Evaluation of the Low-Energy Ultrashort Pulsed Electron Beam Irradiation-Induced Oxidative Stress and Adaptive Response of Select Enzymes in a Rat Brain

The aim of this study is to evaluate the dynamics of oxidative stress (OS) development, as well as adaptive response of select enzymes induced by low-energy laser-driven ultrashort pulsed electron beam whole-body irradiation in a Wistar rat brain. The rats were exposed to irradiation at the LD50 dose, following which the levels of the OS, the activities of major antioxidant enzymes, namely superoxide dismutase (SOD) and catalase (CAT), the activity of purine nucleoside phosphorylase (PNP) serving as an indicator of body's immune status, the activity of the key enzyme of energy metabolism, namely creatine kinase (CK), as well as the amount of creatine were assessed on the 1st, 3rd, 7th, 14th, and 28th post-irradiation days. It has been demonstrated that: 1) the maximum intensity of OS occurs between the 1st and the 7th post-irradiation days, followed by a significant decrease detected on the 14th day and return to a control level on the 28th post-irradiation day; 2) the moderate drop in the activity levels, for SOD and CK, or fluctuations in the activity around the control level for CAT during the first post-irradiation days are replaced by the restoration of the initial activity levels for SOD and CK or a compensatory rise in the enzyme activity level for CAT by the 14th and 28th post-irradiation days-sufficient to neutralize the radiation-induced OS; 3) the identified dynamics of the changes of the parameters studied coincides with the terms of the start and end of the acute phase of brain injury induced by ionizing radiation.