Rhodamine B inhibition of glycosaminoglycan production by cultured human lip fibroblasts.

Rhodamine B (Rh B) is a dye which is used in cosmetics such as lipsticks. We investigated the effect of the dye on the metabolism of [3H]glucosamine-labeled glycosaminoglycans ([3H]-GAG) in confluent cultures of human lip fibroblast KD cells. It was found that Rh B at 10 micrograms/ml and above significantly decreased the accumulation of [3H]-GAG in both the cell layer and the medium after a 24-hr culture. This Rh B (50 micrograms/ml) effect was recognized in the cell layer and the medium after 8 and 24 hr, respectively, and longer. The Rh B at the 25 micrograms/ml-induced decrease in the [3H]-GAG accumulation was reversible in both the cell layer and the medium. On the other hand, the release of [3H]-GAG from the cell layer was unaffected by Rh B. A characterization of [3H]-GAG revealed that all components of the GAG including hyaluronic acid, heparan sulfate, chondroitin 4- and/or 6-sulfate, and dermatan sulfate were significantly decreased by 50 micrograms/ml Rh B in both the cell layer and the medium. Rh B significantly decreased the accumulation of [3H]-GAG in the presence of either 10 microM cycloheximide or 1 mM p-nitrophenyl-beta-D-xyloside, suggesting that Rh B inhibited the sugar chain formation rather than core protein synthesis. Although the number of confluent KD cells was significantly decreased by Rh B at 10 micrograms/ml and above, this Rh B effect was much weaker than that on the [3H]-GAG accumulation. The release of lactate dehydrogenase from the cell layer was significantly increased by 100 micrograms/ml Rh B but not by the dye at 75 micrograms/ml and below. From these results, it was suggested that Rh B decreases the GAG content of human lip fibroblasts through a functional suppression of polysaccharide chain formation in the process of the GAG production.