An Anterior Cingulate Cortex-to-Midbrain Projection Controls Chronic Itch in Mice / 神经科学通报·英文版

Itch is an unpleasant sensation that provokes the desire to scratch. While acute itch serves as a protective system to warn the body of external irritating agents, chronic itch is a debilitating but poorly-treated clinical disease leading to repetitive scratching and skin lesions. However, the neural mechanisms underlying the pathophysiology of chronic itch remain mysterious. Here, we identified a cell type-dependent role of the anterior cingulate cortex (ACC) in controlling chronic itch-related excessive scratching behaviors in mice. Moreover, we delineated a neural circuit originating from excitatory neurons of the ACC to the ventral tegmental area (VTA) that was critically involved in chronic itch. Furthermore, we demonstrate that the ACC→VTA circuit also selectively modulated histaminergic acute itch. Finally, the ACC neurons were shown to predominantly innervate the non-dopaminergic neurons of the VTA. Taken together, our findings uncover a cortex-midbrain circuit for chronic itch-evoked scratching behaviors and shed novel insights on therapeutic intervention.

Complement C3 Aggravates Post-epileptic Neuronal Injury Via Activation of TRPV1 / 神经科学通报·英文版

Epilepsy is a brain condition characterized by the recurrence of unprovoked seizures. Recent studies have shown that complement component 3 (C3) aggravate the neuronal injury in epilepsy. And our previous studies revealed that TRPV1 (transient receptor potential vanilloid type 1) is involved in epilepsy. Whether complement C3 regulation of neuronal injury is related to the activation of TRPV1 during epilepsy is not fully understood. We found that in a mouse model of status epilepticus (SE), complement C3 derived from astrocytes was increased and aggravated neuronal injury, and that TRPV1-knockout rescued neurons from the injury induced by complement C3. Circular RNAs are abundant in the brain, and the reduction of circRad52 caused by complement C3 promoted the expression of TRPV1 and exacerbated neuronal injury. Mechanistically, disorders of neuron-glia interaction mediated by the C3-TRPV1 signaling pathway may be important for the induction of neuronal injury. This study provides support for the hypothesis that the C3-TRPV1 pathway is involved in the prevention and treatment of neuronal injury and cognitive disorders.

Autophagy activation attenuates the neurotoxicity of local anesthetics by decreasing caspase-3 activity in rats / A ativação autofágica atenua a neurotoxicidade dos anestésicos locais ao diminuir a atividade da caspase‐ 3 em ratos

Abstract Background and objectives The mechanisms by which local anesthetics cause neurotoxicity are very complicated. Apoptosis and autophagy are highly coordinated mechanisms that maintain cellular homeostasis against stress. Studies have shown that autophagy activation serves as a protective mechanism in vitro. However, whether it also plays the same role in vivo is unclear. The aim of this study was to explore the role of autophagy in local anesthetic-induced neurotoxicity and to elucidate the mechanism of neurotoxicity in an intrathecally injected rat model. Methods Eighteen healthy adult male Sprague-Dawley rats were randomly divided into three groups. Before receiving an intrathecal injection of 1% bupivacaine, each rat received an intraperitoneal injection of vehicle or rapamycin (1 mg.kg-1) once a day for 3 days. The pathological changes were examined by Haematoxylin and Eosin (HE) staining. Apoptosis was analysed by TdT-mediated dUTP Nick-End Labelling (TUNEL) staining. Caspase-3, Beclin1 and LC3 expression was examined by Immunohistochemical (IHC) staining. Beclin1 and LC3 expression and the LC3-II/LC3-I ratio were detected by western blot analysis. Results After bupivacaine was injected intrathecally, pathological damage occurred in spinal cord neurons, and the levels of apoptosis and caspase-3 increased. Enhancement of autophagy with rapamycin markedly alleviated the pathological changes and decreased the levels of apoptosis and caspase-3 while increasing the expression of LC3 and Beclin1 and the ratio of LC3-II to LC3-I. Conclusions Enhancement of autophagy decreases caspase-3-dependent apoptosis and improves neuronal survivalin vivo. Activation of autophagy may be a potential therapeutic strategy for local anaesthetic-induced neurotoxicity.

Resumo Introdução e objetivos Os mecanismos de neurotoxicidade dos anestésicos locais são complexos. A apoptose e a autofagia são mecanismos altamente organizados que mantêm a homeostase celular durante o estresse. Estudos revelam que a ativação da autofagia atua como mecanismo de proteção in vitro. Não está claro se a autofagia também desempenha essa função in vivo. O objetivo deste estudo foi analisar o papel da autofagia na neurotoxicidade induzida por anestésico local e esclarecer o mecanismo dessa neurotoxicidade utilizando um modelo de injeção intratecal em ratos. Métodos Dezoito ratos Sprague‐Dawley machos adultos saudáveis foram divididos aleatoriamente em três grupos. Antes de receber a injeção intratecal de bupivacaína a 1%, cada rato recebeu injeção intraperitoneal de veículo ou rapamicina (1 mg.kg‐1) uma vez ao dia durante 3 dias. As alterações patológicas foram examinadas por coloração com Hematoxilina e Eosina (HE). A apoptose foi analisada por coloração com o método dUTP Nick‐End Labeling (TUNEL) mediado por TdT. A expressão de caspase‐3, Beclin1 e LC3 foram examinadas por coloração Imunohistoquímica (IHQ). A expressão de Beclin1 e LC3 e a razão LC3‐II/LC3‐I foram detectadas por análise de western blot. Resultados Após a injeção intratecal de bupivacaína, ocorreu lesão patológica nos neurônios da medula espinhal e os níveis de apoptose e caspase‐3 aumentaram. A ativação da autofagia causada pela rapamicina mitigou de forma expressiva as alterações patológicas e diminuiu os níveis de apoptose e caspase‐3, aumentando a expressão de LC3 e Beclin1 e a razão LC3‐II/LC3‐I. Conclusões O aumento da autofagia diminui a apoptose dependente da caspase‐3 e melhora a sobrevivência neuronal in vivo. A ativação da autofagia pode ser uma estratégia terapêutica potencial para a neurotoxicidade induzida por anestésicos locais.

