Gastrointestinal form is the second stage of acute radiation syndrome (ARS) with a threshold dose of 8 Gy in man. It represents an absolutely lethal clinical-pathological unit, necro-hemorrhagic enteritis and proctocolitis, with unknown causal therapy. Elk-1 is a protein acting as a transcription factor activating specified genes. The purpose of our study was to examine the expression of phospho-Elk-1 in irradiated jejunum and transversal colon of rats with radiation-induced enterocolitis and to assess the importance of this transcriptional factor as a biodosimetric marker of radiation-induced enteropathy. The laboratory rats were randomly divided into 21 groups, 10 animals per group, and irradiated with whole body γ-irradiation of 1, 5, 10, 15, and 20 Gy. Samples of jejunum and transversal colon were taken 24, 48, 72, and 96 hours later, immunohisto-chemically stained, and the phospho-Elk-1 expression was examined using computer image analysis. A group of 10 sham-irradiated animals was used as control. Significantly increased expression of phospho-Elk-1 in rat jejunum has been found in all time intervals after irradiation by sublethal doses of 1 and 5 Gy, whereas after the irradiation by lethal doses, the expression of phospho-Elk-1 in rat jejunum varied considerably. Significantly increased expression of phospho-Elk-1 in transversal colon has also been found in the first days after irradiation by sublethal doses of 1 and 5 Gy. After irradiation by lethal doses, tere was no uniform pattern of the changes in the expression of phospho-Elk-1 in rat transversal colon. The detection of phospho-Elk-1 might be considered as a suitable and very sensitive biodosimetric marker of radiation-induced injury of small and large intestine. According to our knowledge, this is the first study on the phospho-Elk-1 expression in irradiated jejunum and transversal colon in the rat., D. Driák, J. Österreicher, Z. Řeháková, Z. Vilasová, J. Vávrová., and Obsahuje bibliografii a bibliografické odkazy
Gastrointestinal form is the second stage of the Acute Radiation Syndrome (ARS) with a threshold dose of 8 Gy. It represents an absolutely lethal clinical-pathological unit, enteritis necro-hemorrhagica (duodenitis, jejunitis, ileitis, respectively) with unknown causal therapy. The purpose of our study has been to evaluate the morphological changes in a model of radiation-induced enteritis in rats and estimate the significance of changes in biodosimetry. Wistar rats were randomly divided into 21 groups, 10 animals per group. Samples of the jejunum were taken 24, 48, 72, and 96 h after the whole-body γ-irradiation with the doses of 1, 5, 10, 15, and 20 Gy, and routinely stained with hematoxylin and eosin. Five morphometric markers – intercryptal distance, enterocytal height on the top and base of villus, length of basal lamina of 10 enterocytes and enterocytal width – in irradiated rat jejunum were examined. The results were compared with sham-irradiat ed control group. After lethal doses of irradiation, all morphometric parameters of jejunum significantly changed. With the exception of intercryptal distance, they might be considered as suitable biodosimetric markers under these experimental conditions. Our morphometry results in radiation-induced jejunitis are in accordance with those in other studies. We were the first who quantified morphological post-irradiation changes in animal jejunum. Some of them might be used under experimental conditions. This experimental study is a predecessor of the clinical assessment of a specific marker. Under clinical practice, the sensitive biodosimetric parameter could serve as one of the guidance for evaluation of the absorbed dose in irradiated troops as well as rescue workers. This is in accordance with tasks and Standardization Agreement of the North Atlantic Treaty Organization., D. Driák, J. Österreicher, J. Vávrová, Z. Řeháková, Z. Vilasová., and Obsahuje bibliografii a bibliografické odkazy