The intra-articular injection of alginate-chitosan beads in an hydrogel prevents the development of osteoarthritis in ACLT model

Purpose
To evaluate the effects of a new biomaterial composed of alginate-chitosan (AC) beads dispersed in a viscous thermogelling chitosan-based (H) hydrogel on the development of osteoarthritis (OA) in rabbit.
Materials & Methods
OA was surgically induced by the transection of the anterior cruciate ligament (ACLT) in rabbits. One week after surgery, animals received a single intra-articular injection (900 µl) of AC beads in H hydrogel (group I), H hydrogel alone (group II) or saline (group III).
OA development was followed by X-rays. Blood samples were collected throughout the study to measure biological markers (PGE2 and CRP). Macroscopic observation and histological evaluation of articular cartilage and synovial membrane were performed 6 weeks after surgery.

Results
The X-rays analysis showed a significant decrease (p <0.05) of the Kellgren and Lawrence score in group I (1.5 ± 0.2) compared with group II (2.2 ± 0.5) and group III (3.0 ± 0.4). The size and the severity of the macroscopic OA cartilage lesion tended to decrease in group I compared to the other groups. The histological global score that refers to all compartments of the knee joint was significantly decreased in group I (11.0 ± 0.7) compared to group II (14.4 ± 0.6, p <0.01) and group III (14.8 ± 0.6, p <0.001). The injection of AC beads in H hydrogel also tended to reduce the synovial membrane inflammation. No significant variation of PGE2 and CRP serum levels were observed in each after 6 weeks follow-up whatever the treatment injected.
Conclusion
This study showed that AC beads dispersed in H hydrogel prevented OA in ACL transection rabbit model. This effect was not observed with the hydrogel alone, suggesting that AC beads play a role in joint protection. The preventive effect was observed in all joint compartments indicating a global protective effect of this new implantable biomaterial.