Synergistic growth stimulation of corneal fibroblasts by components of mesodermal growth factor from murine submaxillary glands

Recycled mesodermal growth factor (R-MGF) is a pool of proteins of 26,000 molecular weight obtained by recycling gel chromatography of male murine submaxillary gland extracts. R-MGF strikingly accelerates corneal stromal wound healing in vivo, fibroblast growth and migration in cultured corneal buttons and is showing here to stimulate stromal fibroblast growth and division in tissue culture. Chromatographic fractionation of R-MGF has yielded several components, none of which has a greater biological potency than the parent R-MGF. In contrast, two components, MGF-I and -II, when recombined synergistically stimulate fibroblast response in tissue culture and organ culture in excess of those obtained with the parent R-MGF. Three MGF components (I, III, and IV) have been purified and are inactive at 10-15 micrograms/ml in organ culture but potently stimulate fibroblast responses when combined in pairs containing 7.5 micrograms of each component. The striking synergism in organ culture suggests that the stimulation of wound healing by R-MGF in vivo may also reflect synergistic action of more than one R-MGF component. Procedures for isolating gram quantities of R-MGF and for the purification of different R-MGF components by ion exchange chromatography are detailed.