Effects of Calcium Hydroxide on Biological Activity of LPS

2006 Fiscal Year Final Research Report Summary

• Project/Area Number: 17592010
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Conservative dentistry
• Research Institution: Osaka Dental University
• Principal Investigator: SHIDA Muneyasu Osaka Dental University, assistant, 歯学部, 助手 (10187354)
• Project Period (FY): 2005 – 2006
• Keywords: bacterial endotoxin / biological activity / inflammatory cytokine / calcium hydroxide / RT-PCR

Research Abstract

Apical periodontitis and its concomitant periapical osteolysis are caused by pulpal infection, and bacterial lipopolysaccharide (LPS) has been known to play a major role in the inflammation and the bone resorption process.
Recently, it was reported that calcium hydroxide hydrolyzed the lipid moiety of bacterial LPS, resulting in the release of free hydroxy fatty acid and may alter biological activities of bacterial LPS.
This study examined whether calcium hydroxide may alter the biological action of bacterial LPS through comparing the expression of inflammatory cytokine genes (IL-1 α, β,IL-6,IL-8 and TNF-α) of human periodontal ligament fibroblasts (HPLF) stimulated by LPS and/or calcium hydroxide for 6,12 and 24 hrs. The results were as follows.
IL-6 and IL-8 genes in every experimental time and TNF-α gene in the 6 hours group were expressed in HPLF stimulated by LPS, but no IL-1 α or β gene were expressed. Further, calcium hydroxide inhibited IL-6, IL-8 and TNF-α gene expression in HPLF stimulated by LPS.
These results suggest that calcium hydroxide inhibits the inflammatory reactions caused by bacterial LPS.