title: Effects of inactivated Enterococcus faecalis on the proliferation and osteogenic induction of osteoblasts.
abstract: The present study aimed to evaluate the effects of Enterococcus faecalis, inactivated by the common intracanal irrigants sodium hypochlorite (NaOCl) and chlorhexidine (CHX), on osteoblasts. E. faecalis was inactivated with 2% CHX or 5.25% NaOCl. Subsequently, the Cell Counting kit‑8 assay was used to examine the effects of CHX‑ and NaOCl-inactivated E. faecalis on MC3T3‑E1 osteoblast cell proliferation. Alizarin red staining was used to determine osteoblast mineralization, and osteogenic induction was quantified by determining the optical density of the dye solution. The relative expression levels of osteogenic genes were detected after 1, 4, 7 and 14 days of stimulation with CHX‑ and NaOCl-inactivated E. faecalis by reverse transcription‑quantitative polymerase chain reaction. The results indicated that CHX‑inactivated E. faecalis inhibited osteoblast proliferation, whereas NaOCl‑inactivated E. faecalis did not suppress cell proliferation. Various concentrations of CHX‑ and NaOCl‑inactivated E. faecalis induced different degrees of osteoblast mineralization. The expression levels of osteocalcin, alkaline phosphatase, runt‑related transcription factor 2, osteopontin and osterix were upregulated in cells following stimulation with 107 and 105 colony‑forming units/ml E. faecalis inactivated by CHX and NaOCl; the upregulation of these osteogenic genes occurred at various time points. In conclusion, the present study demonstrated that CHX‑inactivated E. faecalis exerted more of an effect on osteoblast proliferation compared with NaOCl‑inactivated E. faecalis. In addition, CHX‑ and NaOCl‑inactivated E. faecalis was able to induce mineralization and relevant osteogenic gene expression in osteoblast cells.
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat‑sen University, Guangzhou, Guangdong 510055, P.R. China.
authors.forename: Zhongchun
authors.initials: Z
authors.lastname: Tong
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat‑sen University, Guangzhou, Guangdong 510055, P.R. China.
authors.forename: Jinglei
authors.initials: J
authors.lastname: Ma
authors.affiliation: Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat‑sen University, Guangzhou, Guangdong 510055, P.R. China.
authors.forename: Jiali
authors.initials: J
authors.lastname: Tan
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat‑sen University, Guangzhou, Guangdong 510055, P.R. China.
authors.forename: Lijia
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat‑sen University, Guangzhou, Guangdong 510055, P.R. China.
authors.forename: Junqi
authors.initials: J
authors.lastname: Ling
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D015415:Biomarkers; D002454:Cell Differentiation; D049109:Cell Proliferation; D002710:Chlorhexidine / Q000494:pharmacology; D013293:Enterococcus faecalis / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D005786:Gene Expression Regulation; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism*; D010012:Osteogenesis / Q000235:genetics; D053495:Osteopontin / Q000378:metabolism; D012973:Sodium Hypochlorite / Q000494:pharmacology; D000076182:Sp7 Transcription Factor; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D015415:Biomarkers; D000076182:Sp7 Transcription Factor; C479466:Sp7 protein, mouse; D014157:Transcription Factors; D053495:Osteopontin; D012973:Sodium Hypochlorite; D000469:Alkaline Phosphatase; D002710:Chlorhexidine