INTRODUCTION: It is important to develop an antimicrobial agent without any damage on dental pulp. In the present study, we examined whether pretreatment of bacterial lipopolysaccharides (LPS) with ozonated water (O(3)aq) improves LPS-induced responses of rat odontoblastic cell line, KN-3. METHODS: After the pretreatment of LPS with O(3)aq, effects of LPS and O(3)aq-treated LPS on cell viability; calcification ability; expression of cyclooxygenase 2 (COX-2), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-alpha); and activation of p38 of KN-3 cells were examined. RESULTS: The formation of mineralized nodules by KN-3 cells was suppressed by LPS, whereas that suppression was inhibited by the pretreatment of LPS with ozonated water. We also found that LPS-induced expression of COX-2, IL-6, and TNF-alpha and p38 activation were markedly suppressed when LPS was pretreated with ozonated water. Furthermore, expression of COX-2, IL-6, and TNF-alpha by LPS were mainly induced through p38 activation. CONCLUSION: These results suggest that odontoblastic cells exhibit inflammatory responses against LPS and that ozonated water has the ability to improve LPS-induced inflammatory responses and suppression of odontoblastic properties of KN-3 cells through direct inhibition of LPS.
INTRODUCTION: It is important to develop an antimicrobial agent without any damage on dental pulp. In the present study, we examined whether pretreatment of bacterial lipopolysaccharides (LPS) with ozonated water (O(3)aq) improves LPS-induced responses of rat odontoblastic cell line, KN-3. METHODS: After the pretreatment of LPS with O(3)aq, effects of LPS and O(3)aq-treated LPS on cell viability; calcification ability; expression of cyclooxygenase 2 (COX-2), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-alpha); and activation of p38 of KN-3 cells were examined. RESULTS: The formation of mineralized nodules by KN-3 cells was suppressed by LPS, whereas that suppression was inhibited by the pretreatment of LPS with ozonated water. We also found that LPS-induced expression of COX-2, IL-6, and TNF-alpha and p38 activation were markedly suppressed when LPS was pretreated with ozonated water. Furthermore, expression of COX-2, IL-6, and TNF-alpha by LPS were mainly induced through p38 activation. CONCLUSION: These results suggest that odontoblastic cells exhibit inflammatory responses against LPS and that ozonated water has the ability to improve LPS-induced inflammatory responses and suppression of odontoblastic properties of KN-3 cells through direct inhibition of LPS.