Effect of Platelet-dependent Growth Factor on the Proliferation of Cultured Fibroblasts by Flow Cytometry

Abstract

To date, a number of resarchers have reported that platelets contain some growth factors, including Platelet-derived growth factor (PDGF), Epidermal growth factor (EGF), Transforming growth factor-β (TGF-β) and others. These growth factors are considered to play a role in restoration of wounded blood vessels, arteriosclerosis, metastasis of malignant tumors and other vascular diseases. Though each growth factor has been investigated in details, the study of interaction of these growth factors in vivo has been neglected. The author investigates, by the use of flow cytometry, how these growth factors as a whole stimulate the proliferation of fibroblasts.
These recent studies found that a part of those growth factors are concerned in the prrogress of the G₀→G₁ phase and another part is concerned in the progress of the G1→S phase. The former growth factor is called the “competence factor”, and the latter is called the “progression factor”. The studies to date suggest that PDGF acts as “competence factor” in the cell growth and that EGF and TGF-β; act as “progression factors”.
The author's study suggests that the platelet-dependent growth factors, as a whole, act as “competence factors” on 3T3 fibroblasts, but do not act on SV40 transformed 3T3 fibroblasts. On the other hand, this study points out that action as the “progression factor” of those growth factors is not a majar one in the proliferation of both fibroblasts.
The author surmises that platelet-dependent growth factors in cooperation turn the cells of blood vessel from G₀ phase (passive phase) to G₁ phase (activate phase) and couse proliferation of the cells of blood vessels in cooperation with other serum factors, when the blood vessels are damaged.