DIFFERENT RESPONSES OF HUMAN AND RAT DERMAL FIBROBLASTS TO L-ASCORBIC-ACID 2-PHOSPHATE

We have found human and rat dermal fibroblasts to differ in their resp onse to ascorbic acid 2-phosphate, a stable derivative of ascorbic aci d. Whilst the proliferation of human fibroblasts and their relative ex tent of collagen synthesis were slightly enhanced by exposure to ascor bic acid 2-phosphate, no such enhancement was noted with rat fibroblas ts. The level of DNA synthesis in confluent cultures of human fibrobla sts which had been continuously exposed to the vitamin derivative was suppressed, and electron microscopy demonstrated the cells in these cu ltures to have formed a tissue-like structure, in which layers of fibr oblasts were separated by extracellular matrix. In comparably treated cultures of rat fibroblasts, however, the level of DNA synthesis was e levated, but the cells appeared unable to form a tissue-like matrix, a nd remained in a monolayer. By electron microscopy, these cells were o bserved to display a grossly engorged endoplasmic reticulum, suggestin g that their secretory apparatus was inadequate to cope with increased protein production. These findings have implications with regard to t he use of the rat as an animal model in studies of dermal wound healin g.