOD activity in hippocampus of the rats, as assessed in adulthood, submitted to neonatal hypoxia-ischemia.

Biochemical effects of pretreatment with vitamins E and C in rats submitted to intrastriatal hypoxanthine administration.

We previously demonstrated that intrastriatal injection of hypoxanthine, the major metabolite accumulating in Lesch-Nyhan disease, inhibited Na+,K+-ATPase activity and induced oxidative stress in rat striatum. In the present study, we evaluated the action of vitamins E and C on the biochemical alteration induced by hypoxanthine administration on Na+,K+-ATPase, TBARS, TRAP, as well as on superoxide dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GPx) activities in striatum of adult rats. Animals received pretreatment with vitamins E and C or saline during 7 days. Twelve hours after the last injection of vitamins or saline, animals were divided into two groups: (1) vehicle-injected group and (2) hypoxanthine-injected group. For all parameters investigated in this research, animals were sacrificed 30 min after drug infusion. Results showed that pretreatment with vitamins E and C prevented hypoxanthine-mediated effects on Na+,K+-ATPase, TBARS and antioxidant enzymes (SOD, CAT and GPx) activities; however the reduction on TRAP was not prevented by these vitamins. Although extrapolation of findings from animal experiments to humans is difficult, it is conceivable that these vitamins might serve as an adjuvant therapy in order to avoid progression of striatal damage in patients affected by Lesch-Nyhan disease.

Vitamins E and C pretreatment prevents ovariectomy-induced memory deficits in water maze.

We investigated whether the pretreatment with vitamins E (alpha-tocopherol) and C (ascorbic acid) would act on ovariectomy-induced memory deficits in Morris water maze tasks. Adult female Wistar rats were divided into three groups: (1) naive (control), (2) sham (submitted to surgery without removal of ovaries) and (3) ovariectomized. Thirty days after surgery, they were trained in the Morris water maze in order to verify ovariectomy effects both on reference and working memory tasks. Results show that ovariectomized rats presented impairment in spatial navigation in the acquisition phase, as well as in the time spent in target quadrant and in the latency to cross over the location of the platform in test session, when compared to naive and sham groups (controls), in the reference memory task. Ovariectomy did not affect performance in the working memory task. Confirming our hypothesis, ovariectomized rats pretreated for 30 days with vitamins E and C had those impairments prevented. We conclude that ovariectomy significantly impairs spatial reference learning/memory and that pretreatment with vitamins E and C prevents such effect. Assuming this experimental memory impairment might mimic, at least in part, the cognitive deficit sometimes present in the human condition of lack of reproductive hormones, our findings lend support to a novel therapeutic strategy, based on vitamins E and C, to cognitive impairments in post-menopausal women.

Ptychopetalum olacoides, a traditional Amazonian "nerve tonic", possesses anticholinesterase activity.

The cholinergic hypothesis of Alzheimer disease (AD) has provided the rationale for the current pharmacotherapy of this disease, in an attempt to downgrade the cognitive decline caused by cholinergic deficits. Nevertheless, the search for potent and long-acting acetylcholinesterase (AChE) inhibitors that exert minimal side effects to AD patients is still an ongoing effort. Amazonian communities use traditional remedies prepared with Ptychopetalum olacoides (PO, Olacaceae) roots for treating various central nervous system conditions, including those associated with aging. The fact that PO ethanol extract (POEE) has been found to facilitate memory retrieval in the step down procedure in young and aged mice prompt us to evaluate its effects on AChE activity in memory relevant brain areas. POEE significantly inhibited AChE activity in vitro in a dose- and time-dependent manner in rat frontal cortex, hippocampus and striatum; a significant inhibition was also found in these same brain areas of aged (14 months) mice after acute administration of POEE (100 mg/kg ip). We propose that such AChE inhibitory activity is a neurochemical correlate of a number of therapeutic properties traditionally claimed for P. olacoides, particularly those associated with cognition.