Análise lipídica de tecido cerebral expostos à radiação por DESI-MS

• Ano de defesa: 2018
• Autor(a) principal: Matheus Figueiredo Soares
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Lipídios; Dessorção por ionização (DESI); Espectrometria de massas; Lipidômica; Radiação ionizante; Efeitos das radiações; Radiação-; Metabolomica; Engenharia nuclear; Espectrometria de massa
• Link de acesso: http://hdl.handle.net/1843/BUBD-AX9L5V

The present work deals with radioinducited lipid alterations in brain tissue. Through DESI (electrolytic desorption spray ionization) organic tissues can be subjected to analysis of their structural components, such as the numerous classes of lipids. The characterization of the quantification of phospholipids is of relevance considering that they are correlated to a diversity of cellular functions, besides the possible use as biomarker in the neoplasias. Objective: To investigate the viability of the generation of lipid profiles of irradiated brain tissue, in order to identify radioinducite lipid alterations. METHODS: Healthy Wistar rats were selected and divided into two groups: one control (n = 4), called GC and another one submitted to total body irradiation (TBI), called GIR (n = 24) subdivided into 04 subgroups corresponding to time kinetics 24, 48, 96hrs and 01 weeks containing 06 animals each. Animals from the GIR group (n = 24) had the whole body irradiated through exposure to a Co-60 source, all together placed in 4 boxes, with an absorbed dose of 5 Gy. They were irradiated after a different time kinetics. Euthanasia was performed, with the removal of the organs and freezer storage at -80ºC and cuts in the cryostat in sagittal sections of the cerebral hemispheres with 14 m thickness. The slides were analyzed with an DESI source coupled to a mass spectrometer. The analyzes were conducted in the full scan mode and the mass spectra were obtained in the negative mode, covering a mass range of 200 to 1000 Da. Results: Most of the ions observed in the mass spectra correspond to deprotonated free fatty acids, phosphatidylserines (PS), phosphatidylinositol (PI) and sulfatide (ST). Several ions undergo changes in intensity and region of origin demonstrating the effect of radiation on the metabolome of brain tissue. The m / z 868,529 ion presented a spatial distribution present mainly in the cerebellar lobes (culmina, central lobe, slope, pyramid and uvula) and after irradiation there was a progressive decrease in the intensity of this lipid in all regions in all kinetics of time. Conclusion: Radiation changes the lipid profile in brain tissue and it is necessary to further deepen the studies for the identification of the main biomarkers of injury in the radiotherapy treatment