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

We studied the effect of interleukin-1β on functional activity of lymphoid structures in the gastrointestinal tract of rats with various behavioral parameters during stress of simultaneous immobilization and electrocutaneous stimulation. Morphofunctional characteristics of lymphoid tissue were estimated by studying elimination of intraperitoneally injected Chinese ink particles into the mesenteric lymph nodes and wall of the jejunum. Intraperitoneal injection of interleukin-1β (5 μg/kg, 108 U/mg) was accompanied by accumulation of Chinese ink in the mesenteric lymph nodes of unstressed passive and active rats. The observed changes reflect an immunostimulatory effect of this cytokine. Acute stress was followed by an increase in the number of ink particles in the mesenteric lymph nodes and wall of the jejunum in behaviorally active rats. Under these conditions, the number of ink particles was elevated only in the mesenteric lymph nodes of passive specimens. As differentiated from passive animals, pretreatment of active rats with interleukin-1β before acute stress was followed by the increased elimination of Chinese ink (antigenic material) from the abdominal cavity to the lymph nodes and through the wall of the jejunum. These data illustrate specific features of immune mechanisms for the stress response in mammals with various behavioral characteristics.     

Intensity of Oxidative and Antioxidant Processes in the Brain of Rats with Various Behavioral Characteristics during Acute Stress

We studied the effect of acute emotional stress (1-h immobilization with simultaneous electrocutaneous stimulation) on the prooxidant-antioxidant balance in emotiogenic structures of the brain in rats with various behavioral characteristics. TBA-reactive substance content in the hypothalamus of rats remained practically unchanged after stress exposure. Opposite change in activity of antioxidant defense enzymes in this structure of the brain in behaviorally active specimens probably compensate for the possible variations in LPO during emotional stress. Activities of glutathione reductase and Cu/Zn-containing SOD in the hypothalamus of passive animals decreased under these conditions. As differentiated from active rats, emotional stress in passive specimens was accompanied by the accumulation of TBA-reactive substances in the sensorimotor cortex and amygdala. The observed increase in glutathione peroxidase activity in passive animals probably serves as a secondary compensatory reaction to LPO activation. Our results illustrate specific changes in free radical processes and antioxidant defense in emotiogenic structures of the brain in rats with various behavioral characteristics after acute stress. These changes were more pronounced in behaviorally passive specimens than in active animals. It was probably related to differences in the oxidative status of CNS in rats with various prognostic resistance to similar stress factors.     

Structural and Functional Characteristics of Neurons in the Sensorimotor Cortex of Rats with Different Resistance to Emotional Stress

Wistar rats behaviorally active in the open field test (resistant to emotional stress) are characterized by polymorphism of neurons in layer V of the sensorimotor cortex and the presence of hyperchromatic cells, which probably determines resistance to emotional stress in these rats. Atrophy of hyperchromatic neurons reflecting transient inhibition of cell activity was noted in Wistar rats subjected to stress. In the sensorimotor cortex of behaviorally passive animals (predisposed to emotional stress) groups of densely packed hyperchromatic cells and pronounced pericellular edema were revealed. In these rats stress caused irreversible changes in cortical neurons and death of some cells. The presence of ischemic cortical neurons in rats subjected to emotional stress suggests that cerebral hypoxia plays a role in structural and functional disorganization of the sensorimotor cortex during emotional stress.     

Structural and functional organization of the cerebral cortex neurons in rats with various resistance to emotional stress following administration of delta-sleep-inducing peptide

In Wistar rats with different resistance to emotional stress (ES), subjected to stress exposure (SE), the structural organization of neurons in layer V of sensomotor cortex was studied quantitatively in brain sections stained using Nissl's cresyl violet method. One group of animals was injected with delta sleep-inducing peptide (DSIP) 1 hr before SE. In rats of control group predisposed to ES, the amount of normochromatic and moderately hypochromatic neurons was decreased as compared to the rats resistant to ES. After SE, normochromatic neurons were not demonstrated. In rats predisposed to ES, the contents of moderately hypo- and hyperchromatic neurons was found to fall dramatically with a simultaneous increase in the number of extremely hypo- and hyperchromatic neurons, ghost cells and ischemically changed cells. After DSIP infusion before SE, ischemically damaged cells were not found in any group, while the degree of shrinkage of extremely hyperchromatic neurons was lower in rats predisposed to ES as compared to rats resistant to ES. It is suggested that brain hypoxia plays an important role in cortex disorganization during ES, whereas DSIP, possesses both antistress and antihypoxic effects.     

