Přednášející
Popis
The objective of our study was to design biodosimetric methodology efficient for a practical usage for the population exposed to radiation emergencies. We focused on new approaches enabling rapid triage of irradiated individuals into five categories in accordance with METREPOL system (Fliender and col., 2007).
In our work, we used experimental animal model of minipigs for homogeneous total body gamma irradiation (TBI) by 0–4.2 Gy. First the lethal dose LD$_{50/30}$ was determined on 2.3–2.4 Gy after TBI. According to changes in haematological parameters occurring in the peripheral blood, the animals were divided into five categories H0 (non-irradiated), H1 (≤ 0,4), H2 (0.6–1.2 Gy), H3 (1.4–2.0 Gy) and H4 (≥ 2,2 Gy) differing each other in the prognosis of acute radiation sickness development and the treatment suggestion. Then the indicators of nuclear DNA damage (histone H2AX phosphorylation $\gamma\,$H2AX), induction of cell apoptosis (caspase 3 activation) and changes in relative and absolute cell counts of T and B lymphocytes in peripheral blood (PB) were monitored by flow cytometry in all individuals.
Based on our results the value borders of interested parameters for each category were set and basic parameters suitable for triage into one of five categories were chosen. Early triage is based on monitoring changes on DNA ($\gamma\,$H2AX) 1 hour after TBI. Fast triage combines data of apoptosis induction (caspase 3 test) and changes in absolute counts and relative representation of PB lymphocytes 4 hours and 8 hours after TBI. Confirmation triage is based on data obtained by fast triage together with changes occurring in PB lymphocytes 48 hours after TBI.
So, based on experimental we have shown that minipigs represent a convenient large animal model for in vivo studies on PB leukocyte cell sensitivity with possible implications in practical biodosimetry. Our results were verified by the blind study which included ten total body irradiated animals by unknown dose. Eight of these animals were successfully classified into right category, the other two were classified into higher (more serious) category.
Acknowledgement: Supported by projects of the Ministry of Defence of the Czech Republic (long-term organization development plan Medical Aspects of Weapons of Mass Destruction of the Faculty of Military Health Science, University of Defence in Brno) and Ministry of Interior Affairs of the CR (project VH20172020010).
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