## 3 Results
A histological study also revealed cytoplasmic vacuolization of hepatocytes in all groups. The vacuolization developed by 24 h after ELR and increased by 48 h. However, the changes were not the same for all the groups. The _aHSC_ and _total RNA_ groups had a more pronounced and earlier vacuolization than the _iHSC_ group and the _control_ group. The histological slides of the liver were used to count the mitotic index (MI). In the experiment, the MI was estimated with parametrical tests (_t_ tests) and the \(p\) values were considered as significant if they were <0.05. The MI stayed increased for all groups (rats who had no ELR and served donors for HSCs had a liver MI equal to 0.2-0.3%). However, the groups of _iHSC_, _aHSC_, and _total RNA_ had a more remarkable MI (Figure 4F) than the _control_ group. The _control_ group reached its peak of MI by 48 h (36 mitotic cells among 6653 counted cells). For the _iHSC_ group, the peak occurred by 72 h with 93 mitoses per 8858 cells; for the _aHSC_ group, the peak occurred by 24 h with 136 mitoses per 9762 cells; finally, for the _total RNA_ group, the peak occurred by 48 h with 227 mitoses per 9678 cells. Figure 4: **Graphs for levels of blood markers and mitotic index. ** Daily dynamics of biochemical markers (units/Liter, u/L; or gram per liter, g/L) for all experimental groups: **(A)**—aspartate aminotransferase, AST, **(B)**—alanine aminotransferase, ALT, **(C)**—alkaline phosphatase, ALP, **(D)**—albumin, and **(E)**—total bilirubin in the blood. **(F)**—dynamics of mitotic index (MI, %) in hepatocytes of rats after ELR. Values are given as means \(\pm\) SDs. Counting the rate, the peak MI of the _control_ group was equal to 5.4 \(\pm\) 0.24 %; _iHSC_ equal to 10.5 \(\pm\) 0.47 %; _aHSC_ equal to 14.9 \(\pm\) 0.56 %; and _total RNA_ was equal to 23.5 \(\pm\) 0.21 %. Regarding the timing, intraperitoneal administration of _aHSCs_ and total RNA led to maximal MI values by 24 h or 48 h, respectively, whereas for _iHSCs_ it was by 72 h. We calculated MI in the histological slides stained with H&E, as shown in Figure 3A,D,G,J,M. These slides revealed vacuolar dystrophy of hepatocytes by 48 h after ELR in all groups, while the effect was maximal in the _aHSC_ group (Figure 2J,K). We also studied the rate of proliferation and apoptosis by expression of Ki-67, caspase-3 and caspase-9 in hepatocytes 48 h after ELR. The IHC study with antibodies against Ki-67 revealed the maximal proliferation for groups _aHSC_ and _total RNA_ on Days 1, 2, and 3 after ELR as estimated by paired t tests with \(p\) < 0.05 (M \(\pm\) SD for logarithmic values of Ki-67 expression: 0.65 \(\pm\) 0.07, 0.48 \(\pm\) 0.05, 0.35 \(\pm\) 0.06 for aHSC; 0.48 \(\pm\) 0.04, 1.4 \(\pm\) 0.09, 0.5 \(\pm\) 0.06, respectively), and on Days 2 and 3 after ELR for the _control_ group (0.25 \(\pm\) 0.05, 0.2 \(\pm\) 0.05, respectively) and _iHSC_ (0.35 \(\pm\) 0.03, 0.55 \(\pm\) 0.05, respectively) (Figures 3B and 5). Caspase-9 expression was remarkable in all groups by 48 h after ELR (Figure 2C,F,I,L,O), but no caspase-3 expression was found with null expression for all the groups, while the control slides from other organs were positive for the staining. Measuring liver mass in rats (the parameter was normally distributed with the difference considered significant at \(p\) < 0.05), we found that groups _aHSC_ and _total RNA_ had a higher rate of liver mass recovery (by Days 8-10; 13.5 \(\pm\) 1.2 g and 13.6 \(\pm\) 1.4 g, respectively) compared to the _iHSC_ group (by Days 12-14; 13.4 \(\pm\) 2.1 g) and the _control_ group (by Days 18-20; 13 \(\pm\) 0.9 g) after ELR (Figure 3C). We also assessed the morphometrics of hepatocytes on the histological slides for the MI index count, considering that the changes in liver mass may be due not only to the mitotic activity of hepatocytes but also to their hypertrophic changes with no increase in cell number (Figure 6A-C).