Long Hao, Zheng Hui, Ai Long, Osman Kamil, Liu Zhigang
Department of Pain Management, The Sixth Affiliated Hospital of Xinjiang Medical University, Urumqi, People's Republic of China.
Orthopedics Department, The Sixth Affiliated Hospital of Xinjiang Medical University, Urumqi, People's Republic of China.
Cancer Manag Res. 2020 Oct 30;12:10929-10938. doi: 10.2147/CMAR.S263177. eCollection 2020.
Cancer-induced bone pain (CIBP) is very common in patients with advanced cancer. Recent studies have shown that reactive oxygen species (ROS) can sense and regulate pain response process through spinal cord mechanism, and play a role in CIBP. NADPH oxidase (NOX) is a group of protease complexes that produce ROS. In the current study, we investigated the expression of NOX4 in the spinal dorsal horn of rats with CIBP and its related role and molecular mechanism.
A rat CIBP model was established by injecting Walker-256 cells into the tibia medullary cavity, and the expression of NOX4 in spinal dorsal horn was down-regulated by injecting lentivirus into spinal cord. RT-PCR, Western blot and immunofluorescence staining were used to detect the expression of NOX4 in CIBP rats, cell localization and its effect on CIBP rats, and the effect of down-regulating the expression of NOX4 on the expression of HO, nitric oxide synthase nNO, antioxidant enzyme SOD, and the activity of neuro-receptor in spinal dorsal horn of rats.
In rats with CIBP, the expression of NOX4 was significantly increased, and immunofluorescence showed that NOX4 was mainly expressed in microglia in the dorsal horn of spinal cord. Down-regulating the expression of NOX4 in rats can reduce the level of HO and nNO in dorsal horn tissue, and increase the expression of SOD to reduce the oxidative stress response. At the same time, down-regulating NOX4 can reduce the sensitivity of spinal cord and relieve the pain of bone cancer by inhibiting the expression of NMDAR and GABAA-γ2 in dorsal horn tissue.
NOX4 is a promising therapeutic target in CIBP, and down-regulation of NOX4 expression can alleviate CIBP in rats by reducing oxidative stress and weakening spinal cord sensitization.
癌症诱发的骨痛（CIBP）在晚期癌症患者中非常常见。最近的研究表明，活性氧（ROS）可通过脊髓机制感知并调节疼痛反应过程，且在CIBP中发挥作用。NADPH氧化酶（NOX）是一组产生ROS的蛋白酶复合物。在本研究中，我们调查了CIBP大鼠脊髓背角中NOX4的表达及其相关作用和分子机制。
通过将Walker-256细胞注射到胫骨骨髓腔建立大鼠CIBP模型，并通过向脊髓注射慢病毒下调脊髓背角中NOX4的表达。采用RT-PCR、蛋白质免疫印迹和免疫荧光染色检测CIBP大鼠中NOX4的表达、细胞定位及其对CIBP大鼠的影响，以及下调NOX4表达对大鼠脊髓背角中HO、一氧化氮合酶nNO、抗氧化酶SOD的表达及神经受体活性的影响。
在CIBP大鼠中，NOX4的表达显著增加，免疫荧光显示NOX4主要在脊髓背角的小胶质细胞中表达。下调大鼠中NOX4的表达可降低背角组织中HO和nNO的水平，并增加SOD的表达以减轻氧化应激反应。同时，下调NOX4可降低脊髓的敏感性，并通过抑制背角组织中NMDAR和GABAA-γ2的表达缓解骨癌疼痛。
NOX4是CIBP中一个有前景的治疗靶点，下调NOX4表达可通过减轻氧化应激和减弱脊髓敏化来缓解大鼠的CIBP。
