Confrontation of rodents by natural predators provides a number of advantages as a model for traumatic or stressful experience. Using this approach, one of the aims of this study was to investigate a model for the study of post-traumatic stress disorder (PTSD)-related behaviour in mice. Moreover, because PTSD can facilitate the establishment of chronic pain (CP), and in the same way, patients with CP have an increased tendency to develop PTSD when exposed to a traumatic event, our second aim was to analyse whether this comorbidity can be verified in the new paradigm. C57BL/6 male mice underwent chronic constriction injury of the sciatic nerve (CCI), a model of neuropathic CP, or not (sham groups) and were submitted to different threatening situations. Threatened mice exhibited enhanced defensive behaviours, as well as significantly enhanced risk assessment and escape behaviours during context reexposure. Previous snake exposure reduced open-arm time in the elevated plus-maze test, suggesting an increase in anxiety levels. Sham mice showed fear-induced antinociception immediately after a second exposure to the snake, but 1 week later, they exhibited allodynia, suggesting that multiple exposures to the snake led to increased nociceptive responses. Moreover, after reexposure to the aversive environment, allodynia was maintained. CCI alone produced intense allodynia, which was unaltered by exposure to either the snake stimuli or reexposure to the experimental context. Together, these results specifically parallel the behavioural symptoms of PTSD, suggesting that the snake/exuvia/reexposure procedure may constitute a useful animal model to study PTSD.

天敌与啮齿动物的对抗提供了许多优势，作为创伤或压力体验的模型。使用这种方法，本研究的目的之一是研究用于研究小鼠创伤后应激障碍 (PTSD) 相关行为的模型。此外，由于 PTSD 可以促进慢性疼痛 (CP) 的形成，同样地，CP 患者在遭受创伤事件时更容易发生 PTSD，我们的第二个目的是分析是否可以证实这种合并症在新范式中。C57BL/6 雄性小鼠经历了坐骨神经 (CCI) 慢性收缩性损伤，这是一种神经性 CP 模型，或没有（假手术组），并被置于不同的威胁情况下。受到威胁的老鼠表现出增强的防御行为，以及在环境再暴露期间显着增强的风险评估和逃避行为。先前的蛇暴露减少了高架十字迷宫测试中的开放时间，表明焦虑水平增加。假小鼠在第二次接触蛇后立即表现出恐惧诱导的抗伤害感受，但 1 周后，它们表现出异常性疼痛，这表明多次接触蛇导致伤害性反应增加。此外，在再次暴露于厌恶环境后，异常性疼痛得以维持。CCI 单独产生强烈的异常性疼痛，暴露于蛇刺激或重新暴露于实验环境中不会改变。总之，这些结果特别平行于 PTSD 的行为症状，表明蛇/外皮/再暴露程序可能构成一个有用的动物模型来研究 PTSD。