title: Effects of bacterial products on the activity of odontoblast-like cells and their formation of type 1 collagen.
abstract: OBJECTIVE
  To 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.
  
  
  METHODS
  MDPC-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.
  
  
  RESULTS
  The 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.
  
  
  CONCLUSIONS
  These 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.
authors.affiliation: Department of Endodontics, Faculty of Odontology, Malmö University, Malmö, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Fransson
authors.forename: K
authors.initials: K
authors.lastname: Petersson
authors.forename: J R
authors.initials: JR
authors.lastname: Davies
mesh_terms: D000328:Adult; D000818:Animals; D001681:Biological Assay / Q000379:methods; D024042:Collagen Type I / Q000378:metabolism*; D003731:Dental Caries / Q000378:metabolism* / Q000382:microbiology; D013293:Enterococcus faecalis / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007778:Lactobacillus / Q000302:isolation & purification; D008070:Lipopolysaccharides; D051379:Mice; D009804:Odontoblasts / Q000378:metabolism*
chemical_list: D024042:Collagen Type I; D008070:Lipopolysaccharides
keywords: bacteria; biofilms; collagen type 1; dental caries; dental pulp; odontoblasts