The effects of bacterial sonicates on human keratinizing stratified squamous epithelium in vitro

Direct cytotoxicity of plaque is believed to play a role in the soft tissue destruction observed in periodontal disease. This property has been demonstrated in vitro on cell lines but appears to be dependent upon the target cell used and the plaque organism being tested. The purpose of this investigation was to determine the effects of bacterial products on growth of keratinized stratified squamous epithelium maintained in vitro. Morphological features of these cultures closely resembled normal epidermis. Sterile sonicates of the periodontal pathogenesBacieroides asaccharolyticusandActinomyces, naeslundiiwere diluted to equal protein concentrations and added lo keratinocyte cultures. TheBacteroidessonicate caused up to 97 % inhibition of labelled thymidine uptake of cultured keratinocytes while the peak inhibition of theActinomycessonicate was only 39 % of untreated controls. These results indicate that products ofB.asaccharolyticuswere more inhibitory to the growth of cultured keratinocytes than products ofA. naes lundii.and that keratinocyte cultures make a useful model for investigation of the interactions between periodontal pathogens and differentiating epidermal cells.