Toxoplasma gondii infection damages the perineuronal nets in a murine model

BACKGROUND Behavioral and neurochemical alterations associated with toxoplasmosis may be influenced by the persistence of tissue cysts and activation of an immune response in the brain of Toxoplasma gondii-infected hosts. The cerebral extracellular matrix is organised as perineuronal nets (PNNs) that are both released and ensheath by some neurons and glial cells. There is evidences to suggest that PNNs impairment is a pathophysiological mechanism associated with neuropsychiatric conditions. However, there is a lack of information regarding the impact of parasitic infections on the PNNs integrity and how this could affect the host's behavior. OBJECTIVES In this context, we aimed to analyse the impact of T. gondii infection on cyst burden, PNNs integrity, and possible effects in the locomotor activity of chronically infected mice. METHODS We infected mice with T. gondii ME-49 strain. After thirty days, we assessed locomotor performance of animals using the open field test, followed by evaluation of cysts burden and PNNs integrity in four brain regions (primary and secondary motor cortices, prefrontal and somesthetic cortex) to assess the PNNs integrity using Wisteria floribunda agglutinin (WFA) labeling by immunohistochemical analyses. FINDINGS AND MAIN CONCLUSIONS Our findings revealed a random distribution of cysts in the brain, the disruption of PNNs surrounding neurons in four areas of the cerebral cortex and hyperlocomotor behavior in T. gondii-infected mice. These results can contribute to elucidate the link toxoplasmosis with the establishment of neuroinflammatory response in neuropsychiatric disorders and to raise a discussion about the mechanisms related to changes in brain connectivity, with possible behavioral repercussions during chronic T. gondii infection.

Tauroursodeoxycholic acid attenuates neuronal apoptosis via the TGR5/ SIRT3 pathway after subarachnoid hemorrhage in rats

BACKGROUND: Neuronal apoptosis plays a critical event in the pathogenesis of early brain injury after subarachnoid hemorrhage (SAH). This study investigated the roles of Tauroursodeoxycholic acid (TUDCA) in attenuate neuronal apoptosis and underlying mechanisms after SAH. METHODS: Sprague-Dawley rats were subjected to model of SAH and TUDCA was administered via the internal carotid injection. Small interfering RNA (siRNA) for TGR5 were administered through intracerebroventricular injection 48 h before SAH. Neurological scores, brain water content, Western blot, TUNEL staining and immunofluorescence staining were evaluated. RESULTS: TUDCA alleviated brain water content and improved neurological scores at 24 h and 72 h after SAH. TUDCA administration prevented the reduction of SIRT3 and BCL-2 expressions, as well as the increase of BAX and cleaved caspase-3.Endogenous TGR5 expression were upregulated after SAH and treatment with TGR5 siRNA exacerbated neurological outcomes after SAH and the protective effects of TUDCA at 24 h after SAH were also abolished by TGR5 siRNA. CONCLUSIONS: Our findings demonstrate that TUDCA could attenuated neuronal apoptosis and improve neurological functions through TGR5/ SIRT3 signaling pathway after SAH. TUDCA may be an attractive candidate for anti-apoptosis treatment in SAH.

Knockdown of lncRNA TUG1 inhibits hippocampal neuronal apoptosis and participates in aerobic exercise-alleviated vascular cognitive impairment

OBJECTIVES: Our previous study indicated that aerobic exercise relieves cognitive impairment in patients with vascular cognitive impairment (VCI) via regulating brain-derived neurotrophic factor (BDNF), but the mechanism is not yet clear. This study aimed to explore whether lncRNA taurine upregulated gene 1 (TUG1) participates in the process of VCI by regulating BDNF. METHODS: The expressions of TUG1 and BDNF in the serum of VCI patients were detected. The potential molecular mechanisms of TUG1 in regulating hippocampal neuronal apoptosis were explored in oxygen and glucose deprivation-induced (OGD-induced) hippocampal cell line HT22. The VCI mouse model was established, and TUG1 and BDNF were overexpressed via lentivirus injection. The cognitive impairment of mice was detected by the Morris water maze experiment after the aerobic exercise. RESULTS: The level of TUG1 was elevated in the serum of VCI patients compared with the control group. The knockdown of TUG1 in OGD-induced HT22 cells increased BDNF level and decreased cell apoptosis, and the downregulation of BDNF restored the decreased cell apoptosis. RNA immunoprecipitation and RNA pull-down assays showed that TUG1 could bind to BDNF protein. The aerobic exercise alleviated cognitive impairment and inhibited hippocampal apoptosis in VCI mice. Meanwhile, the overexpression of TUG1 reversed the therapeutic effects of aerobic exercise on cognitive impairment. CONCLUSIONS: The knockdown of TUG1 reduced hippocampal neuronal apoptosis and participates in the aerobic exercise-alleviated VCI, which was partly through regulating BDNF.

