title: [Radiological and histopathological changes of the periapical lesions induced by lipopolysaccharide in rats].
abstract: OBJECTIVE
  To investigate histological and X-ray dynamic changes of periapical lesions induced by lipopolysaccharide(LPS) in rats.
  
  
  METHODS
  Experimental periapical periodontitis models in 24 Wistar rats were established by exposing pulps, placing absorbent cotton with LPS, and exposing in the oral environment. Four experimental animals were sacrificed on the day 0,3,7,14,21, and 35, respectively. Root apical radiographs and tissue sections were taken in all the teeth combined with bone from sacrificed animals. Periapical histological changes and roentgenograms were observed. The results were analyzed statistically by F test and Student's t test with SPSS12.0 software package.
  
  
  RESULTS
  On the day 3, infiltration of inflammatory cells in the periapical tissue was observed. Acute inflammatory states, severe inflammatory states and chronic inflammatory states were detected at 1 week, 2-week and 3-week,respectively. Cementum hyperplasia was observed at 5-week. Increasing periapical radiolucent areas were observed after 1 week. Intervention, there were significant differences in the periapical lesion areas at the different period time(P<0.01).
  
  
  CONCLUSIONS
  The procedures that induced periapical lesions in animal model established by exposing pulps of molar teeth,placing absorbent cotton with LPS, and exposing to the oral environment is similar to human natural progress of the same disease and has a shorter time duration. It is an ideal research model for periapical periodontitis.
authors.affiliation: Department of Endodontics, College of Stomatology, Binzhou Medical College, Binzhou 256603, Shandong Province, China. wqsyahao@yahoo.com.cn
authors.forename: Qing-shan
authors.initials: QS
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.forename: Li
authors.initials: L
authors.lastname: Rong
authors.forename: Ai-qin
authors.initials: AQ
authors.lastname: Wang
mesh_terms: D016301:Alveolar Bone Loss; D000818:Animals; D004195:Disease Models, Animal; D008070:Lipopolysaccharides; D010485:Periapical Periodontitis; D051381:Rats; D017208:Rats, Wistar
chemical_list: D008070:Lipopolysaccharides