Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Research Center of Stomatology, Xi'an Jiaotong University College of Stomatology, China.
Department of Special Dental Care, Xi'an Jiaotong University College of Stomatology, China.
Mol Pain. 2022 Jan-Dec;18:17448069221089591. doi: 10.1177/17448069221089591.
Oxytocin (OT) is recognized as a critical neuropeptide in pain-related disorders. Chronic pain caused by the comorbidity of temporomandibular disorder (TMD) and fibromyalgia syndrome (FMS) is common, but whether OT plays an analgesic role in the comorbidity of TMD and FMS is unknown. Female rats with masseter muscle inflammation combined with 3-day forced swim (FS) stress developed somatic hypersensitivity, which modeled the comorbidity of TMD and FMS. Using this model, the effects of spinal OT administration on mechanical allodynia and thermal hyperalgesia in hindpaws were examined. Furthermore, the protein levels of OT receptors and 5-HT receptors in the L4-L5 spinal dorsal horn were analyzed by Western blot. The OT receptor antagonist atosiban and 5-HT receptor antagonist ritanserin were intrathecally injected prior to OT injection in the separate groups. Intrathecal injection of 0.125 μg and 0.5 μg OT attenuated the hindpaw hyperalgesia. The expression of OT receptors and 5-HT receptors in the L4-L5 spinal dorsal horn significantly increased following intrathecal injection of 0.5 μg OT. Intrathecal administration of either the OT receptor antagonist atosiban or 5-HT receptor antagonist ritanserin blocked the analgesic effect of OT. These results suggest that OT may inhibit hindpaw hyperalgesia evoked by orofacial inflammation combined with stress through OT receptors and/or 5-HT receptors, thus providing a therapeutic prospect for drugs targeting the OT system and for patients with comorbidity of TMD and FMS.
催产素（OT）被认为是与疼痛相关疾病的关键神经肽。由颞下颌关节紊乱症（TMD）和纤维肌痛综合征（FMS）共病引起的慢性疼痛很常见，但 OT 是否在 TMD 和 FMS 的共病中发挥镇痛作用尚不清楚。患有咬肌炎症的雌性大鼠结合 3 天强制游泳（FS）应激会发展出躯体感觉过敏，模拟 TMD 和 FMS 的共病。使用该模型，研究了脊髓 OT 给药对后爪机械性痛觉过敏和热痛觉过敏的影响。此外，通过 Western blot 分析 L4-L5 脊髓背角中 OT 受体和 5-HT 受体的蛋白水平。在 OT 注射前，在单独的组中鞘内注射 OT 受体拮抗剂阿托西班和 5-HT 受体拮抗剂利坦色林。鞘内注射 0.125μg 和 0.5μg OT 可减轻后爪痛觉过敏。鞘内注射 0.5μg OT 后，L4-L5 脊髓背角中 OT 受体和 5-HT 受体的表达显著增加。鞘内给予 OT 受体拮抗剂阿托西班或 5-HT 受体拮抗剂利坦色林均可阻断 OT 的镇痛作用。这些结果表明，OT 可能通过 OT 受体和/或 5-HT 受体抑制口腔炎症与应激引起的后爪痛觉过敏，从而为针对 OT 系统的药物和 TMD 和 FMS 共病患者提供了治疗前景。
