Interaction between Actinobacillus actinomycetemcomitans and oral keratinocytes in vitro

Introduction: Actinobacillus actinomycetemcomitans (Aa) is a pathogenic microorganism responsible for destruction of periodontal tissue. This bacteria produce leokotoxin and Cytolethal Distending Toxin (CDT) that have been known to play a role in the mechanism of periodontal damage, through suppression of proliferation, induction of eukaryotic cell enlargement followed by apoptosis of host cells. Objective: To compare the viability of Human keratinocyte cell line (HaCat) and primary oral mucosal culture after incubation with filtered-sterilized bacterial supernatan. Method: Cultures of HaCat cell line and primary oral mucosal were cultured in complete DMEM under standard condition (37^oC, 5% CO₂), seeded at 2x10⁴ cells/ml in 24 well-tissue culture plate and the supernatant were added at 500ul. After 72 hours co-incubation, the viability of cells was determined qualitatively by morphological size and quantitatively by MTT (3-[4,5-dimethtyltiazol-2-yl]-2,5 diphenyltetrazolium bromide) assay. Results: Groups of supernatan treatment culture showed increased number of cells enlargement compared to those non treated culture. Additionally, MTT assay showed both eukaryotic cells decreased in viability compared to the controlled groups. However, only Primary oral mucosal culture demonstrates statistically significant (p=0.014). Conclusion: CDT-contained supernatant secreted by Aa altered the morphology and the vialbility of oral keratinocyte cells in vitro.

This study was supported by RISBIN IPTEKDOK 2006