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The absence of blood flow in cerebral ischemic conditions triggers a multitude of intricate pathophysiological mechanisms, including excitotoxicity, oxidative stress, neuroinflammation, disruption of the blood-brain barrier and white matter disarrangement. Despite numerous experimental studies conducted in preclinical settings, existing treatments for cerebral ischemia (CI), such as mechanical and pharmacological therapies, remain constrained and often entail significant side effects. Therefore, there is an imperative to explore innovative strategies for addressing CI outcomes. Cannabidiol (CBD), the most abundant non-psychotomimetic compound derived from Cannabis sativa, is a pleiotropic substance that interacts with diverse molecular targets and has the potential to influence various pathophysiological processes, thereby contributing to enhanced outcomes in CI. This chapter provides a comprehensive overview of the primary effects of CBD in in vitro and diverse animal models of CI and delves into some of its plausible mechanisms of neuroprotection.
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Isquemia Encefálica , Canabidiol , Fármacos Neuroprotetores , Canabidiol/farmacologia , Canabidiol/uso terapêutico , Animais , Isquemia Encefálica/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Humanos , Modelos Animais de DoençasRESUMO
OBJECTIVE: To investigate the effects of cannabidiol (CBD) on emotional and cognitive symptoms in rats with intra-nigral 6-hydroxydopamine (6-OHDA) lesions. METHODS: Adult male Wistar rats received bilateral intranigral 6-OHDA infusions and were tested in a battery of behavioral paradigms to evaluate nonmotor symptoms. The brains were obtained to evaluate the effects of CBD on hippocampal neurogenesis. RESULTS: 6-hydroxydopamine-lesioned rats exhibited memory impairments and despair-like behavior in the novelty-suppressed feeding test and forced swim test, respectively. The animals also exhibited dopaminergic neuronal loss in the substantia nigra pars compacta (SNpc), striatum, and ventral tegmental area and a reduction of hippocampal neurogenesis. Cannabidiol decreased dopaminergic neuronal loss in the SNpc, reduced the mortality rate and decreased neuroinflammation in 6-OHDA-lesioned rats. In parallel, CBD prevented memory impairments and attenuated despair-like behavior that were induced by bilateral intranigral 6-OHDA lesions. Repeated treatment with CBD favored the neuronal maturation of newborn neurons in the hippocampus in Parkinsonian rats. CONCLUSION: The present findings suggest a potential beneficial effect of CBD on nonmotor symptoms induced by intra-nigral 6-OHDA infusion in rats.
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Phosphodiesterase 4 inhibitors (PDE4-I), which selectively increase cyclic adenosine monophosphate (cAMP) levels, have shown neuroprotective effects after several neurological injuries inducing blood-brain barrier (BBB) damage including local/focal cerebral ischemia. The present investigated whether roflumilast confers BBB neuroprotection in the hippocampus after transient global cerebral ischemia (TGCI) in rats. TGCI resulted in whole BBB disruption as measured by the increase of Evans blue (EB) and IgG extravasation, neurodegeneration, and downregulation of claudin-5 and endothelial nitric oxide synthase (eNOS) levels in the CA1 hippocampal subfield of ischemic rats. Roflumilast attenuated BBB disruption and restored the levels of eNOS in the CA1 hippocampal area. Moreover, roflumilast increased the levels of B2 cell lymphoma (BcL-2) and neuron-glial antigen-2 (NG2) in the CA1 subfield after global ischemia in rats. The protective effects of roflumilast against TGCI-induced BBB breakdown might involve preservation of BBB integrity, vascularization and angiogenesis, and myelin repair.
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Isquemia Encefálica , Ataque Isquêmico Transitório , Ratos , Animais , Barreira Hematoencefálica/metabolismo , Isquemia Encefálica/metabolismo , Hipocampo/metabolismoRESUMO
AIMS: Brain ischemia and reperfusion may occur in several clinical conditions that have high rates of mortality and disability, compromising an individual's quality of life. Brain injury can affect organs beyond the brain, such as the gastrointestinal tract. The present study investigated the effects of cerebral ischemia on the ileum and jejunum during a chronic reperfusion period by examining oxidative stress, inflammatory parameters, and the myenteric plexus in Wistar rats. MAIN METHODS: Ischemia was induced by the four-vessel occlusion model for 15 min with 52 days of reperfusion. Oxidative stress and inflammatory markers were evaluated using biochemical techniques. Gastrointestinal transit time was evaluated, and immunofluorescence techniques were used to examine morpho-quantitative aspects of myenteric neurons. KEY FINDINGS: Brain ischemia and reperfusion promoted inflammation, characterized by increases in myeloperoxidase and N-acetylglycosaminidase activity, oxidative stress, and lipid hydroperoxides, decreases in superoxide dismutase and catalase activity, a decrease in levels of reduced glutathione, neurodegeneration in the gut, and slow gastrointestinal transit. SIGNIFICANCE: Chronic ischemia and reperfusion promoted a slow gastrointestinal transit time, oxidative stress, and inflammation and neurodegeneration in the small intestine in rats. These findings indicate that the use of antioxidant and antiinflammatory molecules even after a long period of reperfusion may be useful to alleviate the consequences of this pathology.
