Cognitive behavior and sensory function were significantly influenced by restoration of active ovarian function in postreproductive mice

In mammals, the relationship between reproductive function and health has been particularly difficult to define. Previously, in old, postreproductive-aged mice, replacement of senescent ovaries with new ovaries from young, actively cycling mice increased life span. We hypothesized that the same factors that increased life span would also influence health span. In the current experiments, we tested two of the seven domains of function/health, sensory function and cognition to determine if exposure of postreproductive female mice to young transplanted ovaries influenced health span. We evaluated control female CBA/J mice at six, 13 and 16months of age. Additional mice received new (60d) ovaries at 12 or 17months of age and were subsequently evaluated at 16 or 25months of age, respectively. Evaluation of sensory function included two measures of olfactory perception; olfactory identification (buried pellet test) and olfactory discrimination (novel recognition block test). We found a significant age-related decline in olfactory identification in 16-month old mice. This decline was avoided by ovarian transplantation at 12months of age. The olfactory discrimination block test revealed an age-associated increase in time spent on both the novel and familiar blocks. This trend was reversed in 16-month old new-ovary recipients. We evaluated cognitive behavior with a burrowing behavior test. We detected a significant age-related decrease in burrowing behavior at 16months of age. This age-related decrease in burrowing behavior was prevented by ovarian transplantation at 12months of age. In summary, we have shown that cognitive behavior and sensory function, which are negatively influenced by aging, can be positively influenced or restored by re-establishment of active ovarian function in aged female mice. These findings provide strong incentive for further investigation of the positive influence of young ovaries on restoration of health in postreproductive females.