Behavioral characterization of a mouse model of premature immunosenescence

In previous studies we have shown that differences in Life span among membe rs of Swiss mouse populations appear to be related to their performance in a T-maze, with a slow performance ('slow' mice) being linked to an impaired immune function and a shorter life span when compared to 'fast' mice, whic h led us to propose the slow mice as a model of immunosenescence. In the pr esent study we demonstrate that in a tightrope test of neuromuscular vigor and coordination the slow mice show a worse performance, needing more time to complete the task. Moreover, these animals show a decreased locomotor ac tivity and an increased level of emotionality/anxiety in three standard beh avioral tests (the holeboard, the open field and the plus-maze) when compar ed to fast mice. All these behavioral features were most marked in the slow females. The results also indicate that slow animals show a decreased chem otaxis of macrophages and lymphocytes, as well as a reduced lymphoprolifera tive response to mitogens. The data supports our claim that slow or hyperem otional mice, in which immune and neurobehavioural functions appear to be i mpaired, may be a useful model of premature aging. (C) 2001 Elsevier Scienc e B.V. All rights reserved.