Effect of environmental enrichment on the immunoendocrine aging of male and female triple-transgenic 3xTg-AD mice for Alzheimer's disease.

We have previously shown that 3xTgAD mice (triple-transgenic mice for Alzheimer's disease, harboring PS1(M146V), AβPP(Swe), tau(P301L) transgenes) suffer detrimental changes in some key lymphocyte functions, described as health and longevity markers, with males being more affected than females and showing higher mortality rates. In the present work, 3xTgAD and wild type 129/C57BL6 male and female non- and environmentally enriched mice were used. The enriched environment (EE) began in the adulthood (6 months) and lasted for 5.5 months. The animals were sacrificed at advanced stages of the disease (15 month-old), and spleen, thymus, and plasma were obtained. The results indicate that 3xTg-AD males are especially benefitted from EE exposure, as shown by the improvement in lymphocyte functional activities such as chemotaxis and natural killer cytotoxicity, as well as in plasma corticosterone levels. By contrast, wild type females seem to be highly sensitive to EE removal, as regards the proliferation capacity of lymphocytes and their intracellular glutathione content. These results support the relevance of gender differences in AD when screening for new strategies for the control of the disease, and suggest that active life, by means of EE, should be maintained until natural death in order to preserve all the positive effects that this strategy exerts on the immune system.