RESUMO
Both the cholinergic pathway and oxidative stress are important mechanisms involved in the pathogenesis of hypothyroidism, a condition characterized by low levels of thyroid hormone that predispose the patient to brain dysfunction. Phenolic compounds have numerous health benefits, including antioxidant activity. This study evaluates the preventive effects of resveratrol in the cholinergic system and redox status in rats with methimazole-induced hypothyroidism. Hypothyroidism increases acetylcholinesterase (AChE) activity and density in the cerebral cortex and hippocampus and decreases the α7 and M1 receptor densities in the hippocampus. Hypothyroidism also increases cellular levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS), but reduces total thiol content, and catalase and superoxide dismutase activities in the serum. In the cerebral cortex and hippocampus, hypothyroidism increases the levels of ROS and nitrites. In this study, resveratrol (50 mg/kg) treatment prevents the observed increase in AChE in the cerebral cortex, and increases the protein levels of NeuN, a marker of mature neurons. Resveratrol also prevents changes in serum ROS levels and brain structure, as well as the levels of TBARS, total thiol content, and serum catalase enzyme activity. These collective findings suggest that resveratrol has a high antioxidant capacity and can restore hypothyroidism-triggered alterations related to neurotransmission. Thus, it is a promising agent for the prevention of brain damage resulting from hypothyroidism.
Assuntos
Colinérgicos/metabolismo , Hipotireoidismo/metabolismo , Hipotireoidismo/patologia , Neuroproteção/efeitos dos fármacos , Resveratrol/farmacologia , Transdução de Sinais , Acetilcolinesterase/metabolismo , Animais , Antígenos Nucleares/metabolismo , Modelos Animais de Doenças , Proteína Glial Fibrilar Ácida/metabolismo , Hipocampo/metabolismo , Hipotireoidismo/sangue , Masculino , Proteínas do Tecido Nervoso/metabolismo , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos Wistar , Receptores Colinérgicos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Tiroxina/sangue , Tri-Iodotironina/sangueRESUMO
Cannabis and, to a lesser extent, synthetic cannabinoids are used during adolescence, a period in which multiple brain areas are still undergoing development. Among such areas is the hypothalamus, which is implicated in the control of sleep-wake cycle. In the present report, we show that exposing adolescent rats to the cannabinoid receptor agonist WIN 55, 212-2 (0.1, 0.3 or 1.0 mg/kg, i.p) for 14 days during adolescence (i.e., from post-natal day 30-44) resulted in significant sleep disturbances when the animals became adult (post-natal day 80). These included decreased wakefulness and enhanced rapid eye movement sleep. Furthermore, we found that labeling for NeuN, a marker of postmitotic neurons, was significantly increased the dorsomedial hypothalamic nucleus of rats treated with WIN 55, 212-2. The results suggest that excessive cannabinoid receptor activation during adolescence can persistently influence sleep patterns and neuronal activity later in life.
Assuntos
Benzoxazinas/efeitos adversos , Agonistas de Receptores de Canabinoides/efeitos adversos , Morfolinas/efeitos adversos , Naftalenos/efeitos adversos , Transtornos do Sono-Vigília/induzido quimicamente , Animais , Antígenos Nucleares/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Masculino , Proteínas do Tecido Nervoso/metabolismo , Ratos Wistar , Sono/efeitos dos fármacos , Transtornos do Sono-Vigília/metabolismoRESUMO
In this study, we used an experimental model of congenital hypothyroidism to show that deficient thyroid hormones (TH) disrupt different neurochemical, morphological and functional aspects in the cerebral cortex of 15-day-old offspring. Our results showing decreased glutamine synthetase (GS) activity and Ca2+ overload in the cerebral cortex of hypothyroid pups suggest misregulated glutamate metabolism associated with developmentally induced TH deficiency. The 14C-MeAIB accumulation indicates upregulated System A activity and glutamine uptake by neurons. Energy metabolism in hypothyroid cortical slices was preserved, as demonstrated by unaltered glucose metabolism. We also found upregulated acetylcholinesterase activity, depleting acetylcholine from the synaptic cleft, pointing to disrupted cholinergic system. Increased reactive oxygen species (ROS) generation, lipid peroxidation, glutathione (GSH) depletion, which were associated with glutathione peroxidase, superoxide dismutase and gamma-glutamyltransferase downregulation suggest redox imbalance. Disrupted astrocyte cytoskeleton was evidenced by downregulated and hyperphosphorylated glial fibrillary acidic protein (GFAP). Morphological and structural characterization of the sensorimotor cerebral cortex (SCC) showed unaltered thickness of the SCC. However, decreased size of neurons on the layers II & III and IV in the right SCC and increased NeuN positive neurons in specific SCC layers, suggest that they are differently affected by the low TH levels during neurodevelopment. Hypothyroid pups presented increased number of foot-faults in the gridwalk test indicating affected motor functions. Taken together, our results show that congenital hypothyroidism disrupts glutamatergic and cholinergic neurotransmission, Ca2+ equilibrium, redox balance, cytoskeleton integrity, morphological and functional aspects in the cerebral cortex of young rats.
