Yajima Manami, Takahashi Yukari, Sugimura Yae K, Kato Fusao
Center for Neuroscience of Pain and Department of Neuroscience, The Jikei University School of Medicine, Tokyo, Japan.
Department of Dental Anesthesiology, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
Neurobiol Pain. 2023 Apr 28;13:100131. doi: 10.1016/j.ynpai.2023.100131. eCollection 2023 Jan-Jul.
Nociplastic pain, the most recently proposed mechanistic descriptor of chronic pain, is the pain resulting from an altered nociceptive system and network without clear evidence of nociceptor activation, injury or disease in the somatosensory system. As the pain-associated symptoms in many patients suffering from undiagnosed pain would result from the nociplastic mechanisms, it is an urgent issue to develop pharmaceutical therapies that would mitigate the aberrant nociception in nociplastic pain. We have recently reported that a single injection of formalin to the upper lip shows sustained sensitization lasting for more than 12 days at the bilateral hindpaws, where there is no injury or neuropathy in rats. Using the equivalent model in mice, we show that pregabalin (PGB), a drug used for treating neuropathic pain, significantly attenuates this formalin-induced widespread sensitization at the bilateral hindpaws, even on the 6 day after the initial single orofacial injection of formalin. On the 10th day after formalin injection, the hindlimb sensitization before PGB injection was no more significant in mice receiving daily PGB injections, unlike those receiving daily vehicle injections. This result suggests that PGB would act on the central pain mechanisms that undergo nociplastic changes triggered by initial inflammation and mitigate widespread sensitization resulting from the established changes.
伤害性可塑性疼痛是慢性疼痛最新提出的机制描述词,它是由伤害感受系统和网络改变所导致的疼痛,而在体感系统中没有明确的伤害感受器激活、损伤或疾病证据。由于许多患有未确诊疼痛的患者的疼痛相关症状是由伤害性可塑性机制引起的,因此开发能够减轻伤害性可塑性疼痛中异常伤害感受的药物疗法是一个紧迫的问题。我们最近报道,向上唇单次注射福尔马林会在双侧后爪引起持续超过12天的敏化,而大鼠后爪并无损伤或神经病变。利用小鼠的等效模型,我们发现用于治疗神经性疼痛的药物普瑞巴林(PGB)能显著减轻这种福尔马林诱导的双侧后爪广泛敏化,即使在初次经口面部注射福尔马林后的第6天也是如此。在福尔马林注射后的第10天,与每日接受溶媒注射的小鼠不同,每日接受PGB注射的小鼠在注射PGB前的后肢敏化不再显著。这一结果表明,PGB作用于由初始炎症引发的经历伤害性可塑性变化的中枢疼痛机制,并减轻由已形成的变化导致的广泛敏化。