P53 protein expression and cell viability in irradiated peripheral blood mononuclear cells as bioindicators of radiosensitivity

Cellular radiosensitivity is directly correlated with the mechanism of DNA repair, in which p53 protein plays a major role. In this context, this study correlated cell death with p53 expression in lymphocytes irradiated in vitro with different doses of gamma-radiation. For this, peripheral blood samples were collected from 10 healthy subjects. Each sample was divided in aliquots and, separately, irradiated with doses of 0.5; 2 and 4 Gy. After this, peripheral blood mononuclear cells (PBMCs) were isolated and cultivated during 72 hours in 5% CO2 at 37 ̊C without mitogen stimulation. The expression of p53 protein was evaluated by flow cytometry. In parallel, cell viability was determined by trypan blue staining. Statistical analysis was performed using analysis of variance (ANOVA), differences were considered as statistically significant when p < 0.05. The results showed an increase of p53 expression with the absorbed dose, which was proportional to cell death, suggesting that p53 can be used as bioindicator of individual radiosensitivity.