Adriano Zager

Maternal immune activation in late gestation enhances locomotor response to acute but not chronic amphetamine treatment in male mice offspring: role of the D1 receptor.

Exposure to elevated levels of maternal cytokines can lead to functional abnormalities of the dopaminergic system in the adult offspring, including enhanced amphetamine (AMPH)-induced locomotion. Therefore, it seems reasonable to consider that offspring of challenged mothers would behave differently in models of addictive behavior, such as behavioral sensitization. Thus, we sought to evaluate the effects of prenatal exposure to lipopolysaccharide (LPS) on the locomotor response to acute and chronic AMPH treatment in male mice offspring. For this purpose, LPS (Escherichia coli 0127:B8; 120 μg/kg) was administered intraperitoneally to pregnant Swiss mice on gestational day 17. At adulthood, male offspring were studied under one of the following conditions: (1) locomotor response to acute AMPH treatment (2.5 or 5.0 mg/kg) in an open field test; (2) behavioral sensitization paradigm, which consists of a daily injection of AMPH (1.0 mg/kg) for 10 days and observation of locomotion in the open field on days 1, 5, 10 (development phase), 15 and 17 (expression phase). The LPS stimulated offspring showed enhancement of the locomotor-stimulant effect after an acute AMPH challenge in comparison to baseline and saline pre-treated mice. They also showed development of behavioral sensitization earlier than the saline pre-treated group, although no changes between saline and LPS pre-treated groups were observed on development or expression of locomotor behavioral sensitization to AMPH. Furthermore, there was up-regulation of D1 receptor protein level within striatum in the LPS-stimulated offspring which was strongly correlated with increased grooming behavior. Taken together, our results indicate that motor and dopaminergic alterations caused by maternal immune activation are restricted to the acute AMPH challenge, mostly due to up-regulation of the D1 receptor within the mesolimbic and nigrostriatal pathways, but no locomotor differences were observed for behavioral sensitization to AMPH.

Maternal immune activation in late gestation increases neuroinflammation and aggravates experimental autoimmune encephalomyelitis in the offspring.

Multiple sclerosis (MS) is characterized by an autoimmune response against myelin antigens driven by autoreactive T cells. Several lines of evidence indicate that environmental factors, such as previous infection, can influence and trigger autoimmune responses. However, the importance of the gestational period, particularly under inflammatory conditions, on the modulation of MS and related neuroinflammation by the offspring is unknown. This study aimed to evaluate the impact of prenatal exposure to lipopolysaccharide (LPS) during late gestation on the neuroinflammatory response in primary mixed glial cultures and on the progression of experimental autoimmune encephalomyelitis (EAE, an animal model of MS) in the offspring. LPS (Escherichia coli 0127:B8, 120μg/kg) was administered intraperitoneally to pregnant C57BL/6J mice on gestational day 17, and the offspring were assigned to two experiments: (1) mixed glial cultures generated using the brain of neonates, stimulated in vitro with LPS, and (2) adult offspring immunized with MOG35-55. The EAE clinical symptoms were followed for 30days. Different sets of animals were sacrificed either during the onset (7days post-immunization [p.i.]), when spleen and lymph nodes were collected, or the peak of disease (20days p.i.), when CNS were collected for flow cytometry, cytokine production, and protein/mRNA-expression analysis. The primary CNS cultures from the LPS-treated group produced exaggerated amounts of IL-6, IL-1β and nitrites after in vitro stimulus, while IL-10 production was lowered compared to the data of the control group. Prenatal exposure to LPS worsened EAE disease severity in adult offspring, and this worsening was linked to increased CNS-infiltrating macrophages, Th1 cells and Th17 cells at the peak of EAE severity; additionally, exacerbated gliosis was evidenced in microglia (MHC II) and astrocytes (GFAP protein level and immunoreactivity). The IL-2, IL-6 and IL-17 levels in the spleen and lymph nodes were increased in the offspring of the LPS-exposed dams. Our results indicate that maternal immune activation during late gestation predispose the offspring to increased neuroinflammation and potentiate the autoimmune response and clinical manifestation of EAE.

Short-term social isolation induces depressive-like behaviour and reinstates the retrieval of an aversive task: mood-congruent memory in male mice?

BACKGROUND Although mood-congruent memory (MCM), or the tendency to recall information consistent with ones mood, is a robust phenomenon in human depression, to our knowledge, it has never been demonstrated in animals. METHODS Mice were subjected to social isolation (SI) or crowding for 12 hours and had their depressive-like behaviour (evaluated by the forced swim, tail suspension, sucrose preference and splash tests) or their serum corticosterone concentrations evaluated. In addition, we determined the temporal forgetting curve of the plus-maze discriminative avoidance task (PM-DAT) and examined the effects of SI or crowding on memory retrieval in the PM-DAT. Finally, we verified the effects of metyrapone pretreatment on reinstatement of memory retrieval or on the increase of corticosterone levels induced by SI. RESULTS Twelve hours of SI produced depressive-like behaviour, enhanced corticosterone concentration and reinstated retrieval of a forgotten discriminative aversive (i.e., negatively valenced) task. Depressive-like behaviour was critical for this facilitative effect of SI because 12 hours of crowding neither induced depressive-like behaviour nor enhanced retrieval, although it increased corticosterone levels at the same magnitude as SI. However, corticosterone increase was a necessary condition for MCM in mice, in that the corticosterone synthesis inhibitor metyrapone abolished SI-induced retrieval reinstatement. LIMITATIONS Our study did not investigate the effects of the social manipulations proposed here in a positively valenced task. CONCLUSION To our knowledge, the present paper provides the first evidence of MCM in animal models.

