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. 2016 May;21(3):139-45.
doi: 10.1080/13510002.2015.1101891. Epub 2016 Feb 5.

Redox status in workers occupationally exposed to long-term low levels of ionizing radiation: A pilot study

Iman M Ahmad  1 , James B Temme  1 , Maher Y Abdalla  2 , Matthew C Zimmerman  3
Affiliations

Redox status in workers occupationally exposed to long-term low levels of ionizing radiation: A pilot study

Iman M Ahmad et al. Redox Rep. 2016 May.

Abstract

Objectives: Reactive oxygen species (ROS), including superoxide (O2(•-)), play an important role in the biological effects of ionizing radiation. The human body has developed different antioxidant systems to defend against excessive levels of ROS. The aim of the present study is to investigate the redox status changes in the blood of radiologic technologists and compare these changes to control individuals.

Methods: We enrolled 60 medical workers: 20 occupationally exposed to ionizing radiation (all radiologic technologists), divided in three subgroups: conventional radiography (CR), computerized tomography (CT), and interventional radiography (IR) and 40 age- and gender-matched unexposed controls. Levels of O2(•-) and malondialdehyde (MDA) in blood were measured as an index of redox status, as were the activities of antioxidant enzymes superoxide dismutase (SOD) and catalase. Redox status was also assessed by measuring levels of reduced and oxidized glutathione (GSH, GSSG, respectively).

Results: Levels of O2(•-) and MDA, and SOD activity in the blood of IR and CT-exposed subjects were significantly higher than both the CR-exposed subjects and control individuals. However, there were no statistically significant differences in the levels of catalase, GSH and ratio of GSH/GSSG between exposed workers and control individuals.

Discussion: This study suggests that healthcare workers in CT and IR occupationally exposed to radiation have an elevated circulating redox status as compared to unexposed individuals.

Keywords: Catalase; Glutathione; Low-level ionizing radiation; Malondialdehyde; Radiologic technologists; Superoxide; Superoxide dismutase.

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Conflict of interest statement

Authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Representative EPR spectroscopy spectrum obtained from blood collected from control, CR-, IR-, and CT-exposed workers, and incubated with the O2•−-sensitive spin probe, CMH (A). The EPR spectrum amplitude is directly proportional to the levels of O2•− in the sample. Summary data showing EPR spectrum amplitude in control individuals and all radiation-exposed workers (B) and the specific radiation-exposed subgroups (CR, IR, and CT) (C). a.u. = arbitrary unit. Data represent the mean ± SEM. *P < 0.05 versus control and CR.
Figure 2
Figure 2
Plasma MDA levels in control individuals as well as in all radiation-exposed workers (A) and in the different occupational subgroups (CR, IR, and CT) (B). Data represent the mean ± SEM. *P < 0.05 versus controls; ψP < 0.05 versus CR.
Figure 3
Figure 3
SOD activity in erythrocytes isolated from all radiation-exposed workers and control individuals (A), and in the different occupational subgroups (CR, IR, and CT) (B). The levels expressed are mean values ± SEM. *P < 0.05 versus control & CR; ψP < 0.05 versus IR.
Figure 4
Figure 4
Catalase activity (A) and the GSH/GSSB ratio (B) in erythrocytes isolated from all radiation-exposed workers and control individuals. The levels expressed are mean values ± SEM. P > 0.05.
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