Effects of live and heat-killed Bifidobacterium lactis in rats with induced periodontitis

Abstract

BACKGROUND: Probiotics and postbiotics have emerged as promising adjunctive therapies in managing periodontal disease. Bifidobacterium animalis subsp. lactis HN019 has shown antimicrobial and immunomodulatory effects in both experimental and clinical settings when administered orally. However, the systemic impact of this strain, independent of local oral effects, remains unclear. OBJECTIVE: To evaluate the systemic effects of live and heat-killed B. animalis subsp. lactis HN019 in a rat model of ligature-induced periodontitis, excluding direct contact with the oral cavity. METHODOLOGY: A total of 32 Wistar rats were randomly assigned to four groups (n=8): control (C), periodontitis only (EP), periodontitis + probiotic (PRO), and periodontitis + postbiotic (POS). Periodontitis was induced by placing a cotton ligature around the cervical region of the lower right first molar, inserted into the gingival sulcus. Treatments were administered via oral gavage for 30 days before and 15 days after periodontitis induction. Alveolar bone loss and periodontal parameters were assessed using micro-computed tomography (microCT) and histomorphometric analysis. RESULTS: MicroCT revealed that ligature effectively induced periodontitis, reducing BV/TV and Tb.N and increasing Tb.Sp and Po.Tot. Probiotic and postbiotic treatments did not improve outcomes. Bone loss was lowest in the control group, with no differences between EP, PRO, and POS. CONCLUSION: Systemic administration of Bifidobacterium animalis subsp. lactis HN019 or its derived postbiotic resulted in no significant improvements in periodontal outcomes in this experimental model. Further investigations using integrative approaches are needed to better characterize the systemic effects of probiotics and postbiotics.