Zhao Mengmeng, Liu Lei, Chen Zhenghao, Ding Ning, Wen Jiliang, Liu Jiaxin, Ge Nan, Zhang Xiulin
Department of Urology, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
Pain. 2022 Nov 1;163(11):2200-2212. doi: 10.1097/j.pain.0000000000002616. Epub 2022 Feb 21.
The transient receptor potential cation channel subfamily M member-3 (TRPM3) channel is a recently recognized noxious heat sensor that is involved in inflammatory thermal hyperalgesia. To examine its involvement in the development of hyperalgesia in interstitial cystitis/painful bladder syndrome (IC/PBS), rats with cyclophosphamide (CYP)-induced chronic cystitis were used as a model of IC/PBS. Mechanical and thermal hyperalgesia in lower abdominal region overlying the bladder in CYP rats were measured using von Frey filaments and radiant heat, respectively. Transient receptor potential cation channel subfamily M member-3 expression at the mRNA, protein, and functional levels in dorsal root ganglion neurons innervating the bladder was detected using RNA in situ hybridization (RNAscope), Western blotting, immunohistochemistry, and Ca 2+ imaging, respectively. Transient receptor potential cation channel subfamily M member-3 channels were expressed on most of the bladder primary afferent nerve terminals containing calcitonin gene-related peptide and their cell bodies in L6-S1 dorsal root ganglion. Activation of TRPM3 in the bladder wall by its specific agonist pregnenolone sulphate or CIM0216 induced spontaneous bladder pain, calcitonin gene-related peptide release, and neurogenic inflammation that was evidenced by edema, plasma extravasation, inflammatory cell accumulation, and mast cell infiltration. In CYP rats, pretreatment with the TRPM3 antagonist primidone (2 mg/kg, i.p.) significantly alleviated the mechanical and thermal hyperalgesia, bladder submucosal edema, mast cell infiltration, and bladder hyperactivity. Cyclophosphamide-induced cystitis was associated with TRPM3 upregulation at the mRNA, protein, and functional levels in bladder afferent neurons. Our results suggest that upregulation of TRPM3 channels is involved in the development of chronic pain in CYP-induced cystitis, and targeting TRPM3 may be a pharmacological strategy for treating bladder pain in IC/PBS.
瞬时受体电位阳离子通道M亚家族成员3（TRPM3）通道是一种最近被认识的有害热感受器，参与炎症性热痛觉过敏。为了研究其在间质性膀胱炎/疼痛性膀胱综合征（IC/PBS）痛觉过敏发展中的作用，将环磷酰胺（CYP）诱导的慢性膀胱炎大鼠用作IC/PBS模型。分别使用von Frey细丝和辐射热测量CYP大鼠膀胱上方下腹部区域的机械性和热痛觉过敏。分别使用RNA原位杂交（RNAscope）、蛋白质印迹、免疫组织化学和Ca²⁺成像检测支配膀胱的背根神经节神经元中TRPM3在mRNA、蛋白质和功能水平的表达。TRPM3通道在大多数含有降钙素基因相关肽的膀胱初级传入神经末梢及其L6-S1背根神经节中的细胞体上表达。其特异性激动剂硫酸孕烯醇酮或CIM0216激活膀胱壁中的TRPM3可诱导自发性膀胱疼痛、降钙素基因相关肽释放以及神经源性炎症，这通过水肿、血浆外渗、炎症细胞积聚和肥大细胞浸润得以证实。在CYP大鼠中，用TRPM3拮抗剂扑米酮（2mg/kg，腹腔注射）预处理可显著减轻机械性和热痛觉过敏、膀胱黏膜下水肿、肥大细胞浸润以及膀胱活动亢进。环磷酰胺诱导的膀胱炎与膀胱传入神经元中TRPM3在mRNA、蛋白质和功能水平的上调有关。我们的结果表明，TRPM3通道的上调参与了CYP诱导的膀胱炎中慢性疼痛的发展，靶向TRPM3可能是治疗IC/PBS中膀胱疼痛的一种药理学策略。
