Blood Cytokines in Rats with Various Behavioral Characteristics during Emotional Stress and Treatment with Interleukin-1β

Abstract

We studied the effect of acute emotional stress and exogenous IL-1β (5 μg/kg intraperitoneally) on the cytokine profi le of blood serum in Wistar rats with various behavioral characteristics in the open-fi eld test. Blood level of proinfl ammatory cytokine IL-1β decreased in behaviorally passive rats, but increased in active animals after simultaneous immobilization and electrocutaneous stimulation. These changes refl ect the opposite immune responses to a similar stress exposure in rats with different emotional reactivity. Poststress variations in the concentration of circulating IL-1β differed in rats receiving exogenous IL-1β. Blood cytokine concentration decreased in behaviorally active rats, but remained unchanged in passive animals that were exposed to immobilization and electrocutaneous stimulation after pretreatment with IL-1β. Emotional stress and injection of IL-1β had no effect on blood level of an anti-infl ammatory cytokine IL-4 in rats. Our results indicate that rats with various behavioral parameters are characterized by signifi cant differences in the cytokine profi le of blood serum under conditions of emotional stress and treatment with IL-1β. These data illustrate the specifi c functional features of immune mechanisms, which provide an individual resistance of rats to the same stress exposure.A large body of evidence indicates that psychoemotional stress is accompanied by impairment of immune functions in mammals [9]. Immune dysfunction contributes to individual predisposition to stress factors.The pathogenesis of immune dysfunction during emotional stress involves changes in the cytokine profi le. Cytokines are polypeptide transmitters of cellcell interaction playing a regulatory role in normal physiological functions and progression of the defense response to foreign factors and impairment of tissue integrity [1]. Much attention is paid to the superfa mily of IL-1. IL-1β plays a trigger role and induces the cascade of cytokine secretion in the organism. IL-1β is one of the transmitters of the acute phase of the stress response. This cytokine modulates functional activity of the hypothalamic-pituitary-adrenal axis [8]. Our previous studies demonstrated an antistress effect of IL-1β on rats. Intracerebroventricular injection of IL-1β to animals prevents gastric ulceration [3] and involution of the spleen [5] and modulates the oxidative status of the hypothalamus and sensorimotor cortex of the brain under conditions of water-immersion stress [4].

Effect of Interleukin-1β on Functional Activity of Lymphoid Structures in the Gastrointestinal Tract of Rats during Acute Emotional Stress

“…The presence of cytokine receptors on neurons and glial cells of the hypothalamus indicates that these compounds have a neuroimmunomodulatory effect in the central nervous system [11,12]. Our previous experiments showed that acute emotional stress is accompanied by specifi c changes in plasma IL-1β concentration in rats with active and passive behavioral patterns in the open-fi led test [4]. These data illustrate specifi c role of IL-1β in the stress response of animals various individual-and-typological characteristics.…”

“…Simultaneous immobilization and electrocutaneous stimulation of rats served as the model of acute emotional stress [2,4]. The animals were placed in individual plastic cages for 1 h (length 16.5 cm, inner dia meter 5.5 cm).…”

Effect of Interleukin-1β on Lipid Peroxidation in Emotiogenic Structures of the Brain in Rats during Acute Stress

“…This standard method of stress exposure was described previously [4]. Control (nonstressed) rats were maintained in home cages during this period.…”

“…Our previous studies revealed specifi c features of cytokine involvement in the stress response of specimens with different emotional reactivity. Injection of exogenous IL-1β is followed by specifi c changes in serum cytokine concentration [4] and functional state of lymphoid structures in the gastrointestinal tract of behaviorally active and passive rats [1].…”

Comparative Analysis of the Effect of Cytokines on the Thymus, Adrenal Glands, and Spleen in Rats with Various Behavioral Characteristics

“…and anti-infl ammatory cytokines (IL-4, IL-10, IL-13, and transforming growth factor-β) [3]. Increasing interest to IL-1β [11] and IL-4 [3] is due to their biological functions in mammals.Our previous studies revealed specific features of IL-1β involvement in the stress response of animals with different prognostic resistance to stress [2,6]. Much attention was paid to evaluation of the role of IL-4 in immune reactions of the body.…”