Fenilcetonuria de diagnóstico precoz: Bases fisiopatológicas del daño neuronal y opciones terapéuticas / Early diagnosis of phenylketonuria. Physiopathology of the neuronal damage and therapeutic options

La fenilcetonuria, también conocida como PKU, es el error congénito más frecuente del metabolismo de los aminoácidos. La forma grave o PKU clásica no tratada, causa una discapacidad intelectual, aunque los programas de detección en el período neonatal, el diagnóstico y el tratamiento evitan la aparición de los síntomas. A pesar de un diagnóstico y tratamiento temprano hemos observado cierta neurotoxicidad en los pacientes con PKU tratados. Analizamos los demás factores implicados, aparte de la toxicidad por las elevadas concentraciones cerebrales de fenilalanina (Phe), se revisan los defectos de síntesis de neurotransmisores, las alteración de la mielinización cerebral, el efecto de la elevación de Phe en los procesos de transporte y distribución de los aminoácidos neutros con una síntesis anómala de proteínas cerebrales, la deficiencia plasmática y cerebral de tirosina, la neurotoxicidad de los metabolitos de Phe, el defecto de la biosíntesis del colesterol o el aumento del estrés oxidativo. Las alteraciones de la sustancia blanca en los pacientes con PKU tienen un papel importante en las manifestaciones neurológicas. El tratamiento de la PKU es para toda la vida y se basa en la reducción del aporte de alimentos que contienen Phe combinado con la administración de una fórmula especial, o en el tratamiento con tetrahidrobiopterina (BH4). Se analizan nuevas opciones terapéuticas.

Phenylketonuria, also known as PKU, is the most frequent congenital inborn error of metabolism. The severe form or classic PKU untreated causes intellectual disability, although with the early detection programs in the neonatal period, diagnosis and treatment prevent the appearance of the symptoms. Despite early diagnosis and treatment we have observed some neurotoxicity in treated PKU patients. We analyzed the factors involved apart from the toxicity due to the high cerebral concentrations of phenylalanine (Phe), the defects of synthesis of neurotransmitters, the alteration of cerebral myelination, the effect of the elevation of Phe in the processes of transport and distribution of neutral amino acids with an abnormal synthesis of brain proteins, plasma and cerebral tyrosine deficiency, the neurotoxicity of Phe metabolites, the defect of cholesterol biosynthesis or the increase of oxidative stress. White matter alterations in early treated PKU patients have an important role in neurological manifestations. The treatment of PKU is for life and is based on the reduction of foods containing Phe combined with the administration of a special formula or tetrahydrobiopterin (BH4) treatment. New therapeutic options will be analyzed.

Adenosine a1 receptor agonist protects against hippocampal neuronal injury after lithium chloride-pilocarpine-induced epilepsy

Abstract Background Adenosine A1 receptor (AA1R) is widely present in the central nervous system, exerting brain protective antiepileptic effects, mainly by binding corresponding G proteins. We evaluated the neuroprotective effects of AA1R on hippocampal neuronal injury after lithium chloride-pilocarpine-induced epilepsy in rats. Materials and Methods A total of 60 male SD rats were randomly divided into four groups (n = 15/group): normal control, epilepsy, epilepsy + AA1R antagonist (DPCPX), and epilepsy + AA1R agonist (2-CAdo). An epilepsy model was established through kindling by lithium chloride-pilocarpine. The four groups were observed on days 1, 14, and 30. Pathological and morphological changes of hippocampal neurons were observed by HE staining; apoptosis was detected by TUNEL assay. Caspase-3 and GABA receptor expressions were detected by Western blot. Results In the hippocampal CA3 area of the epilepsy group, the cellular structure was not neatly arranged, and some neurons were swelling, thick, and incomplete. Compared with the epilepsy group at the same time point, cells in the epilepsy + DPCPX group had an increased distortion, disorganization, edema, cytoplasmic vacuoles, and degeneration. In the epilepsy + 2-CAdo group, cell arrangement was regular and orderly, and structural damages were lessened. Compared with the normal control group at the same time point, the epilepsy group underwent evident neuronal apoptosis, with a significantly higher apoptotic index (AI) (p < 0.05). Compared with the epilepsy group, the neuronal apoptosis of the epilepsy + DPCPX group was boosted, and the AI significantly increased (p < 0.05). The neuronal apoptosis of the epilepsy + 2-CAdo group was inhibited, and the AI significantly decreased (p < 0.05). Compared with the epilepsy group, the caspase-3 expression levels of the epilepsy + DPCPX group on days 14 and 30 were significantly upregulated (p < 0.05), but those of the epilepsy + 2-CAdo group were significantly downregulated (p < 0.05). Conclusions AA1R abated cell edema and reduced apoptosis, exerting neuroprotective effects on hippocampal neuronal injury after lithium chloride-pilocarpine-induced epilepsy.

Neurogenesis and gliogenesis modulation in cerebral ischemia by CDK5 RNAi-based therapy / Modulación de la neurogénesis y la gliogénesis en la isquemia cerebral mediante una terapia basada en la interferencia de CDK5