Assuntos
Hipotireoidismo/induzido quimicamente , Córtex Sensório-Motor/enzimologia , Acetilcolinesterase/metabolismo , Animais , Animais Recém-Nascidos , Antígenos Nucleares/metabolismo , Comportamento Animal , Transporte Biológico , Composição Corporal , Células Cultivadas , Córtex Cerebral/enzimologia , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Glucose/metabolismo , Glutamato-Amônia Ligase/metabolismo , Ácido Glutâmico/metabolismo , Hipotireoidismo/sangue , Hipotireoidismo/fisiopatologia , L-Lactato Desidrogenase/metabolismo , Simulação de Acoplamento Molecular , Atividade Motora , Proteínas do Tecido Nervoso/metabolismo , Oxirredução , Fosforilação , Propiltiouracila , Ratos Wistar , Receptores Citoplasmáticos e Nucleares/metabolismo , Glândula Tireoide/metabolismo , Hormônios Tireóideos/sangueRESUMO
The aim of this study was to evaluate the viability, antrum formation and in vitro development of isolated secondary follicles from vitrified caprine ovarian cortex in a medium previously established for fresh isolated secondary follicles, in the absence (α-minimum essential medium (α-MEM+) alone) or presence of FSH and vascular endothelial growth factor (VEGF; α-MEM++FSH+VEGF). Ovarian fragments were distributed among five treatments (T1 to T5): fresh follicles were fixed immediately (T1), follicles from fresh tissue were cultured in vitro in α-MEM+ (T2) or α-MEM++FSH+VEGF (T3) and follicles from vitrified tissue were cultured in vitro in α-MEM+ (T4) or α-MEM++FSH+VEGF (T5). After 6 days of culture, treated follicles (T2, T3, T4 and T5) were evaluated for morphology, viability and follicular development (growth, antrum formation and proliferation of granulosa cells by Ki67 and argyrophilic nucleolar organiser region (AgNOR) staining). The levels of reactive oxygen species (ROS) in the culture media were also assessed. Overall, morphology of vitrified follicles was altered (P<0.05) compared with the fresh follicles. Follicular viability, antrum formation and ROS were similar between treatments (P>0.05). The average overall and daily follicular growth was highest (P<0.05) in T3. Granulosa cells in all treatments (T1, T2, T3, T4 and T5) stained positive for Ki67. However, fresh follicles from T3 had significantly higher AgNOR staining (P<0.05) compared with follicles of T1, T2, T4 and T5. In conclusion, secondary follicles can be isolated from vitrified and warmed ovarian cortex and survive and form an antrum when growing in an in vitro culture for 6 days.
