Development of an Ex Vivo Coculture System to Model Pulpal Infection by Streptococcus anginosus Group Bacteria

作者：Roberts Jessica L; Maillard Jean Yves; Waddington Rachel J; Denyer Stephen P; Lynch Christopher D; Sloan Alastair J^*

来源：Journal of Endodontics, 2013, 39(1): 49-56.

DOI：10.1016/j.joen.2012.09.005

• 3-Dimensional Modeling
• bacterial attachment
• pulpal matrix

Introduction: Streptococcus anginosus group (SAG) bacteria are opportunistic pathogens and a major cause of pulpal infection and subsequent abscess formation. Understanding of the processes involved in SAG oral infections has been limited by the lack of an appropriate model system. Methods: Cocultures of SAG bacteria and mammalian tooth slices were maintained using a combination of Dulbecco modified eagle medium and brain-heart infusion broth at 60 rpm, 37 degrees C, 5% CO2 for 4, 8, or 24 hours before histologic examination or staining with acridine orange/ethidium bromide. Tooth slices were also incubated as described with SAG bacteria stained with fluorescein diacetate. Pulps were extirpated from infected and sterile cultured tooth slices, messenger RNA was extracted and converted to complementary DNA, and polymerase chain reaction were performed for genes encoding tumor necrosis factor alpha interleukin 1 beta, and interleukin-6. Results: SAG bacteria were able to adhere directly to the central region of the pulpal matrix in small foci that were associated with a localized matrix breakdown. Acridine orange ethidium bromide staining and cell counts indicated a decrease in mammalian cell viability with increasing incubation times-in the presence of SAG bacteria. The increased expression of. tumor necrosis factor a and interleukin 1 beta was detected in infected tooth slices. Conclusions: A novel ex vivo model system has been developed that allows coculture of SAG bacteria with a 3-dimensional organotypic tooth slice. The model allows observation of bacterial growth patterns and subsequent responses from host tissues.

• 出版日期2013-1