Intra-articular injection of hyaluronan diminishes loss of chondrocytes in a rat immobilized-knee model

Akira Ando, Yoshihiro Hagiwara, Eiichi Chimoto, Kouki Hatori, Yoshito Onoda, Eiji Itoi

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Joint immobilization is a useful and common treatment modality in orthopedics. However, it also causes unfavorable outcome such as articular cartilage degeneration. Intra-articular injection of hyaluronan has been accepted as a treatment of osteoarthritis, but its effects on immobilized joint remain to be clarified. Hyaluronan is a polysaccharide, distributed ubiquitously in various tissues. In this study, we examined the effect of hyaluronan on the articular cartilage in immobilized joints. The unilateral knee joints of adult male rats were immobilized at 150° in flexion with an internal plate and screws for 1, 2, 4, 6, 8, 12, or 16 weeks (n = 84). Hyaluronan or saline (50 μ1/each injection) was administered intra-articularly on the day of surgery and once a week. The articular cartilage from the medial midcondylar region of the knee was obtained, and divided into non-contact, contact and transitional areas (between the non-contact and the contact areas). In each area, a degree of degeneration was evaluated by histomorphometric grading, and measurements of thickness and number of chondrocytes. Histological grading scores in the hyaluronan group were smaller at 12 and 16 weeks compared with those in the saline group. The thickness of the articular cartilage increased in the transitional area in both groups. The number of chondrocytes in the contact and transitional areas gradually decreased, but their number in the hyaluronan group was greater at 12 and 16 weeks compared with that in the saline group. Hyaluronan showed chondroprotective effects on the articular cartilage in a rat immobilized-knee model.

Original languageEnglish
Pages (from-to)321-331
Number of pages11
JournalTohoku Journal of Experimental Medicine
Issue number4
Publication statusPublished - 2008


  • Articular cartilage
  • Degeneration
  • Hyaluronan
  • Immobilization
  • Osteoarthritis

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


Dive into the research topics of 'Intra-articular injection of hyaluronan diminishes loss of chondrocytes in a rat immobilized-knee model'. Together they form a unique fingerprint.

Cite this