title: AFM study of the effects of collagenase and its inhibitors on dentine collagen fibrils.
abstract: OBJECTIVE
  This study evaluated the effects of exogenous collagenase and two collagenase inhibitors on the variation in microstructure of human collagen fibrils.
  
  
  METHODS
  Dentine specimens which were sectioned from 6 freshly extracted human caries-free third molars were wet polished. Each specimen was divided into 4 parts which were treated as experimental groups (group 1, group 2, group 3) and the control group, respectively. All the specimens were etched and further treated with NaClOaq. Subsequently, the topography of each specimen was observed using atomic force microscopy (AFM) in tapping mode in air. Group 1 was then treated with a solution of collagenase II. Group 2 was treated with a solution of collagenase II and chlorhexidine (saturated solution). Group 3 was treated with a solution of collagenase II and captopril (0.3%). The control group was treated with a buffer solution. After 3h and 6h of treatment, the topography of the collagen fibrils was measured with AFM in air, respectively.
  
  
  RESULTS
  AFM images of the dentine collagen fibrils were obtained after treatment with NaOClaq. Following further treatment with collagenase II, the topography of the collagen fibrils changed. Most reticular collagen fibrils disappeared after 6h. After treatment with collagenase II in the presence of chlorhexidine or captopril for 3h and 6h, the morphology of the collagen fibres was not changed obviously.
  
  
  CONCLUSIONS
  Exogenous collagenase II effectively degraded human dentine collagen fibrils, and its collagenolytic activity was inhibited by the exogenous collagenase inhibitors, chlorhexidine and captopril.
authors.affiliation: Department of Conservative Dentistry and Periodontic, Affiliated Hospital of Stomatology, Medical College, Zhejiang University, Hangzhou 310006, China.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Zheng
authors.forename: Jinhao
authors.initials: J
authors.lastname: Hu
authors.forename: Yadong
authors.initials: Y
authors.lastname: Chen
authors.forename: Yunjie
authors.initials: Y
authors.lastname: Zhu
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000328:Adult; D002216:Captopril / Q000494:pharmacology; D002710:Chlorhexidine / Q000494:pharmacology; D003094:Collagen / Q000187:drug effects* / Q000648:ultrastructure; D017364:Collagenases / Q000494:pharmacology*; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D020784:Matrix Metalloproteinase 8 / Q000494:pharmacology; D061965:Matrix Metalloproteinase Inhibitors; D018625:Microscopy, Atomic Force; D012973:Sodium Hypochlorite / Q000737:chemistry; D013997:Time Factors; D055815:Young Adult
chemical_list: D004791:Enzyme Inhibitors; D061965:Matrix Metalloproteinase Inhibitors; D003094:Collagen; D002216:Captopril; D012973:Sodium Hypochlorite; D017364:Collagenases; D020784:Matrix Metalloproteinase 8; D002710:Chlorhexidine