Mechanisms of Age-Related Decline in Insulin-Like Growth Factor-I Dependent Proteoglycan Synthesis in Rat Intervertebral Disc Cells

作者：Shinya Okuda, Akira Myoui, Kenta Ariga, Takanobu Nakase, Kazuo Yonenobu, Hideki Yoshikawa · 发表于：Spine · 年份：2001 · DOI：10.1097/00007632-200111150-00005 · 被引用次数：87 · 研究领域：Spine and Intervertebral Disc Pathology、Osteoarthritis Treatment and Mechanisms、Cervical and Thoracic Myelopathy

STUDY DESIGN: Age-related fluctuations in insulin-like growth factor-I dependent proteoglycan synthesis in rat intervertebral disc cells were investigated. OBJECTIVES: The purpose of this study was to determine whether synthetic responses to insulin-like growth factor-I decline with age and to explore the possibility that an age-related increase in the expression of insulin-like growth factor binding proteins suppresses matrix synthesis in intervertebral disc cells. SUMMARY AND BACKGROUND DATA: Several studies have reported that the responsiveness of chondrocytes to insulin-like growth factor-I decreases with age and furthermore that this phenomenon may be related to increased expression of insulin-like growth factor binding proteins by chondrocytes. MATERIALS AND METHODS: Nucleus pulposus tissue and cells were obtained from the coccygeal vertebrae of 8-week-old, 40-week-old, and 120-week-old rats. Age-related changes in the expression of insulin-like growth factor-I and its receptor were assessed together with insulin-like growth factor-I dependent proteoglycan synthesis by the cultured nucleus pulposus cells. Also, western blot analysis of insulin-like growth factor binding protein-1 was carried out, and further examination was performed of insulin-like growth factor-I signal transduction through tyrosine phosphorylation of insulin receptor substrate-1, which is a signal transducer of insulin-like growth factor-I. RESULTS: Semiquantitative reverse transcription polymerase c...