Chronic restraint stress increases social interaction in C57BL/6J mice monitoring through MiceProfiler analysis

The social deficit is a prevailing symptom in stress-induced depression. Although social interaction behavior has been widely studied in humans and rodents, it is imprecise to record the social behavior between two free-moving mice via perusal. In the present study, we applied an approach to analyze the social behavior in mice using a software named "MiceProfiler." C57BL/6J mice were stressed via chronic restraint stress (CRS) and housed in three populations of different sizes as follows: single, three in a cage, and six in a cage. The MiceProfiler was used to analyze the video of behavioral repertoire and, the result showed that stressed and single housed mice exhibited more social interaction both in the contact time and contact activities. Furthermore, we investigated the effect of CRS on social behavior when the mice were housed in larger populations size (three or six in a cage) and found that, the CRS procedure promoted social interaction. However, the larger population size resulted in the less total contact time, less time of head-tail, and moving in an opposite way. Besides, the CRS mice showed less social avoidance while the mice from a larger population presented less active contact. And the CRS mice also exhibited a higher social hierarchy compared with the control. Our data indicated that mild restraint stress might increase the intercommunication between mice. Collectively, our findings provided a new evidence for social behavior study and the MiceProfiler could be a new tool to measure the social behaviors of rodents.