Protein arginine methyltransferase 5 in osteoblasts promotes the healing of extraction sockets.

Objectives: To explore the effect of protein arginine methyltransferase 5 (PRMT5) on tooth extraction sockets healing, we established an extraction sockets model in osteoblast-conditional Prmt5 knockout mice. The results provided clues for promoting extraction sockets healing in clinical settings.

Materials and methods: Maxillary first molars were extracted from 6 to 8-week-old mice to establish an extraction fossa model. Microcomputed tomography (Micro-CT), histology, and immunostaining assays were performed on samples harvested at 3-, 7-, and 14-day post-extraction. Prmt5-silenced cell lines  were employed to explore the regulatory mechanisms underlying the osteigenic differentiation.

Results: PRMT5 expression was higher in the early stage of socket healing. Micro-CT analysis showed that the percentage of new bone in the extraction sockets was lower in OC-Cre; Prmt5^fl/fl mice than in the control group, consistent with Masson staining. We found that, Prmt5 deficiency delayed the osteogenesis during extraction socket healing, which might be achieved through the decrease of H4R3me2s in the Sp7 promoter region.

Conclusion: PRMT5 in osteoblasts may promote the differentiation of osteoblasts by regulating the Sp7 promoter H4R3me2s and participate in the healing of tooth extraction sockets.