Availability of aged C57BL/6J mice as an aging model

抄録

[Purpose] Aging diminishes cognitive function, motor function and sensory function, and it can be a fundamental factor leading to age-related diseases such as dementia and sarcopenia. To investigate aging or develop medicines for age-related disease, it is indispensable to develop aged laboratory animals with reduced physiological functions. However, due to time and cost constraints for preparing aged animals, the relationship between the characteristics of deterioration of function of aged animals and the degree of aging has not been fully evaluated. In this study, physiological functions of aged C57BL/6J mice were evaluated using cognitive function, motor function and sensory (visual) function as indicators and the availability of this strain as an aging model was verified.

[Method] Young (8 weeks old, n=8), aged (52 weeks old, n=17), and super aged (78 weeks old, n=17) male C57BL/6J mice were used. The following tests and measurements were conducted: a passive avoidance test, a novel object recognition test, a Y maze test and a Morris water maze test as the evaluation of cognitive function; a rotarod test, a beam test and a pole test as the evaluation of motor function; and measurements of retinal potential and visual evoked potential as the evaluation of visual function. Furthermore, muscle weights were measured for the evaluation of motor function.

[Results and Conclusion] In both the aged and super aged mice, a decrease of spatial cognitive function in the Morris water maze, and an impairment in motor coordination in the rotarod test, beam test, and pole test. In the super aged mice, prolonged total latency of oscillatory potential was observed in electroretinography, indicating visual function deterioration. In both the aged and super aged mice, the weight ratios of soleus and gastrocnemius muscles to body weight had decreased.

　It was found that aged C57BL/6J mice are useful aging models indicating declining functions of cognition, motion and vision. In addition, we believe that these findings can be useful for aging research, and design of test for medicine development for age-related diseases.