| Zdroj: |
Ding, M 2006, ' EFFECTS OF HYALURONAN ON THREE-DIMENSIONAL MICROARCHITECTURE OF SUBCHONDRAL BONE TISSUES IN GUINEA PIG PRIMARY OSTEOARTHROSIS : M. Ding, C. C. Danielsen, I. Hvid ', ECTS 33rd European Symposium on Calcified Tissues, Prague, Czech Republic, 10/05/2006-14/05/2006 . |
| Popis: |
Introduction: It is not known whether hyaluronan (HA) has any effect on the underlying subchondral bone tissues. This study was to investigate the effects of high molecular weight HA (1.5x106 Daltons) intra-articular injection on subchondral bone tissues. Methods: Fifty-six male guinea pigs (6.5 months of age) were randomly divided into 5 groups studied in a short-term and a long-term experimental period. All HA groups received intra-articular injection of HA 0.4 mg/kg/week for 5 weeks in both knee joints. HA-II received injection for additional 5 weeks; HA-III received no more injection; and the control groups received vehicle. After sacrifice, the left tibiae were harvested and micro-CT scanned, followed by mechanical testing and collagen and mineral determination. Results: The HA-treated groups had almost normal cartilage, whereas the control groups had typical osteoarthrosis (OA)-related cartilage degradation. In the short-term study, compared with the control group, HA-injection resulted in a significantly decreased subchondral plate volume fraction and plate thickness. HA-treated cancellous bone had significantly lower bone volume fraction, and typical rod-like structure. In the long-term study, these latter changes were more pronounced, with an additionally significant decrease in connectivity and bone surface density. HA groups had greater bone mineral concentration and mineral density, lower collagen to mineral ratio, and preserved the mechanical properties of cancellous bone. The effects of HA on cartilage and subchondral bone were maintained when HA treatment was discontinued. Discussion: Significant positive effects of high molecular weight HA on the articular cartilage and subchondral bone tissues were seen. HA protects against OA-related cartilage degradation to almost normal level, and effectively changes the subchondral bone tissue microarchitecture, collagen and mineral content and density without altering the mechanical properties of cancellous bone. The most striking features are the microarchitectural changes in the subchondral cancellous bone that lead to lower bone density and markedly rod-like structure, and thus reducing cartilage stress during impact loading. Still, the subchondral bone has a greater mineral concentration, and a lower collagen to mineral ratio, and thus preserves the mechanical properties of cancellous bone. Short-term HA is sufficient and early HA is needed for intervention of OA initiation and progression. |
