| Summary: | 碩士 === 國立陽明大學 === 臨床牙醫學研究所 === 99 === Epidemiological studies have demonstrated that individuals with diabetes are more easily to have periodontitis than those without diabetes. Among the population of diabetes with periodontitis, the periodontal tissue destruction in those with poor glycemic control was more severe than those with good glycemic control, which indicated that the pathogenesis and progression of periodontitis may be related to long term hyperglycemia. Macrophages, derived from circulating monocytes, play an important role on inflammatory mediators secretion in periodontal tissue. The main purpose of this study was to investigate the effects of normal or high glucose on inflammatory mediators secretion of macrophages and the possible roles of intracellular calcium concentration. U937 macrophages pre-exposed to normal or high concentration of glucose for 2 weeks were treated with Porphyromonas gingivalis lipopolysaccharide for 24 hours. This study model simulated the stimulation of periodontal pathogen LPS on macrophages. Besides, intracellular calcium chelating agent was used to investigate the importance of intracellular calcium on inflammatory mediators secretion with different concentrations of glucose and LPS. Trypan blue exclusion assay was used to calculate cell numbers and vital cell percentages. MTT (3- (4, 5- dimethylthiazol-2-yl) -2, 5- diphenyl tetrazolium bromide) assay was used to study mitochondrial activity in macrophages. The levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and prostaglandin E2 (PGE2) secretion were determined using enzyme-linked immunosorbent assay (ELISA) or enzyme immunoassay (EIA). The activation of inflammatory related transcription factor, nuclear factor-kappa B (NF-κB), was observed using confocal laser scanning microscopy. In the condition without LPS stimulation, U937 macrophages pre-exposed to high glucose showed higher mitochondrial activity than those pre-exposed to normal glucose, partial NF-κB translocation to the nucleus, and increased IL-6, TNF-α and PGE2 secretion. When LPS stimulation existed, both the NF-κB translocation, and the secretion of IL-6, TNF-α and PGE2 were much more obvious. The results also showed that the calcium chelating agent inhibited the augmentation effect of high glucose and LPS on IL-6, TNF-α and PGE2 secretion, which indicated that intracellular calcium may be involved in the augmentation effects.
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