Dynamics of blood hematological parameters of white rats in postnatal ontogenesis

: In experiments on Wistar rats, dynamics of blood hematological and rheological parameters has been studied from birth to the 3-month age. Results of the study indicate an intensive activity of the red bone marrow anlagen during the first 3 weeks of postnatal ontogenesis. This is manifested in an increase of the number of cells in the erythron system, a change of erythrocyte acidic resistance, and a shift in the leukocytic formula. The boundary between the 2nd and 3rd postnatal weeks is critical: there occur a sharp deceleration of erythropoiesis and a change of the age-related erythrocyte composition and the blood leukocyte ratio towards those characteristic of adult rats. The rise in the number of leukocytes and erythrocytes does not cease after having passed this period. Until the 4-week age, the deformability index increases, which is accompanied by an increase of hemoglobin hydration and by improvement of the erythrocyte toroid form. Subsequently, inversion of these processes occurs.