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Abstract: 148-1

148-1

Study of the radiomitigating potential of Ginkgo biloba extract through the frequency of micronuclei in irradiated human lymphocytes

Authors:
Julio Cesar Gomes da Silva (CRCN-NE - Centro Regional de Ciência Nucleares do Nordeste, UFPE- PPGM - Universidade Federal de Pernambuco (Programa de Pós Graduação em morfotecnologia), UFPE- PROTEN - Universidade Federal de Pernambuco (Programa de Pós Graduação em Tecnologias Energéticas e Nucleares)) ; Eduarda Santos Silva (CRCN-NE - Centro Regional de Ciência Nucleares do Nordeste, UFPE PPGBQF - Universidade Federal de Pernambuco (Programa de Pós Graduação em Bioquímica e Fisiologia)) ; Mirelle Lima de Araújo (CRCN-NE - Centro Regional de Ciência Nucleares do Nordeste) ; Isvânia Maria Serafim da Silva Lopes (UFPE- PPGM - Universidade Federal de Pernambuco (Programa de Pós Graduação em morfotecnologia)) ; Mariana Esposito Mendes (CRCN-NE - Centro Regional de Ciência Nucleares do Nordeste) ; Thiago Henrique Napoleão (UFPE PPGBQF - Universidade Federal de Pernambuco (Programa de Pós Graduação em Bioquímica e Fisiologia)) ; Ana Maria Mendonça de Albuquerque Melo (UFPE- PROTEN - Universidade Federal de Pernambuco (Programa de Pós Graduação em Tecnologias Energéticas e Nucleares), CRCN-NE - Centro Regional de Ciência Nucleares do Nordeste) ; Fabiana Farias de Lima (CRCN-NE - Centro Regional de Ciência Nucleares do Nordeste)

Abstract:

Radiomitigators are natural or synthetic substances that, when administered after exposure to ionizing radiation, can reduce radiation-induced damage [1]. They primarily act on DNA repair through antioxidant action, induction of cellular apoptosis, prevention of hematopoietic damage, or by reducing/blocking inflammatory cascades [2]. This study aimed to evaluate the radiomitigative potential of Ginkgo biloba extract by assessing micronucleus frequency in irradiated human peripheral blood lymphocytes. Peripheral blood was collected from a healthy, non-smoking individual. One sample served as a control in the laboratory, while the others were exposed to 60Co irradiation (using a Gammacel 220 irradiator from the Department of Nuclear Energy of Universidade Federal de Pernambuco, DEN-UFPE) at absorbed doses of 0.5, 2, and 4 Gy. Post-irradiation, the samples were transferred to the Biological Dosimetry Laboratory at the Centro Regional de Ciências Nucleares do Nordeste (CRCN/NE) and incubated in an oven for 2 hours. Ginkgo biloba extract (Merck) was then applied at concentrations of 0.05 and 0.025 µg/ml, as determined by the cell viability test (MTT kit, Merck), to both the irradiated and control groups of extract-treated samples. Subsequently, cell cultures were initiated according to standard protocols [3]. Slides were prepared from cell precipitates and left to dry at room temperature for 24 hours. They were then stained with 5% Giemsa solution for 20 minutes and examined under an optical microscope (Leica DM500). Slides were analyzed to identify viable binucleated (BN) cells based on pre-established criteria [3]. Statistical analyses of micronucleus data included Poisson model conformity tests using the Papworth u test with a 95% confidence interval [3]. ANOVA and Tukey tests were employed to assess differences among sample types. Control samples showed micronucleus frequencies within the reference range of 0 to 40 MN per 1000 binucleated cells [3]. Analysis of samples treated with extract and irradiated with 2 and 4 Gy doses demonstrated reduced micronucleus formation compared to irradiated, untreated blood. Statistical analysis of 2 and 4 Gy doses via ANOVA indicated no significant difference in micronucleus frequencies between irradiated and non-irradiated samples. However, Tukey's test revealed significant statistical differences (p<0.05) among irradiated samples themselves, particularly between irradiated samples treated with extract versus untreated irradiated samples, suggesting efficacy of the extract at both tested concentrations. Samples irradiated with 0.5 Gy showed similar micronucleus frequencies, with no statistical significance between samples, indicating that Ginkgo biloba extract is not effective at lower absorbed doses.  In conclusion, Ginkgo biloba extract was found capable of reducing micronucleus frequency induced by radiation exposure at higher absorbed doses, demonstrating radiomitigative properties.

Keywords:
 Radiation, Radiomitigators, Micronuclei, Cytogenetic, Ginkgo biloba