Department of Orthopedic Surgery, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jie Fang Road, Hangzhou 310009, China; Key Laboratory of Motor System Disease Research and Precision Therapy of Zhejinag Province, Hangzhou 310009, China.
State Key Laboratory of Fluid Power and Mechatronic Systems, College of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China.
Acta Biomater. 2021 Jul 1;128:150-162. doi: 10.1016/j.actbio.2021.04.010. Epub 2021 Apr 22.
Osteochondral regeneration is an orchestrated process of inflammatory immunity, host cell response, and implant degradation in tissue engineering. Here, the effects of a platelet-rich plasma (PRP)-gelatin methacryloyl (GelMA) hydrogel scaffold fabricated using the digital micro-mirror device (DMD) technique for osteochondral repair were investigated in a rabbit model. GelMA hydrogels with different PRP concentrations were fabricated, and their roles in bone marrow mesenchymal stem cells (BMSCs) and macrophage polarization in vitro were investigated. The incorporation of 20% PRP into the hydrogel showed optimal effects on the proliferation, migration, and osteogenic and chondrogenic differentiation of BMSCs. The 20% PRP-GelMA (v/v) hydrogel also promoted M2 polarization with high expression of Arg1 and CD206. Compared to the 20% PRP group, the 50% PRP group showed similar biological roles in BMSCs but less extent of osteogenesis. In the vivo study, the 20% PRP-GelMA composite was used for osteochondral reconstruction and showed more cartilage and subchondral bone regeneration than that observed using the pure GelMA hydrogel. The PRP-GelMA group exhibited more M2 macrophage infiltration and less M1 macrophage presentation at three time points as compared to the nontreatment group. The expression of Arg1 in the PRP-GelMA group increased significantly at 6 weeks but decreased to a lower level at 12 weeks, while CD163 showed sustained high expression until 18 weeks. Our findings demonstrated that the 3D-printed PRP-GelMA composite could promote osteochondral repair through immune regulation by M2 polarization and could be a potential candidate for osteochondral tissue engineering. STATEMENT OF SIGNIFICANCE: PRP-GelMA hydrogels promoted the migration and osteogenic and chondrogenic differentiation of BMSCs. PRP-GelMA hydrogels participated in immune regulation and M1-to-M2 transition of macrophages. PRP-GelMA hydrogels coordinated and promoted several overlapping osteochondral repair events, including dynamic immune regulation, chemotaxis of MSCs, and osteochondral differentiation. PRP-GelMA hydrogels showed superior cartilage and subchondral bone repair properties.
软骨再生是一个炎症免疫、宿主细胞反应和组织工程中植入物降解的协调过程。在这里，我们研究了一种使用数字微镜设备（DMD）技术制造的富含血小板的血浆（PRP）-明胶甲基丙烯酰（GelMA）水凝胶支架在兔模型中对软骨修复的影响。我们制造了不同 PRP 浓度的 GelMA 水凝胶，并研究了它们在骨髓间充质干细胞（BMSCs）和巨噬细胞极化中的作用。水凝胶中加入 20%的 PRP 对 BMSCs 的增殖、迁移以及成骨和成软骨分化表现出最佳效果。20%PRP-GelMA（v/v）水凝胶也促进了 Arg1 和 CD206 高表达的 M2 极化。与 20%PRP 组相比，50%PRP 组在 BMSCs 中表现出相似的生物学作用，但成骨作用较弱。在体内研究中，使用 20%PRP-GelMA 复合材料进行了软骨-骨重建，与仅使用 GelMA 水凝胶相比，观察到更多的软骨和软骨下骨再生。与非治疗组相比，PRP-GelMA 组在三个时间点显示出更多的 M2 巨噬细胞浸润和更少的 M1 巨噬细胞呈现。与 GelMA 组相比，PRP-GelMA 组在 6 周时 Arg1 表达显著增加，但在 12 周时降至较低水平，而 CD163 持续高表达直至 18 周。我们的研究结果表明，3D 打印的 PRP-GelMA 复合材料可通过 M2 极化的免疫调节促进软骨-骨修复，是软骨组织工程的潜在候选材料。
