## 3 Results
In both groups Ir.control and Ir+AC after radiation exposure, efficiency of colony formation (6 \(\pm\) 0.8 and 9 \(\pm\) 1.3) was reduced 3.7 and 2.4 times, respectively, in comparison with healthy control (22 \(\pm\) 1.2) per 1 \(\times\) 10\({}^{5}\) explanted cells. On the 9 th day after irradiation, enterosorption with AC in rats contributed to the significant acceleration of WBC and Lymphocyte count restoration in blood of rats (7.2 \(\pm\) 0.8; 5.0 \(\pm\) 0.7) in comparison with Ir control group (2.7 \(\pm\) 1.1; 1.7 \(\pm\) 1.8). Platelet levels on the 9 th day after irradiation were significantly reduced in both groups with statistical tendency to be higher in AC treated group. The bone marrow of irradiated animals showed 80-90% recovery on the 9 th post irradiation day (Figure 5) In this period after irradiation, statistical difference is seen between irradiated groups in terms of count of all bone marrow cells (10\({}^{6}\) per femur) and its composites (except mitotic index). The mitotic index of bone marrow cells (Table 1) in AC treated group is statistically higher (13.8) than in the untreated irradiated group (8.8). In the irradiated control group, unlike in AC treated group, the mitotic index of erythroid bone marrow cells (4.2) is less than those of healthy controls. Figure 5: Bone marrow cells (10\({}^{6}\) per femur) in rats on the 1 st and 9 th day after irradiation. * \(p\) < 0.05 in comparison with h.control. The results of cytogenetic examination of bone marrow in rats are presented in Table 2. As can be seen, in the cells of healthy control animals the frequency of chromosomal aberrations corresponded to the normal spontaneous level (0-3%). On the 9 th day after irradiation elevated levels of chromosome aberrations in bone marrow cells were observed in all groups of exposed animals. The total frequency of chromosome aberrations in irradiated control animals were more than 2.5 times higher (4.28 \(\pm\) 0.3) per 100 metaphases than in healthy controls (1.6 \(\pm\) 0.3), and 1.9 times higher than in irradiated groups treated with AC (2.2 \(\pm\) 0.2). In the spectrum of chromosomal aberrations of Ir. control group, specific radiation-induced cytogenetic markers, such as dicentric chromosomes and accompanying acentric fragments, were found. In bone marrow of irradiated animals subjected to enterosorption with AC (Ir+AC group) there were no dicentrics observed on the 9 th day of the experiment and the rate of acentric paired fragments was approximately 2.5 times less than in the Ir.control group. As in healthy control, in AC+Ir group the chromatid type aberrations (single chromatid fragments and exchanges) prevailed in the aberration spectrum. To identify the mechanism underlying the effect of AC, superoxide radical generation rate (SOR) was determined in the brain and liver tissues of rats at days 1 and 9 post-irradiation. As shown in Table 3, in terms of SOR generation rate, there was a 25-fold increase in brain tissue (5.0 \(\pm\) 0.4) and (5.1 \(\pm\) 0.7), 5-fold increase in liver tissue (1.5 \(\pm\) 0.2) and (1.7 \(\pm\) 0.2) in the Ir.control group when compared with the h.control group (0.2 \(\pm\) 0.1) and (0.3 \(\pm\) 0.1), respectively at 1 and 9 days post-irradiation. The AC entrosorption pronouncedly decreased the SOR generation rate in the liver (1.7 fold) at days 1 and 9 post-irradiation in comparison with the Ir control group. But in brain in both days after irradiation the high SOR generation rate was not statistical reduced by AC treatment.