Assuntos
Criopreservação/veterinária , Cabras/embriologia , Técnicas de Maturação in Vitro de Oócitos/veterinária , Folículo Ovariano/fisiologia , Ovário/citologia , Animais , Antígenos Nucleares/metabolismo , Proliferação de Células , Forma Celular , Sobrevivência Celular , Células Cultivadas , Feminino , Fármacos para a Fertilidade Feminina/farmacologia , Hormônio Foliculoestimulante/farmacologia , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fatores de Tempo , Fator A de Crescimento do Endotélio Vascular/farmacologiaRESUMO
Aging increases the vulnerability to stress and risk of developing depression. These changes have been related to a reduction of dehydroepiandrosterone (DHEA) levels, an adrenal steroid with anti-stress effects. Also, adult hippocampal neurogenesis decreases during aging and its alteration or impaired is related to the development of depression. Besides, it has been hypothesized that DHEA increases the formation of new neurons. However, it is unknown whether treatment with DHEA in aging may stimulate the dendrite maturation of newborn neurons and reversing depressive-like signs evoked by chronic stress exposure. Here aged male rats (14 months old) were subjected to a scheme of chronic mild stress (CMS) during six weeks, received a treatment with DHEA from the third week of CMS. Changes in body weight and sucrose preference (SP) were measured once a week. DHEA levels were measured in serum, identification of doublecortin-(DCX)-, BrdU- and BrdU/NeuN-labeled cells was done in the dentate gyrus of the hippocampus. CMS produced a gradual reduction in the body weight, but no changes in the SP were observed. Treatment enhanced levels of DHEA, but lack of recovery on body weight of stressed rats. Aging reduced the number of DCX-, BrdU- and BrdU/NeuN- cells but DHEA just significantly increased the number of DCX-cells in rats under CMS and controls, reaching levels of young non-stressed rats (used here as a reference of an optimal status of health). In rats under CMS, DHEA facilitated dendritic maturation of immature new neurons. Our results reveal that DHEA improves neural plasticity even in conditions of CMS in middle age rats. Thus, this hormone reverted the decrement of DCX-cells caused during normal aging.
Assuntos
Envelhecimento/efeitos dos fármacos , Desidroepiandrosterona/farmacologia , Dendritos/efeitos dos fármacos , Giro Denteado/efeitos dos fármacos , Psicotrópicos/farmacologia , Estresse Psicológico/tratamento farmacológico , Envelhecimento/fisiologia , Envelhecimento/psicologia , Animais , Antígenos Nucleares/metabolismo , Peso Corporal/efeitos dos fármacos , Bromodesoxiuridina , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Doença Crônica , Desidroepiandrosterona/sangue , Dendritos/metabolismo , Dendritos/patologia , Giro Denteado/metabolismo , Giro Denteado/patologia , Sacarose Alimentar , Proteínas do Domínio Duplacortina , Proteína Duplacortina , Masculino , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurogênese/efeitos dos fármacos , Neurogênese/fisiologia , Neuropeptídeos/metabolismo , Psicotrópicos/sangue , Distribuição Aleatória , Ratos Wistar , Estresse Psicológico/metabolismo , Estresse Psicológico/patologiaRESUMO
BACKGROUND: Cohesin complex is responsible for sister chromatid cohesion. STAG1/STAG2 is part of the complex, which is regulated by PDS5B. Alterations in these genes were described in tumors. PDS5B is a negative regulator of cell proliferation. We aimed to assess molecular alterations in these genes in oral squamous cell carcinoma (OSCC) and predict their expression by the expression of 84 cell cycle genes. In addition, we investigated whether pds5b protein expression impacted ki-67 and p53 immunopositivity. METHODS: We assessed loss of heterozygosity (LOH) at STAG1 and STAG2 loci in 15 OSCC using three polymorphic markers. Associations between the immunoexpression of pds5b and ki-67 and p53 were tested in 62 samples. Differences between transcriptional levels of STAG1, STAG2, and PDS5B between OSCC and normal oral mucosa (NM) were evaluated by qPCR. An 84 cell cycle genes qPCR array was carried with OSCC samples, and STAG1, STAG2, and PDS5B were independently used as response variables in multiple linear regression models. RESULTS: Loss of heterozygosity in at least one marker was observed in three samples. pds5b, p53, and ki-67 were highly expressed, and no association was found between pds5b immunoexpression and ki-67 or p53 (P > 0.05). OSCC and NM showed similar transcriptional levels of STAG1, STAG2, and PDS5B. STAG1 and CUL3 expression seem to be related (P = 0.004). CONCLUSIONS: There is LOH at STAG1 and STAG2 loci in OSCC, but OSCC and NM showed similar transcriptional levels of STAG1, STAG2, and PDS5B. pds5b immunoexpression in OSCC was high, but it was not associated with proliferation cell index.
