Doxorubicin-Induced Premature Senescence in the Dental Pulp-Periodontal Complex: p53- and DKK1-Associated Alterations

Introduction and aims Ageing impairs the regenerative capacity of the dental pulp-periodontal complex, yet efficient in vivo oral ageing models remain limited. This study evaluated a doxorubicin (DOX)-induced premature senescence model in the murine dental pulp-periodontal complex and explored the mechanisms associated with tissue degeneration. Methods Young C57BL/6J mice received DOX via 2 intraperitoneal (i.p.) injections (cumulative doses: 5, 10, or 20 mg/kg) and were compared with naturally aged mice (12 and 18 months). Systemic tolerance and premature senescence phenotypes were assessed using micro-computed tomography, histopathology, and immunostaining for senescence markers (p16, p21) and senescence-associated secretory phenotype (SASP) factors. Further molecular characterisation was conducted in vitro on DOX-treated primary human dental pulp cells via SA-β-gal staining, RNA sequencing, and RT-qPCR. Results The 10 mg/kg DOX regimen induced multiple features associated with therapy-induced premature senescence, including significant alveolar bone loss and osteoclast activation. In DOX-treated pulps, cellularity and vascularity were reduced alongside p16/p21 accumulation and elevated SASP factors (IL-6, IL-1β), characterised by distinct matrix degradation rather than typical fibrosis. Transcriptomic analysis revealed a p53-associated premature senescence signature. Furthermore, DOX upregulated the Wnt antagonist DKK1 and downregulated the osteogenic factor SP7, suggesting Wnt signalling suppression is closely linked to an altered odontogenesis-associated molecular profile. Conclusion DOX induces multiple senescence-associated and degenerative changes in the murine dental pulp-periodontal complex. This model provides a valuable preclinical platform for studying stress-induced oral tissue degeneration and evaluating therapeutic interventions. Clinical Relevance Age-related tissue destruction in the dental pulp and periodontium compromises tooth survival, yet mechanistic understanding and targeted models are lacking. Characterised by p53/p21-associated stress responses and DKK1-related expression changes, the DOX model provides an experimental platform for investigating therapy-associated premature senescence in the oral cavity, facilitating the evaluation of hypotheses and candidate interventions.