RESUMO
BACKGROUND INFORMATION: There are several reports indicating that starved fibroblasts show higher proliferation rates when re-fed with foetal bovine serum. We have evidence demonstrating that this phenomenon is related to secretory proteins which may be beneficial to wound healing. RESULTS: After re-feeding, 16 and 72 h serum-starved fibroblasts showed the highest and lowest proliferation rates, 1.59 and 0.51-fold difference compared to the non-starved control, respectively (P < 0.05). However, the latest value could be normalised by incubating cells with 16 h-starved fibroblast cell culture supernatant (16-SFS), prior to re-feeding. A strong correlation was found between total protein level in starved fibroblast culture supernatants and post re-feeding proliferation rates (r(2) = 0.90, P < 0.001). Two-dimensional gel electrophoresis analysis of 16-SFS confirmed the presence of proteins with relative molecular weights of 10-120 kDa and pI ranging from 4 to 6. A significant difference in calcium influx course was found between 16-SFS and the negative control (Dulbecco's Modified Eagle Medium) (P < 0.05). There was no significant difference in Ca(2+) concentrations after 1 h between non-starved controls and 16-SFS-treated fibroblasts. The scratch test demonstrated that the 16-SFS is able to induce fibroblast migration. CONCLUSIONS: We concluded that human starved fibroblasts secrete proteins that are able to induce post re-feeding cell proliferation and fibroblasts migration, probably through the induction of a sustained calcium influx. This is worth being considered as a potential tool for wound healing.
