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Objective: The present study analyzed the effects of lipopolysaccharide (LPS) on maternal behavior during lactation and possible correlations with changes in emotional and immune responses in offspring. Methods: Lactating rats received 100 μg/kg LPS, and the control group received saline solution on lactation day (LD) 3. Maternal general activity and maternal behavior were observed on LD5 (i.e. the day that the peak of fever occurred). In male pups, hematological parameters and ultrasonic vocalizations (USVs) were assessed on LD5. At weaning, an additional dose of LPS (50 µg/kg, i.p.) was administered in male pups, and open-field behavior, oxidative burst and phagocytosis were evaluated. Results: A reduction in the time in which dams retrieved the pups was observed, whereas no effects on maternal aggressive behavior were found. On LD5, a reduction of the frequency of USVs was observed in pups, but no signs of inflammation were found. At weaning, an increase in immune system activity was observed, but no differences in open-field behavior were found. Conclusion: These results indicate that inflammation in lactating mothers disrupted mother/pup interactions and may have produced short- and long-term effects on pup behavior as well as biological pathways that modulate inflammatory responses to bacterial endotoxin challenge in pups. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The present study was designed to evaluate the effects of mice cohabitation with a sick conspecific cage mate on peritoneal macrophage activity and on resistance to Ehrlich tumor growth. Female mice housed in pairs were divided into control and experimental groups. One mouse of each control pair was inoculated with NaCl (0.1 ml/10 g) intraperitoneally and the other, called ‘companion of healthy partner’ (CHP), was kept undisturbed. One animal of each experimental pair of mice was inoculated with 5.0 × 106 Ehrlich tumor cells intraperitoneally and the other, the subject of this study, was called ‘companion of sick partner’ (CSP). Peritoneal macrophages were removed from CSP and CHP mice to analyze resident macrophage activity (experiment 1), macrophage activity after Mycobacterium bovis (experiment 2) or Ehrlich tumor cells (experiment 3) in vivo inoculations. The resistance of CSP and CHP mice to Ehrlich tumor growth was also analyzed (experiment 4). Differences between groups were not found on resident macrophage activity. However, Onco-BCG- and Ehrlich tumor-activated macrophages from CSP mice presented a decreased intensity and percentage of phagocytosis and an increased respiratory burst in the presence of Staphylococcus aureus stimulation in vitro. CSP animals at the same time displayed a decreased resistance to Ehrlich tumor growth. These data were discussed in light of a possible psychological stress effect imposed by the housing condition on mice’s peritoneal macrophage activity and, as a consequence, on their resistance to Ehrlich tumor growth. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

This study reviews the neuroimmunological consequences elicited in mice from long-term cohabitation with tumor-bearing conspecifics. Two types of experiments were performed; one used Swiss female mice and Ehrlich tumor cells, and the other used C57Bl/6 female mice and B16F10 melanoma cells. The female Swiss mice and the C57Bl/6 mice were divided into two groups, i.e., control and experimental. One mouse in each control pair was treated with control solutions (1.0 mL/kg); the other was kept undisturbed and called the 'companion of health partner' (CHP). One mouse in each experimental pair was inoculated with 5 x 10(6) Ehrlich tumor cells or with 10(6) murine B16-F10 melanoma cells; the other mouse, which was the subject of the performed studies, was left undisturbed and called the 'companion of sick partner' (CSP). Although we used two different strains of mice and two different tumor types, the CSP mice presented, in relation to the CHP mice, an increased locomotion in the open field and plus maze apparatuses and no changes in the corticosterone serum levels before and after the immobilization-stress challenge. The Swiss CSP mice showed a reduced level and an increased turnover rate of hypothalamic noradrenaline (NE), as well as increased plasmatic levels of adrenaline and NE. Changes in the immune cell phenotype and activity were also observed in the Swiss and C57Bl/6 CSP mice. The study found that odor cues left by the Ehrlich tumor-injected Swiss mice are aversive and may therefore be responsible for the neuroimmune changes reported in the CSP mice. It is proposed that the final neural link between the neuroimmunological changes observed in the CSP mice involves psychogenic stress imposed by the housing condition and the activation of the brain catecholaminergic pathways and the sympathetic nervous systems.

Objective: Several papers arriving from the neuroimmunomodulation field are showing the relevant relationships between the nervous and the immune systems. A review of studies was carried out to describe the bases of the studies on neuroimmunomodulation., Experimental Models: It is clear nowadays that emotional states such as anxiety and depression change immune system activity, an affect also observed after both stress and use of nervous system acting drugs., Sick Behavior: The behavior displayed by sick organisms might be thought as being a consequence of homeostatic strategies., Possible Mechanism of the Action by Means of Immune System to Nervous System: A very big emphasis is being given to Hipothalamus-pituitary-adrenal axis, sympathetic nervous system and cytokines participation on nervous system and immune system relationships., Conclusion: The present revision intend to show some essential studies in the neuroimmunomodulation field; it makes a critical analysis of the mutual relationships between nervous system and immune system.