Abstract Introduction: Cerebral ischemia is the third cause of death risk in Colombia and the first cause of physical disability worldwide. Different studies on the silencing of the cyclin-dependent kinase 5 (CDK5) have shown that reducing its activity is beneficial in ischemic contexts. However, its effect on neural cell production after cerebral ischemia has not been well studied yet. Objective: To evaluate CDK5 silencing on the production of neurons and astrocytes after a focal cerebral ischemia in rats. Materials and methods: We used 40 eight-week-old male Wistar rats. Both sham and ischemia groups were transduced at CA1 hippocampal region with an adeno-associated viral vector using a noninterfering (shSCRmiR) and an interfering sequence for CDK5 (shCDK5miR). We injected 50 mg/kg of bromodeoxyuridine intraperitoneally from hour 24 to day 7 post-ischemia. We assessed the neurological abilities during the next 15 days and we measured the immunoreactivity of bromodeoxyuridine (BrdU), doublecortin (DCX), NeuN, and glial fibrillary acid protein (GFAP) from day 15 to day 30 post-ischemia. Results: Our findings showed that CDK5miR-treated ischemic animals improved their neurological score and presented increased BrdU+ cells 15 days after ischemia, which correlated with higher DCX and lower GFAP fluorescence intensities, and, although mature neurons populations did not change, GFAP immunoreactivity was still significantly reduced at 30 days post-ischemia in comparison with untreated ischemic groups. Conclusion: CDK5miR therapy generated the neurological recovery of ischemic rats associated with the induction of immature neurons proliferation and the reduction of GFAP reactivity at short and longterm post-ischemia.

Resumen Introducción. La isquemia cerebral es la tercera causa de riesgo de muerte en Colombia y la primera causa de discapacidad física en el mundo. En diversos estudios en los que se silenció la cinasa 5 dependiente de la ciclina (CDK5) se ha demostrado que la reducción de su actividad es beneficiosa frente a la isquemia. Sin embargo, su efecto sobre la neurogénesis después de la isquemia no se ha dilucidado suficientemente. Objetivo. Evaluar el silenciamiento de la CDK5 en la neurogénesis y la gliogénesis después de la isquemia cerebral focal en ratas. Materiales y métodos. Se usaron 40 machos de rata Wistar de ocho semanas de edad. Los grupos de control y los isquémicos sometidos a transducción en la región del hipocampo CA1, se inyectaron intraperitonealmente por estereotaxia con 50 mg/kg de bromodesoxiuridina (BrdU) a partir de las 24 horas y hasta el día 7 después de la isquemia, con un vector viral asociado a adenovirus usando una secuencia no interferente (SCRmiR) y una interferente (CDK5miR). Se evaluó la capacidad neurológica durante los quince días siguientes y se detectó la capacidad de inmunorreacción para la BrdU, la proteína doblecortina (DCX), los núcleos neuronales (NeuN), y la proteína fibrilar acídica de la glía (Glial Fibrillary Acidic Protein, GFAP) a los 15 y 30 días de la isquemia. Resultados. Los animales isquémicos tratados con CDK5miR mejoraron su puntuación neurológica y presentaron un incremento de la BrdU+ a los 15 días de la isquemia, lo cual se correlacionó con una mayor intensidad de la DCX+ y una menor de la GFAP+. No hubo modificación de los NeuN+, pero sí una reducción significativa de la GFAP+ a los 30 días de la isquemia en los animales tratados comparados con los animales isquémicos no tratados. Conclusión. La terapia con CDK5miR generó la recuperación neurológica de ratas isquémicas asociada con la inducción de la neurogénesis y el control de la capacidad de reacción de la proteína GFAP a corto y largo plazo después de la isquemia.

Different inoculum loads of Toxoplasma gondii induce reduction of myenteric neurons of the rat colon / Diferentes inóculos de Toxoplasma gondii induzem a redução de neurônios mioentéricos no cólon de ratos

Abstract Toxoplasmosis, a disease caused by Toxoplasma gondii, is an important health problem, especially in immunocompromised hosts. T. gondii uses the gut wall as an infection gateway, with tropism for muscular and nervous tissues causing intestinal alterations, including some in the enteric nervous system. This study aims at investigating the colon of rats infected by T. gondii in order to understand how the amount of oocysts influences in myenteric neuronal changes. Sixty Wistar rats (Rattus norvegicus) were divided into six groups. One group remained as a control and the others received inocula of 10, 50, 100, 500 or 5,000 oocysts of T. gondii. The animals were euthanized after 30 days of infection. The total neuronal population and the nitrergic subpopulation in the colon myenteric plexus of each animal was counted. The data were statistically analyzed showing less weight gain in rats with 10, 500 and 5,000 oocysts. A decrease in the number of total neurons with 50, 100 or 5,000 oocysts and an increase in the nitrergic population with 10, 100, 500 or 5,000 oocysts were verified. These results show that neuronal alterations are more significant when the infection is induced by larger inocula and reinforces the suspicion that neuronal loss is directed at cholinergic neurons.

Resumo A toxoplasmose, doença causada pelo Toxoplasma gondii, é um importante problema de saúde, principalmente em imunocomprometidos. T. gondii utiliza a parede do intestino como porta de entrada no hospedeiro e tem tropismo pelos tecidos muscular e nervoso provocando alterações intestinais, inclusive no sistema nervoso entérico. Este estudo buscou analisar o cólon de ratos infectados por T. gondii para entender como a quantidade de oocistos influencia nas alterações neuronais mientéricas. Foram utilizados 60 ratos Wistar (Rattus norvegicus) em seis grupos. Um dos grupos permaneceu como controle e os demais receberam inóculos de 10, 50, 100, 500 ou 5.000 oocistos de T. gondii. Os animais foram submetidos a eutanásia após 30 dias de infecção. No plexo mientérico do cólon dos animais foram quantificadas a população neuronal total e a subpopulação nitrérgica. Os dados foram analisados estatisticamente demonstrando inferior ganho de peso nos ratos com 10, 500 e 5.000 oocistos. Verificamos diminuição no número de neurônios totais com inóculos de 50, 100 ou 5.000 oocistos e aumento da população nitrérgica com 10, 100, 500 ou 5000 oocistos. Estes resultados mostram que alterações neuronais são mais significativas quando a infecção é induzida por inóculos maiores e reforça a suspeita de perda neuronal direcionada a neurônios colinérgicos.

