title: Low Levels of Vitamin D have a Deleterious Effect on the Articular Cartilage in a Rat Model.
abstract: BACKGROUND
  Vitamin D appears to play an important role in bone and cartilage metabolism since its receptors are widely found in human articular chondrocytes. Thus, effects of variation of vitamin D may directly impact cartilage and bone biology.
  
  
  OBJECTIVE
  The aims of this study are to compare (1) articular cartilage structure and composition and (2) trabecular and cortical bone microstructure in rats with normal versus insufficient vitamin D levels.
  
  
  METHODS
  Twenty-five mature, male Sprague-Dawley rats were allocated to two groups: (1) control arm (vitamin D replete-12 rats) and (2) an experimental arm (vitamin D deficient-13 rats). Vitamin D deficiency was induced using a vitamin D-deficient diet and UV light restriction. Rats were sacrificed after 4 weeks vitamin D deficiency was confirmed. The right knee was harvested for analysis of both the medial (MFC) and lateral femoral condyles (LFC). A region of interest was established on both condyles to correlate subchondral bone architecture and the overlying cartilage. Histological analysis was performed and graded using the modified Mankin score. Subchondral and cortical bony architecture was evaluated with micro-CT.
  
  
  RESULTS
  After 4 weeks, the vitamin D-deficient group had statistically significant changes in cartilage structure in both the MFC and LFC [1.55 ± 0.6 vs. 4.23 ± 4.1 (p = 0.035) and 1.55 ± 0.6 vs. 3.53 ± 2.4 (p = 0.009), respectively]. Micro-CT analysis revealed no correlation between subchondral bone values and the overlying cartilage Mankin score (p = 0.460). No significant difference was evident between the subchondral bone of the control and study group.
  
  
  CONCLUSIONS
  Low levels of vitamin D have a deleterious effect on the cartilage. Given the high prevalence of vitamin D deficiency in the general population, these findings raise important questions about the potential role of vitamin D in articular cartilage health.
authors.affiliation: Hip Preservation Center, Department of Orthopedics, University of Colorado, 2000 South Colorado Blvd. Colorado Center Tower One, 4500, Denver, CO 80222 USA.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Pascual-Garrido
authors.affiliation: Mercy Health System, Janesville, WI USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Angeline
authors.affiliation: Missouri Orthopedic Institute, University of Missouri Healthcare, Columbia, MO USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Ma
authors.affiliation: Steadman Philippon Research Institute, Vail, CO USA.
authors.forename: Jorge
authors.initials: J
authors.lastname: Chahla
authors.affiliation: Orthopedics Department, Lenox Hill Hospital, New York, NY USA.
authors.forename: Cliff
authors.initials: C
authors.lastname: Voigt
authors.affiliation: Laboratory for Soft Tissue Research, Hospital for Special Surgery, New York, NY USA.
authors.forename: Xiang Hua
authors.initials: XH
authors.lastname: Deng
authors.affiliation: Department of Epidemiology and Biostatistics, Hospital for Special Surgery, New York, NY USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Nguyen
authors.affiliation: Laboratory for Soft Tissue Research and Department of Sports Medicine and Shoulder Surgery Service, Hospital for Special Surgery, New York, NY USA.
authors.forename: Russell F
authors.initials: RF
authors.lastname: Warren
authors.affiliation: Laboratory for Soft Tissue Research and Department of Sports Medicine and Shoulder Surgery Service, Hospital for Special Surgery, New York, NY USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Rodeo
keywords: cartilage; osteoarthritis; rat model; subchondral bone; vitamin D