Blood Leukocyte Indices in Male Rats of Different Ages

Blood leukocyte indices were studied in outbred male of rats of five age groups - 1,5; 6, 12, 18 and 24 months. Six month's old rats were served as the control. The increase in age in rats was accompanied by an increase of total leukocyte count (starting from the 12-month-old), in the percentage of neutrophils (both banded and segmented), eosinophils and monocytes as well as by a decrease in the number of lymphocytes, the appearance (starting from the 18-month-old) of polychromatophilic and immature cells, and cytoplasm plasmatization in some leukocytes. In immature 1,5-month-old rats, only the percentage of eosinophils (as in 12-month-old rats) and the total number of leukocytes changed (decreased). The process of restructuring of the immune system altered links in body reflected the dynamics of integral leukocyte indices (ILI). Changes in ILI at increase in age (starting from 18 months of age) indicated an increase in infectious intoxication and inflammation, activation of cellular immunity and effector link, the prevalence of non-specific protection cells (neutrophils) and their immature forms, as well as a delayed type of hypersensitivity, decrease in immunoreactivity and level of adaptation of the body. The lowest Garkavi adaptation index was in 24-month-old rats. Only in 1,5-month-old rats, the microphagocytes increased in the blood, as well as the body level of allergization was the lowest and the level of intoxication level was the highest compared to the other studied age groups.