title: Defective autophagy in chondrocytes with Kashin-Beck disease but higher than osteoarthritis.
abstract: OBJECTIVE
  This study was undertaken to monitor autophagy in chondrocytes with Kashin-Beck disease (KBD) and osteoarthritis (OA).
  
  
  METHODS
  The identification and quantification of autophagy were morphologically visualized by transmission electron microscopy (TEM), together with immunohistochemical localization of Beclin1 and LC3 in cartilage, and immunoblotting of cellular Beclin1, LC3 and p62/SQSTM1 in the normal, KBD and OA groups. Sequentially, regulated-autophagy genes (ATG) were analyzed by IPA software and validated by quantitative real-time polymerase chain reaction (qRT-PCR). Cytotoxicity of cell death was measured by fluorescence detection and flow cytometry (FCM). The co-localization and measurement of autophagy and mitochondria/reactive oxygen species (ROS) were carried out.
  
  
  RESULTS
  KBD chondrocytes exhibited a variety of abnormal cellular contents including nuclei, mitochondrial, glycogen deposits and microfilaments, and OA chondrocytes mainly presented swelled endocytoplasmic reticulum (ER). Beclin1 and LC3 were reduced both in KBD and OA compared with normal controls; however, the two proteins and p62 in KBD were in a higher level than OA. Simultaneously, KBD chondrocytes showed 45 genes that were different from normal controls and 92 genes different from OA, whose functions were mainly involved in cell morphology, cellular functions, cell death and survival. Autophagy was negatively correlated with apoptosis in the three kinds of chondrocytes, and the rates decreased when autophagy was induced by rapamycin. Similarly, KBD and OA chondrocytes showed lower autophagy and higher ROS production compared with the normal chondrocytes.
  
  
  CONCLUSIONS
  Autophagy was defective in KBD chondrocytes, but it was higher than in OA. The insufficient autophagy may be associated with apoptosis and mitochondrial change in the pathogenesis of KBD and OA.
authors.affiliation: School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Key Laboratory of Trace Elements and Endemic Diseases, Ministry of Health, Xi'an, Shaanxi 710061, China. Electronic address: xj.cy.69@stu.xjtu.edu.cn.
authors.forename: C
authors.initials: C
authors.lastname: Wu
authors.affiliation: School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Key Laboratory of Trace Elements and Endemic Diseases, Ministry of Health, Xi'an, Shaanxi 710061, China. Electronic address: 164857627@qq.com.
authors.forename: J
authors.initials: J
authors.lastname: Zheng
authors.affiliation: School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Key Laboratory of Trace Elements and Endemic Diseases, Ministry of Health, Xi'an, Shaanxi 710061, China. Electronic address: yaox_iao@126.com.
authors.forename: X
authors.initials: X
authors.lastname: Yao
authors.affiliation: Department of Respiratory Medicine, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710004, China. Electronic address: yaosha1860@stu.xjtu.edu.cn.
authors.forename: H
authors.initials: H
authors.lastname: Shan
authors.affiliation: Department of Ankle Joint, Hong Hui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an 710054, China. Electronic address: tongrenly@163.com.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Joint Surgery, Hong Hui Hospital, Xi'an Jiaotong University Health Science Center, Xi'an 710054, China. Electronic address: sousou369@163.com.
authors.forename: P
authors.initials: P
authors.lastname: Xu
authors.affiliation: School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Key Laboratory of Trace Elements and Endemic Diseases, Ministry of Health, Xi'an, Shaanxi 710061, China. Electronic address: guox@mail.xjtu.edu.cn.
authors.forename: X
authors.initials: X
authors.lastname: Guo
mesh_terms: D000818:Animals; D017209:Apoptosis; D001343:Autophagy; D002358:Cartilage, Articular / Q000378:metabolism / Q000648:ultrastructure*; D019902:Chondrocytes / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D057767:Kashin-Beck Disease / Q000378:metabolism / Q000473:pathology*; D008297:Male; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species
keywords: Autophagy; Cell death; Kashin-Beck disease; Mitochondria; Osteoarthritis