Exogenous FGF-2 and PDGF have no effect on wound closure enhanced by matrix-FBG. After the time of wounding, no growth factor (none), FGF-2 (50 ng/mL), or PDGF (2 ng/mL) was added to fibroblasts left untreated (CONTROL), treated with FBG-ATOW, or treated with FBG 24 hours prior to wounding (FBG-PRE). (A) At 16 hours after wounding, the cells were fixed and stained with rhodamine-phalloidin to visualize actin filaments in order to count the cells that had migrated into the wound space. The data are presented as the mean ± SEM; n = 5 to 7 per condition. (B) The fibroblasts were treated with or without FBG and with or without growth factors as described above; however, ATOW ³H-thymidine was also added to the culture media. At 16 hours after wounding, the cells were fixed, dehydrated, and dipped into NTB-photographic silver emulsion to detect cells in S phase by the deposition of silver grains over the nuclei that have actively incorporated ³H-thymidine. The data are presented as the mean ± SEM; n = 5 to 6 per condition from 2 separate experiments. (C) A representative low-power field of each treatment condition is shown. Positive DNA synthesis is denoted by the presence of black-appearing silver grains over the nuclei of actively proliferating cells. Scale bar represents 125 μm.