健康与遗传心理学研究室知识库

特质焦虑是一种重要的应激易感性表型，高特质焦虑水平的个体经历应激后更可能会发展为焦虑症、创伤后应激障碍等精神疾病。创伤后应激障碍作为一种情绪和认知功能缺失的异质性疾病，通常伴随着过度警觉、情感麻木、持续的负性情绪体验等创伤应激相关反应，这严重地干扰了个体的日常生活及身心健康。创伤后应激相关反应的影响因素众多，其中，焦虑水平发挥着重要作用。然而，特质焦虑作为一种相对持久稳定的人格特质，是否会对个体的创伤后应激相关反应产生影响尚不明确。性别如何影响个体的某些创伤应激相关反应仍有待研究。更全面地了解特质焦虑水平及性别如何影响个体的创伤应激相关反应有助于我们更好地理解特质焦虑与创伤后应激障碍之间的关系，并对治疗焦虑症、创伤后应激障碍等精神疾病具有一定的借鉴意义。

对创伤相关事件的惊跳反应、恐惧记忆以及应对策略异常是创伤后应激障碍的主要症状表现。目前研究认为，特质焦虑水平可能会影响个体的创伤应激相关反应。本研究基于这三种创伤应激相关反应，从大鼠和小鼠高低特质焦虑水平角度，围绕动物特质焦虑模型的建立以及特质焦虑对焦虑性情景中的惊跳反应、创伤性恐惧记忆、对威胁相关线索应对策略的影响开展相应实验研究。同时，许多研究表明，女性群体比男性群体更容易发展为创伤后应激障碍，更可能表现出较多的创伤应激相关反应。因此，本研究初步探索性别对动物在威胁相关线索的应对策略中的影响。

实验一主要通过高架十字迷宫测试、旷场测试以及明暗箱测试筛选出稳定可靠的特质焦虑测量方法。研究发现，作为焦虑水平的测量工具，大鼠在高架十字迷宫中的焦虑指标稳定性较好、旷场次之，明暗箱较差。因此，高架十字迷宫测试是目前测量大鼠特质焦虑水平较为可靠的方法。

实验二采用对声音的惊跳反应测试研究大鼠的特质焦虑水平对惊跳反应的影响。研究发现，与低特质焦虑水平的大鼠相比，高特质焦虑水平的大鼠对95dB和105dB的声音表现出更高的惊跳反应幅度。

实验三采用对足底电击的恐惧条件化研究大鼠的特质焦虑水平对恐惧记忆的影响。研究发现，高低特质焦虑水平的大鼠在恐惧获得、情境性恐惧记忆的提取上表现出相同强度的僵直行为，然而，在基于声音线索的恐惧记忆消退训练及测试阶段，高特质焦虑水平的大鼠比低特质焦虑水平的大鼠表现出显著更多的僵直行为。同时，大鼠的特质焦虑水平可以正向预测其对条件化声音线索的恐惧反应强度。

实验四采用穿梭箱测试研究雌雄小鼠的特质焦虑水平对威胁相关线索应对策略的影响。研究发现，高低特质焦虑水平的雄性小鼠在威胁相关线索的学习初期未表现出显著的行为差异，然而，经过五天的学习训练后，低特质焦虑水平的小鼠在穿梭箱测试中表现出显著更多的回避次数、更短的回避潜伏期、更少的逃跑次数以及更多的穿梭次数。同时，雄性小鼠的特质焦虑水平可以预测其对相关线索的应对策略。然而，高低特质焦虑水平的雌性小鼠在威胁相关线索的应对策略方面未表现出显著差异。。

实验五采用穿梭箱测试研究小鼠在威胁相关线索应对策略中的性别差异。研究发现，在对威胁相关线索的学习过程中，雄性小鼠比雌性小鼠有着显著更多的回避次数、更短的回避潜伏期、更少的逃跑次数、更短的逃跑潜伏期以及更多的穿梭次数。

实验五采用穿梭箱测试研究小鼠在威胁相关线索应对策略中的性别差异。研究发现，在对威胁相关线索的学习过程中，雄性小鼠比雌性小鼠有着显著更多的回避次数、更短的回避潜伏期、更少的逃跑次数、更短的逃跑潜伏期以及更多的穿梭次数。

