Favoretto Cristiane A, Macedo Giovana C, Quadros Isabel M H
a Department of Psychobiology , Universidade Federal de São Paulo, UNIFESP , São Paulo , Brazil.
Stress. 2017 Jan;20(1):68-74. doi: 10.1080/10253890.2017.1280667. Epub 2017 Jan 31.
In rodents, chronic social defeat stress promotes deficits in social interest and social interaction. We further explored these antisocial effects by comparing the consequences of two different defeat stress protocols (episodic vs. continuous stress) in a social investigation test. We expected that continuous, but not episodic, stress would induce social deficits in this model. Furthermore, we tested whether a potentially anxiolytic dose of ethanol reverses social deficits induced by defeat stress. Male Swiss mice were exposed to a 10-day social defeat protocol, using daily confrontations with an aggressive resident mouse. Episodic stress consisted of brief defeat episodes, after which the defeated mouse was returned to its home cage, until the next defeat 24 h later (n = 7-11/group). For continuous stress, similar defeat episodes were followed by cohabitation with the aggressive resident for 24 h, separated by a perforated divider, until the following defeat (n = 8-14/group). Eight days after stress termination, defeated and control mice were assessed in a social investigation test, after treatment with ethanol (1.0 g/kg, i.p.) or 0.9% saline. Considering the time spent investigating a social target, mice exposed to episodic or continuous social stress showed less social investigation than controls (p < .05). Deficits in social interest were not reversed by acute ethanol treatment. However, ethanol reduced time spent in social interaction in one control group (p < .05). Locomotor activity was not affected by social stress or ethanol. Thus, a history of social defeat stress, whether episodic or continuous, promotes deficits in social investigation that were not reversed by acute treatment with ethanol.
在啮齿动物中，慢性社会挫败应激会导致社会兴趣和社会互动方面的缺陷。我们通过在社会调查测试中比较两种不同的挫败应激方案（间歇性应激与持续性应激）的后果，进一步探究了这些反社会效应。我们预期，在该模型中，持续性而非间歇性应激会诱发社会缺陷。此外，我们测试了具有潜在抗焦虑作用剂量的乙醇是否能逆转由挫败应激诱导的社会缺陷。雄性瑞士小鼠接受为期10天的社会挫败方案，每天与一只具有攻击性的常驻小鼠进行对抗。间歇性应激由短暂的挫败事件组成，之后被击败的小鼠被放回其笼舍，直到24小时后下一次挫败（每组n = 7 - 11只）。对于持续性应激，类似的挫败事件后，被击败的小鼠与具有攻击性的常驻小鼠通过有孔隔板隔开共同居住24小时，直到下一次挫败（每组n = 8 - 14只）。应激终止8天后，在给予乙醇（1.0 g/kg，腹腔注射）或0.9%生理盐水处理后，对被击败的小鼠和对照小鼠进行社会调查测试。考虑到用于探究社会目标的时间，经历间歇性或持续性社会应激的小鼠比对照小鼠表现出更少的社会调查行为（p < 0.05）。急性乙醇处理并未逆转社会兴趣方面的缺陷。然而，乙醇减少了一个对照组中用于社会互动的时间（p < 0.05）。社会应激或乙醇对运动活动没有影响。因此，无论是间歇性还是持续性的社会挫败应激史，都会导致社会调查方面的缺陷，且急性乙醇处理无法逆转这些缺陷。
