Objective: To study the effects of chronic subcutaneous injection of corticosterone on depressive-like behaviors with learning and memory impairment in mice.
Methods: 40 male C57BL/6J mice were divided into 4 groups according to body weight, blank group, corticosterone 20, 40, 80 mg/kg group, subcutaneously injected with corticosterone for 21 d, using empty field test and tail suspension test to detect mice Depression-like behavioral changes. The dose of corticosterone with the most obvious depressive behavior was selected, and the effects of corticosterone on learning and memory impairment associated with depression in mice were studied through tail suspension and forced swimming test, object position recognition test, and Morris water maze test.
Results: Compared with the blank group, corticosterone doses of 40 and 80 mg/kg significantly decreased the distance and time in the central area (exercise) of the open field experiment (P<0.05). The immobility time of the mice was significantly increased (P < 0.01 or P < 0.05). The forced swimming experiment showed that the middle dose of corticosterone significantly increased the immobility time in the mice (P < 0.05). The results of the object cognition experiment showed that, Medium-dose corticosterone can reduce the discrimination index of mice in the object position recognition test; the results of the water maze test showed that the water maze positioning and navigation latency of the corticosterone medium-dose group was significantly higher than that of the blank group (P<0.05), and the cortical Compared with the blank group, the average speed of the ketone group, the average speed of the target quadrant and the number of times of crossing the target quadrant in the water maze space exploration experiment were significantly reduced.
Conclusion: Chronic corticosterone injection can induce depressive-like behavioral changes in mice accompanied by impairment of learning and memory functions.