Huang Xiaoling, Li Zhenxing, Ma Jiahui, Huang Dong, Yan Xuebin, Zhou Haocheng
Department of Pain, The Third Xiangya Hospital and Institute of Pain Medicine, Central South University, Changsha, China.
Department of Anesthesiology, Hunan Provincial People's Hospital, The First Affiliated Hospital of Hunan Normal University, Clinical Research Center for Anesthesiology of ERAS in Hunan Province, Changsha, China.
Front Vet Sci. 2022 Oct 28;9:1028147. doi: 10.3389/fvets.2022.1028147. eCollection 2022.
Orofacial pain, in particular, chronic orofacial pain remains a great challenge in clinical practice. To better understand the underlying mechanism of disease, it is essential to apply a feasible and stable preclinical measurement of facial pain. Here, we introduced a novel electrical noxious stimulator in freely behavioral rodents and examined its validation in both naïve and chronic orofacial pain animals.
One subcutaneous device of electrical stimulator was implanted in the facial region for delivery of the nociceptive input. The sensory component of orofacial pain was assessed by response scoring tool, and conditioned place aversion (CPA) paradigm for pain affect respectively. To confirm its usage in chronic pain state, the chronic constriction injury of the infraorbital nerve (ION-CCI) model was then applied.
We found that responsive scores increased with stimulation intensity, and acted in a dosage-dependent manner, which can be attenuated by the administration of morphine intraperitoneally. Naïve rats displayed significant aversive reaction to the noxious electrical stimulation (25V) in the CPA testing. In addition, an obvious sensory hypersensitivity to electrical stimulation was confirmed by the increased response scores in ION-CCI rats. Furthermore, ION-CCI animal showed significant avoidance to electrical stimulation at relatively low intensity (10V), which was innoxious to naïve rats.
Our findings may provide an alternative pre-clinical measurement of orofacial pain, to quantitively assess both sensory and affective component of orofacial pain.
口面部疼痛，尤其是慢性口面部疼痛，仍然是临床实践中的一大挑战。为了更好地理解疾病的潜在机制，应用一种可行且稳定的口面部疼痛临床前测量方法至关重要。在此，我们在自由活动的啮齿动物中引入了一种新型电刺激器，并在未处理和慢性口面部疼痛动物中对其进行了验证。
将一个皮下电刺激器植入面部区域，用于传递伤害性输入。通过反应评分工具评估口面部疼痛的感觉成分，并分别使用条件性位置厌恶（CPA）范式评估疼痛感受。为了证实其在慢性疼痛状态下的应用，随后应用了眶下神经慢性压迫损伤（ION-CCI）模型。
我们发现反应评分随刺激强度增加而升高，并呈剂量依赖性，腹腔注射吗啡可使其减弱。在CPA测试中，未处理的大鼠对有害电刺激（25V）表现出明显的厌恶反应。此外，ION-CCI大鼠反应评分增加，证实其对电刺激存在明显的感觉超敏。此外，ION-CCI动物在相对低强度（10V）电刺激时表现出明显的回避反应，而该强度对未处理的大鼠无害。
我们的研究结果可能为口面部疼痛提供一种替代性的临床前测量方法，以定量评估口面部疼痛的感觉和情感成分。
