摘要
It has been proven that the mechanical microenvironment can impact the differentiation of mesenchymal stem cells(MSCs).However,the effect of mechanical stimuli in biofabricating hydroxyapatite scaffolds on the inflammatory response of MSCs remains unclear.This study aimed to investigate the effect of mechanical loading on the inflammatory response of MSCs seeded on scaffolds.Cyclic mechanical loading was applied to biofabricate the cell-scaffold composite for 15 min/day over 7,14,or 21 days.At the predetermined time points,culture supernatant was collected for inflammatory mediator detection,and gene expression was analyzed by qRT-PCR.The results showed that the expression of inflammatory mediators(IL1B and IL8)was downregulated(p<0.05)and the expression of ALP(p<0.01)and COL1A1(p<0.05)was upregulated under mechanical loading.The cell-scaffold composites biofabricated with or without mechanical loading were freeze-dried to prepare extracellular matrix-based scaffolds(ECM-based scaffolds).Murine macrophages were seeded on the ECM-based scaffolds to evaluate their polarization.The ECM-based scaffolds that were biofabricated with mechanical loading before freeze-drying enhanced the expression of M2 polarization-related biomarkers(Arginase 1 and Mrc1,p<0.05)of macrophages in vitro and increased bone volume/total volume ratio in vivo.Overall,these findings demonstrated that mechanical loading could dually modulate the inflammatory responses and osteogenic differentiation of MSCs.Besides,the ECM-based scaffolds that were biofabricated with mechanical loading before freeze-drying facilitated the M2 polarization of macrophages in vitro and bone regeneration in vivo.Mechanical loading may be a promising biofabrication strategy for bone biomaterials.
基金
This research was supported by the National Natural Science Foundation of China(Grant no.32071351,81772400 and 31900583,32071341)
the Fundamental Research Funds for the Central Universities(Grant no.19ykzd05)
the Committee for Science and Technology Innovation of Shenzhen(Grant no.JCYJ20190809142211354 and GJHZ20180929160004704)
the Sanming Project of Medicine in Shenzhen(Grant no.SZSM201911002)
the Natural Science Foundation of Guangzhou City(Grant no.201807010031,201704030082)
the Beijing Municipal Health Commission(Grant no.BMHC-2019-9,BMHC-2018-4,PXM2020_026275_000002).