Local Injection of Allogeneic Stem Cells from Apical Papilla Enhanced Periodontal Tissue Regeneration in Minipig Model of Periodontitis

Background. Discovering suitable seeding cells and simple application technique will be beneficial for MSC-mediated treatment of periodontitis. Stem cells from apical papilla (SCAPs) might be the candidate seeding cell for the periodontal tissues regeneration based on their origin and characters. In this research, we investigated the effect of SCAPs on periodontal tissue regeneration in swine by local injection. Methods. We established experimental periodontitis model in miniature pigs and then treated them with SCAPs by local injection. Clinical assessments, computed tomography (CT) scanning, histologic examination, and quantitative measurements were used to evaluate the effect of periodontal tissues regeneration. Results. At 12 weeks after injection, clinical assessments showed that probing depth, gingival recession, and attachment loss values were 5.44 +/- 0.77 mm versus 7.33 +/- 1.0 mm (p<0.01), 2.33 +/- 0.33 mm versus 2.11 +/- 0.69 mm (p>0.05), and 7.78 +/- 0.84 mm versus 9.44 +/- 1.07 mm (p<0.01) in SCAPs group and 0.9% NaCl group, respectively. CT scan results showed a significant increase of 12.86 mm(3) alveolar bone regeneration in SCAPs group compared with 0.9% NaCl group. In addition, histopathology results demonstrated remarkable regeneration in SCAPs group, whereas regeneration of periodontal tissue was hardly found in 0.9% NaCl group. Conclusion. Local injection of SCAPs could effectively restore tissue defects brought about by periodontitis in the swine model. Thus, SCAPs, as an easily accessible dentalderiving stem cell, may serve as an alternative application for periodontitis treatment.