Assuntos
Isquemia Encefálica , Traumatismo por Reperfusão , Ratos , Animais , Ratos Wistar , Qualidade de Vida , Traumatismo por Reperfusão/patologia , Intestino Delgado/patologia , Estresse Oxidativo , Isquemia Encefálica/patologia , Antioxidantes/farmacologia , Isquemia , Inflamação/patologia , ReperfusãoRESUMO
5-HT1A serotonin receptors may play a role in cognitive function changes related to advanced age. Here, we investigated the effects of acute and repeated treatment with NLX-101 (F15599), a postsynaptic 5-HT1A receptor-biased agonist, and F13714, a presynaptic 5-HT1A receptor-biased agonist on spatial object pattern separation (OPS) in aged (22-24 months) rats. Neuroplasticity markers including brain-derived neurotrophic factor, PSD95, synaptophysin, and doublecortin were evaluated in the hippocampus. Unlike younger rats, aged rats were incapable of discriminating any new position of the objects in the arena, reflecting the detrimental effect of aging on pattern separation. However, aged animals treated with NLX-101 showed a significant cognitive improvement in the OPS test, accompanied by increases in hippocampal brain-derived neurotrophic factor and PSD95 protein levels. In contrast, no improvement in OPS performance was observed when aged rats received F13714. Both F13714 and NLX-101 increased the number of newborn neurons in the hippocampi of aged rats. These findings provide a rationale for targeting post-synaptic 5-HT1A as a treatment for cognitive deficits related to aging.
Assuntos
Fator Neurotrófico Derivado do Encéfalo , Receptor 5-HT1A de Serotonina , Ratos , Animais , Serotonina/metabolismo , Agonistas do Receptor 5-HT1 de Serotonina/farmacologia , Agonistas do Receptor de SerotoninaRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Trichilia catigua A. Juss (Meliaceae) is used in Brazilian folk medicine to alleviate fatigue and emotional stress and improve memory. Previous studies from our laboratory reported that an ethyl-acetate fraction (EAF) of T. catigua that was given before cerebral ischemia in vivo prevented memory loss and reduced oxidative stress and neuroinflammation. Despite the value of these findings of a neuroprotective effect of T. catigua, treatment that was given immediately before or immediately after ischemia limits its clinical relevance. Thus, unknown is whether T. catigua possesses a specific time window of efficacy (TWE) when administered postischemia. AIM OF THE STUDY: Given continuity to previous studies, we investigated whether an EAF of T. catigua maintains its neuroprotective properties if treatment begins at different time windows of efficacy after ischemia. We also evaluated, for the first time, whether T. catigua possesses neuroplasticity/neurotrophic properties. MATERIAL AND METHODS: Rats were subjected to transient global brain ischemia (TGCI) and then given a single dose of the EAF (400 mg/kg) or vehicle (1 ml/kg) orally 1, 4, or 6 h postischemia. The levels of protein PCG, GSH, and GSSG, and activity of SOD and CAT were assayed as markers of oxidative stress on the day after ischemia. In another experiment, naive rats underwent spatial learning training in a radial maze task and then subjected to TGCI. Delayed treatment with the EAF began 4 or 6 h later and continued for 7 days. Retrograde memory performance was assessed 10, 17, and 24 days postischemia. Afterward, brains were examined for neurodegeneration and neuronal dendritic morphology in the hippocampus and cerebral cortex. Another group received the EAF at 4 h of reperfusion, and 4 days later their brains were examined for GFAP and Iba-1 immunoreactivity. Lastly, ischemic rats received the EAF 4 h after ischemia and neural plasticity-related proteins, BDNF, SYN, PSD 95, and NeuN were measured in the hippocampus 7 and 14 days after ischemia. RESULTS: A single EAF administration 1, 4, or 6 h postischemia alleviated oxidative stress that was caused by ischemia, expressed as a reduction of the amount of the PCG and GSSG, normalization of the GSH/GSSG ratio, and the restoration of SOD activity. Ischemia caused the persistent loss of memory (i.e., amnesia), an outcome that was consistently ameliorated by treatment with the EAF that was initiated 4 or 6 h postischemia. The 4 h delay in EAF treatment positively impacted dendritic morphology in neurons that survived ischemia. TGCI reduced BDNF, SYN, PSD-95, and NeuN protein levels in the hippocampus and cerebral cortex. The EAF normalized SYN and PSD-95 protein levels. Ischemia-induced neurodegeneration and glial cell activation were not prevented by EAF treatment. CONCLUSION: The present study corroborates prior data that demonstrated the neuroprotective potential of T. catigua and extends these data by showing that the delayed administration of EAF postischemia effectively prevented memory impairment and decreased oxidative stress, dendritic deterioration, and synaptic protein loss within a TWE that ranged from 1 to 6 h. This specific TWE in preclinical research may have clinical relevance by suggesting the possible utility of this plant for the development of neuroprotective strategies in the setting of ischemic brain diseases. Another innovative finding of the present study was the possible neurotrophic/neuroplastic properties of T. catigua.
