title: Nanoparticle delivery of the bone morphogenetic protein 4 gene to adipose-derived stem cells promotes articular cartilage repair in vitro and in vivo.
abstract: OBJECTIVE
  To evaluate the effect of poly(lactic-co-glycolic acid) (PLGA) nanoparticles delivering pDC316-BMP4-EGFP plasmid into rabbit adipose-derived stem cells (ADSCs) in vitro and chondrogenesis of the bone morphogenetic protein 4 (BMP-4)--transfected ADSCs seeded onto poly(L-lactic-co-glycolic acid) (PLLGA) scaffold in a rabbit model.
  
  
  METHODS
  Cell viability and transfection efficiency of PLGA nanoparticles were measured by Cell Counting Kit-8 (Dojindo, Kumamoto, Japan) and flow cytometry. The BMP-4 and chondrogenesis markers were detected by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Thirty rabbits (60 knees) with full-thickness cylinder articular cartilage defects (diameter, 4.5 mm; depth, 0.8 mm) on the femoral trochlea were divided into a group in which the BMP-4--transfected ADSCs were seeded onto PLLGA scaffold and implanted into the defects (group ABNP), a group with untransfected ADSCs seeded onto scaffold (group ABP), and a group with a scaffold without cells (group P). Outcomes were evaluated by histology, Rudert score, Pineda score, and scanning electronic microscopy by 2 blinded observers at weeks 6 and 12 postoperatively. Statistical analyses were performed with analysis of variance and the Kruskal-Wallis test. The statistical significance level was set at P < .05.
  
  
  RESULTS
  The expression of chondrogenesis-related genes and proteins was significantly increased in BMP-4--transfected ADSCs in vitro (P < .05). The cell viability was 79.86% ± 5.04% after 24 hours. The transfection efficiency was 25.86% ± 4.27% after 72 hours. Defects in group ABNP showed the best in vivo cartilage regeneration. At week 12, the Rudert scores in group ABNP (7.00 ± 1.75) were better than those in group ABP (6.00 ± 2.00) or group P (5.00 ± 1.75) (P < .05), as were the Pineda scores (2.50 ± 3.00, 5.00 ± 2.00, and 6.00 ± 1.75, respectively; P < .001).
  
  
  CONCLUSIONS
  BMP-4 plasmid can be successfully delivered into ADSCs by PLGA nanoparticles and promoted in vitro chondrogenesis. When compared with the control cells, BMP-4--transfected ADSCs seeded onto PLLGA scaffold significantly improve in vivo chondrogenesis in a rabbit articular defect model.
  
  
  CONCLUSIONS
  PLGA nanoparticles and BMP-4 have potential for gene therapy in the treatment of chondral defects of the knee.
authors.affiliation: Institute of Sports Medicine, Peking University Third Hospital, Beijing, China.
authors.forename: Junjun
authors.initials: J
authors.lastname: Shi
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Jingxian
authors.initials: J
authors.lastname: Zhu
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Pi
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Hu
authors.forename: Chunyan
authors.initials: C
authors.lastname: Zhou
authors.forename: Yingfang
authors.initials: Y
authors.lastname: Ao
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D000818:Animals; D055415:Bone Morphogenetic Protein 4 / Q000235:genetics*; D002358:Cartilage, Articular / Q000503:physiopathology* / Q000601:surgery* / Q000648:ultrastructure; D002478:Cells, Cultured; D020219:Chondrogenesis / Q000235:genetics*; D018014:Gene Transfer Techniques; D019344:Lactic Acid; D008297:Male; D053758:Nanoparticles; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011817:Rabbits; D054457:Tissue Scaffolds; D014162:Transfection; D014945:Wound Healing / Q000235:genetics*
chemical_list: D055415:Bone Morphogenetic Protein 4; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid