EFFECTS OF HYALURONAN ON CELL-PROLIFERATION AND PROTEOGLYCAN SYNTHESIS IN RABBIT LIGAMENTOUS CELLS

The effect of hyaluronan (HA) on cell proliferation and synthesis of p roteoglycan (PG) in rabbit ligamental cells was examined in vitro. HA promoted the incorporation of S-35-sulfate in a concentration-dependen t manner, significantly at 100 mu g/ml and upward, without effect on c ell proliferation. The chromatographic profile of the S-35-labelled ma terials extracted with 4 M guanidine hydrochloride by Sepharose CL-2B was different in the HA-treated cells as compared with untreated cells . Although the radioactivities of the low-molecular fraction peaked at Kav 0.71 did not change, those of the high-molecular fraction (Kav 0. 30-0.50) increased with treatment of HA. Ligamental cells expressed th e mRNA of the PG family's versican and aggrecan (large-molecular weigh t PGs), biglycan and decorin (small-molecular weight PGs) in dot blot analysis. Although the mRNA expression of aggrecan, biglycan and decor in did not change, that of versican increased upon treatment with HA. These findings suggest that HA is involved in promoting production of the large-molecular-weight PG versican, and in facilitating extracellu lar matrix formation.