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Isquemia Encefálica , Meliaceae , Fármacos Neuroprotetores , Ratos , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Dissulfeto de Glutationa/metabolismo , Dissulfeto de Glutationa/farmacologia , Dissulfeto de Glutationa/uso terapêutico , Extratos Vegetais/farmacologia , Isquemia Encefálica/tratamento farmacológico , Estresse Oxidativo , Infarto Cerebral/tratamento farmacológico , Hipocampo , Transtornos da Memória/tratamento farmacológico , Acetatos/farmacologia , Superóxido Dismutase/metabolismo , Plasticidade Neuronal , Fármacos Neuroprotetores/farmacologiaRESUMO
Evidence for the clinical use of neuroprotective drugs for the treatment of cerebral ischemia (CI) is still greatly limited. Spatial/temporal disorientation and cognitive dysfunction are among the most prominent long-term sequelae of CI. Cannabidiol (CBD) is a non-psychotomimetic constituent of Cannabis sativa that exerts neuroprotective effects against experimental CI. The present study investigated possible neuroprotective mechanisms of action of CBD on spatial memory impairments that are caused by transient global cerebral ischemia (TGCI) in rats. Hippocampal synaptic plasticity is a fundamental mechanism of learning and memory. Thus, we also evaluated the impact of CBD on neuroplastic changes in the hippocampus after TGCI. Wistar rats were trained to learn an eight-arm aversive radial maze (AvRM) task and underwent either sham or TGCI surgery. The animals received vehicle or 10 mg/kg CBD (i.p.) 30 min before surgery, 3 h after surgery, and then once daily for 14 days. On days 7 and 14, we performed a retention memory test. Another group of rats that received the same pharmacological treatment was tested in the object location test (OLT). Brains were removed and processed to assess neuronal degeneration, synaptic protein levels, and dendritic remodeling in the hippocampus. Cannabidiol treatment attenuated ischemia-induced memory deficits. In rats that were subjected to TGCI, CBD attenuated hippocampal CA1 neurodegeneration and increased brain-derived neurotrophic factor levels. Additionally, CBD protected neurons against the deleterious effects of TGCI on dendritic spine number and the length of dendritic arborization. These results suggest that the neuroprotective effects of CBD against TGCI-induced memory impairments involve changes in synaptic plasticity in the hippocampus.
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Canabidiol/uso terapêutico , Hipocampo/efeitos dos fármacos , Ataque Isquêmico Transitório/prevenção & controle , Plasticidade Neuronal/efeitos dos fármacos , Neuroproteção/efeitos dos fármacos , Sinapses/efeitos dos fármacos , Animais , Canabidiol/farmacologia , Modelos Animais de Doenças , Hipocampo/metabolismo , Hipocampo/patologia , Ataque Isquêmico Transitório/metabolismo , Ataque Isquêmico Transitório/patologia , Masculino , Plasticidade Neuronal/fisiologia , Neuroproteção/fisiologia , Técnicas de Cultura de Órgãos , Ratos , Ratos Wistar , Memória Espacial/efeitos dos fármacos , Memória Espacial/fisiologia , Sinapses/metabolismo , Sinapses/patologiaRESUMO
Inhibition of phosphodiesterase 4 (PDE4) is a promising pharmacological strategy for the treatment of cerebral ischemic conditions. To increase the relevance and increase the translational value of preclinical studies, it is important to conduct experiments using different animal species and strains, different animal models, and to evaluate long-term functional outcomes after cerebral ischemia. In the present study, the effects of the selective PDE4 inhibitor roflumilast were evaluated in vivo and in vitro. Balb/c mice were subjected to bilateral common carotid artery occlusion (BCCAO) and tested during 21 days in multiple behavioral tasks to investigate the long-term effects of roflumilast on functional recovery. The effects of roflumilast were also investigated on hippocampal cell loss, white matter injury, and expression of neuroinflammatory markers. Roflumilast prevented cognitive and emotional deficits induced by BCCAO in mice. Roflumilast also prevented neurodegeneration and reduced the white matter damage in the brain of ischemic animals. Besides, roflumilast decreased Iba-1 (microglia marker) levels and increased Arginase-1 (Arg-1; microglia M2 phenotype marker) levels in the hippocampus of these mice. Likewise, roflumilast suppressed inducible nitric oxide synthase (microglia M1 phenotype marker) expression and increased Arg-1 levels in a primary mouse microglia culture. These findings support evidence that PDE4 inhibition by roflumilast might be beneficial in cerebral ischemic conditions. The neuroprotective effects of roflumilast appear to be mediated by a decrease in neuroinflammation.
