Impact of Aggregatibacter actinomycetemcomitans on epithelial repair: in vitro study in wound model

Normal wound healing occurs in four overlapping stages - hemostasis, inflammation, proliferation, and remodeling. In the oral cavity, these processes occur in an infectious environment. Among the pathogens found in the oral community, Aggregatibacter actinomycetemcomitans (Aa) constitutes a well-recognized periodontal pathogen responsible for expressing several virulence factors, which activate a host response. Aim: This study investigated whether Aa’s presence can interfere with oral keratinocyte tissue healing in an in vitro wound healing model. Methods: Two groups were defined: Group KO (n=5) and Group KO+Aa (n=5). The Aa (JP2 strains) were cultivated in anaerobiosis, and the total protein extract was obtained. The keratinocytes were cultivated with the medium of standard culture until their confluence. After confluence, plates were allocated to each group. With the pipette’s tip, a “scratch” was made in the middle of each well of the plate, and the cells were cultured at 37°C in a humidified atmosphere with 5% CO₂. The cells received the stimulus according to groups, and, at times 0, 5, 10, 24, and 48 hours, the wound areas were visualized and standardly recorded using an inverted microscope. Results: When analyzing the timeframe, differences in wound measurements indicate a faster closure in the control group compared to the KO+Aa group, although not statistically significant. However, upon examining the wound closure measures, it was observed that the Aa protein extract significantly reduced wound closure at 10 and 48 hours (p<0.05), negatively impacting the keratinocyte’s behavior. Conclusion: In summary, it was demonstrated that the pathogen Aa can interfere with the re-epithelization in vitro.