RESUMO
Odontogenic cysts arise from tooth-forming epithelial residues. The stimulus for the formation of radicular cysts is thought to be endotoxin released from the infected necrotic tooth pulp. However, in keratocysts and follicular cysts, such a stimulus is not present. In order to investigate what drives the cyst epithelium to proliferate, explant media and fluids from 16 radicular cysts, eight keratocysts and seven follicular cysts and explant media from four specimens of non-inflamed gingival tissue were examined for the presence of endotoxin and cytokines. Cyst fluids were also cultured for 72 h in anaerobic and aerobic conditions to detect micro-organisms. Endotoxin from three different bacteria, cytokines [interleukin-(IL) 1 alpha, IL-1 beta and IL-6] as well as prostaglandin E2 (PGE2) were tested in an epithelial cell-proliferation assay. As the cyst epithelium is supported by a connective tissue capsule, the effect of fibroblast culture media on epithelial cell proliferation was also investigated. The results showed significantly higher concentrations of endotoxin in radicular cyst fluid than in the keratocyst or the follicular cyst. None of the cyst fluids contained micro-organisms. Immunoassays demonstrated the presence of IL-1 alpha and -6 in all fluids and explants tested; IL-1 beta was only found in the inflammatory radicular cysts. However, reverse transcriptase-polymerase chain reaction showed that mRNAs for IL-1 alpha, -1 beta and -6 were present in all cyst types. Proliferation studies indicated that endotoxin and the cytokines had a mitogenic effect on epithelia at low concentrations; PGE2 had very little effect at low concentrations, and had an inhibitory effect at high concentrations. Cyst fibroblast culture media had a mitogenic effect on the epithelia that was enhanced by the presence of endotoxin.
Assuntos
Citocinas/fisiologia , Endotoxinas/fisiologia , Cistos Odontogênicos/etiologia , Aggregatibacter actinomycetemcomitans/fisiologia , Divisão Celular , Células Cultivadas , Tecido Conjuntivo/patologia , Meios de Cultura , Técnicas de Cultura , Necrose da Polpa Dentária/microbiologia , Epitélio/patologia , Escherichia coli/fisiologia , Exsudatos e Transudatos , Fibroblastos/patologia , Cisto Folicular/etiologia , Cisto Folicular/microbiologia , Cisto Folicular/patologia , Gengiva/patologia , Humanos , Interleucina-1/genética , Interleucina-1/fisiologia , Interleucina-6/genética , Interleucina-6/fisiologia , Lipopolissacarídeos/farmacologia , Mitógenos/fisiologia , Cistos Odontogênicos/microbiologia , Cistos Odontogênicos/patologia , Reação em Cadeia da Polimerase , Porphyromonas gingivalis/fisiologia , Prostaglandinas E/fisiologia , Cisto Radicular/etiologia , Cisto Radicular/microbiologia , Cisto Radicular/patologia , Germe de Dente/patologia , Transcrição GênicaRESUMO
Five examples of follicular cysts with papillary projections protruding into the lumen are given. In all cases, the lining was epidermoid. The cystic cavity contained compact, eosinophilic keratinous material. Groups of vacuolated keratinocytes with overlying tiers of parakeratotic cells were seen on the top of the crests. In the intervening valleys, there were irregular clumps of keratohyaline granules. These changes are diagnostic cytopathogenic effects of viral papillomas. However, papillomavirus common antigens were not identified by immunohistochemistry.
