Mesenchymal stem cells-derived and siRNAs-encapsulated exosomes inhibit osteonecrosis of the femoral head.

Osteonecrosis of the femoral head (ONFH) is a progressive, obstinate and disabling disease. At present, the treatment of ONFH is still a global medical problem. We aim to explore the role of bone mesenchymal stem cells (BMSCs)-derived and siRNAs-encapsulated exosomes (siRNAs-encapsulated BMSCexos) in ONFH. We first isolated BMSCexos and screened siRNAs of 6 ONFH-related genes for siRNAs-encapsulated BMSCexo. The expression of these 6 ONFH-related genes in dexamethasone (DXM)-treated MC3T3-E1 cell, cell model of ONFH, was detected by RT-qPCR and Western blot analysis. And then, we performed CCK-8 assay, angiogenesis assay and HE staining analysis to test the promotion role of the siRNAs-encapsulated BMSCexo for angiogenesis during ONFH repair. The results suggest that the obtained particles were BMSCexos. The screened effective siRNAs could effectively knock down their expression in VECs. Moreover, siRNAs-encapsulated BMSCexo could effectively knock down the expression of these genes in VECs. In addition, siRNAs-encapsulated BMSCexo promote angiogenesis during ONFH repair. In conclusion, we found siRNAs-encapsulated BMSCexos could promote ONFH repair by angiogenesis, and indicated exosome as the new siRNA carrier is of great significance to improve the efficiency of RNAi.