Abstract
A rabbit osteoarthritic knee model was used to analyze time-related accessibility of high molecular weight 2,700 kDa hyaluronan to healthy and osteoarthritic articular cartilage and synovium.
Fluorescein-labeled high-molecular weight 2,700 kDa hyaluronan (F-HA) was found in shallow, inner and deep layers of degenerated cartilage within 3-24 h after injection. It quickly reached the deep cartilage layer and was retained within inner and deep layers up to day 28.
In constrast, in healthy knees, F-HA accessibility was confined to superficial and shallow cartilage layers during 3-24 h and did not change until day 28, showing no signs of deep layer retention.
In both healthy and osteoarthritic knees, F-HA penetrated synovium from its synovial lining cell layer to the interstitium in subsynovial fat tissue (deep layer) at 3-24 h after injection.
Though having a high molecular weight, 2,700 kDa HA rapidly penetrated shallow, inner and deep layers of degenerated cartilage and deep layer of synovium after its intra-articular injection.
The joint tissue penetration of 2,700 kDa HA after its intra-articular injection in an animal OA model indicates that soon after the injection, hyaluronan is rapidly accessible to synovial and degenerated cartilage tissues. There, it exerts its anti-inflammatory actions on the synovium and degeneration-inhibiting action on the articular cartilage.
