| Summary: | 碩士 === 國立陽明大學 === 口腔生物研究所 === 93 === Areca quid (AQ) chewing is popular in countries in Southeast Asia. Epidemiological studies have revealed that there are approximately two million AQ chewers in Taiwan. A strong relationship between AQ chewing and oral diseases such as oral cancer, oral leukoplakia, and periodontal disease has been established. Previous studies showed that the exposure of neutrophils to areca nut extract (ANE) reduces the superoxide anion production, the bactericidal and phagocytic activity. However, it is not yet clear whether ANE can affect chemokines secretion by neutrophils. This study aimed to investigate the effects of ANE on chemokines secretion in neutrophils, and to study the potential role of calcium ions.
Neutrophils isolated from peripheral blood of healthy volunteers were treated with various concentrations of ANE in HBSS/Ca2+ or HBSS for 8 hours. Afterwards, the effects of ANE on the viability of neutrophils were determined by flow cytometer using propidium iodide (PI) staining. In addition, the cell supernatants after ANE treatment were collected, and the protein levels of interleukin-8 (IL-8) and macrophage inflammatory protein-1�� (MIP-1��) were analyzed using enzyme-linked immunosorbent assay (ELISA). To study the role of calcium ions, neutrophils were pretreated with extracellular calcium chelator, EGTA [ethylene glycol-bis(2-aminoethylether)-N, N, N’, N’-tetraacetic acid] for 1 hour followed by treatment of neutrophils with 6.25 �慊/ml of ANE in HBSS/Ca2+ for 8 hours. The cell viability was then determined, and the cell supernatants were subjected to IL-8 analysis.
The results showed that neutrophils incubated in HBSS were more susceptible to ANE. The IL-8 production, but not MIP-1a production, was induced by ANE in a dose-dependent manner. Moreover, the modulation of IL-8 by ANE was more evident in the presence of calcium ions. In addition, after pretreated with extracellular calcium chelator, EGTA (2.5 mM), the induction of IL-8 by ANE was inhibited.
To conclude, the results in this study showed that ANE induced IL-8 secretion of neutrophils, and the calcium ions may play a role in the regulation of ANE-induced IL-8 production. The secretion of MIP-1�� by neutrophils was not affected by ANE. The results generated in this study might further elucidate how areca nut influences the functions of neutrophils.
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