title: Hyaluronic acid affects the in vitro induction effects of synthetic PAMPS and PDMAAm hydrogels on chondrogenic differentiation of ATDC5 cells, depending on the level of concentration.
abstract: BACKGROUND
  It has been a common belief that articular cartilage tissue cannot regenerate in vivo. Recently, however, we have found that spontaneous hyaline cartilage regeneration can be induced in vivo by implanting a synthetic double-network (DN) hydrogel, which is composed of poly-(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) and poly-(N,N'-dimethyl acrylamide) (PDMAAm). However, the mechanism of this phenomenon has not been clarified. Recently, we have found that single-network PAMPS and PDMAAm gels can induce chondrogenic differentiation of ATDC5 cells in vitro even in a maintenance medium. In the in vivo condition, there is a strong possibility that the induction effect of the gel itself is enhanced by some molecules which exist in the joint. We have noticed that the joint fluid naturally contains hyaluronic acid (HA). The purpose of this study is to clarify in vitro effects of supplementation of HA on the differentiation effect of the PAMPS and PDMAAm gels.
  
  
  METHODS
  We cultured the ATDC5 cells on the PAMPS gel, the PDMAAm gel, and the polystyrene (PS) dish surface with the maintenance medium without insulin for 7 days. HA having a molecular weight of approximately 800 kDa was supplemented into the medium so that the concentration became 0.00, 0.01, 0.10, or 1.00 mg/mL. We evaluated the cultured cells with phase-contrast microscopy and PCR analyses.
  
  
  RESULTS
  On the PAMPS gel, supplementation with HA of 0.01 and 0.10 mg/mL significantly increased expression of type-2 collagen mRNA (p = 0.0008 and p = 0.0413) and aggrecan mRNA (p = 0.0073 and p = 0.0196) than that without HA. On the PDMAAm gel, supplementation with HA of 1.00 mg/mL significantly reduced expression of these genes in comparison with the culture without HA (p = 0.0426 and p = 0.0218).
  
  
  CONCLUSIONS
  The in vitro induction effects of the PAMPS and PDMAAm gels on chondrogenic differentiation of ATDC5 cells are significantly affected by HA, depending on the level of concentration. These results suggested that there is a high possibility that HA plays an important role in the in vivo spontaneous hyaline cartilage regeneration phenomenon induced by the PAMPS/PDMAAm DN gel.
authors: Department of Sports Medicine and Joint Surgery, Graduate School of Medicine, Hokkaido University, Kita-15 Nishi-7, Sapporo, 060-8638, Japan.
authors: Katsuhisa
authors: K
authors: Yoshikawa
authors: Nobuto
authors: N
authors: Kitamura
authors: Takayuki
authors: T
authors: Kurokawa
authors: Jian Ping
authors: JP
authors: Gong
authors: Yutaka
authors: Y
authors: Nohara
authors: Kazunori
authors: K
authors: Yasuda
mesh_terms: D000178:Acrylamides / Q000494:pharmacology*; D053674:Aggrecans / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D002460:Cell Line; D019902:Chondrocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D020219:Chondrogenesis / Q000187:drug effects* / Q000235:genetics; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006820:Hyaluronic Acid / Q000494:pharmacology*; D020100:Hydrogels; D051379:Mice; D011108:Polymers / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013451:Sulfonic Acids / Q000494:pharmacology*; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D000178:Acrylamides; D053674:Aggrecans; D024043:Collagen Type II; D020100:Hydrogels; D011108:Polymers; D012333:RNA, Messenger; D013451:Sulfonic Acids; C429790:poly(N,N-dimethylacrylamide); C077118:poly(2-acrylamido-2-methyl-1-propanesulfonic acid); D006820:Hyaluronic Acid
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