研究结果表明，特质焦虑会影响个体的创伤应激相关反应，高特质焦虑会对个体的恐惧记忆消退能力以及威胁相关线索的应对策略产生不利影响。同时，性别会影响个体对威胁相关线索的应对策略。因此，在创伤后应激障碍的发生发展及治疗过程中，应充分考虑特质焦虑水平与性别的作用。

Trait anxiety is an important stress susceptibility phenotype, individuals with high trait anxiety level are more likely to develop into anxiety disorder, posttraumatic stress disorder and other mental diseases after experiencing stress. As a heterogeneous disease with deficiency of emotional and cognitive function, posttraumatic stress disorder is usually accompanied by excessive vigilance, emotional numbness, persistent negative emotion experience and other traumatic stress-related responses, which interfere with an individual’s daily life and mental health seriously. There are many factors affecting the traumatic stress-related responses, among which anxiety levels play an important role. However, as a relatively stale personality trait, it is not clear whether trait anxiety will influence an individual’s traumatic stress-related responses. How gender affects certain traumatic stress-related responses also remains to be studied. A more comprehensive understanding of how trait anxiety and gender affect traumatic stress-related responses will help us understand the relationship between trait anxiety and posttraumatic stress disorder better, and provide some reference for the treatment of anxiety, posttraumatic stress disorder and other mental diseases.

The abnormity of startle response, fear memory and coping strategies are the main symptoms of posttraumatic stress disorder. Current research suggests that trait anxiety levels may influence individual’s traumatic stress-related responses. Based on these three traumatic stress-related responses, this study will from the perspective of high and low trait anxiety levels in rats and mice, and focus on the establishment of animal trait anxiety model and the influences of trait anxiety on startle response in anxious situation, traumatic fear memory and coping strategies to threat-related cues. Meanwhile, many studies showed that women are more likely to develop posttraumatic stress disorder and show more traumatic stress-related responses than men. Therefore, this study will explore the influence of gender on the coping strategies to threat-related cues preliminarily.

In experiment 1, a stable and reliable trait anxiety measurement method was selected through elevated plus maze test, open field test, and light-dark box test. The study found that the anxiety index of rats in elevated plus maze was stable, followed by open field, and the light-dark box was poor. Therefore, the elevated plus maze test is a more reliable method to measure rats’ trait anxiety level.

In experiment 2, the effect of trait anxiety on startle response was studied by the acoustic startle response test. The results showed that compared with the rats with low trait anxiety level, rats with high trait anxiety level showed higher startle response amplitude to 95dB and 105dB sounds.

In experiment 3, the effect of trait anxiety of fear memory in rats was studied by fear conditioning of foot shock. Study found that the rats with high and low trait anxiety levels showed same intensity of freezing behaviors in the acquisition of fear and the retrieval of situational fear memory. However, during the training and testing of fear memory extinction based on sound cues, the rats with high trait anxiety level showed significantly more freezing behaviors than the rats with low trait anxiety level. Meanwhile, the trait anxiety levels of rats can predict the intensity of fear response to the conditioning tone cues positively.

In experiment 4, shuttle box test was used to study the effect of trait anxiety on threat-related cues in male and female mice. The study found that male mice with high and low trait anxiety levels showed no significant differences during the early learning of threat-related cues, however, after five days’ learning and training, the male mice with low trait anxiety level showed significantly more avoidance times, shorter avoidance latency, fewer escape times and more shuttle times in the shuttle box test. Meanwhile, the trait anxiety levels of male mice can predict the coping strategy to threat-related cues. However, there was no significant difference in the coping strategy of threat-related cues between female mice with high and low trait anxiety levels.

In experiment 5, sex differences in coping strategies to threat-related cues in mice were studied by shuttle box test. The study found that in the learning threat-relate cues, male mice had significantly more avoidance times, shorter avoidance latency, fewer escape times, shorter escape latency and more shuttle times than female mice.

The research showed that trait anxiety can affect individual’s traumatic stress-related responses. High trait anxiety has a negative impact on the ability of fear memory extinction and the coping strategies to threat-related cues. Meanwhile, gender can affect the coping strategies to threat-related cues. Therefore, the role of trait anxiety and gender should be fully considered during the development and treatment of posttraumatic stress disorder.