Th1/Th2 balance induced by chronic stress exposition is related to different vulnerability to stress effects in BALB/c and C57BL/6 mice.

M.L. PALUMBO; M.C. CANZOBRE; H. RÍOS; M. WALD; A.M. GENARO

Cuidad Autónoma de Buenos Aires, Bs As, Argentina

Congreso; 3nd Iberoamerican Congress on Neuroimmunomodulation.; 2009

Organizado por la International Society for Neuroimmunomodulation.

Stress and Th1/Th2 balance were implicated in psychiatric disorders. Moreover, two genetically different inbred strains of mice, C57BL/6 and BALB/c, with different Th1/Th2 balance show distinct behavioral responses, neurodevelopment and neurochemistry parameters. Here, we perform a comparative study on chronic mild stress (CMS) effects upon learning and memory and immunity in both strains. We demonstrated that stressed BALB/c, but not C57Bl/6 mice, showed a poor learning performance in both open field and Y-maze. Also, CMS induced a decrease in number of neurons and thickness on hippocampus of BALB/c mice, but not in C57BL/6 hippocampus. Reactive oxygen species production was increased in hippocampus of CMS-exposed BALB/c but not in C57BL/6. Also, stressed BALB/c mice showed a diminution of T-cell and an increase of B-cell proliferation. Lymphocytes from CMS-exposed BALB/c mice showed an increased Th2-type cytokines production (IL-6 and IL-10). However, lymphocytes from CMS-exposed C57BL/6 mice had an increase in T-cell proliferation without changes in B-cell proliferation. Also, these lymphocytes showed a higher Th1-type cytokine release (INF-gamma and IL-2). These results suggest a differential effect of stress, being BALB/c more vulnerable to cognitive deficit associated to stress exposition than C57BL/6 mice associated to a differential regulation of TH1/ TH2 cytokine balance.