Department of Oncology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beixiange 5, Xicheng District, 100053, Beijing, China.
Department of Hematology and Oncology, Qinghai Provincial Hospital of Traditional Chinese Medicine, No.338 Qiyi Road, Chengzhong District, 810000, Xining, Qinghai Province, China.
BMC Musculoskelet Disord. 2022 May 30;23(1):514. doi: 10.1186/s12891-022-05312-x.
Cancer-induced bone pain (CIBP) is a kind of pain with complex pathophysiology. Proteinase-activated receptor 2 (PAR-2) is involved in CIBP. This study explored the effects of PAR-2 on CIBP rats.
CIBP rat model was established by injecting Walker 256 rat breast cancer cells into the left tibia of female Sprague-Dawley rats and verified by tibial morphology observation, HE staining, and mechanical hyperalgesia assay. CIBP rats were injected with PAR-2 inhibitor, ERK activator, and CREB inhibitor through the spinal cord sheath on the 13th day after operation. CIBP behaviors were measured by mechanical hyperalgesia assay. On the 14th day after operation, L4-5 spinal cord tissues were obtained. PAR-2 expression, co-expression of PAR-2 and astrocyte marker GFAP, GFAP mRNA and protein levels and the ERK pathway-related protein levels were detected by Western blot, immunofluorescence double staining, RT-qPCR, and Western blot.
CIBP rats had obvious mechanical hyperalgesia and thermal hyperalgesia from the 7th day after modeling; mechanical hyperalgesia threshold and thermal threshold were decreased; PAR-2 was increased in spinal cord tissues and was co-expressed with GFAP. PAR-2 silencing alleviated rat CIBP by inhibiting astrocyte activation. p-ERK/t-ERK and p-CREB/t-CREB levels in CIBP spinal cord were elevated, the ERK/CREB pathway was activated, while the ERK/CREB pathway was inhibited by PAR-2 silencing. The alleviating effect of PAR-2 inhibitor on hyperalgesia behaviors in CIBP rats were weakened by ERK activator, while were partially restored by CREB inhibitor.
PAR-2 knockdown inhibited the ERK/CREB pathway activation and astrocyte activation, thus alleviating CIBP in rats.
癌性骨痛（CIBP）是一种具有复杂病理生理学的疼痛。蛋白酶激活受体 2（PAR-2）参与 CIBP。本研究探讨了 PAR-2 对 CIBP 大鼠的影响。
将 Walker 256 大鼠乳腺癌细胞注入雌性 Sprague-Dawley 大鼠左侧胫骨中建立 CIBP 大鼠模型，并通过胫骨形态观察、HE 染色和机械性超敏反应试验进行验证。在术后第 13 天，通过脊髓鞘向 CIBP 大鼠注射 PAR-2 抑制剂、ERK 激活剂和 CREB 抑制剂。通过机械性超敏反应试验测量 CIBP 行为。在术后第 14 天，获取 L4-5 脊髓组织。通过 Western blot、免疫荧光双重染色、RT-qPCR 和 Western blot 检测 PAR-2 表达、PAR-2 与星形胶质细胞标志物 GFAP 的共表达、GFAP mRNA 和蛋白水平以及 ERK 通路相关蛋白水平。
建模后第 7 天，CIBP 大鼠出现明显的机械性超敏反应和热超敏反应；机械性超敏反应阈值和热阈值降低；脊髓组织中 PAR-2 增加，并与 GFAP 共表达。PAR-2 沉默通过抑制星形胶质细胞激活缓解大鼠 CIBP。CIBP 脊髓中的 p-ERK/t-ERK 和 p-CREB/t-CREB 水平升高，ERK/CREB 通路被激活，而 PAR-2 沉默抑制了该通路。ERK 激活剂削弱了 PAR-2 抑制剂对 CIBP 大鼠痛觉行为的缓解作用，而 CREB 抑制剂部分恢复了这种作用。
PAR-2 敲低抑制了 ERK/CREB 通路的激活和星形胶质细胞的激活，从而缓解了大鼠的 CIBP。
