Reactive changes in the monocytic lineage of the bone marrow during the recovery period after parenchymal liver hemorrhage

BACKGROUND: Damaged tissue repair in the body is a complex system of sequential changes. The healing rate depends on multiple factors, with the humoral immune response playing a critical role. The functional state of monocytic lineage cells significantly influences tissue regeneration. Therefore, investigating regulatory adaptations in response to tissue injury holds both scientific and clinical significance. AIM: To examine reactive changes in the proliferation, differentiation, and recruitment of monocytic lineage cells in the bone marrow during the recovery period following parenchymal liver hemorrhage. MATERIALS AND METHODS: This in vivo experimental study was conducted on outbred rats of both sexes, in which liver injury was modeled as parenchymal hemorrhage. In the experimental group, treatment included a xenogeneic biomaterial derived from reindeer skin collagen as a hemostatic agent. Bone marrow myelograms were analyzed, including monocytogram assessment. The following morphological cell types were differentiated: monoblasts, promonocytes, mature monocytes, and polymorphonuclear monocytes. Due to the non-normal data distribution, variables were described using the median (Me) and quartiles (Q25; Q75). Intergroup differences were assessed using the Kolmogorov–Smirnov test (Z), with statistical significance set at p 0.05. Statistical analysis was performed using SPSS 13.0 for Windows. RESULTS: On day 3 after modeling parenchymal liver hemorrhage, reactive changes in the monocytic lineage included an increase in promonocytes from 0.6% to 1.9% (p 0.001) and monocytes from 1.5% to 4.6% (p=0.010), whereas monoblast levels remained unchanged at 0.8% (p=0.850). By day 7, promonocyte and monoblast counts declined to 0.8% (p=0.006) and 0.6% (p=0.850), respectively. By day 14, no statistically significant changes were observed. On day 21, a decrease in monocytes (4.6%; p=0.120), polymorphonuclear monocytes (0.2%; p=0.990), and promonocytes (0.8%; p=0.290) was recorded, whereas monoblast levels remained stable. CONCLUSION: Reactive changes in the monocytic lineage of the bone marrow following parenchymal liver hemorrhage involve activation of proliferation and differentiation processes by day 3. By day 7, the intensity of monocytic recruitment from the bone marrow into peripheral circulation increases. By week 3, monoblast, promonocyte, and polymorphonuclear monocyte levels return to baseline, whereas monocyte levels remain elevated.