The CreERT2 recombinase system is an advanced method to temporally control site-specific mutagenesis in adult rodents. In this process, tamoxifen is injected to induce Cre recombinase expression, and then, Cre recombinase can excise LoxP-flanked DNA. However, tamoxifen is a nonselective estrogen receptor antagonist that may influence behavioral alterations. Therefore, we designed five different protocols (acute effects, chronic effects, chronic effects after social defeat model, chronic effects after learned helplessness model, chronic effects after isolation models) to explore whether tamoxifen affects mouse behavior. Researching the acute/chronic effects of tamoxifen, we found that tamoxifen could influence locomotor activity, anxiety and immobility time in the forced swimming test. Researching the chronic effects of tamoxifen after social defeat/learned helplessness/isolation models, we found that tamoxifen could also influence locomotor activity, social interaction and anxiety. Therefore, the effects of tamoxifen are more complex than previously reported. Our results show, for the first time, that tamoxifen affects behavior in mouse models. Meanwhile, we compare the effects of tamoxifen in different protocols. These results will provide important information when designing similar experiments.

中文翻译：

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他莫昔芬对小鼠行为的影响。

CreERT2重组酶系统是在成年啮齿动物中暂时控制位点特异性诱变的先进方法。在该过程中，注射他莫昔芬以诱导Cre重组酶表达，然后Cre重组酶可以切除LoxP侧翼的DNA。但是，他莫昔芬是一种非选择性雌激素受体拮抗剂，可能会影响行为改变。因此，我们设计了五种不同的方案（急性效应，慢性效应，社交失败模型后的慢性效应，学习无助模型后的慢性效应，隔离模型后的慢性效应）来研究他莫昔芬是否会影响小鼠行为。在研究他莫昔芬的急性/慢性作用时，我们发现他莫昔芬可以在强迫游泳试验中影响运动能力，焦虑和不动时间。研究他莫昔芬在社交失败/学习到的无助感/孤立模型后的慢性影响，我们发现他莫昔芬还可能影响运动活动，社交互动和焦虑。因此，他莫昔芬的作用比以前报道的更为复杂。我们的结果首次显示，他莫昔芬影响小鼠模型的行为。同时，我们比较了他莫昔芬在不同方案中的作用。这些结果将在设计类似实验时提供重要信息。我们比较了他莫昔芬在不同方案中的作用。这些结果将在设计类似实验时提供重要信息。我们比较了他莫昔芬在不同方案中的作用。这些结果将在设计类似实验时提供重要信息。