Apoptosis is critical in the pathogenesis of several infectious diseases. The induction of apoptosis was assessed in mouse lymph node cells by four bacteria recovered from infected human dental pulp: Gemella morbillorum, Clostridium butyricum, Fusobacterium nucleatum and Bifidobacterium adolescentis. Smaller lymph nodes and smaller numbers of cells were observed after experimental dental pulp infection with C. butyricum, suggesting that this bacterium induces cell death. Apoptosis was evaluated by determination of cell ploidy and detection of DNA degradation in cells cultured with killed bacteria. Paraformaldehyde-killed C. butyricum and heat-killed G. morbillorum induced substantial cell death, while F. nucleatum and B. adolescentis induced cell death at lower levels. No bacterial preparations induced apoptosis in cells from mice genetically deficient for tumour necrosis factor receptor p55 (TNFRp55), implicating this receptor directly or indirectly as a mediator in the process. It was concluded that apoptosis may be induced during periapical lesions of pulpal origin.
JewettA.,
HumeW. R.,
LeH.,
HuynhT. N.,
HanY. W.,
ChengG.,
ShiW.2000; Induction of apoptotic cell death in peripheral blood mononuclear and polymorphonuclear cells by an oral bacterium, Fusobacterium nucleatum
. Infect Immun 68:1893–1898[CrossRef]
KakehashiS.,
StanleyR. H.,
FitzgeraldR. J.1965; The effects of surgical exposures of dental pulps in germ-free and conventional laboratory rats. Oral Surg Oral Med Oral Pathol 20:340–349[CrossRef]
LannaM. A.,
Ribeiro-SobrinhoA. P.,
StehlingR.,
GarciaG. D.,
SilvaB. K. C.,
HamdanJ. S.,
NicoliJ. R.,
CarvalhoM. A. R.,
FariasL. M.2001; Microorganisms isolated from root canals presenting necrotic pulp and their drug susceptibility in vitro
. Oral Microbiol Immunol 16:100–105[CrossRef]
MahidaY. R.,
MakhS.,
HydeS.,
GrayT.,
BorrielloS. P.1996; Effect of Clostridium difficile toxin A on human intestinal epithelial cells: induction of interleukin 8 production and apoptosis after cell detachment. Gut 38:337–347[CrossRef]
MorimotoH.,
BonavidaS.1992; Diphtheria toxin- and Pseudomonas A toxin-mediated apoptosis.ADP ribosylation of elongation factor-2 is required for DNA fragmentation and cell lysis and synergy with tumor necrosis factor-alpha. J Immunol 149:2089–2094
PfefferK.,
MatsuyamaT.,
KundigT. M. & 7 other authors; 1993; Mice deficient for the 55 kd tumor necrosis factor receptor are resistant to endotoxic shock, yet succumb to L.monocytogenes infection. Cell 73:457–467[CrossRef]
Ribeiro SobrinhoA. P.,
LannaM. A.,
FariasL. M.,
CarvalhoM. A. R.,
NicoliJ. R.,
UzedaM.,
VieiraL. Q.2001; Implantation of bacteria from human pulpal necrosis and translocation from root canals in gnotobiotic mice. J Endod 27:605–609[CrossRef]
Ribeiro SobrinhoA. P.,
MaltosS. M.,
FariasL. M.,
CarvalhoM. A. R.,
NicoliJ. R.,
UzedaM.,
VieiraL. Q.2002; Cytokine production in response to endodontic infection in germ-free mice. Oral Microbiol Immunol 17:344–353[CrossRef]
SmithC. A.,
FarrahT.,
GoodwinR. G.1994; The TNF receptor superfamily of cellular and viral proteins: activation, costimulation, and death. Cell 76:959–962[CrossRef]