IMMUNOHISTOCHEMICAL DETECTION OF KI-67 IN REPLICATIVE SMOOTH-MUSCLE CELLS OF RABBIT CAROTID ARTERIES AFTER BALLOON DENUDATION

Background and Purpose Ki-67 immunohistochemistry, has been shown to be useful for paraffin sections from human species after wet heating. We applied Ki-67 immunohistochemistry to rabbit arteries after balloon denudation and compared the results with proliferating cell nuclear antigen (PCNA) immunohistochemistry. Methods Monoclonal antibodies MIB-1 for Ki-67 and PC-10 for PCNA were used to detect replicative smooth muscle cells in rabbit carotid arteries during a period of 1 weeks after balloon endothelial denudation. Results We demonstrated clear immunoreactivities for Ki-67 in paraffin sections of rabbit arteries after hydrated autoclaving. Ki-67-positive smooth muscle cells appeared throughout the thickened intima 1 week after endothelial denudation. At 2 weeks, Ki-67-positive cells were confined to the surface layer of the intima. PCNA-postive cells appeared in almost the same location by 2 weeks after endothelial denuda tion but were significantly greater in number than Ki-67-positive cells. PCNA-positive cells remained in the surface layer of the intima 4 weeks after endothelial denudation, while Ki-67-positive cells had almost disappeared from the intima. Conclusions Our results indicate that Ki-67 immunohistochemistry using MIB-1 monoclonal antibody provides a pow erful tool, even in rabbit species, for the detection of replicative smooth muscle cells during the repair of arterial injury and that it detects replicative cells more accurately than PCNA immunohistochemistry.