RESUMO
AIMS: To investigate the effects of moderate aerobic physical training on cardiac function and morphology as well as on the levels of glial cell-derived neurotrophic factor (GDNF), nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) of animals infected with the Y strain of Trypanosoma cruzi. MAIN METHODS: Twenty-eight male C57BL/6 mice were distributed into 4 groups: sedentary control (SC), trained control (TC), sedentary infected (CHC) and trained infected (CHT). The infection was performed by intraperitoneal injection of trypomastigote forms and the animals were adapted to treadmill in the week before the beginning of the training protocol, initiated 45â¯days post infection. Maximal exercise test (TEM) was performed at the baseline as well as at the end of the 4th, 8th and 12th weeks of training. At the end of the 12th week, all animals were evaluated for cardiac morphology and function by echocardiography. KEY FINDINGS: CHC group showed a larger area of right ventricle (RVA), increased end-systolic volume and reduction in ejection fraction (EF), stroke volume (SV), cardiac output (CO) and fractional area change (FAC). The training reduced the RVA and improved the FAC of chagasic animals. GDNF level was higher in TC and CHC groups compared to SC in heart and BDNF levels were higher in CHC compared to SC in heart and serum. SIGNIFICANCE: Physical training ameliorated the cardiac function of infected animals and promoted adjusts in BDNF and GDNF levels. These findings evidenced these neurotrophins as possible biomarkers of cardiac function responsive to exercise stimulus.
Assuntos
Tolerância ao Exercício/fisiologia , Condicionamento Físico Animal/métodos , Condicionamento Físico Animal/fisiologia , Animais , Biomarcadores/sangue , Fator Neurotrófico Derivado do Encéfalo/análise , Fator Neurotrófico Derivado do Encéfalo/fisiologia , Débito Cardíaco , Doença de Chagas/metabolismo , Modelos Animais de Doenças , Ecocardiografia , Teste de Esforço , Fator Neurotrófico Derivado de Linhagem de Célula Glial/análise , Fator Neurotrófico Derivado de Linhagem de Célula Glial/fisiologia , Coração/fisiologia , Testes de Função Cardíaca , Ventrículos do Coração/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fator de Crescimento Neural/análise , Fator de Crescimento Neural/fisiologia , Fatores de Crescimento Neural/metabolismo , Fatores de Crescimento Neural/fisiologia , Volume Sistólico/fisiologia , Trypanosoma cruzi/patogenicidadeRESUMO
The formation of synaptic connections during nervous system development requires the precise control of dendrite growth and synapse formation. Although glial cell line-derived neurotrophic factor (GDNF) and its receptor GFRα1 are expressed in the forebrain, the role of this system in the hippocampus remains unclear. Here, we investigated the consequences of GFRα1 deficiency for the development of hippocampal connections. Analysis of conditional Gfra1 knockout mice shows a reduction in dendritic length and complexity, as well as a decrease in postsynaptic density specializations and in the synaptic localization of postsynaptic proteins in hippocampal neurons. Gain- and loss-of-function assays demonstrate that the GDNF-GFRα1 complex promotes dendritic growth and postsynaptic differentiation in cultured hippocampal neurons. Finally, in vitro assays revealed that GDNF-GFRα1-induced dendrite growth and spine formation are mediated by NCAM signaling. Taken together, our results indicate that the GDNF-GFRα1 complex is essential for proper hippocampal circuit development.
Assuntos
Dendritos/fisiologia , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/fisiologia , Fator Neurotrófico Derivado de Linhagem de Célula Glial/fisiologia , Hipocampo/crescimento & desenvolvimento , Moléculas de Adesão de Célula Nervosa/fisiologia , Neurogênese/genética , Plasticidade Neuronal/genética , Animais , Diferenciação Celular/genética , Células Cultivadas , Embrião de Mamíferos , Fator Neurotrófico Derivado de Linhagem de Célula Glial/genética , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/genética , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Hipocampo/citologia , Hipocampo/metabolismo , Camundongos , Camundongos Knockout , Complexos Multiproteicos/fisiologia , Rede Nervosa/crescimento & desenvolvimento , Rede Nervosa/metabolismo , Neurônios/fisiologia , Ligação Proteica , Ratos , Ratos WistarRESUMO
Neurotrophic factors regulate the survival and growth of neurons, and influence synaptic efficiency and plasticity. Several studies suggest the existence of a relationship between changes in neurotrophic levels and bipolar disorder (BD). The glial cell-line derived neurotrophic factor (GDNF) influences monoaminergic neurons and glial cells, but its role in BD patients is controversial. In order to elucidate it we evaluated plasma levels of GDNF in a sample of 70 BD patients (35 in mania and 35 in euthymia) and compared with 50 healthy controls matched for age, gender and educational levels. GDNF plasma levels were measured by enzyme-linked immunosorbent assay (ELISA). Patients were assessed by a Mini-International Neuropsychiatric Interview (MINI-plus), Young Mania and Hamilton Depression Rating Scales. Plasma GDNF levels were significantly increased in BD patients in euthymia compared with BD patients in mania and healthy controls (p<0.05). GDNF plasma levels were correlated with age (ρ=0.30, p<0.05) and negatively correlated with manic symptoms in BD patients (ρ=-0.54, p<0.05). Our results provide evidence that peripheral levels of GDNF are related with different mood states in BD, reinforcing the involvement of neurotrophic factors in its physiopathology.
Assuntos
Transtorno Bipolar/sangue , Transtorno Bipolar/fisiopatologia , Fator Neurotrófico Derivado de Linhagem de Célula Glial/sangue , Adulto , Afeto/fisiologia , Feminino , Fator Neurotrófico Derivado de Linhagem de Célula Glial/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Crescimento Neural/sangue , Fatores de Crescimento Neural/fisiologia , Testes Neuropsicológicos , Índice de Gravidade de DoençaAssuntos
Proteínas Ativadoras de GTPase/metabolismo , Proteínas Proto-Oncogênicas c-ret/metabolismo , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Fator Neurotrófico Derivado de Linhagem de Célula Glial/fisiologia , Humanos , Proteínas Proto-Oncogênicas c-ret/fisiologia , Transdução de SinaisRESUMO
In rats, autonomic nerve endings are damaged during Trypanosoma cruzi-induced myocarditis. Gradual recovery occurs after the acute phase. The present work shows the cardiac levels of glial cell line-derived neurotrophic factor (GDNF) and nerve growth factor (NGF), and their cellular sources during T. cruzi infection in rats. Atrial and ventricular NGF levels (ELISA) increased significantly at day 20 post inoculation, the time-point of maximal sympathetic denervation. ELISA failed to show significant increase of cardiac GDNF levels. However immunohistochemistry showed a significant increase of anti-GDNF gold particles over atrial granules at day 20. Light microscopy showed stronger NGF immunostaining in atrial cardiomyocytes and several blood capillaries. In situ hybridization showed NGF and GDNF mRNAs in atrial and ventricular myocytes of both infected and uninfected animals. Endothelial cells exhibited NGF mRNA and protein only in infected rats. No evidence of neurotrophic factor expression by the infiltrating mononuclear cells was found. This is the first report on neurotrophic factor expression during T. cruzi infection. Our findings indicate an important role for NGF in the regenerative phenomena subsequent to a myocarditis able to damage sympathetic nerve endings, with preservation of preterminals and nerve trunks. GDNF could have a minor or a more transient participation.