Chronological analysis of periodontal bone loss in experimental periodontitis in mice

Abstract

Objectives: Periodontal disease is understood to be a result of dysbiotic interactions between the host and the biofilm, causing a unique reaction for each individual, which in turn characterizes their susceptibility. The objective of this study was to chronologically evaluate periodontal tissue destruction induced by systemic bacterial challenge in known susceptible (BALB/c) and resistant (C57BL/6) mouse lineages.

Material and methods: Animals, 6-8 weeks old, were allocated into three experimental groups: Negative control (C), Gavage with sterile carboxymethyl cellulose 2%-without bacteria (Sham), and Gavage with carboxymethyl cellulose 2% + Porphyromonas gingivalis (Pg-W83). Before infection, all animals received antibiotic treatment (sulfamethoxazole/trimethoprim, 400/80 mg/5 mL) for 7 days, followed by 3 days of rest. Microbial challenge was performed 3 times per week for 1, 2, or 3 weeks. After that, the animals were kept until the completion of 42 days of experiments, when they were euthanized. The alveolar bone microarchitecture was assessed by computed microtomography.

Results: Both C57BL/6 and BALB/c mice exhibited significant bone volume loss and lower trabecular thickness as well as greater bone porosity compared to the (C) and (Sham) groups after 1 week of microbial challenge (p < .001). When comparing only the gavage groups regarding disease implantation, time and lineage, it was possible to observe that within 1 week of induction the disease was more established in BALB/c than in C57BL/6 (p < .05).

Conclusions: Our results reflected that after 1 week of microbial challenge, there was evidence of alveolar bone loss for both lineages, with the loss observed in BALB/c mice being more pronounced.

Keywords: alveolar bone loss; host microbiota interactions; inflammation; periodontal diseases.

Figure 1

Experimental design. (a) Antibiotic preparation. (b) Bacteria preparation. (c) Gavage bacteria.

Figure 2

Micro‐CT analysis. (a) Measurement in the CT Analyzer software in the interproximal region for volumetric analysis by means of a sagittal image of the maxillary second molar. (b) Delimitation of the mesial region of interest (ROI) mesial interproximal region. (c) Measurement of mesial region 4. Delimitation of the ROI distal interproximal region. (d) Measurement of the distal region.

Figure 3

Three‐dimensional rendered reconstructions of the microtomographic sections buccal view of Groups C (a and h), Sham 1 week (b and i), 2 weeks (c and j) and 3 weeks (d and k), Gav 1 week (e and l), 2 weeks (f and m), and 3 weeks (g and n) and representation of the chronicity of the disease in Groups C (o and r) and Gav 2 weeks (p and f) and 3 weeks (q and t); the red drawings represent the size of the area without bone.

Figure 4

Means and standard deviations of bone volume Bv/Tv (a), total porosity POtot (b), thickness Tb.Th (c), and trabecular pattern Tb.Pf (d) and comparisons between groups. Asterisks indicate significant differences between groups (analysis of variance, Tukey, p < .05).

Figure 5

Means and standard deviations in the gavage group. Bone volume Bv/Tv (a), total porosity POtot (b), thickness Tb.Th (c), and trabecular pattern Tb.Pf (d) and comparisons as a function of time, lineage, and implantation of periodontal disease in the gavage group. Asterisks indicate significant differences between groups (analysis of variance, Tukey, p < .05).

Figure 6

Means and standard deviations of linear measurements of the alveolar bone level. C57BL/6 group (a), BALB/c (b), Gavage groups (c). Asterisks indicate significant differences between groups (analysis of variance, Tukey, p < .05).