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2 "Hyeon-Mee Yoo"
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Comparison of ultrasonic and sonic root end preparations using anaerobic bacterial leakage model
Nak-Yeon Cho, Dong-Sung Park, Hyeon-Mee Yoo, Tae-Seok Oh
J Korean Acad Conserv Dent 2002;27(5):530-534.   Published online September 30, 2002
DOI: https://doi.org/10.5395/JKACD.2002.27.5.530
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IL-1 and TNF-α release in human polymorphonuclear leukocytes after exposure to calcium hydroxide treated Porphyromonas endodontalis lipopolysaccharide
Chan-Je Park, Dong-Sung Park, Hyeon-Mee Yoo, Tae-Seok Oh, Sung-Sam Lim
J Korean Acad Conserv Dent 2002;27(5):463-472.   Published online September 30, 2002
DOI: https://doi.org/10.5395/JKACD.2002.27.5.463
AbstractAbstract PDFPubReaderePub

Bacterial lipopolysaccharide (LPS) plays a major role in stimulating the synthesis and release of the principal osteoclast-activating cytokines, namely, interleukin 1 and tumor necrosis factor-α from immune cells. Although monocytes/macrophages are the main producers of these cytokines, recent evidence has indicated that polymorphonuclear leukocytes (PMN) have the ability to release IL-1 and TNF-α. Calcium hydroxide has been shown to be an effective medicament in root canal infections, reducing the microbial titre within the canal. It has been proposed that the therapeutic effect of Ca(OH)2 may also be the result of direct inactivation of LPS. The purpose of this study was to investigate whether treatment of Porphyromonas endodontalis LPS with calcium hydroxide alters its biological action as measured by human PMN secretion of IL-1 and TNF-α, and it was compared with Escherichia coli LPS.

P. endodontalis ATCC 35406 was cultured in anaerobic condition, and LPS was extracted using the hot-phenol water extraction method and purified. Purchased E. coli LPS was also purified. 100 µg/ml of each LPS in pyrogen free water were incubated with 25mg/ml Ca(OH)2 at 37℃ for 7 days. The supernatants were subjected to ultrafiltration, and the isolates were lyophilized and weighed. PMNs were obtained from peripheral blood by centrifugation layered over Lymphoprep. The cells were resuspended (4×106 cells/ml) in RPMI 1640 followed by treatment with various concentrations of LPS (0, 0.1, 1, 10µg/ml) for 24 hours at 37℃ in 5% CO2 incubator. The supernatants of cells were collected and the levels of IL-1α, IL-1β and TNF-α were measured by enzyme-linked immunosorbent assay.

The results were as follows;

1. The levels of IL-1α, IL-1β, TNF-α from PMN treated with each LPS were significantly higher than those released from unstimulated PMN of the control group (p<0.05).

2. The levels of all three cytokines released from PMN stimulated with each calcium hydroxide treated LPS were significantly lower than those released from PMN stimulated with each untreated LPS (p<0.05), while they were not significantly different from those released from unstimulated PMN of the control group (p>0.05).

3. The levels of secretion for all three cytokines were affected in a dose-dependent manner in PMN stimulated with each LPS (p<0.05), but not in PMN stimulated with each calcium hydroxide treated LPS (p>0.05).

4. The levels of all three cytokines released from PMN stimulated with P. endodontalis LPS were significantly lower than those released from PMN stimulated with E. coli LPS (p<0.05).

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