Mouse model of experimental periodontitis induced by Porphyromonas gingivalis / Fusobacterium nucleatum infection: bone loss and host response

AIM: To compare the effect of oral infection with Porphyromonas gingivalis or Fusobacterium nucleatum versus infection with both bacteria on mouse periodontal tissues, and to characterize the inflammatory response. MATERIALS AND METHODS: Mice were orally infected with P. gingivalis, F. nucleatum or both. At 42 days post-infection, alveolar bone loss was quantified using micro-computerized tomography. Tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta levels induced by the infection were quantified using the subcutaneous chamber model. RESULTS: Mice orally infected with F. nucleatum/P. gingivalis exhibited significantly more bone loss compared with that of mono-infected and sham-infected mice. F. nucleatum/P. gingivalis infection also increased the levels of TNF-alpha and IL1beta compared with the levels found in the mono-infected groups. CONCLUSIONS: Polymicrobial infection with P. gingivalis/F. nucleatum aggravates alveolar bone loss and induces a stronger inflammatory response compared with that observed upon infection with either bacterium alone. The results suggest that oral infection of mice with a mixture of P. gingivalis and F. nucleatum may be superior to mono-infection models of experimental periodontitis.