Proposal for a novel murine model of human periodontitis using and type II collagen antibody injections.

Introduction: Periodontitis is a chronic disease in humans induced by several pathogens including Although mouse models of human periodontitis have been developed for study using an oral gavage of , existing models take over a month to develop in order to ensure adequate periodontal destruction. The aim of the present study is to determine if using an injection of a cocktail of type II collagen antibodies along with an oral gavage of in mice induces adequate periodontal destruction in a shorter time so as to potentially serve as a more useful mouse model of periodontitis.

Methods: Twenty-eight DBA1/BO male mice were placed in four groups: Group A (antibody injection plus gavage), Group B (gavage only), Group C (antibody injection only), and Group D (neither antibody injection nor gavage, control). Between six and eight weeks old, all mice underwent antibiotic administration, and at eight weeks old, were given antibody injection (Groups A and C) and oral gavage (Groups A and B). Fifteen days after gavage Groups A and B received gavage, all mice were euthanized. Histomorphometric, morphometric, and cell counting analyses were conducted using analysis of variance (ANOVA) and Kruskal Wallis analysis followed by pairwise -tests using Bonferroni correction.

Results: For histomorphometric analysis, mean distance from the cemento-enamel junction to the alveolar bone crest (CEJ-ABC) and the mean epithelial downgrowth (ED) in μm was statistically significantly highest for Group A (CEJ-ABC 1.49.81 vs. Group B 101.46, Group C 78.74, and Group D 66.23, p < 0.0083; ED 66.76 vs. Group B 25.92, Group C 9.21, and Group D 9.10, p < 0.0083). Morphometric analysis also showed that Group A had a significantly higher mean CEJ-ABC in μm compared to all other groups (265.50 vs. Group B 195.77, Group C 150.33, and Group D 133.93, p < 0.0083). A similar pattern was seen in cell counting, in which Group A had a significantly lower mean count of fibroblasts per 45 × 50 μm field (8.02 vs. Group B 9.56, Group C 12.09, and Group D 11.02, p < 0.0083), and a significantly higher mean count polymorphonuclear leukocytes per 45 × 50 μm (4.59 vs. Group B 1.74, Group C 0.83, and Group D 0.68, p < 0.0083).

Conclusion: The results of this study provide proof-of-concept for a mouse model that can be quickly developed for human periodontitis using a type II collagen antibody cocktail injection coupled with oral gavage of in DBA1/BO male mice. Future studies should verify the results of this proof-of-concept, compare this new model to existing models, and evaluate the extent of this model's usefulness.