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Aminopiridinas/farmacologia , Arginase/metabolismo , Benzamidas/farmacologia , Isquemia Encefálica , Proteínas de Ligação ao Cálcio/metabolismo , Disfunção Cognitiva , Proteínas dos Microfilamentos/metabolismo , Doenças Neuroinflamatórias , Animais , Comportamento Animal/efeitos dos fármacos , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/imunologia , Isquemia Encefálica/psicologia , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/metabolismo , Ciclopropanos/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Camundongos , Microglia/efeitos dos fármacos , Microglia/metabolismo , Doenças Neuroinflamatórias/tratamento farmacológico , Doenças Neuroinflamatórias/metabolismo , Fármacos Neuroprotetores/farmacologia , Inibidores da Fosfodiesterase 4/farmacologia , Recuperação de Função Fisiológica/efeitos dos fármacos , Resultado do Tratamento , Substância Branca/efeitos dos fármacos , Substância Branca/metabolismoRESUMO
An ever-increasing body of preclinical studies has shown the multifaceted neuroprotective profile of cannabidiol (CBD) against impairments caused by cerebral ischemia. In this study, we have explored the neuropharmacological mechanisms of CBD action and its impact on functional recovery using a model of transient global cerebral ischemia in mice. C57BL/6J mice were subjected to bilateral common carotid artery occlusion (BCCAO) for 20 min and received vehicle or CBD (10 mg/Kg) 0.5 hr before and 3, 24, and 48 hr after reperfusion. To investigate the neuropharmacological mechanisms of CBD, the animals were injected with CB1 (AM251, 1 mg/kg), CB2 (AM630, 1 mg/kg), 5-HT1A (WAY-100635, 10 mg/kg), or PPAR-γ (GW9662, 3 mg/kg) receptor antagonists 0.5 hr prior to each injection of CBD. The animals were evaluated using a multi-task testing battery that included the open field, elevated zero maze, Y-maze (YM), and forced swim test. CBD prevented anxiety-like behavior, memory impairments, and despair-like behaviors induced by BCCAO in mice. The anxiolytic-like effects of CBD in BCCAO mice were attenuated by CB1 , CB2 , 5-HT1A , and PPAR-γ receptor antagonists. In the YM, both CBD and the CB1 receptor antagonist AM251 increased the exploration of the novel arm in ischemic animals, indicating beneficial effects of these treatments in the spatial memory performance. Together, these findings indicate the involvement of CB1 , CB2 , 5-HT1A, and PPAR-γ receptors in the functional recovery induced by CBD in BCCAO mice.
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Canabidiol , Disfunção Cognitiva , Animais , Isquemia , Camundongos , Camundongos Endogâmicos C57BL , PPAR gama , Receptor CB1 de Canabinoide , Receptor CB2 de Canabinoide , Receptor 5-HT1A de SerotoninaRESUMO
Phosphodiesterase 4 (PDE4) inhibitors have been shown to present beneficial effects in cerebral ischemic injury because of their ability to improve cognition and target different phases and mechanisms of cerebral ischemia, including apoptosis, neurogenesis, angiogenesis, and inflammation. The present study investigated whether repeated treatment with the PDE4 inhibitor roflumilast rescued memory loss and attenuated neuroinflammation in rats following transient global cerebral ischemia (TGCI). TGCI caused memory impairments, neuronal loss (reflected by Neuronal nuclei (NeuN) immunoreactivity), and compensatory neurogenesis (reflected by doublecortin (DCX) immunoreactivity) in the hippocampus. Also, increases in the protein expression of the phosphorylated response element-binding protein (pCREB) and inflammatory markers such as the glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule 1 (Iba-1), were detected in the hippocampus in TGCI rats. Repeated treatment with roflumilast (0.003 and 0.01 mg/kg) prevented spatial memory deficits without promoting hippocampal protection in ischemic animals. Roflumilast increased the levels of pCREB, arginase-1, interleukin (IL) 4, and IL-10 in the hippocampus 21 days after TGCI. These data suggest a protective effect of roflumilast against functional sequelae of cerebral ischemia, which might be related to its anti-inflammatory properties.
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Isquemia Encefálica , Ataque Isquêmico Transitório , Aminopiridinas/farmacologia , Aminopiridinas/uso terapêutico , Animais , Benzamidas , Isquemia Encefálica/tratamento farmacológico , Ciclopropanos , Proteína Duplacortina , Hipocampo , Ratos , Memória EspacialRESUMO
Cerebral ischemia-induced hyperglycemia has been reported to accentuate neurological damage following focal or global cerebral ischemia. Hyperglycemia found in rats following focal brain ischemia occurs in the first 24â¯h and has been claimed to be caused by increased liver gluconeogenesis and insulin resistance. However, liver gluconeogenesis and the mechanisms leading to hyperglycemia after global cerebral ischemia remain uncertain. This study investigated the glycemic homeostasis and hepatic metabolism in rats after transient four-vessel occlusion (4-VO)-induced global cerebral ischemia, an event that mimics to a certain degree the situation during cardiac arrest. Several metabolic fluxes were measured in perfused livers. Activities and mRNA expressions of hepatic glycolysis and glyconeogenesis rate-limiting enzymes were assessed as well as respiratory activity of hepatic isolated mitochondria. Global cerebral ischemia was associated with hyperglycemia and hyperinsulinemia 24â¯h after ischemia. Insulin resistance developed later and was prominent after the 5th day. Hepatic anabolism and catabolism were both modified in a complex and time-dependent way. Gluconeogenesis, ß-oxidation, ketogenesis and glycolysis were diminished at 24â¯h after ischemia. At 5â¯days after ischemia glycolysis had normalized, but gluconeogenesis, ketogenesis and ß-oxidation were accelerated. The overall metabolic modifications suggest that a condition of depressed metabolism was established in response to the new conditions generated by the cerebral global ischemia. Whether the modifications in the liver metabolism found in rats after the ischemic insult can be translated to individuals following global brain ischemia remains uncertain, but the results of this study are hoped to encourage further investigations.