Hippocampal neuronal apoptosis in rat offspring due to gestational diabetes / Apoptosis neuronal del hipocampo en crías de ratas debido a la diabetes gestacional

Gestational diabetes mellitus (GDM) defined as impaired glucose tolerance affects approximately 6 % of all pregnant women who have never before had diabetes, but who do have high blood glucose levels during pregnancy. This study was done to evaluate the apoptosis in the neuronal cells in the CA1, CA2 and CA3 subfields of hippocampus and dentate gyrus in offspring of gestational diabetes at the 7, 21 and 28 d in postnatal rats. Thirty Wistar rat dams were randomly allocated in control and diabetic group. Dams in diabetic group were received 40 mg/kg/BW of streptozotocin at the first day of gestation and control groups received an equivalent volume normal saline injection intraperitoneally (IP). Six offspring of GDM and control dams, at the 7, 21, 28 postnatal day were randomly were sacrificed quickly with anesthesia. The coronal sections of brain serially collected. The apoptosis neurons were evaluated with TUNEL Assay. In the CA1, the number of apoptotic cells in 7, 21 and 28 d of postnatal life were significantly increased in GDM compared to controls (P<0.001). In the CA2, CA3 the number of apoptotic cells in 7, 21 and 28 d age-old offspring were significantly increased in GDM compared to controls (P<0.001). In the dentate gyrus, the number of apoptotic cells in 7, 21 and 28 d of postnatal life were significantly increased in GDM compared to controls (P<0.01). This study showed that the uncontrolled gestational diabetes significantly increases neuronal apoptosis in hippocampal and dentate gyrus in rat offspring.

La diabetes mellitus gestacional (DMG) se define como la intolerancia a la glucosa que afecta aproximadamente al 6 % de todas las mujeres embarazadas que nunca han tenido diabetes, pero que sí tienen niveles de glucosa en la sangre elevados durante el embarazo. El objetivo de este estudio fue evaluar la apoptosis de células neuronales en CA1, CA2 y CA3, subcampos del hipocampo y el giro dentado, en las crías de ratas con diabetes gestacional en los días 7, 21 y 28 luego del nacimiento. Se utilizaron 30 ratas Wistar asignadas aleatoriamente en grupos control y diabético (GDM). Se administró al grupo diabético 40 mg/kg de peso corporal de estreptozotocina en el primer día de gestación y el grupo control recibió un volumen equivalente de solución salina normal por inyección vía intraperitoneal. Seis crías de los grupos GDM y control fueron seleccionadas aleatoriamente y sacrificadas bajo anestesia los días 7, 21, 28. Se tomaron secciones seriales coronales del cerebro. La apoptosis neuronal se evaluó mediante ensayo TUNEL. En el CA1, el número de células apoptóticas a los 7, 21 y 28 d se incrementó significativamente en el grupo GDM en comparación con los controles (P <0.001). En el CA2 y CA3 el número de células apoptóticas en los días 7, 21 y 28 también se incrementó significativamente en GDM en comparación con los controles (P <0,001). En el giro dentado, el número de células apoptóticas en los días 7, 21 y 28 se incrementó significativamente en GDM en comparación con los controles (P <0,01). Este estudio mostró que la diabetes gestacional no controlada aumenta significativamente la apoptosis neuronal en el hipocampo y el giro dentado en las crías de las ratas.

Relationship between the Expression of α-syn and Neuronal Apoptosis in Brain Cortex of Acute Alcoholism Rats / 法医学杂志

OBJECTIVES@#To observe the changes of expression of α-synuclein （α-syn） and neuronal apoptosis in brain cortex of acute alcoholism rats and to explore the mechanism of the damage caused by ethanol to the neurons.@*METHODS@#The model of acute alcoholism rat was established by 50% alcohol gavage. The α-syn and caspase-3 were detected by immunohistochemical staining and imaging analysis at 1 h, 3 h, 6 h and 12 h after acute alcoholism. The number of positive cell and mean of optical density were detected and the trend change was analyzed. The variance analysis and t-test were also performed.@*RESULTS@#The number of α-syn positive cell and average optical density in brain cortex of acute alcoholism rat increased significantly and peaked at 6 hour with a following slight decrease at 12 h, but still higher than the groups at 1 h and 3 h. Within 12 hours after poisoning, the number of caspase-3 positive cell and average optical density in brain cortex of rats gradually increased.@*CONCLUSIONS@#The abnormal aggregation of α-syn caused by brain edema and hypoxia may participate the early stage of neuronal apoptosis in brain cortex after acute alcoholism.

