Qiu Cheng, Liu Jingwei, Li Jinghang, Di Derun, Li Manyu, Liu Tianyi, Wang Xinyu, Zhao Yunpeng, Wang Lianlei, Liu Xinyu
Department of Orthopaedic Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, PR China.
Department of Orthopaedic Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, PR China; Department of Pediatric Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, 250012, PR China; Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250012, PR China.
Biochem Biophys Res Commun. 2023 Oct 15;677:20-25. doi: 10.1016/j.bbrc.2023.08.001. Epub 2023 Aug 2.
Osteoarthritis is one of the most common degenerative joint disorders, characterized by articular cartilage breakdown, synovitis, osteophytes generation and subchondral bone sclerosis. Pentraxin 3 (PTX3) is a long pentraxin protein, secreted by immune cells, and PTX3 is identified to play a critical role in inflammation and macrophage polarization. However, the underlying mechanism of PTX3 in osteoarthritis under the circumstance of Ptx3-knockout (KO) mice model is still unknown.
Murine destabilization of the medial meniscus (DMM) OA model was created in Ptx3-knockout (KO) and wildtype mice, respectively. The degenerative status of cartilage was detected by Safranin O, H&E staining, immunohistochemistry (IHC) and micro-CT. OARSI scoring was employed to assess the proteoglycan of cartilage. Serum inflammatory cytokines were examined by ELISA and systematic macrophage polarization in spleen was analyzed by flow cytometry.
Safranin O and H&E staining confirmed that the joint cartilage was mostly with reduced degeneration in both the senior KO mice and the DMM model generated from the KO mice, compared to the WT group. This is also supported by micro-CT examination and OARSI scoring. Immunohistochemistry illustrated an up-regulation of Aggrecan and Collagen 2 and down-regulation of ADAMTS-5 and MMP13 in KO mice in comparison with the WT mice. ELISA indicated a dramatical decrease in the serum levels of TNF-α and IL-6 in KO mice. Polarization of M2-like macrophages was observed in the KO group.
Pentraxin 3 deficiency significantly ameliorated the severity of osteoarthritis by preventing cartilage degeneration and alleviated systematic inflammation by inducing M2 polarization.
骨关节炎是最常见的退行性关节疾病之一，其特征为关节软骨破坏、滑膜炎、骨赘形成和软骨下骨硬化。五聚体蛋白3（PTX3）是一种由免疫细胞分泌的长链五聚体蛋白，已被证实其在炎症和巨噬细胞极化中起关键作用。然而，在Ptx3基因敲除（KO）小鼠模型情况下，PTX3在骨关节炎中的潜在机制仍不清楚。
分别在Ptx3基因敲除（KO）小鼠和野生型小鼠中建立内侧半月板不稳定（DMM）骨关节炎模型。通过番红O染色、苏木精-伊红染色、免疫组织化学（IHC）和显微CT检测软骨的退变状态。采用骨关节炎研究学会国际（OARSI）评分评估软骨蛋白聚糖。通过酶联免疫吸附测定（ELISA）检测血清炎性细胞因子，并通过流式细胞术分析脾脏中系统性巨噬细胞极化情况。
番红O染色和苏木精-伊红染色证实，与野生型组相比，老年KO小鼠以及由KO小鼠构建的DMM模型中，关节软骨退变大多减轻。显微CT检查和OARSI评分也支持这一结果。免疫组织化学显示，与野生型小鼠相比，KO小鼠中聚集蛋白聚糖和胶原蛋白2上调，而含血小板反应蛋白基序的解聚素样金属蛋白酶-5（ADAMTS-5）和基质金属蛋白酶13（MMP13）下调。ELISA表明KO小鼠血清中肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6）水平显著降低。在KO组中观察到M2样巨噬细胞极化。
五聚体蛋白3缺乏通过防止软骨退变显著改善了骨关节炎的严重程度，并通过诱导M2极化减轻了系统性炎症。
