Bencze Noémi, Scheich Bálint, Szőke Éva, Wilhelm Imola, Körmöndi Sándor, Botz Bálint, Helyes Zsuzsanna
Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, 7624 Pécs, Hungary.
National Laboratory for Drug Research and Development, Magyar Tudósok Krt. 2, 1117 Budapest, Hungary.
Cancers (Basel). 2024 May 7;16(10):1788. doi: 10.3390/cancers16101788.
Bone cancer and its related chronic pain are huge clinical problems since the available drugs are often ineffective or cannot be used long term due to a broad range of side effects. The mechanisms, mediators and targets need to be identified to determine potential novel therapies. Here, we characterize a mouse bone cancer model induced by intratibial injection of K7M2 osteosarcoma cells using an integrative approach and investigate the role of capsaicin-sensitive peptidergic sensory nerves. The mechanical pain threshold was assessed by dynamic plantar aesthesiometry, limb loading by dynamic weight bearing, spontaneous pain-related behaviors via observation, knee diameter with a digital caliper, and structural changes by micro-CT and glia cell activation by immunohistochemistry in BALB/c mice of both sexes. Capsaicin-sensitive peptidergic sensory neurons were defunctionalized by systemic pretreatment with a high dose of the transient receptor potential vanilloid 1 (TRPV1) agonist resiniferatoxin (RTX). During the 14- and 28-day experiments, weight bearing on the affected limb and the paw mechanonociceptive thresholds significantly decreased, demonstrating secondary mechanical hyperalgesia. Signs of spontaneous pain and osteoplastic bone remodeling were detected both in male and female mice without any sex differences. Microglia activation was shown by the increased ionized calcium-binding adapter molecule 1 (Iba1) immunopositivity on day 14 and astrocyte activation by the enhanced glial fibrillary acidic protein (GFAP)-positive cell density on day 28 in the ipsilateral spinal dorsal horn. Interestingly, defunctionalization of the capsaicin-sensitive afferents representing approximately 2/3 of the nociceptive fibers did not alter any functional parameters. Here, we provide the first complex functional and morphological characterization of the K7M2 mouse osteosarcoma model. Bone-cancer-related chronic pain and hyperalgesia are likely to be mediated by central sensitization involving neuroinflammation via glial cell activation in the spinal dorsal horn, but not the capsaicin-sensitive sensory neuronal system.
骨癌及其相关的慢性疼痛是重大的临床问题，因为现有的药物往往无效，或者由于广泛的副作用而不能长期使用。需要确定其机制、介质和靶点，以确定潜在的新疗法。在这里，我们使用综合方法对通过胫骨内注射K7M2骨肉瘤细胞诱导的小鼠骨癌模型进行了表征，并研究了辣椒素敏感的肽能感觉神经的作用。通过动态足底测痛法评估机械性疼痛阈值，通过动态负重评估肢体负荷，通过观察评估与自发疼痛相关的行为，用数字卡尺测量膝关节直径，通过显微CT观察结构变化，并通过免疫组织化学观察两性BALB/c小鼠的胶质细胞活化情况。通过用高剂量的瞬时受体电位香草酸受体1（TRPV1）激动剂树脂毒素（RTX）进行全身预处理，使辣椒素敏感的肽能感觉神经元失活。在14天和28天的实验中，患侧肢体的负重和爪部机械性伤害感受阈值显著降低，表明出现了继发性机械性痛觉过敏。在雄性和雌性小鼠中均检测到自发疼痛和骨形成性骨重塑的迹象，且无任何性别差异。在第14天，同侧脊髓背角中离子钙结合衔接分子1（Iba1）免疫阳性增加表明小胶质细胞活化，在第28天，胶质纤维酸性蛋白（GFAP）阳性细胞密度增加表明星形胶质细胞活化。有趣的是，代表约2/3伤害性纤维的辣椒素敏感传入神经失活并未改变任何功能参数。在这里，我们首次对K7M2小鼠骨肉瘤模型进行了全面的功能和形态学表征。骨癌相关的慢性疼痛和痛觉过敏可能是由脊髓背角胶质细胞活化引起的涉及神经炎症的中枢敏化介导的，而不是由辣椒素敏感的感觉神经元系统介导的。