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Glicemia/metabolismo , Isquemia Encefálica/metabolismo , Homeostase , Fígado/metabolismo , Animais , Masculino , Ratos , Ratos WistarRESUMO
Pharmacological interventions that selectively activate serotonin 5-hydroxytryptramine-1A (5-HT1A) heteroreceptors may prevent or attenuate the consequences of brain ischemic episodes. The present study investigated whether the preferential 5-HT1A postsynaptic receptor agonist NLX-101 (a.k.a. F15599) mitigates cognitive and emotional impairments and affects neuroplasticity in mice that are subjected to the bilateral common carotid artery occlusion (BCCAO) model of brain ischemia. The selective serotonin reuptake inhibitor escitalopram (Esc) was used for comparative purposes because it is able to decrease morbidity and improve recovery in stroke patients and ischemic rodents. Sham and BCCAO mice received daily doses of NLX-101 (0.32 mg/kg, i.p) or Esc (20 mg/kg, i.p) for 28 days. During this period, they were evaluated for locomotor activity, anxiety- and despair-related behaviors and hippocampus-dependent cognitive function, using the open field, elevated zero maze, forced swim test and object location test, respectivelly. The mice's brains were processed for biochemical and histological analyses. BCCAO mice exhibited high anxiety and despair-like behaviors and performed worse than controls in the cognitive assessment. BCCAO induced neuronal and dendritic spine loss and decreases in the protein levels of neuronal plasticity markers, including brain-derived neurotrophic factor (BDNF), synaptophysin (SYN), and postsynaptic density protein-95 (PSD-95), in prefrontal cortex (PFC) and hippocampus. NLX-101 and Esc attenuated cognitive impairments and despair-like behaviors in BCCAO mice. Only Esc decreased anxiety-like behaviors due to brain ischemia. Both NLX-101 and Esc blocked the increase in plasma corticosterone levels and, restored BDNF, SYN and PSD-95 protein levels in the hippocampus. Moreover, both compounds impacted positively dentritic remodeling in the hippocampus and PFC of ischemic mice. In the PFC, NLX-101 increased the BDNF protein levels, while Esc in turn, attenuated the decrease in the PSD-95 protein levels induced by BCCAO. The present results suggest that activation of post-synaptic 5-HT1A receptors is the molecular mechanism for serotonergic protective effects in BCCAO. Moreover, post-synaptic biased agonists such as NLX-101 might constitute promising therapeutics for treatment of functional and neurodegenerative outcomes of brain ischemia.
Assuntos
Isquemia Encefálica/metabolismo , Plasticidade Neuronal/efeitos dos fármacos , Piperidinas/uso terapêutico , Pirimidinas/uso terapêutico , Receptor 5-HT1A de Serotonina/metabolismo , Recuperação de Função Fisiológica/efeitos dos fármacos , Agonistas do Receptor 5-HT1 de Serotonina/uso terapêutico , Animais , Isquemia Encefálica/tratamento farmacológico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Plasticidade Neuronal/fisiologia , Piperidinas/farmacologia , Pirimidinas/farmacologia , Recuperação de Função Fisiológica/fisiologia , Agonistas do Receptor 5-HT1 de Serotonina/farmacologiaRESUMO
Abstract Trichilia catigua A. Juss., Meliaceae, known as "catuaba" in Brazil, has been popularly used as a tonic for fatigue, impotence and memory deficits. Previously, we have demonstrated that T. catigua ethyl-acetate fraction exerted antidepressive-like effects in mice. Affective-like symptoms are also well recognized outcome of cerebral ischemia in clinical and preclinical settings. Therefore, here we evaluated the effects of ethyl-acetate fraction on the emotional outcomes and its relation with hippocampal neurogenesis in ischemic mice. Male Swiss mice were subject to the bilateral common carotid occlusion during 20 min. The animals received ethyl-acetate fraction (400 mg/kg, orally) 30 min before and once per day during 7 days after reperfusion. Emotional outcomes were assessed using the open field test, elevated zero maze, and the tail suspension test. After the behavioral testing, the animals were sacrificed and their brains were processed to immunohistochemistry and Nissl staining. Ischemic mice exhibited anxiogenic-like behaviors in the elevated zero maze, hippocampal neurodegeneration and decreased hippocampal neurogenesis. The anxiogenic-like effect was counteracted by ethyl-acetate fraction administration. Furthermore, ethyl-acetate fraction restored the number of newborn neurons in the dentate gyrus of hippocampus of ischemic mice. In conclusion, T. catigua ethyl-acetate fraction promoted functional recovery and restored hippocampal neurogenesis in ischemic mice.
