Oxidative stress and glutathione S-transferase genetic polymorphisms in medical staff professionally exposed to ionizing radiation

Abstract

Purpose: Ionizing radiation (IR) is considered as a diagnostic and therapeutic tool in medicine. However, chronic occupational exposure of medical staff to IR may affect the antioxidant status and, as a result, DNA damage and cancers as well. The objective of our study was to evaluate the oxidative stress profile caused by IR in 29 Tunisian medical staff from radiology and radiotherapy departments, and to find an association between the GSTM1 null, GSTT1 null, and GSTP1 Ile105Val polymorphisms and oxidative stress biomarkers.

Materials and methods: The oxidant biomarkers malondialdehyde (MDA) and advanced oxidation protein product (AOPP) and the activities of the antioxidant superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) enzymes were spectrophotometrically determined in erythrocytes hemolysates. The analysis of GSTT1 null, GSTM1 null, and GSTP1 Ile105Val polymorphisms was determined for each participant using PCR methods.

Results: A significant increase of white blood cell (WBC) numbers (p < .05) and a significant decrease by 11% of hemoglobin (Hb) (p < .01) were noted in the exposed subjects in our study. Moreover, we report a significant increase of MDA level and the activities of SOD and CAT enzymes of the IR-exposed group compared to controls (p < .001). Interestingly, a close association was noted between the genotypes GSTP1 low active, GSTT1 null, GSTM1 null, and both GSTT1/GSTM1 null and oxidative stress biomarkers, especially with MDA level, SOD, and CAT activities.

Conclusions: Our findings indicate that the medical staff exposed to low IR levels were under risk of significant oxidative stress that was enhanced by their glutathione S-transferase (GST) polymorphisms.

Keywords:

• Ionizing radiation
• occupational exposure
• glutathione S-transferase (GST) genes
• oxidative stress
• erythrocytes

Acknowledgements

The authors sincerely thank the volunteers for their blood donations and interest in this research. We are also grateful to department of occupational medicine staff of Hedi Chaker Hospital, Sfax-Tunisia for their cooperation and their support in this study. The authors are grateful to Dr Wassim Hariz, English professor at the Faculty of Science of Sfax, for proofreading the manuscript.

Disclosure statement

The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.