| Research Abstract |
Inflammation was induced in rat dental pulp by applying bacterial lipopolysaccharide (LPS). Extirpated tissue samples from inflamed pulps were incubated in vitro in a krebs buffer containing Ca^<2+> ionophore A23187, and leukotriene (LT) B_4 released into the medium was determined by radio-immunoassay. Production of LTB_4 could be detected three to 24 h after the application of LPS and showed a maximum at 12 h. Histologically, marked infiltration of neutrophils, but not other leukocytes, was characteristically observed in the LPS-applied pulps, and the temporal change in neutrophil infiltration was almost parallel, but somewhat more delayed than LTB_4 production. When BW755C, a dual inhibitor of cyclo-oxygenase and lipoxygenase, was given to the animals before the application of LPS, both production of LTB_4 and the number of infiltrated neutrophils were significantly decreased, whereas administration of indomethacin had no effect. These results suggest that LTB_4 may be involved in ne
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utrophil infiltration in pulpal inflammation. It was also suggested that a major early source of LTB_4 in experimental pulpitis was leukocytes, primary neutrophils, because the synthesis of LTB_4 in the inflamed pulp was diminished by depletion of circulating leukocytes with cyclophosphamide prior to the application of LPS.
15-lipoxygenase activity was investigated in sonicated polymorphonuclear leukocytes (PMNLs) from patients with juvenile and rapidly progressive periodontitis and adult periodontitis. The group with juvenile and rapidly progressive periodontitis had 17 patients (6 male, 11 female, mean age 27.4 years), and the age matched control group had 18 normal individuals (11 male, 7 female, mean age 26.3 years). The group with adult periodontitis had 14 patients with 9 male, 5 female, mean age 45.2 years and the age matched control group had 6 normal subjects with 5 male, female, mean age 43.7 years. 15-
hydroxyeicosa-tetraenoic acid (15-HETE) synthesized in the group with juvenile and rapidly progressive periodontitis was 0.219( ] SY.+-.[ )0.102ng/mg protein (mean ( ] SY.+-.[ ) S. D.), while it was 0.410( ] SY.+-. [ ) 0.138 ng/mg protein in the age-matched control group. There was a significant difference between the two groups. The group with adult periodontitis produced 0.358( ]SY.+-.[ )0.124ng/mg protein and the age matched control group produced 0.448( ]SY.+-.[ )0.176ng/mg protein (no significant differecne). These results are relevant to reports that PMNLs of patients with juvenile and rapidly progressive periodontitis have abnormal functions, while those of patients with adult periodontitis are normal. Less
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