Al though the changes in tooth morphology and hardness by hydrogen peroxide(H20 z) have been r‘epor‘.ted .‘ the pαr。o야t뻐ec야tive role of heme oxygenase-l(HO-l) against the cytotoxic effects of H202 has not been clarifïed i n human pulp cells ln this st udy. we investigated whether HO-l is involved in Hz0 2-induced cytoLox icity a nd examined the production 0 1' dentin sia lophosphoprotein(DSPP) and other mineralization markers‘ in hllman pu lp cells H202 decreased cell viabi lity, but increased HO-l and DSPP expression in a concentra tion and time dependent manner . Inhibitors of gllanylate cyclase. PI3K, ERK. and p38 MAP kinase blocked H202-indllced cytotoxicity and the expression of HO-l and DSPP mRNAs in pulp cells. These data suggest that the induction of HO-l by H202 in plllp cells plays a protective role against the cytotoxic effects 0 1' HzOz and stimulates DSPP expression‘ reslllting in prematllre odontoblast dilTerentiation throllgh pathways that involve cGMP‘ p38. and ERK.

• Hwa Jeong Lee(These authors contributed equally to this work as first authors)
• Kyung San Min(These authors contributed equally to this work as first authors)
• Sung Hee Pi(Department of Oral & Maxillofacial Pathology, College of Dentistry, Wonkwang University)
• Hoon Sang Chang(Department of Oral & Maxillofacial Pathology, College of Dentistry, Wonkwang University)
• Kyung Hwa Kang(Department of Oral & Maxillofacial Pathology, College of Dentistry, Wonkwang University)
• Hyung Ryong Kim(Department of Oral & Maxillofacial Pathology, College of Dentistry, Wonkwang University)
• Hong In Shin(Department of Oral & Maxillofacial Pathology, College of Dentistry, Wonkwang University)
• Suk Keun Lee(Department of Oral & Maxillofacial Pathology, College of Dentistry, Wonkwang University)
• Eun Cheol Kim(Department of Oral & Maxillofacial Pathology, College of Dentistry, Wonkwang University)