Structural-Functional Organization of Neurons in the Cerebral Cortex of Rats with Different Levels of Resistance to Emotional Stress in Conditions of Exposure to Delta Sleep-Inducing Peptide

Wistar rats with different levels of resistance to emotional stress (ES) were subjected to stress and brain sections stained with Nissl cresyl violet were used for quantitative analysis of the structural organization of neurons in layer V of the sensorimotor cortex. Some animals received delta sleep-inducing peptide (DSIP) 1 h before stress. Control ES-susceptible rats, as compared with resistant rats, had lower levels of normochromic and moderately hypochromic neurons. Normochromic neurons were not seen after stress. Rats susceptible to ES showed particularly sharp decreases in moderately hypo- and hyperchromic neurons, along with increases in the proportions of extremely hypo- and hyperchromic neurons, ghost cells, and ischemically altered cells. After administration of DSIP before stress, ischemically altered cells were not seen in any group: the level of reduction of extremely hyperchromic neurons was smaller in ES-susceptible rats than in ES-resistant rats. It is suggested that brain hypoxia plays a particular role in disorganizing the cortex in conditions of ES, while DSIP has both antistress and antihypoxic properties.     

Delta sleep-inducing peptide as a factor increasing the content of substance P in the hypothalamus and the resistance of rats to emotional stress

The influence of delta sleep-inducing peptide (DSIP, 60 and 120 nmolelkg, intraperitoneally) on the content of substance P (SP) in the hypothalamus of rats was studied in male rats of the August line. It was demonstrated that the administration of DSIP significantly increases the average content of SP in the hypothalamus, as well as its content in animals resistant to and predisposed to emotional stress. A daily one-time administration of DSIP before placing the rats in conditions of stress increases the content of SP in the hypothalamus which was decreased during emotional stress. The preliminary one-time administration of DSIP to animals subjected to a Stressor influence also increases the SP content in the hypothalamus. It was established that a one-time administration of DSIP in a dose of 60 nmolelkg sharply decreases the classical manifestations of stress such as the hypertrophy of the adrenals and involution of the thymus.Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I. P. Pavlova, Vol. 41, No. 3, pp. 558–563, May–June, 1991.     

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

We studied the effects of immunomodulatory cytokine interleukin-1β on lipid peroxidation in emotiogenic structures of the brain (hypothalamus, sensorimotor cortex, and amygdala) of behaviorally active and passive rats with different prognostic resistance to stress. Immobilization of animals with simultaneous electrocutaneous stimulation (1 h) served as the model of acute emotional stress. Intraperitoneal injection of IL-1β (5 μg/kg) was followed by accumulation of malonic dialdehyde (end-product of lipid peroxidation) in all structures of the brain in passive rats, as well as in the hypothalamus of active animals. As differentiated from active rats, stress exposure in passive specimens was accompanied by a selective increase in malonic dialdehyde content in the sensorimotor cortex and amygdala. Pretreatment with IL-1β prevented activation of lipid peroxidation in the studied structures of the brain in passive rats after stress exposure. Our results show the specifi c effect of IL-1β on free-radical processes in the hypothalamus, sensorimotor cortex, and amygdala in rats with various behavioral parameters. Regional features of lipid peroxidation in emotiogenic structures of the brain in animals with different emotional reactivity probably contribute to the existence of signifi cant variations in the individual resistance to emotional stress.     

Pathological changes in the reproductive tract of male rhesus monkeys associated with age and simian AIDS.

The pathological changes associated with ageing and simian immunodeficiency virus (SIV) infection in groups of immature, adult and ageing Rhesus monkeys were studied. Eighty three per cent (5 of 6) of uninfected ageing animals had hyperplasia of the prostate, 33 per cent (2 of 6) had mild prostatitis and in 66 per cent (4 of 6) there were calcified concretions in the seminal vesicles. The testes were normal and showed active spermatogenesis. In the SIV-infected animals, two types of lesion occurred; the most common, in 81 per cent (18 of 22 monkeys), was the presence of focal lymphoid infiltrations in the epididymis, prostate or seminal vesicles. The other was hypospermatogenesis (23 per cent, 4 of 17) with degeneration of seminiferous tubules. Immunocytochemical staining demonstrated that the lymphoid masses contained approximately equal numbers of B and T lymphocytes, but the majority of diffusely scattered cells were T lymphocytes. Staining for SIV antigen identified small numbers of positive lymphocytes and macrophages in all tissues.     

