RESUMO
The effects of a single intraperitoneal injection of a non-metabolizable glucose analog 2-deoxyglucose (2-DG, 500 mg/kg) on the levels of beta-APP expression, and phosphorylated and unphosphorylated tau protein in the rat cerebral cortex were investigated. The effects of 2-DG on the ultrastructure of cortical neurons with particular emphasis on the morphology of the Golgi apparatus, and on brain bioenergetics assessed by in vivo 31P-MRS technique were also evaluated. Seven and a half hours after injection of 2-deoxyglucose a significant increase in brain cortex beta-APP expression, increased tau phosphorylation, and a marked relative expansion of the trans- part of the Golgi intracellular secretory pathway in cortical neurons has been found. The changes of beta-APP expression and tau phosphorylation appeared within 1 h after 2-DG application and continued for at least 24 h. However, brain 31P resonance spectra remained unchanged for up to 7.5 h after 2-DG. It is suggested that the increase of beta-APP expression represents a response of brain tissues to 2-DG-evoked biochemical stress, while tau hyperphosphorylation and the change in Golgi morphology may be secondary phenomena.
Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , Córtex Cerebral/efeitos dos fármacos , Desoxiglucose/toxicidade , Complexo de Golgi/efeitos dos fármacos , Proteínas tau/metabolismo , Análise de Variância , Animais , Antimetabólitos/toxicidade , Contagem de Células/métodos , Córtex Cerebral/citologia , Complexo de Golgi/metabolismo , Complexo de Golgi/ultraestrutura , Imuno-Histoquímica/métodos , Espectroscopia de Ressonância Magnética/métodos , Masculino , Microscopia Eletrônica de Transmissão/métodos , Neurônios/metabolismo , Neurônios/ultraestrutura , Fosforilação/efeitos dos fármacos , Ratos , Ratos Wistar , Fatores de TempoRESUMO
A 3D spin-echo (3D SE) pulse sequence was used on a 4.7 T research MRI system to produce images of extracted human first molar tooth placed in CuSO4 water solution. The maximal resolution achieved was 35 x 63 x 300 microm3 in read and two phase directions, respectively. The high-intensity signal from water in solution together with the lack of signal from mineralized tooth tissue produce very good contrast allowing to visualize topography of outer and inner surfaces of the tooth. The 3D MR data were median filtered, binarized and then divided into separate segments corresponding to the inner tooth cavities and the hard tooth tissue. The topography of the root canals was visualized and the canals volume was calculated. The presented technique may be used for quantitative analysis of the root canal cavities shape and volume. The results of such an analysis may be applied for estimation of the quality of the impressional mapping methods in restorative dentistry or as an alternative non-impressional 3D mapping method.