Assuntos
Antígenos Nucleares/genética , Biomarcadores Tumorais/genética , Carcinoma de Células Escamosas/genética , Proteínas de Ligação a DNA/metabolismo , Neoplasias Bucais/genética , Proteínas Nucleares/genética , Fatores de Transcrição/metabolismo , Antígenos Nucleares/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinoma de Células Escamosas/metabolismo , Proteínas de Ciclo Celular , Humanos , Imuno-Histoquímica , Antígeno Ki-67/metabolismo , Perda de Heterozigosidade , Neoplasias Bucais/metabolismo , Proteínas Nucleares/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteína Supressora de Tumor p53/metabolismoRESUMO
Classical galactosemia is an inborn error of carbohydrate metabolism in which patients accumulate high concentration of galactose in the brain. The most common treatment is a galactose-restricted diet. However, even treated patients develop several complications. One of the most common symptoms is motor coordination impairment, including affected gait, balance, and speech, as well as tremor and ataxia. In the present study, we investigated the effects of intracerebroventricular galactose administration on motor coordination, as well as on histological and biochemical parameters in cerebellum of adult rats. Wistar rats received 5 µL of galactose (4 mM) or saline by intracerebroventricular injection. The animals performed the beam walking test at 1 and 24 h after galactose administration. Histological and biochemical parameters were performed 24 h after the injections. The results showed motor coordination impairment at 24 h after galactose injection. Galactose also decreased the number of cells in the molecular and granular layers of the cerebellum. The immunohistochemistry results suggest that the cell types lost by galactose are neurons and astrocytes in the spinocerebellum and neurons in the cerebrocerebellum. Galactose increased active caspase-3 immunocontent and acetylcholinesterase activity, decreased acetylcholinesterase immunocontent, glutathione, and BDNF levels, as well as caused protein and DNA damage. Our results suggest that galactose induces histological and biochemical changes in cerebellum, which can be associated with motor coordination impairment.
Assuntos
Cerebelo/patologia , Cerebelo/fisiopatologia , Galactose/farmacologia , Atividade Motora/efeitos dos fármacos , Acetilcolinesterase/metabolismo , Animais , Antígenos Nucleares/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Caspase 3/metabolismo , Contagem de Células , Cerebelo/efeitos dos fármacos , Dano ao DNA , Galactose/administração & dosagem , Proteína Glial Fibrilar Ácida/metabolismo , Glutationa/metabolismo , Injeções Intraventriculares , Masculino , Proteínas do Tecido Nervoso/metabolismo , Ratos Wistar , Compostos de Sulfidrila/metabolismoRESUMO
Although the use, and misuse, of methylphenidate is increasing in childhood and adolescence, there is little information about the consequences of this psychostimulant chronic use on brain and behavior during development. The aim of the present study was to investigate hippocampus biochemical, histochemical, and behavioral effects of chronic methylphenidate treatment to juvenile rats. Wistar rats received intraperitoneal injections of methylphenidate (2.0 mg/kg) or an equivalent volume of 0.9 % saline solution (controls), once a day, from the 15th to the 45th day of age. Results showed that chronic methylphenidate administration caused loss of astrocytes and neurons in the hippocampus of juvenile rats. BDNF and pTrkB immunocontents and NGF levels were decreased, while TNF-α and IL-6 levels, Iba-1 and caspase 3 cleaved immunocontents (microglia marker and active apoptosis marker, respectively) were increased. ERK and PKCaMII signaling pathways, but not Akt and GSK-3ß, were decreased. SNAP-25 was decreased after methylphenidate treatment, while GAP-43 and synaptophysin were not altered. Both exploratory activity and object recognition memory were impaired by methylphenidate. These findings provide additional evidence that early-life exposure to methylphenidate can have complex effects, as well as provide new basis for understanding of the biochemical and behavioral consequences associated with chronic use of methylphenidate during central nervous system development.
