title: The preservative effect of Thai propolis extract on the viability of human periodontal ligament cells.
abstract: OBJECTIVE
  Tooth avulsion causes an injury to the periodontal ligament (PDL). The success of tooth replantation depends on the quantity and quality of PDL cells. The aim of this study was to examine the preservative and proliferative effects of Thai propolis extract, previously shown to exert anti-inflammatory and antioxidant activities, on human PDL cells.
  
  
  METHODS
  Ninety-six premolars were left to air dry for 30 min and stored in Hank's balanced salt solution (HBSS), milk, or various concentrations of propolis extract from 0.25 to 10 mg ml-1for 3 h. PDL cells were isolated by collagenase and trypsin digestion, and their viability was determined by a trypan blue dye exclusion assay. PDL tissues were also scraped off the root surface and cultured to determine cell growth and morphology. The alamarBlue®and BrdU assays were performed to determine the cytotoxic and proliferative effects of the extract on cultured PDL cells, respectively.
  
  
  RESULTS
  A non-toxic dose of 2.5 mg ml-1of propolis extract yielded the greatest percentage of cell viability (78.84 ± 3.34%), which was significantly higher than those of the other concentrations (P < 0.001). Nevertheless, this percentage was not significantly different from that of HBSS (80.14 ± 2.44%; P = 1.00), but was significantly higher than that of milk (71.27 ± 2.79%; P < 0.001). The cells grown from PDL explants looked like fibroblasts. However, 2.5 mg ml-1of the extract did not induce PDL cell proliferation.
  
  
  CONCLUSIONS
  Thai propolis extract at 2.5 mg ml-1appears to be the most effective dose for preserving the viability of PDL cells, and this was comparable to HBSS.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Attaporn
authors.initials: A
authors.lastname: Prueksakorn
authors.affiliation: Department of Community Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Subin
authors.initials: S
authors.lastname: Puasiri
authors.affiliation: Department of Oral Biology, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Supanigar
authors.initials: S
authors.lastname: Ruangsri
authors.affiliation: Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Anupong
authors.initials: A
authors.lastname: Makeudom
authors.affiliation: Center of Excellence in Oral and Maxillofacial Biology, Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Thanapat
authors.initials: T
authors.lastname: Sastraruji
authors.affiliation: Center of Excellence in Oral and Maxillofacial Biology, Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Suttichai
authors.initials: S
authors.lastname: Krisanaprakornkit
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Pattama
authors.initials: P
authors.lastname: Chailertvanitkul
mesh_terms: D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D005347:Fibroblasts; D006801:Humans; D007552:Isotonic Solutions; D019188:Organ Preservation Solutions; D010513:Periodontal Ligament / Q000166:cytology / Q000502:physiology; D011429:Propolis / Q000494:pharmacology*
chemical_list: D007552:Isotonic Solutions; D019188:Organ Preservation Solutions; D011429:Propolis
keywords: cell proliferation; cell survival; periodontal ligament; propolis; tooth avulsion