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We previously found that fish oil (FO) facilitated memory recovery in the absence of pyramidal neuron rescue after transient, global cerebral ischemia (TGCI). Fish oil preserved the expression of microtubule-associated protein 2 (MAP-2), suggesting a relationship between dendritic plasticity and memory recovery that is mediated by FO after TGCI. The present study examined whether postischemic treatment with FO prevents ischemia-induced loss of dendritic processes in remaining pyramidal neurons. The effects of FO on neuroplasticity-related proteins were also examined after TGCI. Rats were subjected to TGCI (15 min, four-vessel occlusion model) and then received vehicle or FO (300 mg/kg docosahexaenoic acid) once daily for 7 days. The first dose was administered 4 h postischemia. Golgi-Cox staining was used to evaluate dentrict morphology in the pyramidal neurons of hippocampus (CA1 and CA3 subfields) and prefrontal cortex (PFC). Neuronal nuclei protein (NeuN), brain-derived neurotrophic factor (BDNF), growth-associated protein 43 (GAP-43), synaptophysin (SYP), and postsynaptic density protein 95 (PSD-95) levels were measured by Western blot in both structures. Fifteen minutes of TGCI reduced consistently the length of dendrites, number of dendritic branches and dendritic spine density (average of 25%, 43%, 32%, respectively) 7, 14, and 21 days postischemia, indicating that they did not recover spontaneously. This outcome of TGCI was reversed by FO treatment, an effect that was sustained even after treatment cessation. The NeuN and BDNF protein levels were reduced in both the hippocampus and PFC, which were recovered by FO treatment. GAP-43 protein levels decreased after ischemia in the PFC only, and this effect was also mitigated by FO. Neither SYP nor PSD-95 levels were altered by ischemia, but PDS-95 levels almost doubled after FO treatment in the ischemic group. These data support our hypothesis that synaptic plasticity at the level of dendrites may at least partially underlie the memory-protective effect of FO after TGCI and strengthen the possibility that FO has therapeutic potential for treating the sequelae of brain ischemia/reperfusion injury.
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Dendritos/efeitos dos fármacos , Óleos de Peixe/farmacologia , Ataque Isquêmico Transitório/patologia , Plasticidade Neuronal/efeitos dos fármacos , Sinapses/efeitos dos fármacos , Animais , Dendritos/patologia , Ácidos Docosa-Hexaenoicos/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Masculino , Fármacos Neuroprotetores/farmacologia , Ratos , Ratos Wistar , Sinapses/patologiaRESUMO
O objetivo deste trabalho é estudar a morfologia neuronal a partir de modelos animais, fornecer informações biológicas difíceis de serem obtidas em humanos, permitindo estudar condições neuropsiquiátricas como doença de Alzheimer, ansiedade, dentre outras. O presente trabalho descreveu metodologia de estudo para cérebro de roedores, duas técnicas neuroanatômicas, Klüver-Barrera e Golgi-Cox, e seus respectivos processos de quantificação. A técnica de Klüver-Barrera permitiu visualização da substância branca e cinzenta com destaque na bainha de mielina. A técnica de Golgi-Cox, adaptada para realidade de nosso laboratório, mostrou-se eficiente para visualização de neurônios e seus prolongamentos, como dendritos e espinhas dendríticas, permitindo assim a quantificação. A partir de imagens obtidas de microscópio descreveu-se os diferentes passos para quantificação, a determinação de volume de estruturas internas cerebrais (corpo caloso e camada celular do hipocampo) assim como a quantificação das espinhas dendríticas em neurônios piramidais. Os métodos descritos e detalhados poderão ser utilizados em vários campos da neurociência
Neuronal morphology is analyzed in animal models to provide biological information difficult to obtain in humans. The above makes possible the study of neuro-psychiatric, such as Alzheimer´s disease, anxiety and others. Current study described methodology for rodents´ brains, two neuro-anatomic techniques, Klüver-Barrera and Golgi-Cox, and their respective quantification processes. Klüver-Barrera technique visualized the white and gray matter, particularly the myelin sheath. Golgi-Cox technique, adapted for current research, was efficient to visualize neurons and their prolongations, such as dendrites and dendritic spines, with quantification. Images by microscope described the different steps for the quantification, determination of volume of the brain´s internal structures (callous body and the hypocampus´s cell layer) coupled to the quantification of dendritic spines in pyramid neurons. Described and detailed methods will be useful in several fields of neuroscience
Assuntos
Animais , Sistema Nervoso Central , Espinhas Dendríticas , Bainha de Mielina , NeurociênciasRESUMO
Diabetes and aging are risk factors for cognitive impairments after chronic cerebral hypoperfusion (CCH). Cannabidiol (CBD) is a phytocannabinoid present in the Cannabis sativa plant. It has beneficial effects on both cerebral ischemic diseases and diabetes. We have recently reported that diabetes interacted synergistically with aging to increase neuroinflammation and memory deficits in rats subjected to CCH. The present study investigated whether CBD would alleviate cognitive decline and affect markers of inflammation and neuroplasticity in the hippocampus in middle-aged diabetic rats submitted to CCH. Diabetes was induced in middle-aged rats (14 months old) by intravenous streptozotocin (SZT) administration. Thirty days later, the diabetic animals were subjected to sham or CCH surgeries and treated with CBD (10 mg/kg, once a day) during 30 days. Diabetes exacerbated cognitive deficits induced by CCH in middle-aged rats. Repeated CBD treatment decreased body weight in both sham- and CCH-operated animals. Cannabidiol improved memory performance and reduced hippocampal levels of inflammation markers (inducible nitric oxide synthase, ionized calcium-binding adapter molecule 1, glial fibrillary acidic protein, and arginase 1). Cannabidiol attenuated the decrease in hippocampal levels of brain-derived neurotrophic factor induced by CCH in diabetic animals, but it did not affect the levels of neuroplasticity markers (growth-associated protein-43 and synaptophysin) in middle-aged diabetic rats. These results suggest that the neuroprotective effects of CBD in middle-aged diabetic rats subjected to CCH are related to a reduction in neuroinflammation. However, they seemed to occur independently of hippocampal neuroplasticity changes.
