title: Pulpal Tissue Inflammatory Reactions after Experimental Pulpal Exposure in Mice.
abstract: BACKGROUND
  The purpose of this study was to establish a stable experimental mice pulpal inflammatory model and to evaluate inflammatory reactions of pulpal tissue after pulpal exposure.
  
  
  METHODS
  Pulpal inflammation was induced in 80 C57BL/6 mice by occlusal exposure of the pulp of the maxillary first molar. The mice were sacrificed randomly at 0, 1, 6, 12, 24, 48, and 72 hours after pulpal exposure. Mice without pulpal exposure served as controls. Maxillary teeth were obtained and prepared for histologic analyses and real-time polymerase chain reaction analyses.
  
  
  RESULTS
  As the duration of pulpal exposure increases, the inflammatory reaction is exacerbated. Within 6 to 12 hours after pulpal exposure, pulp tissues experienced red blood cell extravasation to the destruction of the odontoblast layer. After 24 hours, necrosis was observed in the pulpal tissue; until 72 hours, necrosis spread to the whole coronal pulpal tissue, and a large number of inflammatory cells were found in the radicular pulpal tissue. The results of histomorphologic scores have the same trend; samples from the 72-hour group possessed the highest score followed by samples from other groups (P < .01). The expression levels of inflammatory cytokines increased over the 72 hours, and there was a high rate of inflammatory cytokine expression at 6 and 12 hours after pulpal exposure.
  
  
  CONCLUSIONS
  Our study represents a stable mice model for studying pulpal inflammation in vivo. Mouse pupal inflammation progresses rapidly, with dramatic changes evident in just a few hours.
authors.affiliation: Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: He
authors.affiliation: First Stomatological Hospital, Wuhan, China.
authors.forename: Youhua
authors.initials: Y
authors.lastname: Gan
authors.affiliation: Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China.
authors.forename: Jiajian
authors.initials: J
authors.lastname: Lu
authors.affiliation: Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Feng
authors.affiliation: Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China.
authors.forename: Hongbing
authors.initials: H
authors.lastname: Guan
authors.affiliation: Key Laboratory of Oral Medicine, Guangzhou Institute of Oral Disease, Stomatology Hospital of Guangzhou Medical University, Guangzhou 510140, China. Electronic address: jqianzhou@126.com.
authors.forename: Qianzhou
authors.initials: Q
authors.lastname: Jiang
mesh_terms: D000818:Animals; D016207:Cytokines / Q000378:metabolism; D003782:Dental Pulp / Q000378:metabolism / Q000473:pathology; D003789:Dental Pulp Exposure / Q000150:complications* / Q000473:pathology; D004195:Disease Models, Animal; D051379:Mice; D008810:Mice, Inbred C57BL; D011671:Pulpitis / Q000209:etiology / Q000473:pathology*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D016207:Cytokines
keywords: Animal model; histomorphologic evaluation; pulpal inflammation