[TNF-α regulated SHED osteogenic differentiation through ERK1/2-Runx2 signaling pathway].

PURPOSE: To investigate the effect of TNF-α on osteogenic differentiation of stem cells from human exfoliated deciduous teeth (SHED), and to analyze the changes of ERK1/2-Runx2 signaling pathway in the regulation process. METHODS: SHED cells were isolated and cultured from normal deciduous permanent teeth of healthy children aged 6-8 years old, and the third passage of SHED cells were taken and divided into control group (osteogenic inducer culture), observation group (osteogenic inducer and TNF-α co-culture) and agonist group (osteogenic inducer, TNF-α and ERK pathway agonist co-culture). The osteogenic differentiation was determined by alizarin red staining. The protein expression levels of Osterix, OPN, ERK1/2, pERK1/2 and Runx2 in SHED cells were determined by Western blot. The expressions of Osterix, OPN, ERK1/2, pERK1/2 and Runx2 mRNA were detected by qRT-PCR. Statistical analysis was performed with SPSS 26.0 software package. RESULTS: Comparison of osteogenic differentiation ability of the three groups of cells showed that red-brown mineralized nodules were observed in the three groups of cells. Compared among the three groups, the control group had the most mineralized nodules, followed by the activation group, and the observation group had the least mineralized nodules. Compared with the control group, the expression levels of Osterix and OPN protein and mRNA in the observation group and the agonist group were significantly decreased, while the expression levels of Osterix and OPN protein and mRNA in the agonist group were significantly higher than those in the observation group. There was no significant difference in the expression levels of ERK1/2 protein and mRNA among the three groups, while the expression levels of pERK1/2 and Runx2 protein and mRNA in the observation group and the agonist group were significantly higher than those in the control group, and the expression levels of pERK1/2 and Runx2 protein and mRNA in the agonist group were significantly higher than those in the observation group. CONCLUSIONS: TNF-α can inhibit osteogenic differentiation of SHED cells, which may be related to the inhibition of ERK1/2-Runx2 signaling pathway.

Effect of tetracyclines on pulpal and periodontal healing after tooth replantation: a systematic review of human and animal studies.

BACKGROUND: Pulpal and periodontal healing are two main concerns of delayed replantation of avulsed teeth. The objective of this review was to evaluate the effectiveness of topical and systemic application of tetracyclines on pulpal and periodontal healing after tooth replantation. METHODS: A comprehensive electronic search was conducted in six databases. This systematic review was carried out according to Cochrane Handbook and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. RESULTS: After exclusion of 246 irrelevant papers, 14 animal studies and one human study were included in this review. The human study showed that avulsed permanent teeth treated with doxycycline did not show a better clinical outcome for pulp and periodontal healing compared with treatment with normal saline. As for animal studies, significant more pulpal healing was observed in immature teeth treated with topical doxycycline in two researches, while another one study showed that there is no difference between teeth treated with normal saline and teeth treated with doxycycline. Systemic doxycycline exerted no significant effect on pulpal revascularization illustrated by one research. Only one out of four articles illustrated the positive effect of systemic tetracyclines on periodontal healing. One paper reported that intracanal application of demeclocycline promoted favorable periodontal healing. Two articles showed topical doxycycline contributed to favorable periodontal healing, while five studies showed no significant effect of topical tetracyclines on periodontal healing. CONCLUSIONS: As a result of data heterogeneity and limitations of the studies, the effect of topical or systemic application of tetracyclines on pulpal and periodontal healing is inconclusive. More studies are required to get more clinically significant conclusions.