Effect of circRNA_079813 promoting osteogenic differentiation via regurating ROR2 and ERK1/2-MAPK signaling pathway in dental pulp injury rats

Objective:To explore the role and mechanism of circular RNA(circRNA)079813 in osteogenic differentiation in a dental pulp injury model in rats.Methods:A total of 70 SD rats were randomly divided into 7 groups:sham operation group, dental pulp injury group, pcDNA3.1 empty vector(pcDNA-null)+dental pulp injury group, overexpression of circRNA_079813 (pcDNA-circ)+dental pulp injury group, pcDNA-circ+siRNANC+dental pulp injury group, pcDNA-circ+siRNA-ROR2+dental pulp injury group, and pcDNA-circ+PD98059(ERK1/2 inhibitor)+dental pulp injury group, with 10 in each group.Hematoxylin-eosin(HE)staining was used to observe the pathological changes in dental pulp tissue 3 days after surgery.Alkaline phosphatase(ALP) activity was detected in each group, and circRNA_079813 expression was detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR).The expression of ROR2, phosphorylated ERK1/2 (p-ERK1/2), bone sialoprotein (BSP), osteocalcin (OCN), ALP, dentin sialophosphoprotein (DSPP) and dentin matrix protein-1(DMP-1)were detected by western blotting.Results:Compared with the sham operation group, the dental pulp tissue in the dental pulp injury group showed significant inflammatory infiltration and damage characteristics, and the expression of circRNA_079813 was down-regulated (P< 0.05).Compared with the pcDNA-null+dental pulp injury group, the expression levels of circRNA_079813, ROR2, p-ERK1/2, BSP, ALP, OCN, DSPP and DMP-1 and the activity of ALP were up-regulated in the pcDNA-circ+dental pulp injury group(all P< 0.05).After silencing ROR2 expression, compared with the pcDNA-circ+siRNA-NC+dental pulp injury group, the expression of ROR2, p-ERK1/2, BSP, ALP, OCN, DSPP and DMP-1 and the activity of ALP in the pcDNA-circ+siRNA-ROR2+dental pulp injury group were down-regulated(all P< 0.05).Compared with the pcDNA-circ+dental pulp injury group, the expression of p-ERK1/2, ALP, BSP, OCN, DSPP and DMP-1 and the activity of ALP were down-regulated in the pcDNA-circ+PD98059+dental pulp injury group(all P< 0.05).Conclusion:CircRNA_079813 promotes osteogenic differentiation in dental pulp injury rats through activation of the ERK1/2-MAPK signaling pathway by promoting ROR2 expression.