title: Effects of doxycycline on mesenchymal stem cell chondrogenesis and cartilage repair.
abstract: OBJECTIVE
  Strategies to improve cartilage repair tissue quality after bone marrow cell-based procedures may reduce later development of osteoarthritis. Doxycycline is inexpensive, well-tolerated, and has been shown to reduce matrix-metalloproteinases (MMPs) and osteoarthritis progression. This study tests the hypotheses that doxycycline reduces MMP, enhances chondrogenesis of human bone marrow-derived mesenchymal stem cells (hMSC), and improves in vivo cartilage repair.
  
  
  METHODS
  Ninety hMSC pellets were cultured in chondrogenic media with either 0-, 1- or 2-μg/mL doxycycline. Pellets were evaluated with stereomicroscopy, proteoglycan assay, qRT-PCR, and histology. Osteochondral defects (OCDs) were created in the trochlear grooves of 24-Sprague-Dawley rats treated with/without oral doxycycline. Rats were sacrificed at 12-weeks and repair tissues were examined grossly and histologically.
  
  
  RESULTS
  hMSC pellets with 1-μg/mL (P = 0.014) and 2-μg/mL (P = 0.002) doxycycline had larger areas than pellets without doxycycline. hMSC pellets with 2-μg/mL doxycycline showed reduced mmp-13 mRNA (P = 0.010) and protein at 21-days. Proteoglycan, DNA contents, and mRNA expressions of chondrogenic genes were similar (P > 0.05). For the in vivo study, while the histological scores were similar between the two groups (P = 0.116), the gross scores of the OCD repair tissues in doxycycline-treated rats were higher at 12-weeks (P = 0.017), reflective of improved repair quality. The doxycycline-treated repairs also showed lower MMP-13 protein (P = 0.029).
  
  
  CONCLUSIONS
  This study shows that doxycycline improves hMSC chondrogenesis and decreases MMP-13 in pellet cultures and within rat OCDs. Doxycycline exerted no negative effect on multiple measures of chondrogenesis and cartilage repair. These data support potential use of doxycycline to improve cartilage repair to delay the onset of osteoarthritis.
authors.affiliation: Cartilage Restoration Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pennsylvania, USA.|Department of Bioengineering, University of Pittsburgh, Pennsylvania, USA.
authors.forename: Hannah H
authors.initials: HH
authors.lastname: Lee
authors.affiliation: Cartilage Restoration Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pennsylvania, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: O'Malley
authors.affiliation: Cartilage Restoration Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pennsylvania, USA.
authors.forename: Nicole A
authors.initials: NA
authors.lastname: Friel
authors.affiliation: Cartilage Restoration Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pennsylvania, USA.|Department of Bioengineering, University of Pittsburgh, Pennsylvania, USA.
authors.forename: Constance R
authors.initials: CR
authors.lastname: Chu
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000187:drug effects* / Q000293:injuries* / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D020219:Chondrogenesis / Q000187:drug effects* / Q000502:physiology; D004195:Disease Models, Animal; D004318:Doxycycline / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D053509:Matrix Metalloproteinase 13; D004318:Doxycycline