Proliferating cell nuclear antigen immunohistochemistry in rat aorta after balloon denudation. Comparison with thymidine and bromodeoxyuridine labeling.

The authors compared detection of proliferating vascular smooth muscle cells (SMC) in vitro and in vivo with proliferating cell nuclear antigen (PCNA) immunohistochemistry and two established methods: [3H]thymidine autoradiography and bromodeoxyuridine immunohistochemistry. Labeling with [3H]thymidine and bromodeoxyuridine of rat vascular SMC in culture stained 11% +/- 2% and 11% +/- 1% of cells, and PCNA immunohistochemistry 22% +/- 2% of cells. Proliferation in the media of the denuded rat aortae was highest 3 days after denudation: 4.2%, 3.8%, and 4.7% of labeled cells with [3H]thymidine, bromodeoxyuridine, and PCNA, respectively. In the intima, proliferation was highest 7 days after denudation with 42% [3H]thymidine, 40% bromodeoxyuridine, and 46% PCNA-positive cells. With double labeling, all [3H]thymidine-positive cells were PCNA positive, whereas some cells were only positive for PCNA. The authors conclude that PCNA immunohistochemistry compares favorably with [3H]thymidine autoradiography, and bromodeoxyuridine immunohistochemistry.