Sleep Deprivation Increases Mortality in Female Mice Bearing Ehrlich Ascitic Tumor

Objectives: Sleep deprivation is a growing public health hazard, yet it is still under-recognized. Sleep disorders and disruption of sleep patterns may compromise the immune function and adversely affect host resistance to infectious diseases. This is a particular risk in cancer patients, who report a high frequency of sleep disturbances. The present study investigated the effects of sleep deprivation on the development of Ehrlich ascitic tumors (EAT) in female BALB/c mice. Our study also evaluated whether EAT would induce alterations in sleep pattern. Spleen lymphocyte cell populations and mortality were also quantified. Methods: Female BALB/c mice were intraperitoneally inoculated with EAT cells. Immediately after the inoculation procedure, animals were sleep deprived for 72 h. Ten or 15 days after inoculation, the number of tumoral cells was quantified and the lymphocytic cell population in the spleen was characterized by flow cytometry. In addition, the effect of sleep deprivation on EAT-induced mortality was quantified and the influence of EAT on sleep patterns was determined. Results: Sleep deprivation did not potentiate EAT growth, but it significantly increased mortality. Additionally, both EAT and sleep deprivation decreased frequencies of splenic CD4+, CD8+ and CD19+ cells. With respect to sleep patterns, EAT significantly enhanced paradoxical sleep time. Conclusions: Although sleep deprivation did not potentiate EAT growth, it decreased the survival of female tumor-bearing mice.

Short-term sleep deprivation reinstates memory retrieval in mice: the role of corticosterone secretion.

While the effects of sleep deprivation (SD) on the acquisition and consolidation phases of memory have been extensively characterized, its effects on memory retrieval remain overlooked. SD alone is a stressor, and stress-activated glucocorticoids promote bimodal effects on memory. Because we have recently demonstrated that 72h SD impairs memory retrieval in the plus-maze discriminative avoidance task (PM-DAT) in mice, this study investigated whether shorter SD periods would facilitate retrieval. In Experiment I, the temporal forgetting curve of the PM-DAT was determined and an interval between training/testing in which retrieval was no longer present was used in all subsequent experiments. In Experiments II and III, retrieval performance and corticosterone concentration, respectively, were quantified in mice that were sleep deprived for 12 or 24h before testing. In Experiments IV and V, the effects of the corticosterone synthesis inhibitor metyrapone were evaluated on 12h SD-induced retrieval reinstatement and corticosterone concentration enhancement, respectively. Experiment VI determined whether pre-test acute administration of exogenous corticosterone would mimic the facilitatory effects of 12h SD on retrieval. Thirty days after training, mice presented poor performance of the task; however, SD for 12h (but not for 24) before testing reinstated memory retrieval. This facilitatory effect was accompanied by increased corticosterone concentration, abolished by metyrapone, and mimicked by pre-test acute corticosterone administration. Collectively, short-term SD can facilitate memory retrieval by enhancing corticosterone secretion. This facilitatory effect is abolished by longer periods of SD.

Increased cell-mediated immunity in male mice offspring exposed to maternal immune activation during late gestation

Early life experiences, particularly during the gestational period, are homeostatic determinants for an individuals brain development. However, recent data suggest that the immune response of the offspring is also affected by events during the gestational period. Here, we evaluated the impact of prenatal immune activation on the innate and adaptive immune responses of adult offspring. Pregnant Swiss mice received saline or lipopolysaccharide (LPS) on gestational day 17. In adulthood, male offspring were analyzed using 2 experimental techniques: in vitro analysis of cytokine production and immune cell activity and development of the delayed-type hypersensitivity (DTH) responses of ovalbumin-sensitized mice. We analyzed Th1/Th2/Th17 cytokine production in vitro, neutrophil and dendritic cell function, and the DTH response. Offspring from LPS-treated dams displayed increased cell-mediated immunity as indicated by increased IL-12 production by cultured antigen-presenting cells and an enhanced DTH response as well as impaired production of the regulatory cytokine IL-10. This study provides new insights regarding the influence of immune activation during late gestation on the immunological homeostasis of offspring, particularly on Th1 immunity.