Assuntos
Astrócitos/patologia , Comportamento Animal/efeitos dos fármacos , Hipocampo/patologia , Metilfenidato/toxicidade , Neurônios/patologia , Animais , Antígenos Nucleares/metabolismo , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Citocinas/metabolismo , Comportamento Exploratório/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Aprendizagem em Labirinto/efeitos dos fármacos , Memória/efeitos dos fármacos , Modelos Biológicos , Fatores de Crescimento Neural/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos Wistar , Reconhecimento Psicológico , Transdução de Sinais , Proteína 25 Associada a Sinaptossoma/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The present study explores passive avoidance learning and its neural basis in toads (Rhinella arenarum). In Experiment 1, two groups of toads learned to move from a lighted compartment into a dark compartment. After responding, animals in the experimental condition were exposed to an 800-mM strongly hypertonic NaCl solution that leads to weight loss. Control animals received exposure to a 300-mM slightly hypertonic NaCl solution that leads to neither weight gain nor loss. After 10 daily acquisition trials, animals in the experimental group showed significantly longer latency to enter the dark compartment. Additionally, 10 daily trials in which both groups received the 300-mM NaCl solution after responding eliminated this group effect. Thus, experimental animals showed gradual acquisition and extinction of a passive avoidance respond. Experiment 2 replicated the gradual acquisition effect, but, after the last trial, animals were sacrificed and neural activation was assessed in five brain regions using AgNOR staining for nucleoli-an index of brain activity. Higher activation in the experimental animals, relative to controls, was observed in the amygdala and striatum. Group differences in two other regions, lateral pallium and septum, were borderline, but nonsignificant, whereas group differences in the medial pallium were nonsignificant. These preliminary results suggest that a striatal-amygdala activation could be a key component of the brain circuit controlling passive avoidance learning in amphibians. The results are discussed in relation to the results of analogous experiments with other vertebrates.
Assuntos
Aprendizagem da Esquiva/fisiologia , Telencéfalo/metabolismo , Animais , Antígenos Nucleares/metabolismo , Anuros , Aprendizagem da Esquiva/efeitos dos fármacos , Extinção Psicológica , Masculino , Tempo de Reação/efeitos dos fármacos , Tempo de Reação/fisiologia , Solução Salina Hipertônica/farmacologia , Telencéfalo/efeitos dos fármacosRESUMO
Aging is a process characterized by deterioration of the homeostasis of various physiological systems; although being a process under influence of multiple factors, the mechanisms involved in aging are not well understood. Here we investigated the effect of a (PhSe)2-supplemented diet (1ppm, 4weeks) and swimming exercise (1% of body weight, 20min per day, 4weeks) on proteins related to glial cells activation, apoptosis and neuroprotection in the hypothalamus of old male Wistar rats (27month-old). Old rats had activation of astrocytes and microglia which was demonstrated by the increase in the levels of glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule 1 (Iba-1) in hypothalamus. A decrease of B-cell lymphoma 2 (Bcl-2) and procaspase-3 levels as well as an increase of the cleaved PARP/full length PARP ratio (poly (ADP-ribose) polymerase, PARP) and the pJNK/JNK ratio (c-Jun N-terminal kinase, JNK) were observed. The levels of mature brain-derived neurotrophic factor (mBDNF), the pAkt/Akt ratio (also known as protein kinase B) and NeuN (neuronal nuclei), a neuron marker, were decreased in the hypothalamus of old rats. Old rats that received a (PhSe)2-supplemented diet and performed swimming exercise had the hypothalamic levels of Iba-1 and GFAP decreased. The combined treatment also increased the levels of Bcl-2 and procaspase-3 and decreased the ratios of cleaved PARP/full length PARP and pJNK/JNK in old rats. The levels of mBDNF and NeuN, but not the pAkt/Akt ratio, were increased by combined treatment. In conclusion, a (PhSe)2-supplemented diet and swimming exercise promoted neuroprotection in the hypothalamus of old rats, reducing apoptosis and glial cell activation.