title: Cyclic-stretch induces apoptosis in human periodontal ligament cells by activation of caspase-5.
abstract: OBJECTIVE
  As caspase-5 plays a role in apoptosis, the present study aimed to identify the expression and activation of caspase-5 in human periodontal ligament cells in response to cyclic stretch and the role of caspase-5 in stretch-induced apoptosis.
  
  
  METHODS
  Human PDL cells were exposed to 10% or 20% stretch strain for 6 or 24h, and the mRNA and protein expressions of caspase-5 were analyzed with real-time PCR and Western blot, respectively. The caspase-5 activation was detected by colorimetric assay. Then the influence of the inhibition of caspase-5 on the stretch-induced apoptosis and caspase-3 activation were analyzed with flow cytometry and colorimetric assay, respectively.
  
  
  RESULTS
  Both 6 and 24h stretches increased mRNA, protein expression and activation of caspase-5 in human PDL cells. Inhibition of caspase-5 inhibited the stretch-induced apoptosis and caspase-3 activation in human PDL cells.
  
  
  CONCLUSIONS
  This study for the first time identified the expression and activation of caspase-5 in cyclic stretched human PDL cells and found that the stretch-induced apoptosis and caspase-3 activation were caspase-5 dependent.
authors.affiliation: Department of Prosthodontics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhao
authors.affiliation: Department of Prosthodontics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China.
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Prosthodontics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China. Electronic address: imxuchun@163.com.
authors.forename: Chun
authors.initials: C
authors.lastname: Xu
authors.affiliation: Department of Prosthodontics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, Shanghai, China. Electronic address: fqzhang@vip.163.com.
authors.forename: Fuqiang
authors.initials: F
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D017209:Apoptosis / Q000502:physiology; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D020169:Caspases / Q000378:metabolism*; D002648:Child; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D010513:Periodontal Ligament / Q000166:cytology*; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013314:Stress, Mechanical
chemical_list: D012333:RNA, Messenger; C099217:CASP5 protein, human; D053148:Caspase 3; D020169:Caspases
keywords: Apoptosis; Caspase-5; Cyclic stretch; Periodontal ligament cell