Bifidobacterium Strains Present Distinct Effects on the Control of Alveolar Bone Loss in a Periodontitis Experimental Model

Abstract

Periodontitis is an inflammatory disease induced by a dysbiotic oral microbiome. Probiotics of the genus Bifidobacterium may restore the symbiotic microbiome and modulate the immune response, leading to periodontitis control. We evaluated the effect of two strains of Bifidobacterium able to inhibit Porphyromonas gingivalis interaction with host cells and biofilm formation, but with distinct immunomodulatory properties, in a mice periodontitis model. Experimental periodontitis (P+) was induced in C57Bl/6 mice by a microbial consortium of human oral organisms. B. bifidum 1622A [B+ (1622)] and B. breve 1101A [B+ (1101)] were orally inoculated for 45 days. Alveolar bone loss and inflammatory response in gingival tissues were determined. The microbial consortium induced alveolar bone loss in positive control (P + B-), as demonstrated by microtomography analysis, although P. gingivalis was undetected in oral biofilms at the end of the experimental period. TNF-α and IL-10 serum levels, and Treg and Th17 populations in gingiva of SHAM and P + B- groups did not differ. B. bifidum 1622A, but not B. breve 1101A, controlled bone destruction in P+ mice. B. breve 1101A upregulated transcription of Il-1β, Tnf-α, Tlr2, Tlr4, and Nlrp3 in P-B+(1101), which was attenuated by the microbial consortium [P + B+(1101)]. All treatments downregulated transcription of Il-17, although treatment with B. breve 1101A did not yield such low levels of transcripts as seen for the other groups. B. breve 1101A increased Th17 population in gingival tissues [P-B+ (1101) and P + B+ (1101)] compared to SHAM and P + B-. Administration of both bifidobacteria resulted in serum IL-10 decreased levels. Our data indicated that the beneficial effect of Bifidobacterium is not a common trait of this genus, since B. breve 1101A induced an inflammatory profile in gingival tissues and did not prevent alveolar bone loss. However, the properties of B. bifidum 1622A suggest its potential to control periodontitis.

Chronological analysis of periodontal bone loss in experimental periodontitis in mice

“…These attributes make it an ideal candidate for investigating periodontal research in murine models. Our focus was on this specific bone area, assessing volumetric changes and identifying changes in bone mass during microCT analysis, following the protocol published by Shimabukuro et al (2021). The hemimaxillae were scanned and a standard area in the interproximal region between the first and second molars, the second molar and the third molar was selected as the reference point in 15 coronal sections of the ECJ second molar as shown in our figure in question.…”

“…Volumetric analysis of the upper second molar mesial and distal interproximal regions was performed (Shimabukuro et al, 2021). After identification of the cementoenamel junction, 15 sections were counted apically.…”

“…Volumetric analysis of the upper second molar mesial and distal interproximal regions was performed (Shimabukuro et al, 2021).…”

“…This dysbiosis disrupts the delicate balance of tissue homeostasis, leading to an aberrant immuno‐inflammatory response and subsequent tissue damage (Hajishengallis & Moutsopoulos, 2015). The activation of receptors such as Toll‐like receptors (TLRs) triggers the production of inflammatory cytokines and chemokines, culminating in pathological bone loss and eventual destruction of the dental supporting structures (Li & Amar, 2007; Polak et al, 2009; Shimabukuro et al, 2021; Wu et al, 2020). Osteoclasts play a pivotal role in this intricate process, as increased osteoclast formation and activity contribute to the host's secretion of proinflammatory cytokines (Lin et al, 2021; Palioto et al, 2019; Wu et al, 2020).…”