Effect of hyperbaric oxygenation on mitochondrial function of neuronal cells in the cortex of neonatal rats after hypoxic-ischemic brain damage

The timing and mechanisms of protection by hyperbaric oxygenation (HBO) in hypoxic-ischemic brain damage (HIBD) have only been partially elucidated. We monitored the effect of HBO on the mitochondrial function of neuronal cells in the cerebral cortex of neonatal rats after HIBD. Neonatal Sprague-Dawley rats (total of 360 of both genders) were randomly divided into normal control, HIBD, and HIBD+HBO groups. The HBO treatment began immediately after hypoxia-ischemia (HI) and continued once a day for 7 consecutive days. Animals were euthanized 0, 2, 4, 6, and 12 h post-HI to monitor the changes in mitochondrial membrane potential (ΔΨm) occurring soon after a single dose of HBO treatment, as well as 2, 3, 4, 5, 6, and 7 days post-HI to study ΔΨm changes after a series of HBO treatments. Fluctuations in ΔΨm were observed in the ipsilateral cortex in both HIBD and HIBD+HBO groups. Within 2 to 12 h after HI insult, the ΔΨm of the HIBD and HIBD+HBO groups recovered to some extent. A secondary drop in ΔΨm was observed in both groups during the 1-4 days post-HI period, but was more severe in the HIBD+HBO group. There was a secondary recovery of ΔΨm observed in the HIBD+HBO group, but not in the HIBD group, during the 5-7 days period after HI insult. HBO therapy may not lead to improvement of neural cell mitochondrial function in the cerebral cortex in the early stage post-HI, but may improve it in the sub-acute stage post-HI.

Effects of estrogen on functional and neurological recovery after spinal cord injury: An experimental study with rats

OBJECTIVES:To evaluate the functional and histological effects of estrogen as a neuroprotective agent after a standard experimentally induced spinal cord lesion.METHODS:In this experimental study, 20 male Wistar rats were divided into two groups: one group with rats undergoing spinal cord injury (SCI) at T10 and receiving estrogen therapy with 17-beta estradiol (4mg/kg) immediately following the injury and after the placement of skin sutures and a control group with rats only subjected to SCI. A moderate standard experimentally induced SCI was produced using a computerized device that dropped a weight on the rat's spine from a height of 12.5 mm. Functional recovery was verified with the Basso, Beattie and Bresnahan scale on the 2nd, 7th, 14th, 21st, 28th, 35th and 42nd days after injury and by quantifying the motor-evoked potential on the 42nd day after injury. Histopathological evaluation of the SCI area was performed after euthanasia on the 42nd day.RESULTS:The experimental group showed a significantly greater functional improvement from the 28th to the 42nd day of observation compared to the control group. The experimental group showed statistically significant improvements in the motor-evoked potential compared with the control group. The results of pathological histomorphometry evaluations showed a better neurological recovery in the experimental group, with respect to the proportion and diameter of the quantified nerve fibers.CONCLUSIONS:Estrogen administration provided benefits in neurological and functional motor recovery in rats with SCI beginning at the 28th day after injury.

Alterations of the giant pyramidal neurons (Betz cells) in brain cortex of rat offspring born from gestational diabetic dams: a morphometric study / Alteraciones de las neuronas piramidales gigantes de la corteza cerebral en crías de ratas nacidas de hembras con diabetes gestacional: un estudio morfométrico

A few studies reported the adverse effects of gestational diabetes on hippocampus and spinal cord of rat offspring. Giant pyramidal neurons are giant pyramidal neurons located in fifth layers of the gray matter in the primary motor cortex. Therefore, this study was conducted to determine the effect of gestational diabetes on the giant pyramidal neurons and the thickness of internal pyramidal layer in the brain cortex of rat offspring. On day 1 of gestation, 10 Wistar rat dams were randomly allocated into two control and diabetic groups. Five animals in diabetic group received 40 mg/kg/BW of Streptozotocin (intraperitoneally) and control animals received normal saline. We randomly selected six offspring of every subject in both groups at day 28, 56 and 84. Rat offspring were scarified and then coronal sections were taken from the right brain cortex and sections were stained with Cresyl violet. The density of giant pyramidal neurons in brain cortex and thickness of internal pyramidal layer of brain cortex were evaluated. In P28, P56, P84 the Betz cells density of brain cortex were significantly reduced from 107.6±6.2, 131.6±4.6 and 143.5±4.0 in controls to 84.96±2.1, 109.8±7.3 and 121.05±5.6 in cases (p<0.05), respectively. The thickness of the internal pyramidal layer of brain cortex in P28, 56 and P84 was significantly higher in gestational diabetic group in comparison with the control group (p<0.05). This study showed that uncontrolled gestational diabetes reduces the giant pyramidal neurons density and internal pyramidal layer thickness in brain cortex of rat offspring.

Pocos estudios han informado de los efectos adversos de la diabetes gestacional sobre las células del hipocampo y médula espinal. Este estudio, se realizó para determinar el efecto de la diabetes gestacional sobre las neuronas piramidales gigantes ubicadas en la quinta capas de la sustancia gris en la corteza motora primaria y el espesor de la capa piramidal interna en la corteza cerebral en crías de ratas. En el día 1 de la gestación, 10 ratas Wistar se asignaron aleatoriamente en dos grupos: control y diabéticos. Cinco animales del grupo diabético, fueron inyectados con 40 mg/kg de peso corporal de estreptozotocina (por vía intraperitoneal), y los de el grupo control, con solución salina. Aleatoriamente, se seleccionaron seis crías de cada hembra de ambos grupos los días 28, 56 y 84. Las crías fueron sacrificadas, se tomaron secciones coronales de la corteza cerebral derecha y se tiñeron con violeta de cresilo. Se evaluó la densidad de las neuronas piramidales gigantes en la corteza cerebral y el espesor de la capa piramidal interna de la corteza cerebral. En los días 28, 56, 84 la densidad de las neuronas piramidales gigantes en corteza cerebral se redujo significativamente al comparar los controles (107,6±6,2, 131,6±4,6 y 143,5±4,0 respectivamente) con los casos (84,96±2,1, 109,8±7,3 y 121,05±5,6 respectivamente) (p<0,05). El espesor de la capa piramidal interna de la corteza cerebral en los días 28, 84 y 56 fue significativamente mayor en el grupo diabético gestacional en comparación con el grupo control (p<0,05). Este estudio muestra que la diabetes gestacional no controlada reduce la densidad de neuronas piramidales gigantesy el espesor interno de la capa piramidal en la corteza cerebral de las crías de rata.

