EFFECTS OF HUMAN EXFOLIATED DECIDUOUS TEETH DENTAL PULP STEM CELLS ON THE BIOLOGICAL BEHAVIOUR OF OSTEOBLASTS

Xin Ouyang¹, Liping Zhang², Zhilei Yu¹, Huilan Yang¹, Yingchun Xu¹, Jin Zhu^{3, *}

¹Stomatological Centre, The First People's Hospital of Yunnan Province, Kunming 650032, Yunnan Province, China - ²Department of Stomatology, Yunnan Hospital of Traditional Chinese Medicine, Kunming 650021, Yunnan Province, China - ³Department of Oral and Maxillofacial Surgery Stomatological Hospital Affiliated to Kunming Medical University, Kunming 650032, Yunnan Province, China

Objective: To investigate the effect of human deciduous teeth pulp stem cells on the biological behaviour of osteoblasts.

Methods: The natural deciduous tooth samples of normal deciduous and permanent teeth of 5–7-year-old children collected in the Department of Stomatology of our hospital from December 2018 to January 2020 were selected as the experimental group. The impacted canines extracted in our hospital during the same period were selected as the control group. The pulp stem cells of deciduous and permanent teeth in each sample were separated. The cell proliferation ability (OD) of the two groups was observed and analysed on 1d, 3d, 5d and 7d. The clone formation rate, alkaline phosphatase (ALP) activity, mineralized nodule area, and the osteocalcin-related gene mRNA expression levels of osteoblast-specific transcription factor Runx2-related gene 2 (Runx2), ALP, osteoprotegerin (OPG) and osteocalcin (OCN) were compared between the two groups after 7 days of osteogenic induction.

Results: No significant differences were found in the OD values of pulp stem cells between the two groups at 1d (P>0.05). At 3d, 5d and 7d, the OD value of pulp stem cells in the experimental group was significantly higher than in the control group (P<0.05). The clone formation rate of dental pulp stem cells in the experimental group was significantly higher than that in the control group (P<0.05). The ALP activity and the positive area of alizarin staining in the experimental group were significantly higher than in the control group (P<0.05). The mRNA expression levels of Runx2, OCN, ALP and OPG in the experimental group were significantly higher than in the control group (P<0.05).

Conclusion: Human exfoliated deciduous teeth dental pulp stem cells have strong proliferation and clone formation abilities and stronger osteogenic differentiation ability after osteogenic induction.