QUANTITATION OF SMOOTH-MUSCLE PROLIFERATION IN CULTURED AORTA - A COLOR IMAGE-ANALYSIS METHOD FOR THE MACINTOSH

Color image analysis was used to assess proliferative changes in smoot h muscle cells from cultured segments of rabbit aortas. Proliferating cells were labeled with bromodeoxyuridine (BrdU) and visualized by imm unohistochemical staining of histologic sections. A Macintosh IIfx com puter with a Data Translation digitizer board, Javelin color camera an d a color-enhanced version of National Institutes of Health Image 1.31 image analysis software (ColorImage 1.31) was used to acquire red, gr een and blue (RGB)-filtered grayscale images from microscopic slides o f control and treated aortas. The BrdU-labeled (brown) and nonlabeled, hematoxylin (blue)-stained nuclei were identified on the RGB gray-sca le images using a thresholding technique and sampled for nuclear numbe r and area. An increase in the number of BrdU-labeled nuclei in the re gion of experimental perturbation was demonstrated by this semiautomat ed method. Thus, this Macintosh-based color image analysis method prov ed to be effective in rapidly quantitating immunohistochemically defin ed smooth muscle proliferation in microscopic tissues.