title: The presence of stem cells in potential stem cell niches of the intervertebral disc region: an in vitro study on rats.
abstract: OBJECTIVE
  The potential of stem cell niches (SCNs) in the intervertebral disc (IVD) region, which may be of great significance in the regeneration process, was recently proposed. To the best of our knowledge, no previous in vitro study has examined the characteristics of stem cells derived from the potential SCN of IVD (ISN). Therefore, increasing knowledge on ISN-derived stem cells (ISN-SCs) may provide a greater understanding of IVD degeneration and regeneration processes. We aimed to demonstrate the existence of ISN-SCs and to compare their characteristics with bone marrow mesenchymal stem cells (BMSCs) in vitro.
  
  
  METHODS
  Sprague-Dawley rats (male, 10-week-old) were used in this study. ISN tissues were separated by ophthalmic surgical instruments under a dissecting microscope according to the anatomical areas. BMSCs and cells isolated from the ISN tissues were cultured and expanded in vitro. Passage 4 populations were used for further analysis with respect to colony-forming ability, cellular immunophenotype, cell cycle, stem cell-related gene expression, and proliferation and multipotential differentiation capacities.
  
  
  RESULTS
  In general, both of ISN-SCs and mesenchymal stromal cells (MSCs) met the minimal criteria for the definition of multipotent mesenchymal stromal cells, including adherence to plastic, specific surface antigen expression, and multipotent differentiation potential. Especially, ISN-SCs even showed greater potential of osteogenesis and chondrogenesis. The ISN-SCs also expressed stem cell-related genes that were comparable to those of BMSCs, and had colony-forming and self-renewal abilities.
  
  
  CONCLUSIONS
  To the best of our knowledge, this is the first in vitro study aimed towards determining the existence and characteristics of ISN-SCs, which belong to the MSC family and with greater osteogenic and chondrogenic abilities than BMSCs according to our data. This finding may be of great significance for additional studies that investigate the migration of ISN-SCs into the IVD, and may provide a new perspective on different biological approaches for IVD self-regeneration.
authors.affiliation: Spine Center, Zhongda Hospital, Medical School, Southeast University, 87 Dingjiaqiao, Nanjing, 210009, Jiangsu, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Shi
authors.affiliation: Spine Center, Zhongda Hospital, Medical School, Southeast University, 87 Dingjiaqiao, Nanjing, 210009, Jiangsu, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Spine Center, Zhongda Hospital, Medical School, Southeast University, 87 Dingjiaqiao, Nanjing, 210009, Jiangsu, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Hong
authors.affiliation: Spine Center, Zhongda Hospital, Medical School, Southeast University, 87 Dingjiaqiao, Nanjing, 210009, Jiangsu, China.
authors.forename: Yun-Tao
authors.initials: YT
authors.lastname: Wang
authors.affiliation: Spine Center, Zhongda Hospital, Medical School, Southeast University, 87 Dingjiaqiao, Nanjing, 210009, Jiangsu, China.
authors.forename: Jun-Ping
authors.initials: JP
authors.lastname: Bao
authors.affiliation: Spine Center, Zhongda Hospital, Medical School, Southeast University, 87 Dingjiaqiao, Nanjing, 210009, Jiangsu, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Cai
authors.affiliation: Spine Center, Zhongda Hospital, Medical School, Southeast University, 87 Dingjiaqiao, Nanjing, 210009, Jiangsu, China. wuxiaotao@medmail.com.cn.
authors.forename: Xiao-Tao
authors.initials: XT
authors.lastname: Wu
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D020219:Chondrogenesis; D007403:Intervertebral Disc / Q000166:cytology*; D008297:Male; D010012:Osteogenesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D055153:Stem Cell Niche / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology
keywords: Cell differentiation; Cellular immunophenotype; Intervertebral disc; Mesenchymal stem cells; Stem cell niches