REGULATION OF COLLAGEN-SYNTHESIS IN HUMAN DERMAL FIBROBLASTS BY THE SODIUM AND MAGNESIUM SALTS OF ASCORBYL-2-PHOSPHATE

Ascorbic acid has been shown to stimulate collagen synthesis in dermal fibroblasts by increasing the rate of transcription of collagen genes . Experiments involving the use of ascorbic acid require daily supplem entation due to the instability of the molecule in aqueous solutions. In order to provide a more stable alternative to ascorbic acid, two sa lts of ascorbyl-2-phosphate, having a greater chemical stability than ascorbic acid, were tested for their ability to stimulate collagen syn thesis in monolayer fibroblast cultures. The concentration and time de pendence of their activities were compared with ascorbic acid. The mag nesium salt of ascorbyl-2-phosphate was found to be equivalent to asco rbic acid in stimulating collagen synthesis in these assays, while the sodium salt required at least a tenfold greater concentration to prod uce the same effect as ascorbic acid. Solutions of either ascorbic aci d or the ascorbyl-2-phosphate analogs (at 10 mM) in phosphate-buffered saline (PBS) were relatively stable as shown by their decay rates and their ability to stimulate collagen synthesis even after nine days in solution prior to testing their effects on cultured cells. Ascorbic a cid was unstable at neutral pH compared to solutions of either sodium or magnesium ascorbyl-2-phosphate. These data support the use of magne sium ascorbyl-2-phosphate in experiments where stability of ascorbic a cid is a concern, e.g. in long-term cultures or in in vivo studies.