Avaliação in vitro da viabilidade de linhagens radiossensível e resistente em cinéticas de taxa e dose de radiação com cobalto-60

• Ano de defesa: 2012
• Autor(a) principal: Barbara Miranda Motta
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Ciências e Técnicas Nucleares; Mamas Câncer; Radiação ionizante; Engenharia nuclear
• Link de acesso: http://hdl.handle.net/1843/BUBD-AK8RRW

Breast cancer is a disease of great significance, being reason of a deep concern of the public health politics. In vitro studies using strains from breast tumors have shown to be efficient regarding the comprehension of biological effects due to the ionizing radiation, especially those that occur at a cellular level. This study aimed to evaluate and compare the behavior in vitro of the breast adenocarcinoma MDA MB-231, that usually shows a radioresistant behavior in radiotherapy treatments, and of the peripheral blood mononuclear cells (PBMC), that compose the lineages directly involved in the the immune response and are sensitive to radiation. These lineages were submitted to low LET (Linear Energy Transfer) radiation beams according to a kinetic of predetermined doses (2, 4, 6, 8 and 10 Gy), with two distinct exposion rates, the last one being a quarter of the first. The post irradiation collections were performed in predetermined times of 24, 48 and 72 hours. The cellular viability after the irradiation kinetics presented to the PBMC had shown the decrease of the Optic Density (OD) directly proportional to the increase of the administered doses. Although the cellular viability of the MDA MB-231 had not shown a marked decrease in relation to the control on the smallest administered dose (2 Gy), the extreme dose (10 Gy) had a significant difference between control and irradiated culture. However, in all assays maintaining constant the dose and employing two dose rates, it was observed that for the dose rate representing a quarter of the standard, the irradiated cells had a better recover between 48 and 72 hours, indicating that the time of exposure to radiation influences the cellular responses. It was clearly possible to observe the correlation between the dose of radiation administered and the cellular viability. The differences in the times of cellular recover against to the different dose rates show the importance of therapeutical planning once that radiation effects become different when it is applied varying time and distance.