Abstract:
Background Inhibition of the biological activity of periodontal ligament stem cells (PDLSCs) in an inflammatory microenvironment is an important cause for the difficulty of periodontal regeneration. The exosome (Exo) derived from umbilical cord stem cells (UCMSCs) has similar biological effects to UCMSCs and is widely used for the regeneration and repair of a variety of tissues, but research on periodontal regeneration is still lacking, and the effect on PDLSCs in the inflammatory microenvironment is not clear.
Objective To investigate the role of UCMSCs-derived exosomes in the proliferation and migration of PDLSCs under an inflammatory microenvironment.
Methods Exosomes were extracted and identified from UCMSCs. PDLSCs were isolated and identified. Uptake of exosomes by endocytosis of PDLSCs was observed under fluorescence microscope. The experimental groups were divided into blank control group, TNF-α group, TNF-α plus 25 μg/mL exosome group, TNF-α plus 50 μg/mL exosome group, and TNF-α plus 100 μg/mL exosome group. The effects of exosomes in inflammatory microenvironment on the proliferation, lateral and longitudinal migration of PDLSCs were detected by CCK-8 assay, scratch test and Transwell assay, respectively.
Results Under transmission electron microscopy, the morphology of exosomes from UCMSCs were round, with a diameter of about 100 nm. The expression of CD9, CD63 and CD81 on the surface of exosomes was positive detected by Western Blot. PDLSCs were successfully extracted and expressed MSCs-related surface markers including CD90, CD73, CD29, CD105. Immunofluorescence results showed that exosomes from UCMSCs could be endocytosed by PDLSCs. CCK-8 test results showed that UCMSCS-derived exosomes promoted the proliferation of PDLSCs under inflammatory microenvironment (P<0.05), and the proliferation rate at the concentration of 100 μg/mL was the highest (P<0.05). Transwell test and scratch test showed that the UCMSCS-derived exosomes promoted the migration of PDLSCs laterally and longitudinally in the inflammatory microenvironment in a concentration-dependent manner, with the highest rate at the concentration of 100 μg/mL (P<0.05).
Conclusion Under the inflammatory microenvironment, UCMSCs-derived exosomes can effectively promote PDLSCs proliferation and migration, and high concentrations of exosomes promote proliferation and migration more effectively.