The wake-promoting drug Modafinil prevents motor impairment in sickness behavior induced by LPS in mice: Role for dopaminergic D1 receptor

&NA; The wake‐promoting drug Modafinil has been used for many years for treatment of Narcolepsy and Excessive Daytime Sleepiness, due to a dopamine‐related psychostimulant action. Recent studies have indicated that Modafinil prevents neuroinflammation in animal models. Thus, the aim of the present study was to evaluate the effect of Modafinil pretreatment in the Lipopolysaccharide (LPS)‐induced sickness and depressive‐like behaviors. Adult male C57BL/6J mice were pretreated with Vehicle or Modafinil (90 mg/Kg) and, 30 min later, received a single saline or LPS (2 mg/Kg) administration, and were submitted to the open field and elevated plus maze test 2 h later. After 24 h, mice were subjected to tail suspension test, followed by either flow cytometry with whole brain for CD11b+CD45+ cells or qPCR in brain areas for cytokine gene expression. Modafinil treatment prevented the LPS‐induced motor impairment, anxiety‐like and depressive‐like behaviors, as well as the increase in brain CD11b+CD45high cells induced by LPS. Our results indicate that Modafinil pretreatment also decreased the IL‐1&bgr; gene upregulation caused by LPS in brain areas, which is possibly correlated with the preventive behavioral effects. The pharmacological blockage of the dopaminergic D1R by the drug SCH‐23390 counteracted the effect of Modafinil on locomotion and anxiety‐like behavior, but not on depressive‐like behavior and brain immune cells. The dopaminergic D1 receptor signaling is essential to the Modafinil effects on LPS‐induced alterations in locomotion and anxiety, but not on depression and brain macrophages. This evidence suggests that Modafinil treatment might be useful to prevent inflammation‐related behavioral alterations, possibly due to a neuroimmune mechanism. HighlightsModafinil prevents sickness and depressive‐like behavior induced by LPS in mice.This effect is correlated with infiltration of macrophages in the brain.D1R blockage prevents Modafinil effects on sickness, but not on depressive behavior.

Maternal immune activation increases the corticosterone response to acute stress without affecting the hypothalamic monoamine content and sleep patterns in male mice offspring.

Background/Aims: Early life experiences are homeostatic determinants for adult organisms. We evaluated the impact of prenatal immune activation during late gestation on the neuroimmune-endocrine function of adult offspring and its interaction with acute stress. Methods: Pregnant Swiss mice received saline or lipopolysaccharide (LPS) on gestational day 17. Adult male offspring were assigned to the control or restraint stress condition. We analyzed plasmatic corticosterone and catecholamine levels, the monoamine content in the hypothalamus, striatum and frontal cortex, and the sleep-wake cycle before and after acute restraint stress. Results and Conclusion: Offspring from LPS-treated dams had increased baseline norepinephrine levels and potentiated corticosterone secretion after the acute stressor, and no effect was observed on hypothalamic monoamine content or sleep behavior. The offspring of immune-activated dams exhibited impairments in stress-induced serotonergic and dopaminergic alterations in the striatum and frontal cortex. The data demonstrate a distinction between the plasmatic levels of corticosterone in response to acute stress and the hypothalamic monoamine content and sleep patterns. We provide new evidence regarding the influence of immune activation during late gestation on the neuroendocrine homeostasis of offspring.

Sleep Deprivation Alters Rat Ventral Prostate Morphology, Leading to Glandular Atrophy: A Microscopic Study Contrasted with the Hormonal Assays

We investigated the effect of 96 h paradoxical sleep deprivation (PSD) and 21-day sleep restriction (SR) on prostate morphology using stereological assays in male rats. After euthanasia, the rat ventral prostate was removed, weighed, and prepared for conventional light microscopy. Microscopic analysis of the prostate reveals that morphology of this gland was altered after 96 h of PSD and 21 days of SR, with the most important alterations occurring in the epithelium and stroma in the course of both procedures compared with the control group. Both 96 h PSD and 21-day SR rats showed lower serum testosterone and higher corticosterone levels than control rats. The significance of our result referring to the sleep deprivation was responsible for deep morphological alterations in ventral prostate tissue, like to castration microscopic modifications. This result is due to the marked alterations in hormonal status caused by PSD and SR.

Repeated Domperidone treatment modulates pulmonary cytokines in LPS-induced acute lung injury in mice

&NA; The dopaminergic antagonist drug Domperidone has immunomodulatory effects. We investigated the effects of repeated Domperidone treatment in a model of Lypopolyssacharide (LPS)‐induced acute lung inflammation. Adult C57BL/6J mice were treated with either Vehicle or Domperidone for 5 days, and challenged intranasally with LPS in the following day. The behavior of mice was analyzed in the open field and elevated plus‐maze test before and 24 h after LPS challenge. The bronchoalveolar lavage fluid, blood and lung tissue were collected 24 h and 48 h after LPS challenge. Domperidone treatment increased LPS‐induced tumor necrosis factor (TNF) and interleukin (IL)‐6 production in the bronchoalveolar lavage fluid, without altering tissue damage and the number of immune cells in the lungs and circulation. Locomotor and anxiety‐like behavior were unchanged after Domperidone and/or LPS treatment. Cytokine data indicate that Domperidone promotes a change in activity of other cell types, likely alveolar epithelial cells, without affecting immune cell migration in the present model. Due to the role of these cytokines in progression of inflammation, Domperidone treatment may exacerbate a subsequent inflammatory injury.