Fig. 4

Local injection of rhIGFBP5 promoted periodontal tissue regeneration and relieved local inflammation in a swine periodontitis model. a, b A minipig model of periodontitis was established. Intraoral photographs (a). Three-dimensional reconstructive CT image (b). c, d Intraoral manifestations indicated that local injection of rhIGFBP5 alleviated local inflammation in comparison with the 0.9% NaCl group at 12 weeks after injection. e Clinical assessment of periodontal tissue regeneration. f, g Three-dimensional reconstructive CT scan exhibiting bone formation after injection at 12 weeks. h Quantitative analysis of the volume of new bone formation. i-p H&E staining exhibiting new periodontal tissue regeneration in the periodontal lesion area in the 0.9% NaCl group (i, j, m, o), and the rhIGFBP5 injection group (k, l, n, p). m–p H&E staining indicated new cementum and Sharpey’s fibers in the 0.9% NaCl group (m, o), and the rhIGFBP5 injection group (n, p). q, r Quantitative analysis of new cementum. Scale bar: 1 mm (i, k), 50 μm (m, n), 20 μm (o, p). CEJ cemento-enamel junction, HAB height of alveolar bone, c cementum, b bone, d dentin, NC new cementum, Blue arrow, inflammatory cells; green arrow, Sharpey’s fibers; red arrow, cementoblast; black arrow, PDLSCs. Student’s t test was implemented to test statistical significance. Error bars represent SD (n = 6). NS no significant difference. **P ≤ 0.01. AL attachment loss, GR gingival recession, NBV new bone volume, PD probing depth, rhIGFBP5 recombinant human insulin-like growth factor binding protein 5