0970 Regulation of HO-1 expression by root canal sealers in HGFs
F.-M. HUANG, Chung Shan Medical University, Taichung R.O.C, Taiwan, and Y.C. CHANG, Chung Shan Medical University, Taichung, Taiwan

Objectives: Heme oxygenase-1 (HO-1) is known as a stress-inducible protein and functions as an antioxidant enzyme. It has been shown that HO-1 is induced rapidly by a variety of chemical and physical stimuli. However, little is known about the induction of HO-1 after cell exposure to root canal sealers. The aim of the present study was to investigate the effects of zinc oxide-eugenol based root canal sealer N2 and epoxy resin based root canal sealer Topseal on the expression of HO-1 protein in cultured human gingival fibroblasts (HGFs). Methods: Western blot assay was used to investigate the effects on HGFs exposed to root canal sealers. Furthermore, to determine whether oxidative stress could modulate HO-1 expression in HGFs by N2 and Topseal, HGFs were treated with cysteine precursor 2-oxothiazolidine-4-carboxylic acid (OTZ) and glutathione synthesis inhibitor buthionine sulfoximine (BSO). Results: The exposure of quiescent HGFs to N2 and Topseal resulted in the induction of HO-1 protein expression in a time-dependent manner (p<0.05). The addition with OTZ decreased the N2-induced HO-1 protein level by approximately 32 % (p<0.05). However, BSO enhanced the N2-induced HO-1 protein level by up to 2-fold (p<0.05). Similar results were found by Topseal. The treatment with OTZ decreased the Topseal-induced HO-1 protein level by approximately 12 % (p<0.05). However, BSO enhanced the Topseal-induced HO-1 protein level by up to 1.7-fold (p<0.05). Conclusions: HO-1 expression might be one signal transduction pathway linked to the induction of stress-inducible protein by root canal sealers. In addition, the activation of HO-1 is augmented by oxidative stress.

Seq #79 - Oral Health, Toxicology
11:00 AM-12:00 PM, Thursday, 29 June 2006 Brisbane Convention & Exhibition Centre Exhibit Hall 1

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