Aguiar L A A, Silva I M S, Fernandes T S, Nogueira R A
Departamento de Morfologia e Fisiologia Animal, Laboratório de Biofísica Teórico-Experimental e Computacional, Universidade Federal Rural de Pernambuco, PE, Recife, BR.
Departamento de Biofísica e Radiobiologia, Universidade Federal de Pernambuco, PE, Recife, BR.
Braz J Med Biol Res. 2015 Oct;48(10):915-22. doi: 10.1590/1414-431X20154473. Epub 2015 Jun 12.
Understanding the effects of radiation and its possible influence on the nervous system are of great clinical interest. However, there have been few electrophysiological studies on brain activity after exposure to ionizing radiation (IR). A new methodological approach regarding the assessment of the possible effects of IR on brain activity is the use of linear and nonlinear mathematical methods in the analysis of complex time series, such as brain oscillations measured using the electrocorticogram (ECoG). The objective of this study was to use linear and nonlinear mathematical methods as biomarkers of gamma radiation regarding cortical electrical activity. Adult Wistar rats were divided into 3 groups: 1 control and 2 irradiated groups, evaluated at 24 h (IR24) and 90 days (IR90) after exposure to 18 Gy of gamma radiation from a cobalt-60 radiotherapy source. The ECoG was analyzed using power spectrum methods for the calculation of the power of delta, theta, alpha and beta rhythms and by means of the α-exponent of the detrended fluctuation analysis (DFA). Using both mathematical methods it was possible to identify changes in the ECoG, and to identify significant changes in the pattern of the recording at 24 h after irradiation. Some of these changes were persistent at 90 days after exposure to IR. In particular, the theta wave using the two methods showed higher sensitivity than other waves, suggesting that it is a possible biomarker of exposure to IR.
了解辐射的影响及其对神经系统可能产生的影响具有重大临床意义。然而，关于暴露于电离辐射（IR）后大脑活动的电生理研究却很少。一种关于评估IR对大脑活动可能影响的新方法是在分析复杂时间序列时使用线性和非线性数学方法，例如使用皮层脑电图（ECoG）测量的脑振荡。本研究的目的是使用线性和非线性数学方法作为伽马辐射对皮层电活动影响的生物标志物。成年Wistar大鼠分为3组：1个对照组和2个辐照组，在暴露于来自钴-60放射治疗源的18 Gy伽马辐射后24小时（IR24）和90天（IR90）进行评估。使用功率谱方法分析ECoG，以计算δ、θ、α和β节律的功率，并通过去趋势波动分析（DFA）的α指数进行分析。使用这两种数学方法都可以识别ECoG的变化，并识别辐照后24小时记录模式的显著变化。其中一些变化在暴露于IR后90天时仍然存在。特别是，使用这两种方法的θ波显示出比其他波更高的敏感性，表明它可能是暴露于IR的生物标志物。
