Enhanced immunomodulation and periodontal regeneration efficacy of subgingivally delivered progranulin‐loaded hydrogel as an adjunct to non‐surgical treatment for Class II furcation involvement in dogs

Aim To evaluate the effect of subgingival delivery of progranulin (PGRN)/gelatin methacryloyl (GelMA) complex as an adjunct to scaling and root planing (SRP) on an experimental periodontitis dog model with Class II furcation involvement (FI). Materials and Methods A Class II FI model was established, and the defects were divided into four treatment groups: (a) no treatment (control); (b) SRP; (c) SRP + GelMA; (d) SRP + PGRN/GelMA. Eight weeks after treatment, periodontal parameters were recorded, gingival crevicular fluid and gingival tissue were collected for ELISA and RT‐qPCR, respectively, and mandibular tissue blocks were collected for micro computed tomography (micro‐CT) scanning and hematoxylin and eosin (H&E) staining. Results The SRP + PGRN/GelMA group showed significant improvement in all periodontal parameters compared with those in the other groups. The expression of markers related to M1 macrophage and Th17 cell significantly decreased, and the expression of markers related to M2 macrophage and Treg cell significantly increased in the SRP + PGRN/GelMA group compared with those in the other groups. The volume, quality and area of new bone and the length of new cementum in the root furcation defects of the PGRN/GelMA group were significantly increased compared to those in the other groups. Conclusions Subgingival delivery of the PGRN/GelMA complex could be a promising non‐surgical adjunctive therapy for anti‐inflammation, immunomodulation and periodontal regeneration.