Effects of systemic Bifidobacterium longum and Lactobacillus rhamnosus probiotics on the ligature-induced periodontitis in rat

Background/purpose: Probiotics might be beneficial in preventing periodontitis. Ef-fects of Bifidobacterium and Lactobacillus on periodontitis were examined using the ligature -induced rat model. Materials and methods: Thirty-five male Sprague-Dawley rats were divided into control, liga-tion, Bifidobacterium longum (BL986), Lactobacillus rhamnosus (LRH09), and combination groups. Periodontitis was induced in maxillary second molars. From the day before ligation, phosphate-buffered saline (for control and ligation groups) or probiotics (2 x 109 CFU/g for probiotic groups) were fed daily. On day 8, gingival mRNA expressions for interleukin (IL) -1b, IL-6, tissue necrosis factor (TNF)-a, IL-10, and NF-kB were determined via qPCR. Micro -computed tomography (mCT) and histomorphometry were employed to examine periodontal destruction.Results: Compared to the ligation group, mRNA of IL-1b, TNF-a, IL-6, and NF-kB in probiotic groups were significantly decreased, but IL-10 was increased. Besides, the IL-10 was more sig-nificant in the combination group than in single-use group. Through mCT, the cementoenamel junction (CEJ)-to-bone distance and trabecular separation in combination group were less than that in ligation group, although the bone volume fraction and trabecular number/thickness showed an increase in three probiotic groups. Histopathologically, the combination group had significantly smaller gingival inflammatory cell-infiltrated area and CEJ-to-epithelium distance than the ligation group and the group with BL986 or LRH09. Additionally, the CEJ-to-bone distance was significantly smaller in the combination group than in the ligation and BL986 groups. Conclusion: Systemic combination of BL986 and LRH09 had a synergistic effect on enhancing IL-10 and ameliorating the induced experimental periodontitis, although the single-use still presented partially alleviative effects. 2023 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).