Irradiation
Animals in groups II and IV animals were irradiated 90 d before the study on the TERAGAM radiotherapeutic cobalt unit (“ISOTREND spol. S.r.o.”, Czech Republic); the radionuclide source used was cobalt-60 (Co60). Experimental animals received a single sublethal dose of 6 Gy. All experiments on animals were conducted according to the Geneva Convention (1990), the Helsinki Declaration on Humane Treatment of Animals, and the ethical standards of the local ethics committee of the JSC ”Astana Medical University,” Kazakhstan under the protocol No. 4 of 07.09.2017.
Before irradiation, we carried out a topometric and dosimetric preparation of all experimental animals for radiation. Briefly, the object was placed on the isocentric therapeutic table of the ”Terasix” (X-ray simulator Czech Republic), which based on its design and parameters corresponded to the therapeutic table of a gamma-irradiator. After being displayed on screens, the pattern of irradiated animals was directly entered into the planning system via the network connection of the computer using the digitizer. We calculated the isodose with the help of the ”PlanW-2000” (UJP Praha) planning system with the topometric-dosimetric map containing technical parameters and planned doses of irradiation. Animals were exposed once to a total gamma radiation dosage of 6 Gy: SSD - 97.2 cm, SAD - 100.0 cm, field 40 × 40 cm, t = 356 s (SSD - distance from the source of ionizing radiation in the device to the conventional center of the irradiated pathological focus; SAD - distance from the source of ionizing radiation in the device to the nearest surface of the irradiated object) [21]. During irradiation, animals were in a specially designed organic glass cell, with multiple isolated cells being employed for each animal [22].
In groups III and IV, animals were modeled for acute emotional stress by immobilization for 6 h in bright light. For this, experimental animals were placed in individual plastic compartments adapted for immobilization (length - 20 cm, width - 6 cm). Animals were euthanized 1 h after the induction of acute emotional stress, by incomplete decapitation under mild ether anesthesia.