title: Chondrogenic effects of exogenous retinoic acid or a retinoic acid receptor antagonist (LE135) on equine chondrocytes and bone marrow-derived mesenchymal stem cells in monolayer culture.
abstract: OBJECTIVE
  To determine effects of various concentrations of retinoic acid (RA) or a synthetic RA receptor antagonist (LE135) on equine chondrocytes or bone marrow-derived equine mesenchymal stem cells (BMDMSCs) in monolayer cultures.
  
  
  METHODS
  Articular cartilage and BMDMSCs from 5 clinically normal horses.
  
  
  METHODS
  Monolayers of chondrocytes cultured in standard media and of BMDMSCs cultured in chondrogenic media were treated with RA at concentrations of 0, 0.1, 1, or 10 μM or LE135 at concentrations of 0, 0.1, 1, or 10 μM on day 0. On days 7 and 14, samples were analyzed for DNA concentration, chondrocyte morphology or features consistent with chondrogenesis (ie, chondral morphology [scored from 0 to 4]), and gene expression of collagen type Ia (CI), collagen type II (CII), and aggrecan.
  
  
  RESULTS
  Chondrocytes treated with RA had more mature chondral morphology (range of median scores, 3.0 to 4.0) than did untreated controls (range of median scores, 0.5 to 0.5). Chondrocytes treated with LE135 did not sustain chondrocyte morphology. All BMDMSCs had evidence of chondral morphology or high CII:CI ratio. Retinoic acid (1 or 10 μM) or LE135 (10 μM) treatment decreased DNA content of BMDMSC cultures. At 0.1 and 1 μM concentrations, LE135 weakly but significantly increased chondral morphology scores, compared with untreated controls, but lack of aggrecan expression and lack of increased CII:CI ratio, compared with that of controls, did not affect chondrogenesis.
  
  
  CONCLUSIONS
  RA promoted maturation and hypertrophy in chondrocytes but not BMDMSCs in monolayer cultures. Deficiency or blockade of RA may prevent hypertrophy and maturation of differentiated chondrocytes.
authors: Comparative Orthopedic Molecular Medicine and Applied Research Laboratory, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
authors: Sally E
authors: SE
authors: Henderson
authors: Kelly S
authors: KS
authors: Santangelo
authors: Alicia L
authors: AL
authors: Bertone
mesh_terms: D053674:Aggrecans / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002358:Cartilage, Articular / Q000166:cytology / Q000187:drug effects; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects; D020219:Chondrogenesis; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D003984:Dibenzazepines / Q000378:metabolism*; D005786:Gene Expression Regulation; D006736:Horses / Q000033:anatomy & histology / Q000502:physiology*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D018168:Receptors, Retinoic Acid / Q000037:antagonists & inhibitors* / Q000235:genetics; D014212:Tretinoin / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D053674:Aggrecans; D024042:Collagen Type I; D024043:Collagen Type II; D003984:Dibenzazepines; C104182:LE 135; D018168:Receptors, Retinoic Acid; D014212:Tretinoin