Duration dependent effect of chronic stress on primary and secondary lymphoid organs and their reversibility in rats

The present study was undertaken to investigate whether or not chronic stress effect and its reversibility on lymphoid organs is duration dependent. Male rats were exposed to restraint (1?h) followed by a gap of 4?h to forced swimming exercise (15?min) daily for 2, 4 and 8 weeks. After each exposure period, rats were allowed to recover for 6 weeks. Stress exposure resulted in duration dependent decreases in weight of thymus and axillary lymph nodes, lymphocyte counts of spleen, thymus and axillary lymph nodes and number of islets of white pulp of spleen and increases in apoptotic index of splenocytes, thymocytes and lymphocytes of axillary lymph nodes. All the parameters of lymphoid organs studied showed significant alterations in 2 weeks of stress exposure indicated their sensitivity to stress effects in short term exposure and thymus was the most sensitive organ among all. The alterations in all the parameters of spleen and majority of parameters of thymus and axillary lymph nodes returned to control level in recovery group rats of 2 and 4 weeks exposure but not in that of 8 weeks exposure. The present study for the first time reveal that severity of stress effects on lymphoid organs increases with increasing duration of exposure and shorter the exposure period faster the recovery. In addition, an in vitro study showed that corticosterone caused apoptosis of thymocytes, splenocytes and lymphocytes of axillary lymph nodes in dose dependent manner. Thus corticosterone induced death of cells of lymphoid organs under stress is the major cause of involution of lymphoid organs.     

Modulating Effect of Interleukin-4 on Free Radical Processes in the Brain of Rats during Emotional Stress

We studied the effect of anti-inflammatory cytokine IL-4 on the intensity of free radical processes in emotiogenic brain structures (hypothalamus, sensorimotor cortex, and amygdala) in rats with different prognostic emotional resistance. One-hour immobilization of animals with simultaneous electrocutaneous stimulation was used as a model of acute stress. The stress was accompanied by accumulation of MDA (LPO end-product) in the sensorimotor cortex and amygdala of passive rats. Intraperitoneal administration of IL-4 (5 μg/kg) increased MDA content in the amygdala and hypothalamus of non-stressed rats with different behavioral activity. In the sensorimotor cortex of passive and, especially, active rats, a decrease in MDA level was observed after injection of this cytokine. Preliminary administration of IL-4 prevented LPO activation in the sensorimotor cortex of behaviorally passive animals observed after stress against the background of saline injection. Regional peculiarities of LPO under the influence of this cytokine can be determined by differences in both biochemical processes in the brain tissue and specific involvement of different emotiogenic structures in the formation of the stress response. The revealed differences in the effects of IL-4 on free radical processes in active and passive rats indicate peculiarities of immune mechanisms in animals with different resistance to the same type of stress.     

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

We studied the effect of acute emotional stress and exogenous IL-1β (5 μg/kg intraperitoneally) on the cytokine profile of blood serum in Wistar rats with various behavioral characteristics in the open-field 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 significant differences in the cytokine profile of blood serum under conditions of emotional stress and treatment with IL-1β. These data illustrate the specific functional features of immune mechanisms, which provide an individual resistance of rats to the same stress exposure.     

Image analysis of cell proliferation in rat thymus throughout development

A System for Analytical Microscopy in Biological Applications (SAMBA 200) was used to digitize, process and statistically analyze the cell proliferation of rat lymphoid cells throughout thymus development. This cytometric study shows that lymphoid cell proliferation starts in 14-day-old embryos, remains high throughout embryogenesis with a maximum around day 18, decreases after birth then rises again in 21-day-old rats, after which proliferation decreases gradually with age, this decrease appears even before the onset of the sexual maturation, and is very marked in 2-year-old animals. Image cytometry analysis makes it possible to distinguish 5 lymphoid cell subpopulations (lymphoid stem-cells, lymphoblasts, large lymphocytes, medium lymphocytes, and small lymphocytes), and to discriminate in each cycling and non-cycling cells. The S-fraction of the lymphoid stem-cells decreases in 16-day-old rats, while the S-fraction of the lymphoblasts increases rapidly during the embryonic period. The large lymphocytes show the highest S-fraction at the stage E18, while the medium lymphocytes show the more stable S-fraction. The S-fraction variation for small lymphocytes can be divided into three periods: 1. up to E16 (S-fraction increases rapidly); 2. between newborn and 21 days (S-fraction increases slowly and irregularly); 3. after 21 days (S-fraction decreases progressively).     

