Expression of basic fibroblast growth factor and its receptor by smooth muscle cells and endothelium in injured rat arteries. An en face study

Abstract

Release of endogenous basic fibroblast growth factor (bFGF) has been shown to initiate smooth muscle cell (SMC) proliferation following balloon catheter denudation in rat arteries. The mechanisms that contribute to the continued replication of the cells that subsequently form the neointima are not well understood. We have examined expression of bFGF and fibroblast growth factor receptor 1 (FGFR-1) in luminal SMCs as well as endothelium at various times after injury, which allowed us to study both replicating as well as quiescent cells. Using in situ hybridization on en face preparations, we were able to detect mRNA in luminal cells that was not observed by analysis of artery cross sections. We demonstrate that mRNA for bFGF was found in replicating SMCs and endothelial cells. bFGF mRNA was not detectable in either cell type at quiescence despite nuclear staining for bFGF. Expression of FGFR-1 mRNA was observed in replicating endothelial and SMCs at similar times after injury. These data provide evidence that in injured arteries the ligand/receptor system of bFGF and FGFR-1 may be involved in the continued proliferative response of SMCs leading to neointima formation. Furthermore, our results suggest a role for bFGF in reestablishing the endothelial lining in denuded vessels.