Immunolocalization of proliferating cells in the rabbit iliac artery afterballoon angioplasty

PURPOSE: Experiments were performed to characterize the location of prolife rating cells in the balloon-dilated rabbit iliac artery, MATERIALS AND METHODS: Balloon angioplasty was performed on the external il iac arteries in each of four rabbits. The arteries were removed 3 days late r, frozen, cryosectioned, and immunostained with Ki-67, an antibody that id entifies proliferating cells, The sections were then examined to determine the patterns of cell proliferation within the arterial media and the ratio of proliferating to nonproliferating cells. RESULTS: Of the 31 arterial cross-sections examined, cell proliferation was circumferential in five (16%), and focal in 26 (84%), Of the 86 foci of pr oliferation examined within the 81 cross-sections, proliferation was locali zed to the inner media in 30 (35%), to the outer media in four (5%), and wa s transmural in 52 (60%). The internal elastica lamina (IEL) appeared norma l at 22 foci (26%), but appeared stretched or torn at 64 (74%). Proliferati on was usually confined to the inner media at foci having no IEL injury (18 of 22; 82%), but was most often transmural where the IEL was stretched or torn (49 of 64; 77%). The ratio of proliferating to nonproliferating cells, which averaged 0.31 +/- .20, was greater (P < .01) in areas with PEL injur y than in areas without IEL injury. CONCLUSION: These results suggest that angioplasty-induced cell proliferati on is typically focal rather than circumferential and is associated with st retching or tearing of the IEL.