title: [Influence of BMP-7 on chondrocyte secretion and expression of Col-II,AGG and Sox9 mRNA in porous tantalum-chondrocyte composites in vitro].
abstract: OBJECTIVE
  To study the influence of bone morphogenetic protein-7 (BMP-7) on chondrocyte secretion and expression of type II collagen (Col-II), aggrecan (AGG) and SRY-related high mobility group-box gene 9 (Sox9) mRNA in porous tantalum-chondrocyte composites.
  
  
  METHODS
  The articular chondrocytes were isolated from 3-week-old New Zealand immature rabbits and identified. The 2nd generation of chondrocytes with 1×10(6)/mL inoculate concentration was seeded in porous tantalum and divided into 4 groups, and control group (tantalum/chondrocyte), 50 μg/L BMP-7 group (50 μg/L BMP-7/tantalum/chondrocyte), 100 μg/L BMP-7 group (100 μg/L BMP-7/tantalum/chondrocyte), and 200 μg/L BMP-7 group (200 μg/L BMP-7/tantalum/chondrocyte). The proliferation of chondrocytes was measured by CCK-8 assay. The chondrocyte growth and morphology were observed by scanning electron microscopy (SEM). The synthesis of glycosaminoglycan (GAG) in chondrocytes was tested by dimethyl methylene blue (DMMB) colorimetric quantification method. Col-II, AGG and Sox9 mRNA in chondrocytes were detected by real-time PCR.
  
  
  RESULTS
  The chondrocytes were spindle-shaped in 24 hours of primary cell culture and most cells became polygonal shaped in 4 days. The chondrocytes were affirmed by alcian blue, safranin O and Col-II immunocytochemistry staining. The result of CCK-8 assay showed that the level of cell proliferation in 100 μg/L BMP-7 groups were higher than those in the other groups (P<0.05). The chondrocytes implanted into porous tantalum scaffolds with BMP-7 had better functions, by which cytoplasmic processes developed and extended to the surface and inner of porous tantalum by SEM observation. DMMB quantitative determination of GAG showed that GAG amount of chondrocytes in 100 μg/L BMP-7 groups was significantly higher than those in the other groups (P<0.05). The expressions of Col-II, AGG and Sox9 mRNA in chondrocytes were up-regulated in the experimental groups, compared with the control group and the best effect appeared when concentration of BMP-7 was 200 μg/L. (P<0.05).
  
  
  CONCLUSIONS
  BMP-7/tantalum/chondrocytes composites enhanced in vitro chondrocyte proliferation and extracellular matrix greatly, and can promote chondrogenic gene expression.
authors.affiliation: Graduate School, Southern Medical University, Guangzhou 510515, China; Department of Joint Surgery, the Second Hospital of Tangshan, Hebei Tangshan 063000, China.
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, Hebei United University Affiliated Hospital, Hebei Tangshan 063000, China.
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.affiliation: Graduate School, Southern Medical University, Guangzhou 510515, China; Department of Anatomy, Basic Medical College of Hebei United University, Hebei Tangshan 063000, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, Hebei United University Affiliated Hospital, Hebei Tangshan 063000, China.
authors.forename: H Q
authors.initials: HQ
authors.lastname: Gan
authors.affiliation: Graduate School, Southern Medical University, Guangzhou 510515, China; Department of Hand Surgery, the Second Hospital of Tangshan, Hebei Tangshan 063000, China.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.affiliation: Graduate School, Southern Medical University, Guangzhou 510515, China; Department of Orthopaedics, Hebei United University Affiliated Hospital, Hebei Tangshan 063000, China.
authors.forename: C
authors.initials: C
authors.lastname: Bi
authors.affiliation: Experimental Center, Hebei United University, Hebei Tangshan 063000, China.
authors.forename: Q J
authors.initials: QJ
authors.lastname: Li
authors.affiliation: Graduate School, Southern Medical University, Guangzhou 510515, China; Department of Orthopaedics, Hebei United University Affiliated Hospital, Hebei Tangshan 063000, China.
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Wang
mesh_terms: D053674:Aggrecans / Q000378:metabolism*; D000818:Animals; D055419:Bone Morphogenetic Protein 7 / Q000502:physiology*; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D024043:Collagen Type II / Q000378:metabolism*; D005109:Extracellular Matrix; D006025:Glycosaminoglycans / Q000096:biosynthesis; D012333:RNA, Messenger; D011817:Rabbits; D060888:Real-Time Polymerase Chain Reaction; D055758:SOX9 Transcription Factor / Q000378:metabolism*; D013635:Tantalum; D023822:Tissue Engineering
chemical_list: D053674:Aggrecans; D055419:Bone Morphogenetic Protein 7; D024043:Collagen Type II; D006025:Glycosaminoglycans; D012333:RNA, Messenger; D055758:SOX9 Transcription Factor; D013635:Tantalum