title: Autophagy protects end plate chondrocytes from intermittent cyclic mechanical tension induced calcification.
abstract: Calcification of end plate chondrocytes is a major cause of intervertebral disc (IVD) degeneration. However, the underlying molecular mechanism of end plate chondrocyte calcification is still unclear. The aim of this study was to clarify whether autophagy in end plate chondrocytes could protect the calcification of end plate chondrocytes. Previous studies showed that intermittent cyclic mechanical tension (ICMT) contributes to the calcification of end plate chondrocytes in vitro. While autophagy serves as a cell survival mechanism, the relationship of autophagy and induced end plate chondrocyte calcification by mechanical tension in vitro is unknown. Thus, we investigated autophagy, the expression of the autophagy genes, Beclin-1 and LC3, and rat end plate chondrocyte calcification by ICMT. The viability of end plate chondrocytes was examined using the LIVE/DEAD viability/cytotoxicity kit. The reverse transcription-polymerase chain reaction and western blotting were used to detect the expression of Beclin-1; LC3; type I, II and X collagen; aggrecan; and Sox-9 genes. Immunofluorescent and fluorescent microscopy showed decreased autophagy in the 10- and 20-day groups loaded with ICMT. Additionally, Alizarin red and alkaline phosphatase staining detected the palpable calcification of end plate chondrocytes after ICMT treatment. We found that increased autophagy induced by short-term ICMT treatment was accompanied by an insignificant calcification of end plate chondrocytes. To the contrary, the suppressive autophagy inhibited by long-term ICMT was accompanied by a more significant calcification. The process of calcification induced by ICMT was partially resisted by increased autophagy activity induced by rapamycin, implicating that autophagy may prevent end plate chondrocyte calcification.
authors: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China. Electronic address: xuhg@medmail.com.cn.
authors: Hong-guang
authors: HG
authors: Xu
authors: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China.
authors: Yun-fei
authors: YF
authors: Yu
authors: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China.
authors: Quan
authors: Q
authors: Zheng
authors: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China.
authors: Wei
authors: W
authors: Zhang
authors: The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai Jiao Tong University School of Medicine (SJTUSM), 200025, China.
authors: Chuang-dong
authors: CD
authors: Wang
authors: The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai Jiao Tong University School of Medicine (SJTUSM), 200025, China.
authors: Xiao-yn
authors: XY
authors: Zhao
authors: The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai Jiao Tong University School of Medicine (SJTUSM), 200025, China.
authors: Wen-xue
authors: WX
authors: Tong
authors: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China.
authors: Hong
authors: H
authors: Wang
authors: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China.
authors: Ping
authors: P
authors: Liu
authors: The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai Jiao Tong University School of Medicine (SJTUSM), 200025, China. Electronic address: xlzhang@sibs.ac.cn.
authors: Xiao-ling
authors: XL
authors: Zhang
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects; D002113:Calcification, Physiologic / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D019902:Chondrocytes / Q000187:drug effects / Q000473:pathology*; D019610:Cytoprotection / Q000187:drug effects; D006132:Growth Plate / Q000187:drug effects / Q000473:pathology*; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D020123:Sirolimus / Q000494:pharmacology; D013314:Stress, Mechanical
chemical_list: D020123:Sirolimus
keywords: Autophagy; Calcification; Chondrocytes; End plate; Mechanical tension