Changes of mitochondrial respiratory function during odontogenic differentiation of rat dental papilla cells

Dental papilla cells (DPCs) belong to precursor cells differentiating to odontoblasts and play an important role in dentin formation and reproduction. This study aimed to explore the changes and and involvement of mitochondrial respiratory function during odontogenic differentiation. Primary DPCs were obtained from first molar dental papilla of neonatal rats and cultured in odontogenic medium for 7, 14, 21 days. DPCs, which expressed mesenchymal surface markers CD29, CD44 and CD90, had the capacity for self-renewal and multipotent differentiation. Odontoblastic induction increased mineralized matrix formation in a time-dependent manner, which was accompanied by elevated alkaline phosphatase (ALP), dentin sialophosphoprotein and dentin matrix protein 1 expression at mRNA and protein levels. Notably, odontogenic medium led to an increase in adenosine-5'-triphosphate content and mitochondrial membrane potential, whereas a decrease in intercellular reactive oxygen species production and NAD⁺/NADH ratio. Furthermore, odontogenic differentiation was significantly suppressed by treatment with rotenone, an inhibitor of mitochondrial respiratory chain. These results demonstrate that enhanced mitochondrial function is crucial for odontogenic differentiation of DPCs.