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Cohabitation with a sick cage mate: effects on ascitic form of Ehrlich tumor growth and macrophage activity
Glaucie Jussilane Alves1, Luciana Vismari, João Palermo-Neto
1Laboratory of Applied Pharmacology and Toxicology, School of Veterinary Medicine, University of São Paulo, São Paulo, Brazil.
Abstract:
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 x 10(6) 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.
Insights
Cohabitation with a sick mouse impaired peritoneal macrophage function and reduced tumor resistance in healthy mice. This suggests psychological stress may impact immune response and cancer progression.
Area of Science:
- Immunology
- Animal Behavior
- Oncology
Background:
- Peritoneal macrophages play a crucial role in immune surveillance and tumor resistance.
- Understanding factors influencing macrophage activity is vital for developing effective cancer therapies.
Purpose of the Study:
- To investigate the impact of cohabiting with a sick conspecific on peritoneal macrophage activity.
- To assess the effect of this housing condition on resistance to Ehrlich tumor growth in mice.
Main Methods:
- Female mice were paired, with one serving as a control (companion of healthy partner - CHP) and the other exposed to either saline or Ehrlich tumor cells (companion of sick partner - CSP).
- Peritoneal macrophages were analyzed for activity, phagocytosis, and respiratory burst.
- Tumor growth resistance was evaluated in CSP and CHP mice.
Main Results:
- No differences in resident macrophage activity were observed between groups.
- Macrophages from CSP mice showed decreased phagocytosis and increased respiratory burst after activation with Onco-BCG and Ehrlich tumor cells.
- CSP mice exhibited reduced resistance to Ehrlich tumor growth.
Conclusions:
- Cohabitation with a sick cage mate, potentially due to psychological stress, can impair peritoneal macrophage function.
- This impairment in immune cell activity may lead to decreased resistance to tumor growth.
