Effect of Interleukin-1β on Peripheral Blood Leukocytes in Rats with Various Behavioral Characteristics during Acute Stress

We studied the effect of a pro-inflammatory cytokine IL-1β (5 μg/kg intraperitoneally) on blood leukocytes in Wistar rats various behavioral characteristics during acute emotional stress (1-h immobilization with simultaneous delivery of subthreshold electrocutaneous stimulation). Stress exposure was accompanied by a decrease in the total number of peripheral blood leukocytes in rats. Active animals were characterized by the increase in neutrophil count during stress. The number of eosinophils in passive specimens was shown to decrease under these conditions. Emotional stress was followed by a decrease in the lymphocyte index (by Shaganin) of active rats and increase in the leukocyte intoxication index (according to Kalf–Kalif) of passive specimens. Stress-induced changes in leukocytes differed after pretreatment with IL-1β. The number of blood leukocytes increased in animals receiving a cytokine injection before stress exposure. Exogenous IL-1β inverted (in active rats) or prevented (in passive specimens) a change in the percentage of various types of blood leukocytes, which was found after stress exposure. These data contribute to the understanding of peripheral mechanisms for the involvement of immunomodulatory cytokines in the systemic organization of physiological functions in specimens with different prognostic resistance to a similar stress exposure.