Effect of HM-Exos on the migration and inflammatory response of LPS-exposed dental pulp stem cells

The purpose of this study was to investigate the effects of human milk exosomes (HM-Exos) on the viability, migration, and inflammatory responses of lipopolysaccharide (LPS)-exposed human dental pulp stem cells (HDPSCs) in vitro.

HM-Exos were isolated, and dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze their physical properties (size and shape). To construct an in vitro inflammation model, HDPSCs were exposed to LPS. The MTT test and migration assay were used to investigate the effect of HM-Exos on cell proliferation and migration, and the quantitative polymerase chain reaction (qPCR) was used to assess the expression of inflammatory genes in HDPSCs. Data were analyzed using a one-way analysis of variance (ANOVA) with Tukey's post-test.

DLS measurement revealed that HM-Exos were 116.8 ± 3.6 nm in diameter. The SEM and TEM images revealed spherical shapes with diameters of 97.2 ± 34.6 nm. According to the results of the cell viability assay, the nontoxic concentration of HM-Exos (200 µg/ml) was chosen for the subsequent investigations. The migration assay results showed that HM-Exos improved the potential of LPS-exposed HDPSCs to migrate. The qPCR results indicated that HM-Exos significantly reduced the expression of inflammatory cytokines such as TNF-α, IL-1β, and IL-6 in HDPSCs after LPS stimulation.

HM-Exos increased LPS-exposed HDPSCs migration and proliferation and reduced gene expression of inflammatory cytokines. They may be a viable candidate for pulpitis therapy.