High glucose promotes collagen synthesis by cultured cells from rat cervical posterior longitudinal ligament via transforming growth factor-beta1.

Non-insulin-dependent diabetes is known as a risk factor of ossification of posterior longitudinal ligament, but the mechanism has not been well understood. We hypothesized that hyperglycemia, as a typical characteristic of diabetes, is closely associated with ligament hypertrophy in ossification of posterior longitudinal ligament. In this in vitro study, we investigated the effect of high glucose on collagen synthesis and transforming growth factor-beta1 (TGF-beta1) production using cells isolated from rat cervical posterior longitudinal ligament. The cells were subjected to high D-glucose concentration (25 mM) media for 4 days. Notable increases were observed in gene expression and protein synthesis of collagen types I, III in the cells. The increase was inhibited in the presence of anti-TGF-beta1 antibodies. Production of TGF-beta1 by the cells was also increased significantly by high glucose concentration. Exogenous application of TGF-beta1 was confirmed to increase collagen synthesis of the cells. These data suggested that high glucose could promote collagen synthesis in the posterior longitudinal ligament mainly via endogenous TGF-beta1, resulting in hypertrophy of the ligament.