2.6 Chronic social defeat stress
The social defeat stress model of depression was performed according to
our previously reported methods(X. Jiang, Lin, Cheng, & Wang, 2020).
Adult male C57BL/6J mice were the subjects, and CD1 retired breeders
were the aggressors. Each C57BL/6J mice was exposed to a different
aggressive CD1 mice each day for 10 minutes over a total of 14 days.
After the 10 minutes of contact, the defeated C57BL/6J mice were
separated from the CD1 aggressors for the next 24 hours by plastic
dividers containing holes, where they were exposed to chronic defeat
stress in the form of threaten. Undefeated control mice were handled
daily. Twenty-four hours after the last stress, defeated C57BL/6J mice
were subjected to the social interaction test and sorted into either
susceptible or unsusceptible phenotype based on interaction scores. All
the CSDS-unsusceptible mice were removed. Then the CSDS-susceptible mice
were housed individually and received daily injections of tested drugs
or vehicle for another 14 days. After that, various behavioral tests
were performed.