title: Gene expression profile of the cartilage tissue spontaneously regenerated in vivo by using a novel double-network gel: comparisons with the normal articular cartilage.
abstract: BACKGROUND
  We have recently found a phenomenon that spontaneous regeneration of a hyaline cartilage-like tissue can be induced in a large osteochondral defect by implanting a double-network (DN) hydrogel plug, which was composed of poly-(2-Acrylamido-2-methylpropanesulfonic acid) and poly-(N, N'-Dimetyl acrylamide), at the bottom of the defect. The purpose of this study was to clarify gene expression profile of the regenerated tissue in comparison with that of the normal articular cartilage.
  
  
  METHODS
  We created a cylindrical osteochondral defect in the rabbit femoral grooves. Then, we implanted the DN gel plug at the bottom of the defect. At 2 and 4 weeks after surgery, the regenerated tissue was analyzed using DNA microarray and immunohistochemical examinations.
  
  
  RESULTS
  The gene expression profiles of the regenerated tissues were macroscopically similar to the normal cartilage, but showed some minor differences. The expression degree of COL2A1, COL1A2, COL10A1, DCN, FMOD, SPARC, FLOD2, CHAD, CTGF, and COMP genes was greater in the regenerated tissue than in the normal cartilage. The top 30 genes that expressed 5 times or more in the regenerated tissue as compared with the normal cartilage included type-2 collagen, type-10 collagen, FN, vimentin, COMP, EF1alpha, TFCP2, and GAPDH genes.
  
  
  CONCLUSIONS
  The tissue regenerated by using the DN gel was genetically similar but not completely identical to articular cartilage. The genetic data shown in this study are useful for future studies to identify specific genes involved in spontaneous cartilage regeneration.
authors.affiliation: Department of Sports Medicine and Joint Surgery, Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: Ryusei
authors.initials: R
authors.lastname: Imabuchi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ohmiya
authors.forename: Hyuck Joon
authors.initials: HJ
authors.lastname: Kwon
authors.forename: Shin
authors.initials: S
authors.lastname: Onodera
authors.forename: Nobuto
authors.initials: N
authors.lastname: Kitamura
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kurokawa
authors.forename: Jian Ping
authors.initials: JP
authors.lastname: Gong
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yasuda
mesh_terms: D000178:Acrylamides / Q000008:administration & dosage / Q000737:chemistry; D000818:Animals; D001672:Biocompatible Materials / Q000008:administration & dosage; D002358:Cartilage, Articular / Q000293:injuries / Q000502:physiology*; D004195:Disease Models, Animal; D005269:Femur / Q000601:surgery; D015870:Gene Expression; D020869:Gene Expression Profiling; D048091:Guided Tissue Regeneration / Q000379:methods*; D051457:Hyaline Cartilage / Q000502:physiology*; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000008:administration & dosage* / Q000737:chemistry; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry; D011817:Rabbits; D012038:Regeneration / Q000235:genetics*; D013451:Sulfonic Acids / Q000008:administration & dosage / Q000737:chemistry; D023822:Tissue Engineering; D054457:Tissue Scaffolds
chemical_list: D000178:Acrylamides; D001672:Biocompatible Materials; D011108:Polymers; D013451:Sulfonic Acids; C429790:poly(N,N-dimethylacrylamide); D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; C077118:poly(2-acrylamido-2-methyl-1-propanesulfonic acid)