title: Expression of inflammatory cytokines and MMPs on replanted teeth at different extra-alveolar time: an ex vivo and in vivo study.
abstract: BACKGROUND
  Immediately after the avulsed tooth is replanted, a complex inflammatory response ensues. As part of the periodontium healing process, the extracellular matrix macromolecules are essential to create the cellular environment required during healing and morphogenesis.
  
  
  OBJECTIVE
  This study was designed to evaluate the correlation between different extra-alveolar dry times and inflammatory cytokines and matrix metalloproteinases (MMPs) as part of the periodontal ligament (PDL) gene expression.
  
  
  METHODS
  The first phase of the study aimed testing human PDL cells ex vivo. Extracted teeth were dried for 15 and 30 min. The PDL cells were extracted and analyzed by qRT-PCR. The second phase was performed in vivo, and 36 Sprague Dawley rat first maxillary molars were extracted and replanted after 15, 30, and 60 min extra-alveolar time. We tested the levels of inflammatory cytokines and MMPS in periodontal tissue at 3, 7, and 28 days after tooth replantation. The replanted area was dissected, grounded, and analyzed by RT-PCR.
  
  
  RESULTS
  Expressions of IL-1β, IL-6, TNF-α, and MMP-3 and MMP-9 were significantly higher in the replanted teeth. Extended dry time had a direct correlation with induction of pro-inflammatory cytokine and MMPs in PDL cells.
  
  
  CONCLUSIONS
  Our study showed that pro-inflammatory cytokines were more significantly expressed in the tissues surrounding the replanted teeth. Future research must be undertaken to additionally confirm the release of these cytokines and be focused on the inhibition of these cytokines to reduce inflammation of replanted teeth.
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Hyo Jung
authors.initials: HJ
authors.lastname: Ahn
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Ok Hyung
authors.identifier: http://orcid.org/0000-0002-6386-803X
authors.initials: OH
authors.lastname: Nam
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Hyo-Seol
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Maxillofacial Tissue Regeneration and Research Center for Tooth & Periodontal Regeneration (MRC), School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Eun-Cheol
authors.initials: EC
authors.lastname: Kim
authors.affiliation: Department of Endodontics and Pediatric Dentistry, University of Washington, Seattle, WA, USA.
authors.forename: Nestor
authors.initials: N
authors.lastname: Cohenca
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: Sung Chul
authors.initials: SC
authors.lastname: Choi
mesh_terms: D000818:Animals; D016207:Cytokines / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D008963:Molar; D010446:Peptide Fragments / Q000378:metabolism; D010513:Periodontal Ligament / Q000378:metabolism*; D010519:Periodontium / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D014084:Tooth Avulsion / Q000378:metabolism; D014081:Tooth Extraction; D014090:Tooth Replantation; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014945:Wound Healing
chemical_list: D016207:Cytokines; D053583:Interleukin-1beta; D015850:Interleukin-6; D010446:Peptide Fragments; D014409:Tumor Necrosis Factor-alpha; C052994:interleukin-1beta (163-171); D020782:Matrix Metalloproteinases; D019278:Matrix Metalloproteinase 3; D020780:Matrix Metalloproteinase 9