Xu Jiawei, Chen Xiuping, Zhang Haina, Zhang Xiyue, Liu Rujuan, Li Xin, Wang Junwei, Li Tieshan
Department of Rehabilitation Medicine, The Affiliated Hospital of Qingdao University, Qingdao, Shandong Province, China.
Department of Rehabilitation Medicine, Ji'an Central People's Hospital, Ji'an, Jiangxi Province, China.
Sci Rep. 2025 Apr 14;15(1):12805. doi: 10.1038/s41598-025-97501-6.
Knee osteoarthritis (KOA) is a common, chronic, degenerative disease. Platelet-rich plasma (PRP) can significantly relieve KOA pain; however, the mechanism of PRP-induced analgesia remains to be studied. Macrophages are closely related to KOA pain, and regulating macrophage polarization may be an effective way to relieve KOA pain. Therefore, the aim of this study is: First, to explore whether PRP can effectively relieve pain in a KOA animal model and whether it relieves pain by regulating macrophage polarization. Second, to explore the mechanism by which PRP regulates macrophage polarization. Thirty-six healthy male SD rats were randomly divided into sham group, MIA group and PRP group. The KOA rat model was established by injecting 1 mg of MIA into the joint cavity. Behavioral tests, including weight-bearing asymmetry, hot plate, and von Frey hairs tests, were performed. The positive expression rates of inducible nitric oxide synthase (iNOS) and CD163 in the synovium were detected via immunohistochemical staining. Meanwhile, RAW 264.7 cells induced by lipopolysaccharide were treated with PRP in vitro. The production levels of the nuclear factor kappa-B (NF-κB) pathway-related proteins NF-κB p65, inhibitor-κ binding protein α (IκBα), p-NF-κB p65, p-IκBα and the iNOS and CD163 proteins were measured via western blotting. An enzyme-linked immunosorbent assay was used to detect the release of tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β), interleukin-10 (IL-10), and nerve growth factor (NGF). The behavioral results revealed that PRP relieved pain. PRP reduced the proportion of M1/M2 macrophages among synovial macrophages, significantly inhibited the secretion of TNF-α and IL-1β in the synovium, and increased the secretion of IL-10. In addition, in vivo experiments revealed that PRP decreased the protein expression of iNOS, p-IκBα/IκBα, and p-p65/p65 and increased the protein expression of CD163. Furthermore, PRP decreased TNF-α, IL-1β, and NGF levels in RAW 264.7 cells and increased the secretion of IL-10. Our findings indicate that PRP can improve long-term relief from KOA pain. The analgesic mechanism promotes the transformation of M1 macrophages to M2 macrophages by inhibiting the NF-κB signaling pathway, which reduces the release of downstream pain-causing factors, thus relieving inflammation and pain.
膝骨关节炎（KOA）是一种常见的慢性退行性疾病。富血小板血浆（PRP）可显著缓解KOA疼痛；然而，PRP诱导镇痛的机制仍有待研究。巨噬细胞与KOA疼痛密切相关，调节巨噬细胞极化可能是缓解KOA疼痛的有效途径。因此，本研究的目的是：第一，探讨PRP是否能有效缓解KOA动物模型的疼痛，以及它是否通过调节巨噬细胞极化来缓解疼痛。第二，探讨PRP调节巨噬细胞极化的机制。将36只健康雄性SD大鼠随机分为假手术组、MIA组和PRP组。通过向关节腔内注射1mg MIA建立KOA大鼠模型。进行了行为测试，包括负重不对称、热板和von Frey毛发测试。通过免疫组织化学染色检测滑膜中诱导型一氧化氮合酶（iNOS）和CD163的阳性表达率。同时，用PRP体外处理脂多糖诱导的RAW 264.7细胞。通过蛋白质印迹法测定核因子κB（NF-κB）途径相关蛋白NF-κB p65、抑制蛋白κBα（IκBα）、磷酸化-NF-κB p65、磷酸化-IκBα以及iNOS和CD163蛋白的产生水平。采用酶联免疫吸附测定法检测肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）、白细胞介素-10（IL-10）和神经生长因子（NGF）的释放。行为学结果显示PRP可缓解疼痛。PRP降低了滑膜巨噬细胞中M1/M2巨噬细胞的比例，显著抑制了滑膜中TNF-α和IL-1β的分泌，并增加了IL-10的分泌。此外，体内实验表明PRP降低了iNOS、磷酸化-IκBα/IκBα和磷酸化-p65/p65的蛋白表达，并增加了CD163的蛋白表达。此外，PRP降低了RAW 264.7细胞中TNF-α、IL-1β和NGF的水平，并增加了IL-10的分泌。我们的研究结果表明，PRP可以改善KOA疼痛的长期缓解。镇痛机制是通过抑制NF-κB信号通路促进M1巨噬细胞向M2巨噬细胞转化，从而减少下游致痛因子的释放，进而缓解炎症和疼痛。
