Effect Of Age On Object Recognition Memory In Kunming Mice

Background Object recognition is an increasingly valuable memory paradigm, which it could detect non-spatial memory by novel object recognition and spatial memory by object-place recognition. A large advantage over other memory tasks, such as the water maze, is that it requires little training and is also, by far, less stressful and arousing. It has been widely used to study the neurobiology of learning and memory. However, whether the age-related impairment of object recognition memory exists in normal mice, which is very useful to understand the pathogency of nervous system degenerative disease such as Alzheimer disease and to introduce the strategy of therapy, remains unclear, and few data of it is not coincidence, especially in the novel object recognition. Meanwhile there are different apparatus and corresponding procedure were used in different studies. It is unknown whether the behaviors of mouse were affected by apparatus and corresponding procedure during the object recognition task. Kunming mouse, a mouse strain used most frequently in Chinese laboratories, is an excellent model of aging. We turn to Kunming mice in the study of object recognition in different apparatuses.Objectiveâ‘ To explore the effect of apparatus and corresponding procedure on the behaviors of Kunming mice during the object recognition tasks;â‘¡To explore the effect of age on the object recognition memory during normal aging in KM mice;â‘¢To explore the sensitive period during the object recognition tasks.Methodsâ‘ Three age groups in the Kunming mice (old group aged 21 months, middle-aged group at age of 12 months and young group aged 6 months) were used;â‘¡ The ability of spatial memory and non-spatial memory were evaluated by object-place recognition task and novel object recognition task respectively. Three apparatus were used to explore their difference in novel object recognition task.â‘¢Using analysis of variance method, t-tests and Kruskal- Wallis H tests, experiment parameters of the object recognition was analysed statisticallyResults There was no significant differences in the preferential index in novel object recognition task in three apparatus during the trials of 10-minute delay between the groups (Ps>0.05). During the trials of 24- hour delay, the preferential index in novel object recognition task in the 21-month-old group was lower than those in the middle-aged group and young group (Ps <0.05) in the Y-shape apparatus, with being mainly attributable to females, and 21-month-old female group was lower than that in the middle-aged female group (P <0.05) in the square apparatus, meanwhile there was no significant differences in the rectangle apparatus. In the object-place recognition task, the preferential index in the 21-month-old male group was lower than those in the middle-aged male group and young male group (Ps <0.01) during the trials of no delay, and 21-month-old group was lower than that in the middle-aged group (P <0.05) with being mainly attributable to females during the trials of 10- minute delay, meanwhile 21-month-old group was lower than those in the middle-aged group and young group (Ps <0.05) with also being mainly attributable to females during the trials of 24- hour delay.Conclusionâ‘ The behaviors of animals during the novel object recognition task were affected by apparatus and it's procedure. The Y-shape box was the most sensitive of the three apparatus in KM mice in novel object recognition;â‘¡There were age-related novel object recognition memory decline in KM mice during the trials of 24-hour delay, with more significantly in females, and there were age-related object-place recognition memory decline in KM mice during the trials of 10-minute and 24-hour delays, also more significant decrease was found in females. There were dissociations between spatial memory decrement and non-spatial memory decrement during normal aging in KM mice;â‘¢The first minute may be the most sensitive period during the delay tests.