Influence of bone marrow stromal cell secreted molecules on pulpal and periodontal healing in replanted immature rat molars

Aim: To investigate the effect of paracrine factors secreted from human bone marrow stromal cell (BMSC-CM) on pulpal and periodontal healing following immediate replantation of maxillary rat first molars.

Material and methods: Fifty maxillary rat first molars were elevated and replanted after 2 min. The left teeth were replanted without treatment, whereas BMSC-CM was injected into the right socket prior to replantation. Twelve un-operated teeth served as reference teeth. The expression of vascular endothelial growth factor A, alkaline phosphatase, Runt-related transcription factor 2 and osteoclast stimulating factor 1 was studied by real-time reverse transcription polymerase chain reaction at day 3 and 14. The dentin thickness together with Laminin- and PGP 9.5-immunoreactivity were studied after 3, 14 and 90 days.

Results: Real-Time qRT-PCR data showed up-regulated expression of ALP mRNA in the socket specimens of conditioned medium treated replanted teeth after 3 days. No morphological differences were found for the expression of Laminin and PGP 9.5 between control and conditioned medium treated replanted teeth. At day 14, external cervical and surface root resorption was found in one BMSC-CM and one control tooth. At 90 days, all control replanted teeth had external cervical and surface root resorptions, whereas only one sample was seen among the conditioned medium treated teeth. At day 90, more extensive dentine formation with narrowing of the pulpal space was observed in the control compared with conditioned medium treated teeth.

Conclusions: The present findings showed that BMSC-CM treatment reduced the number of replanted teeth with external root resorption and resulted in a significant reduction in new dentin formation.