Effects of hyaluronic acid on the morphology and proliferation of human chondrocytes in primary cell culture

Hyaline articular cartilage is a specialised connective tissue with weight bearing and adsorbing functions. Injury or loss of which often leads to imp aired joint function and severe pain. Since the self-renewing abilities of hyaline articular cartilage are limited, there is major interest in the dev elopment of bioengineered cartilaginous implants. A cell-matrix-biocomposit e composed of a collagen I/III scaffold seeded with autologous chondrocytes is currently being used in clinical trials; however, in order to optimise culture conditions, we cultured human condrocytes and seeded them on type I /III collagen membranes and on Thermanox plastic coverslips with media cont aining 0 to 500 mug/ml Hyaluronic Acid. After 4 days, the cells were either fixed or BrdU incorporation procedures begun. HE staining clearly demonstr ated that cells grown in HA form three dimensional clusters and produce sec retory vesicles as opposed to the monolayer control cells with noticeably f ewer secretory vesicles. BrdU incorporation revealed a noticeable increase in cell proliferation in cells grown in 100 mug/ml; however, no comparable increase in 500 mug/ml but rather a slight depression in proliferation. Imm unohistochemistry for collagen II and aggrecan revealed an obvious increase in deposition of these two substances with increased HA administration as compared to the control: however, again, the higher concentration of HA, 50 0 mug/ml, did not result in a further increase in production. These results suggest that HA at 100 mug/ml not only influences chondrocytes to differen tiate and produce more Collagen II and aggrecan, but also increases prolife ration. We, therefore, propose that the addition of HA at low to middle dos ages in condrocyte culturing might help improve condrocyte redifferentation and thus, the bioengineered cartilage.