The in situ expression of PDGF-B mRNA increased after the denudation of rabbit iliac arteries

AIM: To elucidate the in vivo mechanisms of the proliferation of vascular smooth muscle cells (VSMCS) in injuried arteries. METHODS: A VSMCS proliferative model was constructed by injury of rabbit iliac arteries with balloon catheters and a probe designed for rabbit platelet-derived growth factor B chain (PDGF-B ) mRNA was used to detect the expression of it by intimal VSMCS on the vascular cross sections using an in situ hybridization technique at the indicated times. The relation of this expression to the proliferation of VSMCS by their expression of proliferating cell nuclear antigen (PCNA) and vascular intimal areas were estimated. RESULTS: The expression of PDGF-B mRNA of intimal VSMCS was increased when calculating the intimal PDGF-B mRNA positive cells per millimetre area at ×400 magnification with average numbers of 31.93±14.64 in 1 week group, 26 50±9 25 in 2 weeks group and 24 85±13 65 in 4 weeks group. This was in accordance with the expression of PCNA by VSMCS and the increase of intimal areas. CONCLUSION: The local production of PDGF-B by VSMCS via an autocrine mechanism is responsible for the continuous proliferation of these cells and formation of neointima after the injury. The probe designed is very useful for detecting rabbit PDGF-B mRNA.