Effects of roxithromycin on tumor necrosis factor-alpha-induced vascular endothelial growth factor expression in human periodontal ligament cells in culture

Background: Aberrant angiogenesis is associated with lesion formation in chronic periodontitis. However, little is known about the mediators that contribute to angiogenesis or about therapeutic agents that control the production of the mediators. Roxithromycin (RXM), which is a new 14-member macrolide antibiotic, has a wide antibacterial spectrum against oral pathogens and an immunomodulatory effect. In the present study, we examined the effects of RXM on tumor necrosis factor (TNF)-alpha -induced vascular endothelial growth factor (VEGF) in human periodontal ligament (HPDL) cells. In addition, the effect of RXM on VEGF expression in HPDL cells was examined. Methods: HPDL cells were plated at 5 x 10(5) cells/ml in 150 cm(2) cell culture dishes. The confluent-stage cells were pretreated with or without 10 mug/ml of RXM or other antibiotics in 1% FBS-containing alpha -MEM for 24 hours, followed by simultaneous treatment with 10 ng/ml of TNF-alpha and 10 mug/ml of these antibiotics. After incubation for various periods, the culture supernatants and sediments were collected and analyzed by ELISA, Northern blot, and gel shift assays. Results: VEGF mRNA and its protein were constitutively expressed in HPDL cells, and the level of expression was markedly enhanced by stimulation with TNF-alpha. RXM strongly inhibited the expression of VEGF mRNA and the production of VEGF Furthermore, RXM suppressed activation of transcription factors AP-1 and SP-1, which were critical factors in VEGF transcription, in TNF-alpha -stimulated HPDL cells. Conclusion: These results indicate that TNF-alpha, one of the proinflammatory cytokines implicated in the pathogenesis of periodontitis, induces excess induction of VEGF in HPDL, which may account for increased angiogenesis in periodontitis lesions. Interestingly, the antibiotic roxithromycin inhibits TNF-mediated VEGF induction, suggesting its possible therapeutic utility in periodontitis and other chronic inflammatory conditions involving VEGF induction.