FEATURES OF PROLIFERATION AND APOPTOSIS OF COLONIC EPITHELIOCYTES AFTER ELECTRON IRRADIATION AT A DOSE OF 8 GY

Intestinal epithelial cells are characterized by high mitotic activity and have high radiosensitivity to all types of ionizing radiation that cause their damage. In modern morphology and radiology, there is no data on the effect of active electrons on the intestinal mucosa, despite the promise and active implementation of this type of radiation for therapeutic purposes in oncology. Purpose of the study: immunohistochemical assessment of proliferation and apoptosis of colon epithelial cells in male Wistar rats after local irradiation with electrons at a dose of 8 Gy. Animals were irradiated using a linear accelerator NOVAC-11, at a dose rate of 1 Gy/min, energy of 10 MeV and frequency of 9 Hz, the diameter of the irradiation field of the pelvic-abdominal region was 100 mm. Animals from each group were removed from the experiment on the first and third days. Histological preparations of the colon (n=30) from two groups, the first control group (n=10) and the second experimental group (n=20), were examined by immunohistochemical method with antibodies to Ki-67 and Cas3. In preparations of rats bred one day after irradiation, a predominance of apoptotic processes was revealed. The number of positive cells stained with antibodies to caspase 3 was increased by 1.5 times in the experimental group compared to the control group, and the number of Ki-67-positive cells, on the contrary, was reduced by 1.5 times. On day 3 after electron irradiation in the epithelium of the colon, the number of immunopositive cells did not differ from control values. Thus, with local single irradiation of the pelvic-abdominal region of rats with electrons at a dose of 8 Gy, a decrease in the number of stem epithelial cells of the intestinal crypts of the colon is observed every other day, which is confirmed by a shift in the proliferative-apoptotic balance towards cell death. In the dynamics of observation on the third day of the experiment, an increase in the pool of proliferating cells is observed, followed by restoration of intestinal crypts.

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