Hyaluronic acid suppresses the reduction of alpha2(VI) collagen gene expression caused by interleukin-1beta in cultured rabbit articular chondrocytes.

In order to investigate how α2(VI) collagen gene is regulated by inflammatory cytokines in cultured rabbit articular chondrocytes, we examined the effect of interleukin-1β (IL-1β) on this collagen mRNA expression. Polylayer cultures of chondrocytes were exposed to IL-1β (0.1, 1, 10 ng/ml). Quantitative detection of specific mRNA for this collagen was carried out by reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, to investigate the effect of hyaluronic acid (HA) on α2(VI) collagen mRNA expression by IL-1β, chondrocytes were exposed to IL-1β (10 ng/ml) in the presence of HA (0.01, 0.1, 1 mg/ml) with molecular weight of 900 kDa. Chondrocytes were also exposed to IL-1β (10 ng/ml) in the presence of HA (1 mg/ml) with molecular weights of 200, 900 and 2000 kDa. α2(VI) collagen mRNA expression was decreased significantly in chondrocytes cultured with 1 and 10 ng/ml of IL-1β. However, the addition of both IL-1β and HA (0.1, 1 mg/ml) or both IL-1β and HA (1 mg/ml) with all the molecular weight significantly suppressed these reduced mRNA levels. No tendency for this suppression to depend on the molecular weight was observed. These results suggest that suppression of transcriptional activity for type VI collagen will be associated with the reduction of cartilage matrix tissue and that HA will be associated with the suppression of the effect of IL-1β.