title: Intraarticular Injection of Allogenic Mesenchymal Stem Cells has a Protective Role for the Osteoarthritis.
abstract: BACKGROUND
  Researchers initially proposed the substitution of apoptotic chondrocytes in the superficial cartilage by injecting mesenchymal stem cells (MSCs) intraarticularly. This effect was termed as bio-resurfacing. Little evidence supporting the treatment of osteoarthritis (OA) by the delivery of a MSC suspension exists. The aim of this study was to investigate the effects of injecting allogenic MSCs intraarticularly in a rat OA model and to evaluate the influence of immobility on the effects of this treatment.
  
  
  METHODS
  We established a rat knee OA model after 4 and 6 weeks and cultured primary bone marrow MSCs. A MSC suspension was injected into the articular space once per week for 3 weeks. A subgroup of knee joints was immobilized for 3 days after each injection, while the remaining joints were nonimmobilized. We used toluidine blue staining, Mankin scores, and TdT-mediated dUTP-biotin nick end labeling staining to evaluate the therapeutic effect of the injections. Comparisons between the therapy side and the control side of the knee joint were made using paired t-test, and comparisons between the immobilized and nonimmobilized subgroups were made using the unpaired t-test. A P value < 0.05 was considered significant.
  
  
  RESULTS
  The three investigative approaches revealed less degeneration on the therapy sides of the knee joints than the control sides in both the 4- and 6-week groups (P < 0.05), regardless of immobilization. No significant differences were observed between the immobilized and nonimmobilized subgroups (P > 0.05).
  
  
  CONCLUSIONS
  Therapy involving the intraarticular injection of allogenic MSCs promoted cartilage repair in a rat arthritis model, and 3-day immobility after injection had little effect on this therapy.
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.forename: Tian-Yue
authors.initials: TY
authors.lastname: Zhu
authors.forename: Li-Cheng
authors.initials: LC
authors.lastname: Wen
authors.affiliation: Department of Orthopedics, Peking University First Hospital, Beijing 100034, China.
authors.forename: Yong-Ping
authors.initials: YP
authors.lastname: Cao
authors.forename: Chao
authors.initials: C
authors.lastname: Liu
authors.forename: Yun-Peng
authors.initials: YP
authors.lastname: Cui
authors.forename: Zhi-Chao
authors.initials: ZC
authors.lastname: Meng
authors.forename: Heng
authors.initials: H
authors.lastname: Liu
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology*; D007270:Injections, Intra-Articular; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D020370:Osteoarthritis, Knee / Q000517:prevention & control* / Q000628:therapy*; D051381:Rats