Memory deficit associated with increased brain proinflammatory cytokine levels and neurodegeneration in acute ischemic stroke / Déficit de memória associado ao aumento dos níveis cerebrais de citocinas pró-inflamatórias e neurodegeneração na isquemia cerebral aguda

The present study aimed to investigate behavioral changes and neuroinflammatory process following left unilateral common carotid artery occlusion (UCCAO), a model of cerebral ischemia. Post-ischemic behavioral changes following 15 min UCCAO were recorded 24 hours after reperfusion. The novel object recognition task was used to assess learning and memory. After behavioral test, brains from sham and ischemic mice were removed and processed to evaluate central nervous system pathology by TTC and H&E techniques as well as inflammatory mediators by ELISA. UCCAO promoted long-term memory impairment after reperfusion. Infarct areas were observed in the cerebrum by TTC stain. Moreover, the histopathological analysis revealed cerebral necrotic cavities surrounded by ischemic neurons and hippocampal neurodegeneration. In parallel with memory dysfunction, brain levels of TNF-a, IL-1b and CXCL1 were increased post ischemia compared with sham-operated group. These findings suggest an involvement of central nervous system inflammatory mediators and brain damage in cognitive impairment following unilateral acute ischemia.

O presente estudo teve como objetivo investigar alterações comportamentais e processos inflamatórios na isquemia cerebral induzida pela oclusão unilateral da carótida comum esquerda (UCCAO) em camundongos. As alterações comportamentais foram avaliadas após 15 minutos de isquemia e 24 horas de reperfusão. O teste de reconhecimento de objetos foi utilizado para avaliação da memória e do aprendizado. Em seguida, os animais foram mortos e os encéfalos foram coletados e processados para avaliação das alterações patológicas pelas técnicas de TTC e H&E, assim como da dosagem de mediadores inflamatórios por ELISA. A UCCAO promoveu alterações de memória após a reperfusão. Foram visualizadas áreas de infarto cerebral pela coloração de TTC e cavidades necróticas circundadas por neurônios isquêmicos no cérebro e neurodegeneração hipocampal. A UCCAO causou aumento dos níveis encefálicos de TNF-a, IL-1b e CXCL1. Estes achados demonstraram o envolvimento dos mediadores inflamatórios no sistema nervoso central e da neurodegeneração no déficit cognitivo após isquemia cerebral aguda.

Mecanismos neuroprotectores de los canabinoides en la isquemia cerebral y las enfermedades neurodegenerativas / Neuroprotective mechanisms of cannabinoids in brain ischemia and neurodegenerative disorders

Una de las causas más importantes de morbilidad y mortalidad es la disfunción neurológica; su alta incidencia ha estimulado una intensa búsqueda de mecanismos para proteger al sistema nervioso central de situaciones que producen hipoxia e isquemia. El mayor reto es interrumpir los eventos bioquímicos que involucra y que llevan a la muerte neuronal. Esto puede conseguirse a través de la neuroprotección que tiene por objeto frenar las cascadas inmunológica y metabólica que aparecen después de un daño neurológico agudo. Cuando esto sucede, se producen eventos fisiopatológicos que incluyen la producción de citocinas, el estrés oxidante y la excitotoxicidad. Respecto a todos esos mecanismos, se han reportado efectos protectores de los endocanabinoides, los cuales parecen ser neuroprotectores en modelos animales de isquemia cerebral, excitotoxicidad, trauma cerebral y en enfermedades neurodegenerativas. Algunos análogos de canabinoides se encuentran actualmente en evaluación (fases clínicas I-III) para el tratamiento de enfermedades agudas que involucran a la muerte neuronal (isquemia y trauma cerebrales). El estudio del sistema canabinoide podría generar agentes neuroprotectores efectivos de amplio espectro de acción para el tratamiento de afecciones neurológicas en un futuro cercano.

One of the most important causes of morbidity and mortality is neurologic dysfunction; its high incidence has led to an intense research of the mechanisms that protect the central nervous system from hypoxia and ischemia. The mayor challenge is to block the biochemical events leading to neuronal death. This may be achieved by neuroprotective mechanisms that avoid the metabolic and immunologic cascades that follow a neurological damage. When it occurs, several pathophysiological events develop including cytokine release, oxidative stress and excitotoxicity. Neuroprotective effects of cannabinoids to all those mechanisms have been reported in animal models of brain ischemia, excitotoxicity, brain trauma and neurodegenerative disorders. Some endocannabinoid analogs are being tested in clinical studies (I-III phase) for acute disorders involving neuronal death (brain trauma and ischemia). The study of the cannabinoid system may allow the discovery of effective neuroprotective drugs for the treatment of neurological disorders.

