ABSTRACT
Various stresses such as ionizing radiation can increase cellular damage, especially to nuclear DNA. To protect cellular damages, normal regulatory genes [such as Tp53 tumor suppressor] become activated. Accordingly, in this study, the p53 gene and its expression among employees occupationally exposed to low doses of ionizing radiation were compared with a selected control group. Using an ELISA kit, the amount of p53 protein in the blood serum of case and control groups was measured. Statistical analysis was performed using student t-test procedure. As a case group, 42 healthy individuals [with a mean age of 37.8 +/- 1.3 years] occupationally dealing with different kind of radiation sources in Atomic Energy Organization of Iran were chosen. As a control group, 16 healthy unexposed volunteers [with a mean age of 34.5 +/- 2.0 years] who were matched for age, sex and smoking habits were selected. A 2 ml aliquot of heparinized peripheral blood was collected from each case. The results of this research indicate the higher levels of p53 expression in occupationally radiation group. Moreover, the work history or smoking had no effects on p53 expression. Although the absorbed doses were below the permissible limits, this study confirms the role of low-level chronic exposure in increasing p53 expression among occupationally radiation workers. These results confirm that monitoring of radiation workers should not only be solely based on physical dosimetry, but also on the biological indicators, which have the advantage of measuring the individual radiation damage