Comparison of chondroitin sulphate composition of femoral head articular cartilage from patients with femoral neck fractures and osteoarthritis and controls

The glycosaminoglycan (GAG) and uronic acid (UA) composition of human hip articular cartilage from patients with femoral neck fractures [assumed osteoporosis (OP); n=12], from patients with osteoarthritis (OA; n=12) and from normal controls (n=9) was determined. Full depth tissue samples from the control and OP groups were analysed from the superior, inferior, anterior and posterior regions, while the OA tissue was from cystic (tissue growing on top of cystic bone lesions) and osteophytic regions, from normal and fibrillated resident cartilage and from regions immediately adjacent to eburnated bone. The total sulphated GAG and UA content was reduced in the inferior region of control cartilage compared to the other regions and the values of all regions of the assumed OP group. Cystic regions and OA cartilage adjacent to the bone also showed lower GAG and UA levels than the other regions. The ratios of chondroitin 6-sulphate (C6S) to chondroitin 4-sulphate (C4S) indicated a similar pattern in the different regions of controls and the patient group with femoral neck fractures (OP group). The cystic and osteophytic cartilage of the OA group exhibited lower C6S/C4S ratios than any other region. The levels of dermatan sulphate (DS) in the cartilage of all regions of the OP and control groups were very similar and low, while the tissues of the OA group contained significantly higher amounts, particularly the cartilage from osteophytes. The previously presumed compositional similarity between normal aged and osteoporotic articular hip cartilage was essentially confirmed in a comparative analysis. Significant changes in GAG and UA composition of OA cartilage from distinct regions was also recorded.