AUTHOR=Liu Zi-Wei , Yu Yu , Lu Cong , Jiang Ning , Wang Xiao-Ping , Xiao Shui-Yuan , Liu Xin-Min 

TITLE=Postweaning Isolation Rearing Alters the Adult Social, Sexual Preference and Mating Behaviors of Male CD-1 Mice

JOURNAL=Frontiers in Behavioral Neuroscience

VOLUME=13

YEAR=2019

URL=https://www.frontiersin.org/journals/behavioral-neuroscience/articles/10.3389/fnbeh.2019.00021

DOI=10.3389/fnbeh.2019.00021

ISSN=1662-5153

ABSTRACT=<p><bold>Objective:</bold> No study has comprehensively evaluated the effect of postweaning isolation on the social and sexual behaviors of a certain strain of rodents in ethology. The present study aims to explore how and to what extent isolation rearing after postweaning affects the social and sexual behaviors of male CD-1 mice in adulthood systematically.</p><p><bold>Methods:</bold> Male CD-1 mice were randomly assigned to two groups: isolation reared (IS, one mouse per cage, <italic>n</italic> = 30) and group housed (GH, five mice per cage, <italic>n</italic> = 15). The mice underwent isolation rearing from postnatal day 23 to day 93. Then, social affiliation, recognition and memory were measured through selection task experiments. Social interaction under a home cage and novel environment were measured via resident–intruder and social interaction test, respectively. Furthermore, sexual preference, homosexual and heterosexual behaviors were measured.</p><p><bold>Results:</bold> Our study found that postweaning isolation increased the social affiliation for conspecifics (<italic>p</italic> = 0.001), reduced social recognition (<italic>p</italic> = 0.042) and impaired social memory. As for social interaction, isolated mice showed a remarkably increased aggression toward the intruder male in a home cage or novelty environment. For instance, isolated mice presented a short attack latency (<italic>p</italic> &lt; 0.001), high attack frequency (<italic>p</italic> &lt; 0.001) and long attack duration (<italic>p</italic> &lt; 0.001). In addition, isolated mice exhibited further social avoidance. Contrastingly, isolated mice displayed a reduced sexual preference for female (IS: 61.47 ± 13.80%, GH: 70.33 ± 10.06%, <italic>p</italic> = 0.038). As for heterosexual behavior, isolated mice have a short mating duration (<italic>p</italic> = 0.002), long mounting latency (<italic>p</italic> = 0.002), and long intromission latency (<italic>p</italic> = 0.015). However, no association was observed between postweaning isolation and homosexual behavior in male CD-1 mouse.</p><p><bold>Conclusion:</bold> Postweaning isolation increased the social affiliation, impaired the social cognition and considerably increased the aggression in social interaction of adult male CD-1 mice. Postweaning isolation induced a decreased sexual preference for female in adulthood. Postweaning isolation extended the latency to mate, thereby reducing mating behavior. No association was observed between isolation and homosexual behavior.</p>