Ascorbic acid modulates proliferation and extracellular matrix accumulation of hyalocytes

Ascorbic acid is known to influence proliferation and functional properties of several cell types and is therefore widely used in tissue engineering. In this study, the effect of ascorbic acid on the proliferation and functional properties of hyalocytes was evaluated. Hyalocytes were cultured with different amounts of ascorbic acid in classical two-dimensional (2-D) cultures and a three-dimensional (3-D) pellet culture system. Ascorbic acid enhanced hyalocyte proliferation dose-dependently at concentrations between 0.1 and 3 mu g/mL; proliferation was constant over a wide concentration range up to 150 mu g/mL, concentrations of 500 mu g/mL showed toxic effects. In 2-D hyalocyte culture, the accumulation of glycosaminoglycans (GAG) and collagens increased in response to ascorbic acid supplementation of 10 or 200 mu g/mL. Normalized to the cell number, GAG production was not influenced, whereas collagen production increased. These results could be verified in a pellet-like 3-D culture system. Ascorbic acid also influenced hyalocytes on the mRNA level; the expression of COL11A1 was clearly enhanced by ascorbic acid. To conclude, ascorbic acid modulates proliferation and collagen accumulation of hyalocytes; it also influences mRNA expression of the cells. Taken together with the fact that ascorbic acid is present in high concentrations in the vitreous body, this vitamin seems to be an important factor for in vitro hyalocyte culture.