Zhao Xintong, Hua Yujie, Wang Tao, Ci Zheng, Zhang Yixin, Wang Xiaoyun, Lin Qiuning, Zhu Linyong, Zhou Guangdong
Department of Plastic and Reconstructive Surgery, Shanghai Key Laboratory of Tissue Engineering, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
National Tissue Engineering Center of China, Shanghai, China.
Front Bioeng Biotechnol. 2022 Jun 27;10:916146. doi: 10.3389/fbioe.2022.916146. eCollection 2022.
Because of the superior characteristics of photocrosslinkable hydrogels suitable for 3D cell-laden bioprinting, tissue regeneration based on photocrosslinkable hydrogels has become an important research topic. However, due to nutrient permeation obstacles caused by the dense networks and static culture conditions, there have been no successful reports on cartilage regeneration with certain thicknesses based on photocrosslinkable hydrogels. To solve this problem, hydrostatic pressure (HP) provided by the bioreactor was used to regulate the cartilage regeneration based on hybrid photocrosslinkable (HPC) hydrogel. Chondrocyte laden HPC hydrogels (CHPC) were cultured under 5 MPa HP for 8 weeks and evaluated by various staining and quantitative methods. Results demonstrated that CHPC can maintain the characteristics of HPC hydrogels and is suitable for 3D cell-laden bioprinting. However, HPC hydrogels with concentrations over 3% wt% significantly influenced cell viability and cartilage regeneration due to nutrient permeation obstacles. Fortunately, HP completely reversed the negative influences of HPC hydrogels at 3% wt%, significantly enhanced cell viability, proliferation, and extracellular matrix (ECM) deposition by improving nutrient transportation and up-regulating the expression of cartilage-specific genes, and successfully regenerated homogeneous cartilage with a thickness over 3 mm. The transcriptome sequencing results demonstrated that HP regulated cartilage regeneration primarily by inhibiting cell senescence and apoptosis, promoting ECM synthesis, suppressing ECM catabolism, and ECM structure remodeling. Evaluation of fate indicated that regenerated cartilage in the HP group further developed after implantation and formed homogeneous and mature cartilage close to the native one, suggesting significant clinical potential. The current study outlines an efficient strategy for cartilage regeneration based on photocrosslinkable hydrogel scaffolds and its application.
由于适用于载有三维细胞的生物打印的可光交联水凝胶具有卓越特性，基于可光交联水凝胶的组织再生已成为一个重要的研究课题。然而，由于致密网络和静态培养条件导致的营养物质渗透障碍，尚无基于可光交联水凝胶实现一定厚度软骨再生的成功报道。为解决这一问题，利用生物反应器提供的静水压力（HP）来调控基于混合可光交联（HPC）水凝胶的软骨再生。将负载软骨细胞的HPC水凝胶（CHPC）在5兆帕的HP下培养8周，并通过各种染色和定量方法进行评估。结果表明，CHPC能够保持HPC水凝胶的特性，适用于载有三维细胞的生物打印。然而，浓度超过3%（重量）的HPC水凝胶由于营养物质渗透障碍，显著影响细胞活力和软骨再生。幸运的是，HP完全逆转了3%（重量）HPC水凝胶的负面影响，通过改善营养物质运输和上调软骨特异性基因的表达，显著提高了细胞活力、增殖以及细胞外基质（ECM）沉积，并成功再生出厚度超过3毫米的均匀软骨。转录组测序结果表明，HP主要通过抑制细胞衰老和凋亡、促进ECM合成、抑制ECM分解代谢以及ECM结构重塑来调控软骨再生。转归评估表明，HP组再生软骨在植入后进一步发育，形成了与天然软骨相近的均匀且成熟的软骨，显示出显著的临床应用潜力。当前研究概述了一种基于可光交联水凝胶支架的软骨再生有效策略及其应用。
