Effects of bacterial products on the activity of odontoblast- like cells and their formation of type 1 collagen

AimTo study how products released from different bacteria in a deep carious lesion affect the metabolic activity of odontoblast-like cells and their ability to produce the major organic component of dentine, collagen 1. MethodologyMDPC-23 cells were exposed to supernatants from biofilm cultures of strains isolated from the deepest part of a carious lesion as well as from a clinical isolate of Enterococcus faecalis. Lipoteichoic acid (LTA) and lipopolysaccharide (LPS) were used for comparison. Cell activity was assessed using an methyl-thiazolyl-diphenyl tetrazolium bromide (MTT) assay, and collagen 1 levels were determined by ELISA. ResultsThe lesion microflora was dominated by Lactobacillus spp. Neither extracellular products from the isolates nor LPS affected the activity of the MDPC-23 cells, whereas extracellular products from E.faecalis and LTA significantly reduced total cell activity (P<0.01). Enterococcus faecalis had an inhibitory effect upon collagen 1 production by the cells, whereas no such effect or even a slight stimulatory effect was seen for the isolates from the deep carious lesion. ConclusionsThese studies indicate that culture supernatants from E.faecalis reduced the metabolic activity of odontoblast-like cells as shown using the MTT assay. No effect was seen for supernatants from biofilms of bacteria recovered from a deep carious lesion. Different bacteria varied in their effects upon collagen 1 production suggesting that the nature of the bacterial species in a carious lesion may have a direct influence upon the ability of the odontoblasts to produce tertiary dentine.