Conditioned medium from human bone marrow stromal cells attenuates initial inflammatory reactions in dental pulp tissue

Aim To evaluate the effect of MSC-conditioned medium (CM) on the secretion of pro- and anti-inflammatory cytokines from dental pulp cells (hDPC) in vitro, and on the gene expression in vivo after replantation of rat molars. Materials and methods hDPC were cultured in CM for 24 h, and the concentration of interleukin IL-10, IL-4, IL-6, and IL-8, regulated on activation, normal T Cell expressed and secreted (RANTES), and prostaglandin E2 (PGE2) in the media were measured by multiplex assay and ELISA, respectively. Expression of cyclooxygenase-2 (COX-2) was also examined by Western blot analysis after 24 h. Left and right maxillary first rat molars (n = 20) were elevated for 2 min and then replanted with or without application of CM into the tooth sockets. Levels of IL-1β, IL-10, IL-4, IL-6, and IL-8, and tumor necrosis factor-alpha (TNF-α) mRNA were evaluated by real-time qRT-PCR 3 and 14 days following tooth replantation. Results The production of IL-8, IL-10, and IL-6, RANTES and PGE2 by cells cultured in CM was significantly higher than production by cells cultured in standard medium (DMEM). At day 3 following replantation in vivo, the levels of IL-1β and IL-6, and TNF-α mRNA were significantly lower in the CM-treated replanted teeth compared with control teeth. Further, at day 3, the IL-6/IL-10 ratio was significantly lower in the CM-treated replanted teeth compared with control. At day 14 following replantation, no differences in the mRNA ratios were detected between the pulp tissues of replanted and control teeth. Conclusions These findings indicated that CM promotes secretion of pro- and anti-inflammatory cytokines from hDPCin vitro and attenuates the initial inflammatory response in the rat dental pulp in vivo following tooth replantation.