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

We compared the effect of a pro-inflammatory cytokine IL-1β and anti-inflammatory cytokine IL-4 on the state of stress-marker organs in rats with various behavioral characteristics in the open-field test. Intraperitoneal injection of the cytokines was followed by a slight decrease in the relative weight of the thymus, adrenal glands, and spleen in behaviorally active and, especially, in passive animals. These changes are probably associated with the effect of the test immunomodulators on apoptosis and migration of cells of the immunocompetent organs. Pretreatment with IL-1β and IL-4 was shown to prevent involution of the thymus and spleen in rats during acute stress on the model of immobilization with simultaneous electrocutaneous stimulation. Hence, these cytokines have the same effects on functional state of stressmarker organs in animals. IL-1β and IL-4 have a greater effect in passive rats than in active specimens, which reflects specific features of immune mechanisms in animals with different emotional reactivity.     

Lymphomatoid granulomatosis: a clinicopathologic study of 42 patients

We studied the histological and clinicopathological findings in 42 patients who had lymphomatoid granulomatosis (LYG). In addition to small round lymphocytes, small to intermediate lymphocytes with serpentine nuclei, large immature mononuclear lymphoid cells, abundant histiocytes, and vascular invasion by the cell infiltrate were observed in all cases. Fifty percent of lesions had occasional "atypical" cells with multi-lobed nuclei. Three of four follow-up autopsies showed large cell lymphoma, while one other autopsy and the single repeat biopsy showed increased numbers of large immature mononuclear lymphoid cells. Patients were most frequently men 40-60 yr old who had a history of pulmonary symptoms, such as cough or chest pain, and who showed multiple bilateral lung nodules without hilar adenopathy in the chest x-ray. Thirteen patients (38%) died of disease, 11 of them within 12 mth of initial diagnosis. The presence of neurological signs and symptoms, increased mitoses, or increased numbers of atypical multi-nucleated cells in the initial biopsy were not statistically significant predictors of survival.     

Phenotypic analysis of lymphocyte populations in the lungs and regional lymphoid tissue of sheep naturally infected with maedi visna virus.

We have analysed the phenotype of lymphocytes in lung and regional lymph node of symptomatic and asymptomatic sheep infected with the ovine lentivirus, maedi visna virus (MVV). Compared to equivalent tissues from age-matched, non-infected controls, MVV-infected sheep show increased numbers of lymphocytes in the lung, both in the bronchus-associated lymphoid tissue (BALT) and in the alveolar septae. Both CD8+ and CD4+ T lymphocyte numbers in alveolar septae were increased, particularly in animals with clinical respiratory disease. The ratio of CD8+ to CD4+ lymphocytes was similar to that in normal lung. In both MVV-infected and uninfected animals a high proportion of pulmonary lymphocytes, particularly in the alveolar septae, did not express the CD5 antigen, suggesting that they were activated. The number of activated cells was higher in infected sheep. Variable numbers of alveolar macrophages containing MVV-core protein were present in alveolar lumina, the majority of positive cells showing morphological evidence of activation. In regional lymphoid tissue there were increased numbers of CD8+ and gamma delta expressing T cells in lymphoid follicles and germinal centres of infected animals. The specificity of these cells is unknown and we could find no evidence for the presence of cells productively infected with the virus in these structures. This study shows that activated T lymphocytes, particularly of the CD8 subset, play a major part in the pathogenesis of MVV-induced pulmonary and regional lymph node lesions.     