Assuntos
Encéfalo/irrigação sanguínea , Encéfalo/efeitos dos fármacos , Canabidiol/uso terapêutico , Circulação Cerebrovascular/efeitos dos fármacos , Diabetes Mellitus Experimental/tratamento farmacológico , Fatores Etários , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Encéfalo/metabolismo , Canabidiol/farmacologia , Circulação Cerebrovascular/fisiologia , Doença Crônica , Comorbidade , Diabetes Mellitus Experimental/sangue , Masculino , Ratos , Ratos Wistar , Resultado do TratamentoRESUMO
Chronic cerebral hypoperfusion (CCH) has been associated with aging-related vascular dementia, including Alzheimer's disease. It can be induced by the four-vessel occlusion/internal carotid artery (4VO/ICA) model in aged rats, resulting in persistent memory deficits, white matter injury, and significant neuronal loss in the hippocampus and cerebral cortex. The phosphodiesterase type 4 inhibitor (PDE4-I) roflumilast has been reported to have pro-cognitive effects in several behavioral paradigms. The present study evaluated the effects of repeated roflumilast treatment in aged rats that were subjected to CCH. After surgery, roflumilast (0.003 and 0.01â¯mg/kg) was administered intraperitoneally once per day for 29 days. Memory performance was assessed in the aversive radial maze (AvRM) 7, 14, and 21 days after CCH. The effects of roflumilast on hippocampal neurodegeneration and white matter injury were investigated using Nissl and Kluver-Barrera staining, respectively. Western blot and RT-qPCR were used to explore microglial polarization using M1 (Iba-1 and iNOS) and M2 (Arginase-1) markers. Chronic cerebral hypoperfusion caused persistent memory deficits, hippocampal neurodegeneration, and vacuolization and fiber disarrangement in white matter. Repeated roflumilast treatment restored CCH-induced cognitive impairments in aged rats but in the absence of the rescue of hippocampal neurons. Attenuation of white matter injury was detected in the optic tract in aged CCH rats that were treated with roflumilast. In vitro, roflumilast increased Arg-1 gene expression in myelin-laden primary microglia. The present data suggest that roflumilast might be useful for the treatment of cognitive sequelae associated with CCH.
Assuntos
Aminopiridinas/farmacologia , Benzamidas/farmacologia , Isquemia Encefálica/tratamento farmacológico , Transtornos da Memória/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Nootrópicos/farmacologia , Substância Branca/efeitos dos fármacos , Envelhecimento/efeitos dos fármacos , Envelhecimento/patologia , Animais , Arginase/metabolismo , Isquemia Encefálica/complicações , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Doença Crônica , Ciclopropanos/farmacologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Aprendizagem em Labirinto/fisiologia , Transtornos da Memória/etiologia , Transtornos da Memória/metabolismo , Transtornos da Memória/patologia , Microglia/efeitos dos fármacos , Microglia/metabolismo , Microglia/patologia , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/etiologia , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Trato Óptico/efeitos dos fármacos , Trato Óptico/metabolismo , Trato Óptico/patologia , Distribuição Aleatória , Ratos Wistar , Substância Branca/metabolismo , Substância Branca/patologiaRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Trichilia catigua A. Juss (Meliaceae) preparations have been used in folk medicine to alleviate fatigue, stress, and improve memory. Antinociceptive, antiinflammatory, and in vitro neuroprotective effects have been observed in animals. Cerebral ischemia/reperfusion (I/R) leads to severe neuropsychological deficits that are largely associated with oxidative stress, inflammation and neurodegeneration. We reported previously that an ethyl-acetate fraction (EAF) of T. catigua reduced brain ischemia-induced learning and memory impairments in the absence of histological protection. AIM OF THE STUDY: Continuing those studies, here we aimed to investigate the antioxidant and antiinflammatory properties of T. catigua in an in vivo model of I/R. MATERIAL AND METHODS: Rats were subjected to 15â¯min of brain ischemia (4-VO model) followed by up to 15 days of reperfusion. Vehicle was given by gavage 30â¯min before ischemia and at 1â¯h of reperfusion. In a first experiment, brain ischemia-induced changes in oxidative stress markers, i.e., reduced glutathione (GSH), oxidized glutathione (GSSG), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and protein carbonyl groups (PCGs) were measured on days 1, 3, and 5 post-ischemia. Similar time course analysis was done for neuroinflammation markers, i.e., microglia (OX42 immunorreactivity) and astrocytes (GFAP immunorreactivity), in the hippocampus. In a second experiment, the time points at which these markers of oxidative stress and neuroinflammation peaked were used to test the effects of T. catigua (400â¯mg/kg, p.o.). RESULTS: Oxidative stress markers peaked on day 1 post-ischemia. GSH decreased (-23.2%) while GSSG increased (+ 71.1%), which yielded a significant reduction in the GSH/GSSG ratio (-39.1%). The activity of CAT was largely reduced by ischemia (-54.6% to -65.1%), while the concentration of PCG almost doubled in the brain of ischemic rats (+99.10%) in comparison to sham. Treatment with the EAF of T. catigua normalized these changes in oxidative markers to the control levels (GSH: +27.5%; GSSG: -23.8%; GSH/GSSG: +44.6%; PCG: -80.3%). In the hippocampus, neuroinflammation markers peaked on day 5 post-ischemia, with microglial and astrocytic responses increasing to 54.8% and 37.1%, respectively. The elevation in glial cells response was completely prevented by EAF. CONCLUSION: These results demonstrate that T. catigua has both antioxidant and antiinflammatory activities after transient global cerebral ischemia in rats, which may contribute to the previously reported memory protective effect of T. catigua.
