title: [Change of autophagy in endplate chondrocytes of rats during aging process].
abstract: OBJECTIVE
  To explore the expression and significance of autophagy in endplate cartilage of rats during aging process.
  
  
  METHODS
  The end-plate chondrocytes were isolated from 3, 6 and 12-month SD rats respectively. And the natural culture and rapamycin groups were assigned. Alizarin red staining was used to observe the morphological changes of cells. And RT-PCR was employed to detect the expressions of type II collagen, proteoglycan, SOX-9 and matrix metalloproteinase (MMP-13). The expressions of Beclin-I and LC3 were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. The rate of autophagy was observed by monodansylcadaverine (MDC) staining and methyl thiazolyl tetrazolium (MTT) for cell survival rate.
  
  
  RESULTS
  Alizarin red staining showed that cells might reflect the process of intervertebral disc degeneration. The expressions of polysaccharide, Sox-9, type II collagen, Beclin-1 and LC3 in endplate chondrocytes significantly decreased with advancing age (P < 0.05). The incidence of autophagy significantly decreased (P < 0.05). The cell viability of each group significantly decreased (P < 0.05). Compared with control group, the cell viability of rapamycin group significantly increased (P < 0.05).
  
  
  CONCLUSIONS
  During aging process, the expressions of autophagy related-gene LC3 and Beclin-1 significantly decrease with the reduced activity of end-plate chondrocyte. And autophagy activity may be correlated with the development and degeneration of intervertebral disc.
authors.affiliation: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu 241001, China.
authors.forename: Yun-fei
authors.initials: YF
authors.lastname: Yu
authors.affiliation: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu 241001, China. Email: xuhg@medmail.com.cn.
authors.forename: Hong-guang
authors.initials: HG
authors.lastname: Xu
authors.affiliation: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu 241001, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu 241001, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu 241001, China.
authors.forename: Shou-liang
authors.initials: SL
authors.lastname: Xiong
authors.affiliation: Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu 241001, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000375:Aging; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy; D000071186:Beclin-1; D002356:Cartilage / Q000166:cytology* / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D007403:Intervertebral Disc / Q000166:cytology*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; D008869:Microtubule-Associated Proteins; C512829:Becn1 protein, rat; C526109:Anxa3 protein, rat