MITOGENIC ACTION OF TUMOUR NECROSIS FACTOR-ALPHA AND INTERLEUKIN-8 ON EXPLANTS OF HUMAN DUODENAL MUCOSA

Abstract Our aim is to examine whether tumour necrosis factor-α (TNF-α) and interleukin affect the mitotic activity in explants of human duodenal mucosa and to estimate the release of cytokines from explants incubated with TNF-α. Biopsy specimens of normal duodenal mucosa were taken from 19 subjects that underwent upper endoscopy for investigation of dyspeptic symptoms or chronic gastrointestinal bleeding. The specimens were processed following guidelines for organ culture technique. Paired biopsy specimens from 12 subjects were cultured for 23 h to achieve steady state and thereafter the explants were incubated 25 h with 10 −13 –10 −9  M of TNF-α or IL-8. Mitoses were arrested in the metaphase by adding vincristine sulphate for the last three hours. The explants were then fixed and processed for microdissection. Fifteen crypts were microdissected and the total number of metaphases was determined using the whole crypt as reference volume. The number of metaphases per crypt was also estimated in explants incubated with 10 −10  M TNF-α in the presence of anti-IL-8 antibodies. Additional duodenal explants from seven subjects were incubated with 10 −10  M TNF-α for 25 h. Thereafter the release of IL-1-β, IL-6, IL-8 and interferon gamma (IFN-γ) into the culture medium was measured by enzyme immunoassay and expressed as pg/mg protein. TNF-α and IL-8 significantly increased the number of metaphases/crypts ( P −10  M TNF-α alone ( P −10  M TNF-α in the presence of anti-IL-8 antibodies was, however, markedly and significantly higher than that of the controls ( P P P