Seham M El-Marakby, Ahmed A Abdel-Aal, Hussein M Abdelhafez, Ahmed A Abdelrahman, Misara M Awad
Among all priming doses, 0.5 Gy produced the most pronounced radio-adaptive response. The observed hematological and electrical changes appear to be associated with oxidative stress-mediated alterations in red blood cell membrane structure and function. These findings provide additional evidence for low-dose radiation-induced adaptation, contribute to understanding early blood biophysical responses, and may improve radiation risk assessment, radiation protection strategies, and approaches to reducing the biological effects of subsequent higher-dose exposures.
PURPOSE: This study evaluated the short-term effects of acute low-dose gamma radiation on the induction of the radio-adaptive response (RAR) and its associated hematological and biophysical blood alterations. The limited understanding of early blood biophysical changes following low-dose exposure provides the rationale for this investigation.
MATERIALS AND METHODS: Male rats were exposed to single low gamma doses (0.25, 0.5, or 0.75 Gy), a single challenge dose (2 Gy), or a priming dose followed by 2 Gy. Blood conductivity and conductance were measured to assess membrane electrical properties. Hematological parameters, including hemoglobin, mean corpuscular volume (MCV), and red cell distribution width (RDW), were determined. Lipid peroxidation was evaluated by malondialdehyde (MDA) levels, while electron paramagnetic resonance (EPR) spectroscopy was used to quantify radiation-induced free radicals.
RESULTS: Blood conductivity increased following exposure to 0.25, 0.5, and 0.75 Gy, as well as after 2 Gy and 0.75 Gy + 2 Gy, indicating increased red blood cell membrane permeability. Animals receiving a 0.5 Gy priming dose before the 2 Gy challenge exhibited a clear adaptive response, demonstrated by reduced membrane damage and improved MCV, RDW, and conductivity compared with the challenge-dose group. EPR analysis confirmed radiation-induced free radical generation, whereas MDA measurements supported the involvement of oxidative stress in radiation-associated membrane alterations.
CONCLUSIONS: Among all priming doses, 0.5 Gy produced the most pronounced radio-adaptive response. The observed hematological and electrical changes appear to be associated with oxidative stress-mediated alterations in red blood cell membrane structure and function. These findings provide additional evidence for low-dose radiation-induced adaptation, contribute to understanding early blood biophysical responses, and may improve radiation risk assessment, radiation protection strategies, and approaches to reducing the biological effects of subsequent higher-dose exposures.