Immunohistochemical localization of proliferating cells, basic fibroblast growth factor and Fos protein following iliac artery balloon angioplasty in hypercholesterolemic rabbits.

The restenotic process in iliac arteries of hyperlipidemic rabbits following balloon angioplasty was evaluated in a temporal sequence by monitoring smooth muscle cell (SMC) proliferation (proliferating cell nuclear antigen -PCNA marker), growth factor (basic fibroblast growth factor -bFGF) production, and Fos oncogene protein expression using immunohistochemical methods. The percutaneous transluminal angioplasty was performed in iliac artery of rabbits fed a 1% cholesterol diet, with a balloon catheter inflated from 4 to 8 atm for 2 min under cineangiographic control until an acceptable (at least 50% stenosis reduction) result was obtained. The morphometric analysis indicated that the number of PCNA-positive cells in contralateral control arteries was low, but was increased in balloon-injury. The bFGF-positive labeled cells were localized in the media and in recently-migrated SMCs within the intima. Two days following angioplasty these cells were more abundant and scattered in the entire neo-intima. After 14 days their number was still higher than that of the controls. Cellular Fos protein expression was detected in the intima and, to a lesser extent, in the media 2 hours after angioplasty. These data suggest that early expression of Fos protein and bFGF in iliac arteries of hyperlipidemic rabbits following balloon angioplasty could be involved in development of restenosis in this animal model.