Assuntos
Anti-Inflamatórios/uso terapêutico , Antioxidantes/uso terapêutico , Isquemia Encefálica/tratamento farmacológico , Meliaceae , Fármacos Neuroprotetores/uso terapêutico , Extratos Vegetais/uso terapêutico , Traumatismo por Reperfusão/tratamento farmacológico , Acetatos/química , Animais , Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Isquemia Encefálica/metabolismo , Antígeno CD11b/metabolismo , Catalase/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Glutationa/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Masculino , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Fitoterapia , Extratos Vegetais/farmacologia , Caules de Planta/química , Ratos Wistar , Traumatismo por Reperfusão/metabolismo , Solventes/química , Superóxido Dismutase/metabolismoRESUMO
We originally reported that an ethyl-acetate fraction (EAF) of Trichilia catigua prevented the impairment of water maze learning and hippocampal neurodegeneration after transient global cerebral (TGCI) in mice. We extended that previous study by evaluating whether T. catigua (i) prevents the loss of long-term retrograde memory assessed in the aversive radial maze (AvRM), (ii) confers hippocampal and cortical neuroprotection, and (iii) mitigates oxidative stress and neuroinflammation in rats that are subjected to the four vessel occlusion (4-VO) model of TGCI. In the first experiment, naive rats were trained in the AvRM and then subjected to TGCI. The EAF was administered orally 30min before and 1h after TGCI, and administration continued once per day for 7days post-ischemia. In the second experiment, the EAF was administered 30min before and 1h after TGCI, and protein carbonylation and myeloperoxidase (MPO) activity were assayed 24h and 5days later, respectively. Retrograde memory performance was assessed 8, 15, and 21days post-ischemia. Ischemia caused persistent retrograde amnesia, and this effect was prevented by T. catigua. This memory protection (or preservation) persisted even after the treatment was discontinued, despite the absence of histological neuroprotection. Protein carbonyl group content and MPO activity increased around 43% and 100%, respectively, after TGCI, which were abolished by the EAF of T. catigua. The administration of EAF did not coincide with the days of memory testing. The data indicate that antioxidant and/or antiinflammatory actions in the early phase of ischemia/reperfusion contribute to the long-term antiamnesic effect of T. catigua.
Assuntos
Amnésia Retrógrada/tratamento farmacológico , Amnésia Retrógrada/etiologia , Isquemia Encefálica/complicações , Inflamação/tratamento farmacológico , Inflamação/etiologia , Meliaceae/química , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/uso terapêutico , Animais , Biomarcadores/metabolismo , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Modelos Animais de Doenças , Hipocampo/metabolismo , Aprendizagem em Labirinto/efeitos dos fármacos , Extratos Vegetais/química , RatosRESUMO
Chronic cerebral hypoperfusion (CCH) may be involved in the etiology of aging-related dementias, and several risk factors contribute to their development and/or aggravation. We previously reported on the development of the 4-VO/ICA model of CCH, and the impact of hypertension on the cognitive and histological outcomes of CCH. Here, we advanced those studies by investigating how 4-VO/ICA alone or in combination with diabetes affects survival, body weight and cognitive performance in both young and middle-aged rats. Subsequently, middle-aged rats were examined for the impact of diabetes on CCH-induced neurodegeneration, white matter damage, and glial cells response. Diabetes alone reduced body weight and increased mortality rate slightly in young rats; these effects were striking, however, in the older animals. After CCH alone, neither body weight nor mortality rate changed significantly in both age groups. However, when CCH was combined with diabetes, mortality rate increased significantly in both aged groups. Young rats were cognitively asymptomatic to CCH, but they became 'mildly' impaired after CCH combined with diabetes. In middle-aged rats, CCH severely impaired memory, which was significantly worsened by diabetes. Moreover, diabetes aggravated neurodegeneration in the hippocampus and white matter injury in the corpus callosum and it promoted glial activation in the hippocampus and white matter of CCH middle-aged rats. These data suggest that diabetes interacts synergistically with age and reduces the capacity of the brain to adequately respond to CCH and highlight the importance of associating risk factors in the preclinical investigation of age-related cerebrovascular diseases physiopathology and potential therapies.