Rodents are highly dependent on maternal care after birth. Maternal separation (MS) is an animal model for studying neglect and abuse. Depriving the pup of such care renders the animal with Hypothalamic-Pituitary-adrenal (HPA) dysfunction and these animals are more susceptible to anxiety and stress as well as poor cognition. These effects are due to abnormal brain development in these animals. We have tried to investigate how maternal separation can affect pain sensation and whether a non-pharmacological intervention such as enriched environment (EE) can restore an abnormal pain sensation. Animals were put into four groups MS, control (CTRL) and MS+EE and CTRL+EE groups that underwent EE after weaning until adulthood. These groups were tested for pain sensitivity with hotplate and tail flick for sensory pain and formalin for affect pain. The results showed that MS rats are more sensitive to pain in the hotplate test and formalin test, however, no significant difference was seen between groups for tail flick test. When MS rats experience EE their pain sensitivity is restored at the behavioral level. Further research is required to see how EE restores pain sensation in MS rats.

中文翻译：

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环境丰富性和疼痛敏感性；一项针对母鼠分离的研究

啮齿类动物出生后高度依赖母亲的护理。母婴分离 (MS) 是研究忽视和虐待的动物模型。剥夺幼犬的这种护理会使动物出现下丘脑-垂体-肾上腺（HPA）功能障碍，这些动物更容易焦虑和压力以及认知能力差。这些影响是由于这些动物的大脑发育异常造成的。我们试图研究产妇分离如何影响疼痛感，以及丰富环境（EE）等非药物干预是否可以恢复异常疼痛感。将动物分为四组：MS组、对照组(CTRL)以及MS+EE组和CTRL+EE组，这些组在断奶后直至成年接受EE。这些组用热板和甩尾测试感觉疼痛，用福尔马林测试影响疼痛。结果表明，MS大鼠在热板试验和福尔马林试验中对疼痛更加敏感，而甩尾试验组间无显着差异。当 MS 大鼠经历 EE 时，它们的疼痛敏感性在行为水平上恢复。需要进一步的研究来了解 EE 如何恢复多发性硬化症大鼠的疼痛感觉。