The aim of our study was to examine the in vivo expression of p21 and expression and activation of ATF-2, c-Myc, and CREB in rat peripheral blood mononuclear cells (PBMC) after whole body γ-irradiation and to assess its contribution to biodosimetry. For Western blot experiments, male Wistar rats were whole-body irradiated by a single dose of 0, 0.5, 1, 3, and 5 Gy (⁶⁰Co, 1 m, 0.7 Gy/min). As a positive control, leukaemic MOLT-4 cells were used. For ELISA experiments, male Wistar rats were whole-body irradiated by a single dose of 0, 1, 2, 3, 4, and 5 Gy (⁶⁰Co, 1 m, 0.6 Gy/min). Blood samples were taken 4 h after the irradiation and PBMC were isolated using centrifugation on Histopaque-1077. Expressions of p21, ATF-2, phospho-ATF-2^Thr69/71, c-Myc, phospho-c-Myc^Thr-58/Ser62, CREB, and phospho-CREB^Ser133 were measured using Western blot method. Expression of p21 was also quantified using ELISA. We observed increase of p21 expression in rat PBMC 4 h after irradiation. According to ELISA, p21 levels increased 2.0-, 3.1-, 5.5-, 3.0-, and 3.1fold after irradiation by 1, 2, 3, 4, and 5 Gy, respectively. We did not detect any expression or activation of ATF-2, c-Myc and CREB. Protein p21 could be considered as a perspective biodosimetric marker of clinically significant irradiation (≥1 Gy) in vivo in unstimulated PBMC.

Keywords: p21; ATF-2; c-Myc; CREB; blood; rat; biodosimetry; Western blot; ELISA