Mecanismos patogénicos en el desarrollo de la esclerosis múltiple: ambiente, genes, sistema inmune y estrés oxidativo / Pathogenic mechanisms of neuronal damage in multiple sclerosis

La esclerosis múltiple (EM) es la principal causa de discapacidad neurológica de origen no traumático en adultos jóvenes. EM es una enfermedad crónica inflamatoria que se caracteriza por daño a las fibras nerviosas y la cubierta de mielina. Esto produce una gran variedad de síntomas una vez que nervios específicos muestran inflamación y pérdida de su función. Estudios epidemiológicos y experimentales han identificado alteraciones genéticas, anormalidades en enzimas antioxidantes y autoinmunidad como algunos de los factores de riesgo para el desarrollo de la enfermedad. Evidencia reciente sugiere que la inflamación y el estrés oxidativo en el sistema nervioso central contribuyen al daño del tejido cerebral. Las células residentes en el sistema nervioso central así como las células inflamatorias invasivas liberan una gran cantidad de especies reactivas de oxígeno y nitrógeno, las cuales causan desmielinización y destrucción de los axones: los hallazgos histopatológicos de la esclerosis múltiple. La interacción entre los procesos inflamatorios y neurodegenerativos producen perturbaciones neurológicas intermitentes seguidas por la acumulación progresiva de la discapacidad. Para tratar de limitar o disminuir la progresión de la enfermedad es necesario reducir la inflamación y el estrés oxidativo como estrategia terapéutica importante. Con la finalidad de mejorar la sobrevivencia y la calidad de vida de los pacientes, se están desarrollando ensayos clínicos con suplementos alimenticios tales como los antioxidantes y los ácidos grasos poliinsaturados omega-3.

Multiple sclerosis is the most common cause of progressive neurological disability in young adults. This disease involves damage to the myelin sheath that normally insulates the electrical activity of nerve fibers. This leads to a wide range of symptoms as specific nerves become injured and lose their function. Epidemiological and experimental studies show that genetic alterations, antioxidant enzyme abnormalities and autoimmunity are risk factors for developing the disease. Recent evidence suggests that inflammation and oxidative stress within the central nervous system are major causes of ongoing tissue damage. Resident central nervous system cells and invading inflammatory cells release several reactive oxygen and nitrogen species which cause the histopathological features of multiple sclerosis: demyelization and axonal damage. The interplay between inflammatory and neurodegenerative processes results in an intermittent neurological disturbance followed by progressive accumulation of disability. Reductions in inflammation and oxidative stress status are important therapeutic strategies to slow or halt the disease processes. Therefore, several drugs are currently in trial in clinical practice to target this mechanism; particularly the use of supplements such as antioxidants and omega-3 polyunsaturated fatty acids, in order to improve the survival and quality of patients’ lives.

El uso de placebo en ensayos clínicos de fase III en Brasil / The use of placebos in phase III clinical trials in Brazil

El Consejo Federal de Medicina de Brasil (CFM) -órgano normativo y fiscalizador del ejercicio ético de la medicina- prohibió, en 2008, la participación de médicos brasileños en investigaciones que utilizaran placebo para enfermedades con tratamiento eficaz y efectivo, en contraposición a la Declaración de Helsinki, que permite su uso en condiciones metodológicamente justificadas. Con el objetivo de verificar si la normativa ética del CFM modificó el uso de placebo en ensayos clínicos de fase III en Brasil, se analizaron varias características de sus registros en el ClinicalTrials.gov, en los períodos de 2003 a 2007 y de 2009 a 2013. Se concluye que: a) la normativa promulgada por el CFM en 2008 fue ineficaz y prevaleció la posición adoptada por la Declaración de Helsinki; b) el patrocinio de ensayos con placebo por parte de la industria farmacéutica multinacional fue significativo; c) predominaron las investigaciones de fármacos para enfermedades crónicas, y fueron poco significativas para las enfermedades postergadas, de importancia para Brasil.

In 2008, Brazil's Federal Council of Medicine [Conselho Federal de Medicina] (CFM) - regulatory and supervisory agency on the ethical practice of medicine - banned the participation of Brazilian doctors in studies using placebos for diseases with efficient and effective treatment. This position differs with the Helsinki Declaration, which allows the use of placebos in methodologically justified conditions. To ascertain whether the CMF's ethical regulation modified the use of placebos in phase III clinical trials in Brazil, characteristics of the records in ClinicalTrials.gov were researched in the periods from 2003 to 2007 and from 2009 to 2013. The conclusions reached were: a) the regulations issued by the CFM in 2008 were ineffective and the position adopted by the Helsinki Declaration prevails; b) there was significant sponsorship by the multinational pharmaceutical industry of trials with placebos; c) the research was predominantly on new drugs for chronic diseases, with little study done of the neglected diseases which are of great importance to Brazil.

Herbicide paraquat induces sex-specific variation of neuroinflammation and neurodegeneration in Drosophila melanogaster.

There are several reports on herbicide paraquat (PQ)-induced Parkinsonian-like pathology in different animal models, including Drosophila melanogaster. Also, the role of some inflammatory factors, such as nitric oxide is reported in PQ-induced neuroinflammation of Drosophila. Although invertebrate model is valuable to study the conserved inflammatory pathway at the time of neurodegeneration, but neuroinflammation during PQ-mediated neurodegeneration has not been studied explicitly in Drosophila. In this study, the inflammatory response was examined in Drosophila model during PQ-induced neurodegeneration. We found that after exposure to PQ, survivability and locomotion ability were affected in both sexes of Drosophila. Behavioural symptoms indicated similar physiological features of Parkinson’s disease (PD) in different animal models, as well as in humans. Our study revealed alteration in proinflamatory factor, TNF-α and Eiger (the Drosophila homologue in TNF superfamily) was changed in PQ-treated Drosophila both at protein and mRNA level during neurodegeneration. To ensure the occurrence of neurodegeneration, tyrosine hydroxylase (TH) positive neuronal cell loss was considered as a hallmark of PD in the fly brain. Thus, our result revealed the conserved inflammatory events in terms of expression of TNF-α and Eiger present during a sublethal dose of PQ-administered neurodegeneration in male and female Drosophila with significant variation in proinflamatory factor level among both the sexes.