Young Dental Pulp Stem Cells (DPSCs) and Tissue Repair
The dental pulp stem cells (DPSCs) from younger stem cell donors are more effective at tissue repair than those from older donors, providing further evidence of the importance of banking stem cells while young.
Int Endod J. 2019 Aug 16. doi: 10.1111/iej.13205. [Epub ahead of print]
- Department of Stomatology, Nanfang Hospital, Southern Medical University.
- College of Stomatology, Southern Medical University.
- Department of Endodontics, Stomatological Hospital, Southern Medical University.
- Department of Stomatology, Guangzhou Hospital of Integrated Traditional and West Medicine.
To comparatively evaluate changes in proliferation and mineralization abilities of dental pulp stem cells (DPSCs) from juvenile and adult rats in a lipopolysaccharide (LPS)-induced inflammatory microenvironment to provide a theoretical basis for the age-related differences observed in DPSCs in repair of inflammatory injury.
DPSCs were isolated from juvenile rats (JDPSCs) and adult rats (ADPSCs), and senescence associated β-galactosidase staining was used to compare senescence between JDPSCs and ADPSCs. Effects of LPS on JDPSCs and ADPSCs proliferation were investigated by cell counting kit-8 assays and flow cytometry. Alizarin red staining, quantitative reverse transcription polymerase chain reaction, and western blot assay were used to examine the effects of LPS on mineralization-related genes and proteins in JDPSCs and ADPSCs. Immunohistochemistry was used to compare interleukin-1β (IL-1β) and osteocalcin (OCN) expression in the pulpitis model. Unpaired Student’s t-test and one-way ANOVA were used in statistical analysis.
DPSCs could be isolated from juvenile and adult rat dental pulp tissues. At low concentrations (0.1-1 μg/mL), LPS significantly promoted the proliferation of JDPSCs (P < 0.01) and ADPSCs (P < 0.01 or P < 0.05), with the effect being stronger in JDPSCs than in ADPSCs. In addition, mineralized nodules and the expression of mineralization-related genes (OCN, DSPP, ALP, BSP) increased significantly after stimulation with LPS (0.5 μg/mL) in JDPSCs and ADPSCs (P < 0.01 or P < 0.05), and JDPSCs displayed a more obvious increase than did ADPSCs. Western blots revealed OCN and ALP expression levels in JDPSCs treated with LPS were significantly upregulated (P < 0.05); meanwhile, ALP expression in ADPSCs increased slightly but significantly (P < 0.05), and OCN expression was not affected. Finally, IL-1β expression was significantly higher (P < 0.05) and OCN expression was significantly lower (P < 0.05) in the inflamed dental pulp of adult rats than in juvenile rats.
A certain degree of inflammatory stimulation promoted the proliferation and mineralization of DPSCs; however, this effect declined with age. The DPSCs of older donors in an inflammatory microenvironment have a weaker repair ability than that of young donors, who are better candidates for tissues damage repair.