Biochemical Indexes of the Skin and Blood Melatonin Concentration in Rats during Acute Stress and Treatment with Exogenous Melatonin

We studied the effect of acute stress on serum melatonin concentration, content of major components in the connective tissue (uronic acids, hexosamines, and hydroxyproline), and beta-galactosidase activity in the skin of rats with different activity in the open-field test receiving intraperitoneal injections of physiological saline or melatonin. Acute stress intensified catabolism of carbohydrate components and affected characteristics of the main skin biopolymers. The content of uronic acids in connective tissue carbohydrates decreased. Collagen structures of the skin underwent less pronounced changes. The observed changes were similar in behaviorally active and passive animals. Administration of melatonin increased the contents of uronic acids and hexosamines in the skin. Pretreatment with melatonin prevented the decrease in the content of glycosaminoglycans in rat skin during acute stress.     

Changes produced by pertussis antigen on the blood cells and lympho-haemapoietic tissues after early and late thymectomy or splenectomy

The effect of thymectomy and splenectomy in C3H/Bi mice on the responses of circulating leucocytes and on morphological changes of the haematopoietic tissues after injection of pertussis vaccine has been studied.

After pertussis all mice showed depletion of lymphoid cells in all the lymphoid organs as well as in bone-marrow and an increased number of leucocytes, lymphocytes, neutrophils and monocytes in the circulation. Neonatal thymectomy decreased lymphocytosis produced by pertussis. Thymectomy, at all ages studied, fostered an increase in the number of monocytes and polymorphonuclears in circulation. Splenectomy at birth or early in life provoked an increase in levels of circulating polymorphonuclears and lymphocytes in pertussis treated animals.

In neonatally thymectomized mice the depletion of lymphoid cells from lymphoid tissues after pertussis could be shown to include the thymic-independent areas. The depletion of small lymphocytes from thymus following pertussis persisted longer than depletion of small lymphocytes from spleen, marrow or lymph nodes. The longer persistence of lymphoid depletion in the thymus than in peripheral lymphoid tissues is, we believe, to be related to the central lymphoid function of thymus as a site of differentiation of lymphoid cells and to the aloofness of thymus from recirculation of fully differentiated peripheral lymphocytes.

     

Lymphoid structure of the spleen in rats exposed to acute emotional stress

The objects of this investigation were the sections of the spleen and peripheral blood smears of 40 male Wistar rats of control and experimental groups that were stained using histological and histochemical methods. The rats of experimental groups were killed by decapitation immediately after discontinuation of an emotional stress (exposure to a combination of immobilization and electric skin stimulation for one hour). The changes of cellular composition and cytoarchitectonics of different functional zones of the spleen were estimated. It was found that following the emotional stress the number of small lymphocytes in the periarterial lymphoid sheath (PALS) decreased as compared to that one in control groups. At the same time, the amount of cells in PALS with the signs of destruction increased (from single cells in the animals of control groups to 7.7 and 1.5% in rats of the experimental groups that were predisposed or resistant to stress, respectively). The proportion of T-lymphocytes per PALS unit area in the spleen of experimental rats, predisposed or resistant to stress, decreased 1.6 and 1.2 times, respectively, in comparison to the control groups.     

The differentiation of murine thymocytes in vivo and in vitro.

The differentiation of lymphoid cells in the early foetal mouse thymus was studied in vivo and in organ culture. The lymphoid precursors found in the 13 and 14 day foetal thymus constituted about 50% of the total thymus cell population. These T precursors were large blast-like cells which already expressed the Thy-1 antigen but were mostly TL negative. Both in vivo and in vitro the blasts were rapidly replaced by a population of typical small lymphocytes which were strongly Thy-1 and TL positive but Ig negative. In organ cultures grown under optimal conditions, large bimodal increases in cell numbers occurred. An initial population of about 2 x 10(4) T precursors per thymus lobe gave rise to nearly 10(6) predominantly Thy-1 and TL positive small lymphocytes by the 6--8th day in vitro. After this time lymphocyte numbers decreased until about the 10th day when they again increased to form a second peak of small lymphocytes on the 12--13th day. These cells were also predominantly Thy-1 positive but the majority were now TL negative. No Ig positive B lymphocytes were detected either by immunofluorescence or by autoradiography using polyvalent anti-MIg sera and no plasma cells were detected by electronmicroscopy. At all times however, minor subpopulations of Thy-1 negative small cells were present. The production of small lymphocytes during the 1st week of culture was critically dependent on culture conditions and particularly on the batch of FCS used. The population developing during the 2nd week required less stringent conditions and was less dependent on FCS. The culture systems described should prove useful in the study of T-lymphocyte differentiation.