Rat periodontal fibroblast responses to bacterial lipopolysaccharide in vitro.

Rat periodontal ligament fibroblasts and gingival fibroblasts were stimulated with lipopolysaccharide from Escherichia coli. Cell proliferation and both interleukin-1beta and nitric oxide production were determined by a colorimetric, enzyme-linked immunosorbent assay and the Griess reaction, respectively. The results showed that at lipopolysaccharide concentration up to 100 ng per well, the cell proliferation of periodontal ligament fibroblasts was higher than that of gingival fibroblasts. No significant difference between the levels of interleukin-1beta produced by periodontal ligament and gingival fibroblasts can be observed. At high concentration of lipopolysaccharide (1000 ng/well), the levels of nitric oxide in the periodontal ligament fibroblasts cultures were higher than those in the gingival fibroblasts cultures. These results suggest those rat periodontal ligament and gingival fibroblasts may respond differently to lipopolysaccharide and, thus, may be different periodontal fibroblast subpopulations.