Effect of Antibiotics on PMNs-Mediated Damage to Human Periodontal Ligament Fibroblast-Like Cell (HPLF)

Polymorphonuclear leukocytes (PMNs) play an important role in host defence against periodontal tissue invading bacteria. On the other hand, PMNs may enhance tissue destruction through the formation of toxic oxygen radicals and the release of tissue reactive proteins. In previous studies, we have shown that lipopolysaccharide (LPS) enhanced N-formyl-mithionyl-leucyl-phenyl-alanine (FMLP) stimulated PMMs-mediated damage to culture human periodontal ligament fibroblast-like cell (HPLF). The present study was to investigate the effect of antibiotics on PMNs-mediated damage of HPLFs. HPLFs were grown to confluent in culture and exposed antibiotics, and then stimulated PMNs by LPS (1000ng/ml) and FMLP (10-6M). Cytotoxicity of HPLFs were determined by double staining method using fluorescein diacetate (FDA) and propidium iodide (PI). Minocycline (20μg/ml) and doxcycline (20μg/ ml) had significant inhibitory effect on the PMNs -mediated HPLF injury over the three hour of assay. However, same concentration of ampicillin, streptomycin, chlortetracycline and oxytetracycline had no significant effect on the same system. These results suggest that, in this system, minocycline and doxcycline may suppress PMNs-associated enzymes activity, degranulation and toxic oxygen radicals synthesis.